Different reactivity to recombinant Aspergillus fumigatus allergen I/a in patients with atopic dermatitis or allergic asthma sensitised to Aspergillus fumigatus.

We report a clinical study comparing the skin test reactivity to recombinant Aspergillus fumigatus allergen 1 (rAsp fI/a) in patients with atopic dermatitis and A. fumigatus sensitisation (n = 15), A. fumigatus-allergic patients with asthma (n = 10) and healthy control subjects (n = 10). All patients sensitised to A. fumigatus reacted at intradermal skin tests with commercial A. fumigatus extracts in contrast to the healthy subjects. Six out of 10 patients with well-characterised A. fumigatus allergic asthma were sensitised to rAsp fI/a as shown by a positive skin test. The patients with skin test reactivity to rAsp fI/a also showed rAsp f I/a-specific serum IgE as determined by ELISA. None of the patients with atopic dermatitis, healthy control subjects and 4 out of 10 A. fumigatus-allergic asthmatics reacted in intradermal tests to rAsp fI/a. Serologic investigations revealed that these subjects did not express detectable amounts of rAsp fI/a-specific IgE in agreement with the negative skin test results. Extended serologic investigations have not shown significant differences in rAsp fI/a-specific IgA, IgG4 and IgG1 serum levels between atopic dermatitis patients and healthy control subjects. The results suggest that sensitisation to A. fumigatus in patients with atopic dermatitis is not related to the major A. fumigatus allergen I in contrast to the high incidence of sensitisation to Asp fI/a occurring in allergic asthmatics.