In vivo diagnosis with purified tropomyosin in mite and shellfish allergic patients.

BACKGROUND: Tropomyosin is the most studied shellfish allergen and has been involved in cross-reactivity among different invertebrates (crustacean, mollusks, mites, insects, and nematodes). OBJECTIVE: To determine the relevance of tropomyosin in mite- and shellfish-sensitized patients using tropomyosin skin testing. METHODS: Patients were divided into 3 groups: group M included mite allergic patients (ie, individuals with respiratory symptoms and a positive result on skin prick testing [SPT] to house dust mites), group S included shellfish allergic patients (ie, individuals who reported symptoms with shellfish), and group MS included mite- and shellfish allergic patients (ie, individuals who simultaneously fulfilled the inclusion criteria for groups M and S). Tropomyosin was purified from shrimp, characterized, and used in SPT for diagnosis in the patient population. RESULTS: Eight hundred fifty patients were included in the study: 790 (92.9%) in group M, 21 (2.5%) in group S, and 39 (4.6%) in group MS. Tropomyosin was purified from shrimp with a purity higher than 95%. Forty-two individuals tested positive to tropomyosin: the prevalence was 2.7% in group M, 28.6% in group S, and 38.5% in patients of group MS. Twenty-one (50%) of the tropomyosin-positive individuals had symptoms with shellfish, and 3 (14.3%) reported anaphylaxis. CONCLUSION: The prevalence of tropomyosin was low in mite-sensitized patients (2.7 %) and high in shellfish allergic patients (28.6%). The higher prevalence of tropomyosin was found in patients sensitized to both mite and shellfish (38.5%). The selection of tropomyosin-sensitized patients by SPT might help in the choice of appropriate treatments or management for these patients.

Recently introduced foods as new allergenic sources: sensitisation to Goji berries (Lycium barbarum).

Goji berries (GB) have been introduced in Western diet. Preliminary reports have demonstrated its allergenic capacity. The objectives of the study were to investigate the frequency of sensitisation and the allergens involved. 566 individuals, with respiratory or cutaneous symptoms were skin-prick tested with GB extract. Thirty three were positive (5.8%). 94% were sensitised to other allergens. Specific IgE to GB, peach, tomato and nut-mix was measured. Thirteen individuals from 24 available sera (54.2%) had positive specific IgE. 92.3% of GB positive patients were positive to peach. Seven individuals recognised 8 bands and six recognised a 7kDa band. This band was identified as a LTP by MS/MS. Cross-reactivity was demonstrated with tomato, tobacco, nutmix, Artemisia pollen and purified Lyc e 3 and Pru p 3. GB are a new allergenic source with high prevalence of sensitisation. LTP seems to be the major allergen involved in sensitisation and cross-reactivity.