Malassezia sympodialis als krankheitsspezifisches Allergen bei der atopischen Dermatitis

The opportunistic yeast Malassezia belongs to the normal cutaneous flora but can also cause IgE-mediated sensitization in patients suffering from atopic dermatitis (AD). We investigated the prevalence of sensitization to M sympodialis serologically and by skin test in various allergic conditions. Furthermore, a purpose of this study was to identify the causing allergenic structures of the yeast by using different recombinant allergens of M. sympodialis. Totally, 613 patients with allergic rhinoconjunctivitis to seasonal or perennial allergens (378), allergic asthma (83), AD (55), urticaria (31), food allergy (24), insect sting allergy (42) and 38 healthy controls were investigated. As natural allergen, a crude extract prepared from the M. sympodialis strain ATCC 42132 was used. Specific serum IgE was analyzed by ImmunoCAP ("m70, Pharmacia Diagnostics, Uppsala, Sweden); for the recombinant allergens an ELISA assay was established. Recombinant M. sympodilialis allergens (rMal sl, rMal s5, rMal s6, rMal s7, rMal s8, and rMal s9) were cloned and expressed in the E. coli M15 system and used for detection of allergen-specific IgE in the serum measured by ELISA. In 34 of 55 patients with AD, specific IgE against M. sympodialis was detected. The ELISA assay with recombinant allergens showed differential recognition patterns against the different molecular structures with a predominance of sensitization to rMal s5, rMal f6 and rMal f9. No reactivity to rMal s allergens was seen in other patients or healthy controls. In conclusion, sensitization to M. sympodialis occurs almost exclusively in patients with AD. The use of antifungals may therefore be highly beneficial in some AD patients. Recombinant allergens are an excellent tool to determine the immunologic relevance of fungi in AD.