Inserm

Severe allergic transfusion reactions to group B/AB plasma or platelets in group O recipients are linked to α-Gal sensitization.

Allergic transfusion reactions (ATR) are potentially lethal adverse events that occur in ∼0.3% to 6% of plasma or platelet transfusions. The main mechanism described is an immunoglobulin E (IgE)-mediated response to donor proteins, such as IgA and haptoglobin in deficient patients. Recently, in a nationwide retrospective observational study, we reported that group O recipients of group B or AB platelet concentrates or plasma were at significantly higher risk of severe ATR than recipients with other ABO combinations. Given the antigenic proximity between group B determinant and the galactose-α-1,3-galactose (α-Gal) epitope, we hypothesize a role for α-Gal IgE-mediated sensitization in these ATR. In this report, we investigated the presence of anti-α-Gal IgE in a cohort of 59 patients with severe ATR. We found that group O recipients of group B or AB blood components (plasma or platelet concentrates) were substantially more likely to exhibit high titers of group B cross-reactive anti-α-Gal IgE than other patients, supporting our hypothesis that α-Gal sensitization underlies these severe ATR. These findings suggest that α-Gal sensitization is an additional mechanism responsible for ATR in major ABO-incompatible transfusion and should be systematically explored in group O patients having received group B/AB plasma or platelets.

Risk factors for α-Gal syndrome: A case-control study exploring the role of tick bites in French Guiana.

α-Gal Syndrome (AGS) is an IgE-mediated allergy to galactose-α-1,3-galactose (α-Gal), a carbohydrate found in non-primate mammalian tissues. AGS manifests as delayed anaphylactic reactions following the consumption of mammalian meat or exposure to products containing α-Gal. Recent studies confirm tick bites may be a key sensitizing factor. This study aimed to investigate tick bites and other potential risk factors for AGS in French Guiana. A retrospective case-control study was conducted at the Cayenne Hospital Center between January 2021 and October 2022. Cases were defined as adults with clinical symptoms of anaphylaxis after consumption of mammalian meat or α-Gal-containing products, and with detectable anti-α-Gal IgE (> 0.1 kUA/L). Controls were patients consulting for other IgE-mediated allergies, without any symptoms after mammalian meat consumption. Data were collected through a standardized questionnaire and specific IgE assays. Bivariate and multivariate analyses were performed to identify associated risk factors. Confounding biases were limited using a propensity score. A total of 54 patients (18 cases, 36 controls) were included. All AGS cases reported at least one tick bite in French Guiana, versus only 22% of controls (Adjusted OR = 170.250; 95% CI [5.981 - 3.528 × 10^6], p < 0.001). Blood group B or AB was less frequent in cases (0% vs 19%, AOR = 0.227; 95% CI [0 - 8.899], p = 0.488). Atopy was not associated with AGS. In this tropical setting, tick bites, especially from the more anthropophilic Amblyomma cajennense sensu stricto, appear to be a major risk factor for AGS, along with forest-related occupational exposure. These findings support the assumption that ticks are probably at least the main vector of symptomatic sensitization to α-Gal in French Guiana.

Association between group B major ABO-incompatible platelet or plasma transfusion and severe allergic reactions: A nationwide haemovigilance analysis suggesting a role for α-gal syndrome. A Biomedical Excellence for Safer Transfusion Collaborative study.

Severe transfusion reactions to group B-incompatible platelets and plasma possibly related to the α-gal syndrome (AGS) have been recently described. AGS is a potentially severe Immunoglobulin E mediated allergy to mammalian meat and meat-derived products associated with tick bites. The involved allergen, galactose-α-1,3-galactose (α-gal), is antigenically similar to the blood group B antigen. To further assess a potential association between AGS and allergic transfusion reactions (ATRs), we comparatively assessed the frequency of ATRs after plasma or platelet concentrate (PC) transfusion in relation to the degree of ABO compatibility between the recipient and the involved blood component in France. In France, all transfusions are centrally recorded, and ATR reporting is mandatory. Frequencies of severe ATRs involving PC or plasma in relation to ABO group distributions were analysed between 1 January 2022 and 31 December 2024. Among 981,955 PC and 580,230 plasma evaluable transfusions, severe ATRs were significantly higher in group O recipients transfused with group B or AB platelets (relative risk [RR]: 5.06, 95% confidence interval [CI]: 3.27-7.83, p < 0.001) and plasma (RR: 2.15, 95% CI: 1.37-3.36, p < 0.001) while not in group A recipients of group B or AB platelets (RR: 0.95, 95% CI: 0.30-2.96) or plasma (RR: 0.92, 95% CI: 0.45-1.88), when compared to ATR rates in all other recipients of PC or plasma, respectively. In this national retrospective haemovigilance analysis, group B or AB PC or plasma transfused to group O recipients is associated with an increased risk of severe ATRs. Further studies will establish whether AGS is involved in this increased risk.

French Guiana and AGS: a path to uncovering hidden clues.

This article is a narrative review exploring how research in French Guiana could unlock the mysteries surrounding Alpha-Gal Syndrome (AGS), a recently identified IgE-mediated allergy with delayed reactions to exposure to non-Catarrhine mammalian-derived products. Although fewer than 10 cases have been reported across Latin America, two case series involving 11 and 18 patients with AGS have been documented in French Guiana. This article discusses risk factors such as ethnicity, prior pathogen-induced immunization to α-Gal, vectors responsible for AGS, their environment and ecosystems, observed phenotypes, and therapeutic implications for sensitized individuals. Literature research was based on PubMed between 12/2023 and 08/2024, using: α-Gal/Alpha-1,3-Galactose/galactose-α 1,3-galactose/Red meat allergy/Mammalian meat allergy/Alpha gal syndrome/Antivipmyn. Grey literature from French Guiana were obtained from Prof. Loïc Epelboin. Advancing AGS research in French Guiana could yield valuable epidemiological insights, as existing data predominantly stem from European, North American, Australian, and Japanese contexts - regions with comparatively lower diversity in tick species, their mammalian hosts, associated pathogens, and parasitic infestations. Additionally, French Guiana presents unique therapeutic scenarios, such as Viperidae envenomation and transfusions under inventory constraints, that merit further investigation.

Editorial: Animal models of allergic diseases: from basic to preclinical research.

Membrane lipid composition of Carnobacterium maltaromaticum CNCM I-3298, a highly cryoresistant lactic bacterium.

The growing consumption of fermented products has led to an increasing demand for lactic acid bacteria (LAB), especially for LAB tolerant to freezing/thawing conditions. Carnobacterium maltaromaticum is a psychrotrophic and freeze-thawing resistant lactic acid bacterium. The membrane is the primary site of damage during the cryo-preservation process and requires modulation to improve cryoresistance. However, knowledge about the membrane structure of this LAB genus is limited. We presented here the first study of the membrane lipid composition of C. maltaromaticum CNCM I-3298 including the polar heads and the fatty acid compositions of each lipid family (neutral lipids, glycolipids, phospholipids). The strain CNCM I-3298 is principally composed of glycolipids (32%) and phospholipids (55%). About 95% of glycolipids are dihexaosyldiglycerides while less than 5% are monohexaosyldiglycerides. The disaccharide chain of dihexaosyldiglycerides is composed of α-Gal(1-2)-α-Glc chain, evidenced for the first time in a LAB strain other than Lactobacillus strains. Phosphatidylglycerol is the main phospholipid (94%). All polar lipids are exceptionally rich in C18:1 (from 70% to 80%). Regarding the fatty acid composition, C. maltaromaticum CNCM I-3298 is an atypical bacterium within the genus Carnobacterium due to its high C18:1 proportion but resemble the other Carnobacterium strains as they mostly do not contain cyclic fatty acids.

Validation of an anti-α-Gal IgE fluoroenzyme-immunoassay for the screening of patients at risk of severe anaphylaxis to cetuximab.

The link between immediate hypersensitivity reactions (HSR) following the first cetuximab infusion and the IgE sensitization against anti-galactose-α-1,3-galactose (α-Gal) is now well-established. An automated Fluoroenzyme-Immunoassay (FEIA) is available and may facilitate the screening of patients with anti-α-Gal IgE before treatment. This study aimed to evaluate its performances as compared to a previously validated anti-cetuximab IgE ELISA, using 185 samples from two previously studied cohorts. Despite 21.1% of discrepancies between the two techniques, FEIA discriminated better positive patients and similarly negative ones with a ≥ 0.525 kU/L threshold. Sensitivity was 87.5% for both tests, specificity was better for FEIA (96.3% vs ELISA: 82.1%). FEIA had a higher positive likelihood ratio (23.9 vs ELISA: 4.89) and a similar negative likelihood ratio (0.13 vs ELISA: 0.15). In our population, the risk of severe HSR following a positive test was higher with FEIA (56.7% vs ELISA: 19.6%) and similar following a negative test (0.7% vs ELISA: 0.8%). Although the predictive value of the IgE screening before cetuximab infusion remains discussed, this automated commercial test can identify high-risk patients and is suitable for routine use in laboratories. It could help avoiding cetuximab-induced HSR by a systematic anti-α-Gal IgE screening before treatment.

Assessment of the Safety and Efficacy of an Oral Probiotic-Based Vaccine Against Aspergillus Infection in Captive-Bred Humboldt Penguins ().

Aspergillosis is a fungal infection caused mainly by that often results in respiratory disease in birds. Aspergillosis is a major cause of morbidity and mortality in captive-bred penguin species. Currently, there is no registered vaccine to prevent aspergillosis. Recent research demonstrated that oral administration of gram-negative bacteria expressing high levels of galactose-α-1,3-galactose (α-Gal) modulates anti-α-Gal immunity and protects turkeys from clinical aspergillosis caused by experimental infection. The role of anti-α-Gal immunity in penguins has not been studied. Here, we tested the distribution of α-1,3-galactosyltransferase (α1,3GT) genes in the fecal microbiome of Humboldt penguins (). The occurrence of natural anti-α-Gal antibodies (Abs) in sera and eggs of healthy Humboldt penguins was also assessed. A trial was then conducted to test whether oral administration of Nissle, expressing high α-Gal levels, modulates anti-α-Gal immunity in a colony of Humboldt penguins. Animals in the vaccination and placebo groups were evaluated before the trial and followed for one year for aspergillosis detection using a diagnostic panel including computed tomography scans, capillary zone electrophoresis, 3-hydroxybutyrate levels, and anti- Abs. Anti-α-Gal Abs were detected in sera (IgM and IgY) and eggs (IgY) of healthy penguins. Microbiota analysis and functional predictions revealed the presence of α1,3GT genes in the microbiota of Humboldt penguins and other penguin species. A strong decrease in anti-α-Gal IgM levels was observed in all animals in the placebo group three months after vaccination protocol. This decrease was not observed in Nissle-treated penguins. After the vaccination protocol, we found a positive correlation between anti- IgY and anti-α-Gal IgY in the Nissle group, suggesting a correlation between the presence of the bacteria and these Abs. During the study period, three penguins exhibited respiratory signs consistent with aspergillosis. Two were from the placebo group whose symptoms resolved with specific treatments, while a single vaccinated individual developed fatal respiratory aspergillosis eight months after the trial. We conclude that Nissle represents a safe potential probiotic with a protective effect against aspergillosis in Humboldt penguins that deserves to be further explored for therapeutic uses in these animals.

Allergy to Mammalian Meat Linked to Alpha-Gal Syndrome Potentially After Tick Bite in the Amazon: A Case Series.

The past decade has seen the emergence of a new type of food allergy occurring after ingestion of mammalian meat. This allergy is related to immunoglobulin (Ig)E specific for galactose-alpha-1,3 galactose (α-Gal). Originally described in the United States in 2009, other cases have subsequently been described in Australia and in Europe, but still very few in Latin America. The purpose of this study was to show the existence of this pathology in French Guiana and to describe the historical, clinical, and biological characteristics of these patients. Patients reporting an allergy to mammalian meat were included between September 2017 and August 2019. Eleven patients were included, nine of whom exhibited digestive symptoms; four, urticaria reactions; three, respiratory reactions; and five angioedema. The time between ingestion of red meat and reaction varied between 1.5 and 6 hours. The implicated meats were most often beef and pork. All patients had been regularly exposed to tick bites before the appearance of symptoms. All the samples (n = 7) were positive for anti-α-Gal anti-mammalian meats IgE. All the patients were Caucasian French expatriates. This study confirms the presence of this new entity in French Guiana and is the largest reported in Latin America. Our results do not clearly allow us to state that tick bites are the cause of this allergy, but all patients reported being exposed regularly to these arthropods.

Aortic homograft for aortic valve replacement in patient with Alpha-Gal allergy.

Allergy to Galactose-Alpha-1,3-Galactose is an allergy to mammalian proteins, that are present on the surface of standard bioprosthestic valves, and could result in a catastrophic allergic reaction or may cause early deterioration of the bioprostheses. Aortic homograft is an acceptable alternative to standard prosthetic valves (biological and mechanical) to avoid a potential allergic manifestation and the need for definitive oral anticoagulation. We report the implantation of an aortic homograft in a patient with an aortic stenosis who presents a documented AlphaGal allergy.

Recurrent anaphylaxis to a gelatin-based colloid plasma substitute and to cetuximab following sensitisation to galactose-alpha-1,3-galactose.

Infection with Inhibits the Production of IgE Antibodies to α-Gal in Humans: Towards a Conceptual Framework of the Hygiene Hypothesis?

α-Gal syndrome (AGS) is a type of anaphylactic reaction to mammalian meat characterized by an immunoglobulin (Ig)E immune response to the oligosaccharide α-Gal (Galα1-3Galβ1-4GlcNAc-R). Tick bites seems to be a prerequisite for the onset of the allergic disease in humans, but the implication of non-tick parasites in α-Gal sensitization has also been deliberated. In the present study, we therefore evaluated the capacity of helminths (, , ), protozoa (), and parasitic fungi () to induce an immune response to α-Gal. For this, different developmental stages of the infectious agents were tested for the presence of α-Gal. Next, the potential correlation between immune responses to α-Gal and the parasite infections was investigated by testing sera collected from patients with AGS and those infected with the parasites. Our results showed that and produce the terminal α-Gal moieties, but they were not able to induce the production of specific antibodies. By contrast, , and lack the α-Gal epitope. Furthermore, the patients with infection had significantly decreased anti-α-Gal IgE levels when compared to the healthy controls, suggesting the potential role of this nematode parasite in suppressing the allergic response to the glycan molecule. This rather intriguing observation is discussed in the context of the 'hygiene hypothesis'. Taken together, our study provides new insights into the relationships between immune responses to α-Gal and parasitic infections. However, further investigations should be undertaken to identify components with potent immunomodulatory properties and to assess their potential to be used in immunotherapy and control of AGS.

Anaphylaxis to Bovine Serum Albumin Tissue Adhesive in a Non-Meat-Allergic Patient.

Quantitative and qualitative changes in anti-Neu5Gc antibody response following rabbit anti-thymocyte IgG induction in kidney allograft recipients.

Antibodies of non-human mammals are glycosylated with carbohydrate antigens, such as galactose-α-1-3-galactose (α-Gal) and N-glycolylneuraminic acid (Neu5Gc). These non-human carbohydrate antigens are highly immunogenic in humans due to loss-of-function mutations of the key genes involved in their synthesis. Such immunogenic carbohydrates are expressed on therapeutic polyclonal rabbit anti-human T-cell IgGs (anti-thymocyte globulin; ATG), the most popular induction treatment in allograft recipients. To decipher the quantitative and qualitative response against these antigens in immunosuppressed patients, particularly against Neu5Gc, which may induce endothelial inflammation in both the graft and the host. We report a prospective study of the antibody response against α-Gal and Neu5Gc-containing glycans following rabbit ATG induction compared to controls. We show a drop in the overall levels of anti-Neu5Gc antibodies at 6 and 12 months post-graft compared to the pre-existing levels due to the major early immunosuppression. However, in contrast, in a cross-sectional study there was a highly significant increase in anti-Neu5Gc IgGs levels at 6 months post-graft in the ATG-treated compared to non-treated patients(P = 0.007), with a clear hierarchy favouring anti-Neu5Gc over anti-Gal response. A sialoglycan microarray analysis revealed that the increased anti-Neu5Gc IgG response was still highly diverse against multiple different Neu5Gc-containing glycans. Furthermore, some of the ATG-treated patients developed a shift in their anti-Neu5Gc IgG repertoire compared with the baseline, recognizing different patterns of Neu5Gc-glycans. In contrast to Gal, Neu5Gc epitopes remain antigenic in severely immunosuppressed patients, who also develop an anti-Neu5Gc repertoire shift. The clinical implications of these observations are discussed.

Biochemical characterization and immunogenicity of Neureight, a recombinant full-length factor VIII produced by fed-batch process in disposable bioreactors.

Hemophilia A is a X-linked recessive bleeding disorder consecutive to the lack of circulating pro-coagulant factor VIII (FVIII). The most efficient strategy to treat or prevent bleeding in patients with hemophilia A relies on replacement therapy using exogenous FVIII. Commercially available recombinant FVIII are produced using an expensive perfusion technology in stainless steel fermenters. A fed-batch fermentation technology was recently developed to produce 'Neureight', a full-length recombinant human FVIII, in Chinese hamster ovary (CHO) cells. Here, we investigated the structural and functional integrity and lack of increased immunogenicity of Neureight, as compared to two commercially available full-length FVIII products, Helixate and Advate, produced in baby hamster kidney or CHO cells, respectively. Our results demonstrate the purity, stability and functional integrity of Neureight with a standard specific activity of 4235 ± 556 IU/mg. The glycosylation and sulfation profiles of Neureight were similar to that of Advate, with the absence of the antigenic carbohydrate epitopes α-Gal and Neu5Gc, and with sulfation of Y1680, that is critical for FVIII binding to von Willebrand factor (VWF). The endocytosis of Neureight by human immature dendritic cells was inhibited by VWF, and its half-life in FVIII-deficient mice was similar to that of Advate, confirming unaltered binding to VWF. In vitro and in vivo assays indicated a similar immunogenicity for Neureight, Advate and Helixate. In conclusion, the production of full-length FVIII in a fed-batch fermentation mode generates a product that presents similar biochemical, functional and immunogenic properties as products developed using the classical perfusion technology.

Correlation of types of food and asthma diagnosis in childhood: A case-control study.

: Studies concerning asthma in Lebanon investigated environmental and personal factors but none of them took into account the effect of nutritional habits. Our objective is to assess the effect of nutritional habits on asthma and allergies in Lebanese children aged 3-16 years old. : This is a case-control study, conducted between December 2015 and April 2016. The Food Frequency Questionnaire was composed of 16 semi-quantitative questions covering different food categories. : This study included 1,276 children (976 healthy and 300 asthmatic children). Eating dairy products less than twice a week, 3-6 times per week and daily were significantly and inversely associated with asthma, as compared to never eating dairy products ( = 0.02, ORa = 0.285, CI 0.099-0.821; < 0.001, ORa = 0.140, CI 0.052-0.378 and < 0.001, ORa = 0.161, CI 0.061-0.422), whereas eating red meat daily compared to never was associated with asthma significantly ( = 0.037, ORa = 2.051, CI 1.046-4.024). Eating nuts less than twice weekly as compared to never was significantly and inversely associated with asthma ( = 0.035, ORa = 0.597, CI 0.369-0.965). The age categories 7-10 and 11-13 years were significantly associated with asthma as compared to the 3-6 years category ( < 0.001, ORa = 3.359, CI 1.869-6.038 and = 0.008, ORa = 2.191, CI 1.228-3.909, respectively), while male gender was significantly more prone to asthma ( = 0.014, ORa = 0.686, CI 0.507-0.926). : Knowing the correlation between nutritional habits and asthma is important to promote healthy eating. Educational programs for parents about healthy food and breastfeeding encouragement is warranted.

High incidence of cetuximab-related infusion reactions in head and neck patients.

Cetuximab is crucial in the management of squamous cell carcinoma of the head and neck of patients. Grade 3-4 cetuximab-induced infusion reactions (CI-IRs) occur in 2% of patients with colorectal cancer. Despite the 2.7% CI-IR rate in the EXTREME trial, higher rates were reported in small series of patients with head and neck squamous cell carcinoma (HNSCC) (6%-18%). There is an urgent need to better appraise the natural history and the predictive factors for CI-IRs in patients with HNSCC exposed to cetuximab. The medical records from patients with HNSCC (n=428) treated by cetuximab at Gustave Roussy from January 2013 to December 2015 were reviewed. The impact of potential risk factors was analysed. Out of 428 patients, 24 patients (5.4%) presented CI-IR, including grade 3-4 (95.7%); about 21% (5/24) requiring intensive care unit referral and quasi all occurred within the first cycle (21/24). In a multivariate analysis, the occurrence of grade 3-4 CI-IR was associated with tobacco and alcohol history (p=8.5e-3) and with prior allergy history (p=2.9e-3). CI-IRs tended to be associated with poor overall survival in patients with recurrent and metastatic HNSCC and with a higher number of further lines of chemotherapy. In real life, CI-IRs appear far more common in patients with HNSCC (5.4%) than reported in prospective trials. This is the largest series of patients ever focusing on the risk of CI-IR in patients with HNSCC. Prior allergy history and tobacco history are associated with CI-IR and could be used to better allocate treatment. Further prospective data are required to confirm these findings.

Effect of blood type on anti-α-Gal immunity and the incidence of infectious diseases.

The identification of factors affecting the susceptibility to infectious diseases is essential toward reducing their burden on the human population. The ABO blood type correlates with susceptibility to malaria and other infectious diseases. Due to the structural similarity between blood antigen B and Galα1-3Galβ1-(3)4GlcNAc-R (α-Gal), we hypothesized that self-tolerance to antigen B affects the immune response to α-Gal, which in turn affects the susceptibility to infectious diseases caused by pathogens carrying α-Gal on their surface. Here we found that the incidence of malaria and tuberculosis, caused by pathogens with α-Gal on their surface, positively correlates with the frequency of blood type B in endemic regions. However, the incidence of dengue fever, caused by a pathogen without α-Gal, was not related to the frequency of blood type B in these populations. Furthermore, the incidence of malaria and tuberculosis was negatively correlated with the anti-α-Gal antibody protective response. These results have implications for disease control and prevention.

Prolonged Overall Treatment Time and Lack of Skin Rash Negatively Impact Overall Survival in Locally Advanced Head and Neck Cancer Patients Treated with Radiotherapy and Concomitant Cetuximab.

Cetuximab, a chimeric monoclonal antibody against EGFR sensitizes tumors to radiotherapy (RT), but is associated with skin and mucosal toxicity. We report outcomes and tolerance of definitive RT in association with cetuximab in patients with locally advanced squamous cell carcinoma (LASCC) of the head and neck. Between 2006 and 2011, 92 consecutive patients with LASCC of the head and neck were treated with RT and concomitant weekly cetuximab. Median age was 61.7 years. Most patients presented with oropharyngeal tumors (52.2%) and stage IV disease (77.2%). Sixty-nine patients received at least 7 cycles of cetuximab. Cetuximab was stopped at the first infusion following allergic reactions in four patients. During RT, 37% of patients developed grade ≥ 3 dermatitis; grade ≥ 2 cetuximab-induced rash occurred in 43 patients (46.7%). Severe mucositis (grade ≥ 3) affected 57.6% of patients. Ten percent of patients did not receive the full course of RT, and temporary discontinuation due to acute toxicity was frequent and affected 37 patients (53%). The median RT overall treatment time (OTT) in patients with interrupted RT was 56 days (47-75) compared to 51 days (47-65) in patients who did not require toxicity-related radiation interruptions (p < 0.05). After a median follow-up of 17.5 months (1.3-107.6) for all patients, median overall survival was 17.9 months (95% CI: 12.7-23.2), and loco-regional control (LRC) was 9.2 months (95% CI: 3.9-14.4). On multivariate analysis, hemoglobin concentration and occurrence of rash grade ≥ 2 were independent prognostic factors for LRC (p = 0.023 and p = 0.006, respectively). Lack of rash and extended OTT negatively impacted overall survival (p = 0.048 and 0.052, respectively). Skin and mucosal toxicity remains an issue in patients with LASCC of the head and neck treated with concomitant cetuximab and RT. Severe toxicity leads to treatment interruptions and prolonged overall treatment time, with consequent decreased overall survival in these patients.

Cross-reactivity to fish and chicken meat - a new clinical syndrome.

Fish is one of the most allergenic foods. While clinical cross-reactivity among different fishes is a widely accepted feature of fish allergy, associations with other food allergies are not well understood. This study aims at analyzing the relevance of clinical cross-reactivity between fish and chicken meat in patients with allergy to chicken meat without sensitization to hen's eggs. Patients with food allergy to fish and chicken meat (n = 29) or chicken meat only (n = 7) were recruited. IgE-reactive chicken proteins were identified (Edman, MS analysis) and quantified (ELISA). Allergens were used in IgE ELISA and skin testing. Chicken parvalbumin and two new allergens, aldolase and enolase, were identified at 12, 40, and 50 kDa, respectively. They were recognized by sIgE of 61%, 75%, and 83% of all patient sera which were in the majority of the cases positive for the fish homologues as well. Fish and chicken meat allergens were highly cross-reactive while high inhibition rates with fish or chicken allergens correlated with the patients' primary sensitization to fish or chicken. In cooked or roasted foods, enolase and aldolase were detectable in chicken breast while parvalbumin was detectable in chicken legs and wings. Fish and chicken meat are cross-reactive foods; both fish-allergic and chicken meat-allergic patients might be at risk of developing a food allergy to chicken meat or to fish, respectively. This clinical phenomenon is proposed to be termed 'fish-chicken syndrome' with cross-reactive allergens involved being parvalbumins, enolases, and aldolases.

Control of vector-borne infectious diseases by human immunity against α-Gal.

Regulation of the Immune Response to α-Gal and Vector-borne Diseases.

Vector-borne diseases (VBD) challenge our understanding of emerging diseases. Recently, arthropod vectors have been involved in emerging anaphylactic diseases. In particular, the immunoglobulin E (IgE) antibody response to the carbohydrate Galα1-3Galβ1-(3)4GlcNAc-R (α-gal) following a tick bite was associated with allergies to red meat, cetuximab, and gelatin. By contrast, an anti-α-gal IgM antibody response was shown to protect against mosquito-borne malaria. Herein, we highlight the interplay between the gut microbiota, vectors, transmitted pathogens, and the regulation of the immune response as a model to understand the protective or allergic effect of α-gal. Establishing the source of α-gal in arthropod vectors and the immune response to vector bites and transmitted pathogens will be essential for diagnosing, treating, and ultimately preventing these emerging anaphylactic and other vector-borne diseases.

Genogroup IV and VI canine noroviruses interact with histo-blood group antigens.

Human noroviruses (HuNV) are a significant cause of viral gastroenteritis in humans worldwide. HuNV attaches to cell surface carbohydrate structures known as histo-blood group antigens (HBGAs) prior to internalization, and HBGA polymorphism among human populations is closely linked to susceptibility to HuNV. Noroviruses are divided into 6 genogroups, with human strains grouped into genogroups I (GI), II, and IV. Canine norovirus (CNV) is a recently discovered pathogen in dogs, with strains classified into genogroups IV and VI. Whereas it is known that GI to GIII noroviruses bind to HBGAs and GV noroviruses recognize terminal sialic acid residues, the attachment factors for GIV and GVI noroviruses have not been reported. This study sought to determine the carbohydrate binding specificity of CNV and to compare it to the binding specificities of noroviruses from other genogroups. A panel of synthetic oligosaccharides were used to assess the binding specificity of CNV virus-like particles (VLPs) and identified α1,2-fucose as a key attachment factor. CNV VLP binding to canine saliva and tissue samples using enzyme-linked immunosorbent assays (ELISAs) and immunohistochemistry confirmed that α1,2-fucose-containing H and A antigens of the HBGA family were recognized by CNV. Phenotyping studies demonstrated expression of these antigens in a population of dogs. The virus-ligand interaction was further characterized using blockade studies, cell lines expressing HBGAs, and enzymatic removal of candidate carbohydrates from tissue sections. Recognition of HBGAs by CNV provides new insights into the evolution of noroviruses and raises concerns regarding the potential for zoonotic transmission of CNV to humans. Infections with human norovirus cause acute gastroenteritis in millions of people each year worldwide. Noroviruses can also affect nonhuman species and are divided into 6 different groups based on their capsid sequences. Human noroviruses in genogroups I and II interact with histo-blood group antigen carbohydrates, bovine noroviruses (genogroup III) interact with alpha-galactosidase (α-Gal) carbohydrates, and murine norovirus (genogroup V) recognizes sialic acids. The canine-specific strains of norovirus are grouped into genogroups IV and VI, and this study is the first to characterize which carbohydrate structures they can recognize. Using canine norovirus virus-like particles, this work shows that representative genogroup IV and VI viruses can interact with histo-blood group antigens. The binding specificity of canine noroviruses is therefore very similar to that of the human norovirus strains classified into genogroups I and II. This raises interesting questions about the evolution of noroviruses and suggests it may be possible for canine norovirus to infect humans.

Cetuximab infusion reactions: French pharmacovigilance database analysis.

To compare characteristics of patients exhibiting cetuximab infusion reactions or another adverse drug reaction related to cetuximab and to identify factors associated with the severity of cetuximab infusion reactions. All cases of adverse drug reaction reported with cetuximab from 1985 to 2010 were extracted from the French Pharmacovigilance database. The severity of infusion reactions was assessed according to the NCI-CTCAE criteria (v4.0). Multiple logistic regression analysis was performed to identify factors associated with the severity of infusion reactions. Among the 602 adverse drug reaction reported with cetuximab during the study period, 374 infusion reactions were identified. Indication is more likely to be head and neck than colorectal cancer among patients experiencing an infusion reaction (p < 0.001). Among the seven deaths related to an infusion reaction, five patients were treated for head and neck cancer. Infusion reactions were more likely to be severe when they occurred during the first administration (OR = 7.40 95% CI [2.21-24.71]), adjusted for age, sex, region of France, quarter of the year, indication, year of occurrence, and premedication. Our study found that reports of infusion reactions more often concerned patients treated for head and neck cancer, that in these patients the adverse drug reaction was more often fatal and severe infusion reactions were more likely during the first administration. In daily practice, the close monitoring of patients during the first infusion, especially patients with head and neck cancer, is recommended. Considering the possible immunoglobulin E-mediated mechanism, reliable tests for their detection need to be readily available.

Feasibility of cetuximab given with a simplified schedule every 2 weeks in advanced colorectal cancer: a multicenter, retrospective analysis.

Cetuximab was approved using a weekly schedule, alone or in combination with chemotherapy (CT). However, many CT regimens in metastatic colorectal cancer (CRC) are delivered every 2 weeks (q2wks). Preliminary data suggested that a simplified schedule using cetuximab q2wks, 500 mg/m² would be equivalent to the standard weekly administration. Medical data of all patients with advanced CRC who received cetuximab q2wks were retrospectively collected and checked for consistency by an independent monitor in 4 European centers. Ninety-one patients were treated between 2005 and 2007 when the K-RAS mutational status of tumors was not determined routinely. They received a median of 4 (0-5) previous drugs, including previous weekly cetuximab in 38.5% of patients. Cetuximab q2wks was associated with an irinotecan-based regimen in 85.7% of patients. The median number of cetuximab administrations was 6 (1-23). Skin toxicity was observed in 68.2% of evaluable patients (grade 3 in 15%). Only one grade 1 allergy was reported. In the 84 patients beyond first-line therapy, response rate was 29.3%. The median progression-free survival was 3.0 months (range 2.2-3.8), and median overall survival was 9.0 months (range 6.2-11.8). Cetuximab q2wks appears safe and effective in heavily pretreated patients and convenient in combination with q2wks CT schedules.

Bovine norovirus: carbohydrate ligand, environmental contamination, and potential cross-species transmission via oysters.

Noroviruses (NoV) are major agents of acute gastroenteritis in humans and the primary pathogens of shellfish-related outbreaks. Previous studies showed that some human strains bind to oyster tissues through carbohydrate ligands that are similar to their human receptors. Thus, based on presentation of shared norovirus carbohydrate ligands, oysters could selectively concentrate animal strains with increased ability to overcome species barriers. In comparison with human GI and GII strains, bovine GIII NoV strains, although frequently detected in bovine feces and waters of two estuaries of Brittany, were seldom detected in oysters grown in these estuaries. Characterization of the carbohydrate ligand from a new GIII strain indicated recognition of the alpha-galactosidase (α-Gal) epitope not expressed by humans, similar to the GIII.2 Newbury2 strain. This ligand was not detectable on oyster tissues, suggesting that oysters may not be able to accumulate substantial amounts of GIII strains due to the lack of shared carbohydrate ligand and that they should be unable to contribute to select GIII strains with an increased ability to recognize humans.

A complete alpha1,3-galactosyltransferase gene is present in the human genome and partially transcribed.

The synthesis of Galalpha1-3Gal-terminated oligosaccharides (alpha-Gal) epitopes has been interrupted during the course of evolution, starting with Old World primates. Partial sequences similar to the alpha1,3-galactosyltransferase (alpha1,3GalT) gene, which governs the synthesis of alpha-Gal epitopes, have been detected in the human genome and were found to correspond to pseudogenes. We completed the sequence of the human alpha1,3GalT pseudogene present on chromosome 9 and found it to be organized like the murine alpha1,3GalT gene. In human cell lines and several normal and tumor tissues we detected truncated transcripts corresponding to this pseudogene. Considering these mRNAs, translation of an open reading frame containing the first four translated exons but missing the two catalytic exons could predict a truncated alpha1,3GalT polypeptide that should be enzymatically inactive. We show that transcription of human alpha1,3GalT is prematurely terminated at the level of a strong transcriptional stop signal in the middle of intron VII. We were able to reproduce this effect in vitro by subcloning the implicated DNA region upstream from a reporter cDNA. The premature transcriptional arrest of human alpha1,3-GalT gene leads to an ectopic splicing event and to the connection of a short intronic sequence downstream from translated exons. Finally, we show that these truncated transcripts are overexpressed in cell lines with modifications of O-glycans.

Two novel isoneolacto-undecaglycosylceramides carrying Galalpha1-->3Lewis(x) on the 6-linked antenna and N-acetylneuraminic acidalpha2-->3 or Galactose alpha1-->3 on the 3-linked antenna, expressed in porcine kidney.

Three sialosylated and three neutral glycosphingolipids sharing a common iso-neolacto core were isolated from porcine kidney cortex. They were purified by preparative HPTLC, and were characterized by partial exoglycosidase hydrolysis followed by thin layer chromatography and immunostaining with anti-Galalpha1-->3Gal, anti-type 2 lactosamine and anti-Lewis(x) antibodies, methylation analysis, MALDI-TOF mass spectrometry and 1H-NMR spectroscopy. Among neutral glycolipids, one was a known structure, VI3VI'3(alphaGal)2-iso-nLc8Cer, and two were novel structures differing by the number of Galalpha3Lewis(x) determinants: VI3VI'3(alphaGal)2V'3alphaFuc-iso-nLc8, and VI3VI'3(alphaGal)2 V3V'3(alphaFuc)2-iso-nLc8. The single Galalpha3Lewis(x) determinant was found on the 6-linked antenna. Among sialosylated glycolipids, two had been previously found in other species and tissues, VI3VI'3(NeuAc)2-iso-nLc8, and VI3NeuAcVI'3alphaGal-iso-nLc8. A novel structure was discovered presenting a Galalpha3Lewis(x) determinant on the 6-linked antenna and a N-acetylneuraminic acid on the 3-linked antenna, VI3NeuAcVI'3alphaGalV'3alphaFuc-iso-nLc8. These results indicate that, in vivo, the porcine kidney alpha3fucosyltransferase synthesizes the Gala3Lewis(x) determinant, acting on the 6-linked before the 3-linked Galalpha3neolactosamine, and appears unable to synthesize the sialosylated Lewis(x) determinant on neolactoseries glycolipids.

Characterization of a polyclonal anti-Galalpha1-3Gal antibody from chicken.

A polyclonal antibody was raised against the Galalpha1-3Gal carbohydrate epitope, which is expressed by all mammals (except man and the closest primate species) by immunizing hens with rabbit erythrocyte membranes. IgY was isolated from egg yolks, and affinity-purified on a Galalpha1-3Gal-Synsorb column. Two percent of the initial IgY fraction was recovered. The specificity of the affinity-purified antibody was characterized by: absorption with human, rabbit and pig erythrocytes; by using Synsorb columns; by inhibition with different saccharides; and by immunostaining of glycolipids separated on thin layer chromatograms. A weak reactivity was found toward blood group B or blood group Pk determinant, depending on the assay system used. Such reactivities were abolished after absorption by the appropriate sorbents, yielding a polyclonal anti-Galalpha1-3Gal antibody with narrow specificity.

Removal of anti-Gal alpha (1,3)Gal antibodies diminishes the cytotoxic effect of primate xenoreactive antibodies on rat endothelial cells.

Associations of blood group-related antigens to FEV1, wheezing, and asthma.

Discordant results have been observed regarding the associations of chronic obstructive pulmonary diseases with secretor, Lewis, and ABO histo-blood groups, which are defined by glycosyltransferases. These enzymes build up oligosaccharide structures that play a role in the adhesion of environmental factors to epithelial cells. The objectives of the present study were to assess the role of all three systems, Lewis (Le), salivary ABH secretor (Se), and red cell blood group ABO, on lung function, wheezing, and asthma in a cohort of 228 coal miners studied cross-sectionally, considering the potential modifying effect of environmental factors on these associations. Asthma was significantly related to nonsecretor phenotype. Significantly lower lung function and higher prevalences of wheezing and asthma were observed in Lewis-negative or nonsecretor subjects of blood group O. Very low lung function values were observed in the small group of Lewis-negative nonsecretors who lack both Le and Se controlled fucoses (1% of Caucasians). Lewis-positive, salivary ABH secretors who have these two fucoses represent 70% of Caucasians. Among these subjects, lower lung function was observed in blood group A, and in a lesser extent in blood group B, i.e., with terminal alpha GaINAc or alpha Gal respectively, than in blood group O subjects. ABO, Lewis, and secretor phenotypes did not account for the potential genetic heterogeneity of subjects toward smoking, but alcohol consumption appeared to exert a protective effect on lung function in Lewis-negative subjects (10% of Caucasians). If confirmed in other populations, the magnitude of the effects observed regarding low lung function in Lewis-negative ABH nonsecretors, and the protective effect of Lewis negative on the deleterious effect of alcohol, may be of clinical importance. Further studies of the combined effects of various histo-blood group genetic systems seem worthwhile, particularly for airflow limitation, wheezing, and asthma, possibly with reference to susceptibility to infectious agents.

The reducing end of alpha Gal oligosaccharides contributes to their efficiency in blocking natural antibodies of human and baboon sera.

Synthetic galactosyl oligosaccharides were tested for their ability to inhibit the cytotoxic reaction of human and baboon natural antibodies on PK15 cells in culture. Methyl-alpha-Gal gave weak inhibition, Gal alpha 1-3Gal substantially inhibited the reaction (400muM), and Gal alpha 1-3Gal beta 1-4GLcNAc was ten times more efficient (30 muM). The modification from alpha to beta anomeric configuration of the nonreducing end resulted in a complete loss of activity, while substitutions at the reducing end induced only a partial loss of activity. These observations suggest that natural anti-alphaGal antibodies recognize the epitope from its nonreducing end, but that substitutions at the reducing terminus can modify the antibody-binding capacity. Modified tri- and tetrasaccharides are better inhibitors than the disaccharide but not as good as Gal alpha 1-3Gal beta 1-4GlcNAc. The reducing terminus therefore contributes some energy to the reaction, indicating that certain oligosaccharides will be of more potential clinical use than others.