Frequency analysis of allergen-reactive T-lymphocytes in individuals allergic against the house-dust mite Dermatophagoides pteronyssinus.

We have investigated the frequencies of Dermatophagoides pteronyssinus (Dpt)-reactive circulating T cells in individuals allergic to this house dust mite and in asymptomatic controls. In allergic patients the median for frequencies of Dpt-reactive T cells (80/10,000 T cells) was significantly higher (p = 0.0001) than that in the controls (19/10,000 T cells). Frequencies of spontaneously proliferating T cells were also determined. Here too, marked differences (p = 0.0001) were observed between the allergics (median = 32/10,000 T cells) and the non-allergics (median = 7.5/10,000 T cells). The allergen-reactive T cells tended to occur at a higher frequency with increasing serum level of Dpt-specific IgE. Thus the median value for Dpt-reactive T cells in patients showing RAST class greater than or equal to 4 (176.5/10,000 T cells) was higher than that shown by patients with RAST class 3 (62/10,000 T cells). Frequency estimations of allergen-reactive T cells before, during and after the completion of hyposensitization therapy might help to clarify their possible role in the allergic symptoms.