House dust mite allergy and shrimp allergy: a complex interaction

Summary

Background and Objective. Sensitization and allergy to shrimp among Italian house dust mite allergic patients are not well defined and were investigated in a large multicenter study. Methods. Shrimp sensitization and allergy were assessed in 526 house dust mite (HDM)-allergic patients submitted to the detection of IgE to Der p 10 and 100 atopic control not sensitized to HDM. Results. Shrimp allergy occurred in 9% of patients (vs 0% of 100 atopic controls not sensitized to HDM; p minor 0.001). Shrimp-allergic patients were less frequently hypersensitive to airborne allergens other than HDM than crustacean-tolerant subjects (35% vs 58.8%; p minor 0.005). Only 51% of tropomyosin-sensitized patients had shrimp allergy, and these showed significantly higher Der p 10 IgE levels than shrimp-tolerant ones (mean 22.2 KU/l vs 6.2 KU/l; p minor 0.05). Altogether 53% of shrimp-allergic patients did not react against tropomyosin. Conclusions. Shrimp allergy seems to occur uniquely in association with hypersensitivity to HDM allergens and tropomyosin is the main shrimp allergen but not a major one, at least in Italy. Along with tropomyosin-specific IgE levels, monosensitization to HDM seems to represent a risk factor for the development of shrimp allergy among HDM allergic patients.

Recommendations for the Use of Tryptase in the Diagnosis of Anaphylaxis and Clonal Mastcell Disorders

Summary

Tryptase is a serin-protease produced and released by mast cells after IgE-mediated or non-IgE mediated stimuli. We here review the various aspects related to the molecular characteristics of the enzyme and its biological effects, the genetic basis of its production and the release kinetics. Recommendations for the clinical use of tryptase measurement developed by a task force of Società Italiana di Patologia Clinica e Medicina di Laboratorio and Associazione Allergologi Immunologi Italiani Territoriali e Ospedalieri are given on the best procedure for a correct definition of the reference values in relation to the inter-individual variability and to the correct determination of tryptase in blood and other biological liquids, in the diagnosis of anaphylaxis (from drugs, food, insect sting, or idiophatic), death from anaphylaxis (post mortem assessment) and cutaneous or clonal mastcell disorders.

Heterogenity of IgE response to walnut and hazelnut in Italian allergic patients

BACKGROUND

The prevalence of IgE reactivity against genuine walnut and hazelnut allergens is poorly defined.

OBJECTIVE

The IgE response to walnut and hazelnut was investigated in Italian patients with primary allergy to these nuts.

METHODS

Sera from 36 patients allergic to hazelnut and/or walnut, not reactive to PR-10, profilin, and LTP, underwent immunoblot analysis with extracts of both nuts.

RESULTS

Most patients had a history of systemic symptoms following the ingestion of the offending food(s). Twelve patients were sensitized to both walnut and hazelnut, and 13 were sensitized to other nuts and seeds (cashew, peanut, sesame, pine nut, almond, Brazil nut, and pistachio). On walnut immunoblot, the 7 sera which scored positive showed much variability in their IgE profile. Two reacted uniquely at 10 kDa, and the others at 35 , 40, 45, 50, 67, and > 67 kDa. The profiles obtained under reducing and non-reducing conditions showed several differences. The 7 sera positive on hazelnut immunoblot under reducing conditions recognized sera at 10 kDa and at <10 kDa (n=1), 20 kDa (n=4), at about 22, 24, 30, 40, 43, 58, 60, and 90 kDa, and higher m.w. in other cases. Under non-reducing conditions IgE reactivity at 20, 28, 35, 40, 45, 60, 90, and 100 kDa, was detected. Only two sera scored positive under both conditions and showed an IgE profile that partly changed from one assay to another.

CONCLUSION

The current list of walnut and hazelnut allergens is far from being complete. Both reducing and non-reducing conditions are needed to detect IgE reactivity in individual patients.