Tropomyosin: Pan-allergen

Tropomyosin is present both in muscle and non muscle cells. Vertebrate tropomyosins are non allergenic, but are allergenic in invertebrates. The high identity between amino acids of tropomyosins from different species is responsible for numerous cross reactivities which cause them to be considered as pan-allergens. Tropomyosins of different natural sources have been identified and cloned. They are major allergens in crustaceans but not in house dust mites or in cockroaches or snails for instance. Dosages of specific IgEs against shrimp tropomyosin (rPen a 1) are now available. New sensitisations to tropomyosin have been described in the course of mite immunotherapy, but the clinical consequences of these new sensitisations still remain uncertain. We describe two clinical cases in which the dosage of specific IgEs against tropomyosin allowed better assessment of the diagnosis and better therapeutic decisions. (C) 2009 Elsevier Masson SAS. All rights reserved.