Lymphocyte responsiveness to Dermatophagoides farinae extract in mite-sensitive patients: effect of immunotherapy on cellular proliferative response and specific immunoglobulin E antibody (RAST score).

Lymphocyte responsiveness in vitro and serum levels of specific IgE antibody to mite extracts (Dermatophagoides farinae) were evaluated in mite-sensitive asthmatic patients and in nonatopic individuals. Lymphocytes from untreated mite-sensitive patients (n = 16) responded to mite extracts with greater 3H-thymidine uptake than those from nonatopic individuals (n = 20; p less than 0.01). Specific IgE antibody and total IgE levels were significantly higher in mite-sensitive patients than those in nonatopic individuals. These results suggest that mite-sensitive patients respond to mite allergen with exaggerated lymphocyte proliferation as well as with enhanced specific IgE antibody production. Lymphocyte response to mite extracts was significantly lower in the patients with long-term dust immunotherapy than that in the untreated patients (p less than 0.05), but there was no significant difference in the total IgE and the specific IgE antibody levels between them. Lymphocyte response to Candida albicans was not significantly affected in these patients. These results suggest that as far as mite allergy is concerned, there is some difference in the effect of immunotherapy between lymphocyte proliferative response and specific IgE antibody to mite allergen.