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INTRODUCTION: Onion (Allium cepa) handling can induce contact dermatitis, rhinoconjunctivitis and asthma. However, only sporadic reports exist on allergic reactions to onion consumption. AIM: We describe herein a case of a 35-year-old man who had an episode of anaphylaxis following cooked onion ingestion. We evaluated onion-specific IgE, the possible cross-reactivity between onion and peach and lymphocyte proliferation in response to onion. MATERIAL AND METHODS: Specific IgE was evaluated using two techniques: skin test and ImmunoCAP technology. Cross-reactivity between onion and peach was evaluated by IgE-ELISA inhibition test. As for lymphocyte proliferation, blood mononuclear cells were stained with CFSE dye and cultured with an in-house onion extract. Proliferation and phenotype was assessed by flow-cytometry. RESULTS: The skin test and ImmunoCAP confirmed the IgE-dependent response towards onion. The incubation of the patient serum with increasing concentrations of the peach extract reduced only scarcely (~30%) onion-specific IgE. Interestingly, B cells but not T cells showed proliferation in response to onion extract. CONCLUSIONS: In conclusion, our report shows that cooked onion can induce severe allergic reactions, suggesting the presence of thermostable components. Moreover, we applied for the first time a B-cell-based approach to the diagnosis of food allergy. This latter approach might also be applied to other allergic conditions.
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BACKGROUND: Randomized Controlled Trials showed that omalizumab exhibited a good safety and tolerability profile in patients with moderate-to-severe asthma. However, safety data of long-term treatment with omalizumab are scarce. Our aim was to assess the safety of omalizumab in patients under long-term treatment in a real-life setting. METHODS: Difficult-to-control asthmatic patients treated with omalizumab up to 9 years were retrospectively evaluated. Mild to severe adverse events any and reasons for discontinuation were recorded. RESULTS: Ninety-one patients (26.4% males, mean age 49.9 ± 14.9 years) were included: mean treatment length, 3.8 ± 2.6 years; mean individual monthly dose, 514.5 ± 345.7 mg (range, 150-1200 mg). A total of 10,472 single injections were given cumulatively to the 91 patients (115 single injections per patients, on average, over a treatment period up to 9 years). Fifty-nine patients (64.8%) were treated for a period of time from 3 to 9 years, 14 of whom from 6 to 9 years. A high proportion of patients who discontinued treatment dropped out within the first year (18, 39.1%), mainly for reasons unrelated to treatment. Six patients (6.6%) discontinued omalizumab for treatment-related adverse events: arthralgia/myalgia (3 patients); urticaria, angioedema (1 patients); metrorrhagia (1 patient); relapsing herpes labialis (1 patient). Four other patients complained of mild adverse events (rhinitis/conjunctivitis, injection site reaction, fatigue, thrombosis) but continued the treatment. Anaphylaxis was not reported. CONCLUSIONS: Long-term treatment with omalizumab appears remarkably safe and well tolerated in real-life setting. Prolonged omalizumab treatment for many consecutive years did not increase the risk of side effects, particularly anaphylaxis.