Component-resolved diagnosis (CRD) using microarray technology has recently been introduced with the aim to improve diagnosis of allergy. The aim of this study was to compare performance of this allergen microarray to those of an established extract-based skin prick testing (SPT). 45 patients with allergic rhinitis were studied (16 children and 29 adults). SPT to Dermatophagoides pteronyssinus, Dermatophagoides farinae and Blomia tropicalis extracts and allergen microarray ImmunoCAP ISAC were carried out for all patients. Forty out of 45 patients demonstrated positive SPT to all mite extracts tested. These 40 patients were considered to be mite- allergic based on the positive SPT results. The remaining 5 patients with negative SPT to any mite extracts were classified as non-mite allergic. Comparatively, based on the microarray results, only 34 mite-allergic patients had detectable serum IgE to at least one of the mite allergen components tested whereas 6 patients with positive SPT to mite extracts showed no detectable IgE reactivity to any of the components tested. One non-mite allergic patient had a positive test- Blo t 5. Der p 10- positive patients also reacted to other cross-reactive tropomyosin from anisakis (Ani s 3) (25%), cockroach (Bla g 7) (50%) and shrimp (Pen m 1) (75%). CRD is a reliable tool for the diagnosis of allergy to mites. Der p 10 might be a useful indicator to identify a subset of mite-allergic patient that have additional sensitization due to cross-reactivity and thus allows selection of patients for immunotherapy.

Background: Prawns and shrimp are a frequent cause of seafood allergy mediated by IgE antibodies. Penaeus monodon and Penaeus latisulcatus, commonly known as black tiger prawn and king prawn, respectively, are among the most frequently consumed prawns in Malaysia. The aim of this study was to identify the IgE-binding proteins of these 2 prawn species. Methods: Raw and boiled prawn extracts were prepared and then resolved by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). IgE-immunoblotting was then performed using sera from patients with positive skin prick tests to the raw prawn extracts. Results: SDS-PAGE analysis of the raw extracts of both prawn species revealed 23 protein bands; the boiled extracts yielded fewer protein bands. The bands in the range of 40 to 100 kDa were sensitive to heat and therefore were not found in the boiled extracts. Immunoblot of raw extracts of black tiger prawns and king prawns yielded 14 and 11 IgE-binding proteins, respectively, with molecular weights of between 15 and 200 kDa. Proteins at 36, 42, and 49 kDa were detected as the major allergens in both species of prawns. A protein of 75 kDa was also identified as a major allergen in black tiger prawns. Other potential allergens were also observed at various molecular masses. Conclusion: Proteins of 36, 42, and 49 kDa were identified as the major allergens of both species of prawns. The 36 and 42 kDa proteins are hypothesised to be tropomyosin and arginine kinase, respectively. A high molecular weight protein of 75 kDa was found to be an additional major allergen in black tiger prawns.

Objective: To characterize the major allergens of Macrobrachium rosenbergii (giant freshwater prawn). Methods: Raw and cooked extracts of the giant freshwater prawn were prepared. The IgE reactivity pattern was identified by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and immunoblotting technique with the sera of 20 skin prick test (SPT) positive patients. The major allergen identified was then characterized using the proteomics approach involving a combination of two-dimensional (2-DE) electrophoresis, mass spectrometry and bioinformatics tools. Results: SDS-PAGE of the raw extract showed 23 protein bands (15-250 kDa) but those ranging from 40 to 100 kDa were not found in the cooked extract. From immunoblotting experiments, raw and cooked extracts demonstrated 11 and 5 IgE-binding proteins, respectively, with a molecular mass ranging from 15 to 155 kDa. A heat-resistant 36 kDa protein was identified as the major allergen of both extracts. In addition, a 42 kDa heat-sensitive protein was shown to be a major allergen of the raw extract. The 2-DE gel fractionated the prawn proteins to more than 50 different protein spots. Of these, 10 spots showed specific IgE reactivity with patients' sera. Matrix assisted laser desorption/ionization-time of flight (MALDI-TOF) analysis led to identification of 2 important allergens, tropomyosin and arginine kinase. Conclusions: It can be concluded that the availability of such allergens would help in component-based diagnosis and therapy of prawn allergies.