Clopidogrel is a new antiplatelet prescribed for the secondary prevention of atherosclerotic events. The literature shows that the clinical manifestations of clopidogrel hypersensitivity include urticaria1, skin rash2-4, and angioedema5. The precise immunological mechanism underlying clopidogrel hypersensitivity has not been established. We describe two cases of hypersensitivity reaction due to clopidogrel. The first constituted an immediate reaction after clopidogrel intake. In this case we demonstrated type 1 hypersensitivity using cutaneous tests. The second case represented a delayed hypersensitivity reaction confirmed by oral challenge testing, in which good tolerance to other antiplatelet drugs such as ticlopidine was demonstrated.

Background: Ixekizumab is a high-affinity IgG4 monoclonal humanized antibody useful for the treatment of ankylosing spondylitis. Benign skin reactions are a common adverse event with ixekizumab but systemic hypersensitivity reactions are much more unusual. Case report: We describe the case of a 54-female patient with HLAB27+ spondyloarthritis. Treatment with ixekizumab 80 mg subcutaneous (containing polysorbate) was prescribed. The patient experienced immediate severe dyspnea, skin erythema and flushing. Intradermal test (0.8 mg/ml) was clearly positive in the immediate reading. The patient was planned to undergo ixekizumab desensitization according to an 8-step protocol with good tolerance. Conclusion: We report a patient with HLAB27+ spondyloarthritis treated with ixekizumab who developed a systemic IgE-mediated reaction. A successful and easy to perform subcutaneous desensitization protocol is described. Keywords: Hypersensitivity; Ixekizumab; Systemic reaction; Skin test; Desensitization protocol.

Background: The pathophysiological mechanism of eosinophilic esophagitis (EoE) is complex and is still being investigated. We believe that there is a group of patients with eosinophilic esophagitis which could be differentiated as having an allergic phenotype who exhibit a sensitization profile (aeroallergens, panallergens, foods and specific IgG4 levels) with significant differences compared to patients with conventional allergic disease without associated eosinophilic esophagitis and healthy controls. Method: We measured the prevalence of sensitization to aeroallergens, foods and panallergens by means of molecular diagnostic techniques (ImmunoCAP^TM ISAC) and determined the levels of specific IgG4 against foods and eosinophilic-derived neurotoxin (EDN) (ImmunoCAP technology) in patients with EoE of an allergic phenotype to study whether there are statistically significant differences with respect to the control groups (patients with different allergic pathologies without EoE and healthy patients without documented allergies). The total number of patients under study was 118, distributed among the different study groups. The case group (Allergic phenotype EoE patients) had 48 subjects. The food and respiratory allergy control groups had 30 subjects each. Finally, we included 10 in the healthy control group. Results: We were able to identify statistically significant differences when comparing levels of food-specific IgG4. Milk, egg, wheat, nuts, soy, cod, and Pru p3/LTP stood out. We did not observe significant differences in relation to sensitization to aeroallergens, foods, or panallergens. We also did not observe differences in EDN levels. Conclusions: We present a study in which statistically significant differences in IgG4 levels were observed in response to different types of food, comparing patients with eosinophilic esophagitis of allergic phenotype (case group) against subjects with allergic pathology without EoE and healthy subjects (control groups). Determining whether the detected foods are clinically relevant or not in these patients would be fundamental to establishing their usefulness as a treatment alternative in our patients.

Background: Eosinophilic esophagitis (EoE) pathophysiological mechanism is complex and it s still being investigated. We believe there is a group of patients with eosinophilic esophagitis which we could differentiate as having an allergic phenotype, who exhibit a sensitization profile (aeroallergens, panallergens, foods and specific IgG4 levels) with significant differences when compared to patients with conventional allergic disease without associated eosinophilic esophagitis and healthy controls. Method: We have measured the prevalence of sensitization to aeroallergens, foods and panallergens by means of molecular diagnostic techniques (ImmunoCAPTM ISAC) and determined the levels of specific IgG4 against foods and eosinophilic derived neurotoxin (EDN) (ImmunoCAP technology) in patients with EoE of allergic phenotype to study if there are statistically significant differences with respect to the control groups (patients with different allergic pathologies without EoE and healthy patients without documented allergies). The total number of patients under study was 118, distributed among the different study groups. The case group (Allergic phenotype EoE patients) has 48 subjects. The food and respiratory allergy control groups, 30 subjects each. Finally, we included 10 in the healthy control group. Results: We were able to identify statistically significant differences when comparing levels of food-specific IgG4. Milk, egg, wheat, nuts, soy, cod, and LTP stood out. We did not observe significant differences in relation to sensitization to aeroallergens, foods, or panallergens. We also did not observe differences in EDN levels. Conclusion: We present a study in which statistically significant differences in IgG4 levels were observed in response to different types of food, comparing patients with eosinophilic esophagitis of allergic phenotype (case group) against subjects with allergic pathology without EoE and healthy subjects (control groups). Determining whether the detected foods are clinically relevant or not in these patients would be fundamental to establishing their usefulness as a treatment alternative in our patients.