Specific V beta T cell subsets are associated with cat and birch pollen allergy in humans

Cognate interaction between TCRs and MHC class II molecules plays an import ant role in initiating the allergen-specific immune response. Therefore, we analyzed the TCR distribution of human PBLs of 56 atopic and nonatopic (NA ) individuals, including 4 monozygotic twin pairs, from two extended and fo ur nuclear families. The expression of 23 V beta and 3 V alpha elements was analyzed. The blood samples of symptomatic birch pollen-sensitized individ uals that were taken less than or equal to 6 wk after the birch pollen seas on (n = 8) showed a significantly higher frequency of V beta 16.1(+) and V beta 20.1(+) T cells compared with the blood samples of birch pollen-sensit ized individuals that were obtained out of allergen season (n = 10) or from NA individuals (p < 0.0005 and p < 0.0001, respectively). Allergen-specifi c lymphocyte proliferation was detected in the allergic individuals, and th e distribution of V beta 16.1(+) and V beta 20.1(+) T cells returned to nor mal levels after the pollen season, The frequency of these V beta-expressin g T cells correlated with the levels of allergen-specific IgE Abs, In addit ion, cat-sensitized individuals (n = 8) showed a significantly higher frequ ency of V beta 17.1-expressing T cells than did NA individuals (p < 0.005). Our results indicate restricted TCR-V beta gene usage in cat and birch pol len allergies; we suggest that both genetic and environmental factors contr ibute to TCR-V beta gene expression and to the development of a specific T cell response.