Peanut-specific B and T cell responses are correlated in peanut-allergic but not in non-allergic individuals

Objective We aim to find what is the relationship between B cell antibody responses and specific T cell help in the specific cases of allergy and tolerance to peanuts. Background B cell antibody responses to foreign proteins usually depend upon antigen-specific T cell help. However, specific antibody levels can sometimes be maintained lifelong after infections or vaccination. Methods We measured peanut-specific proliferation and antibody levels in peanut-allergic and non-allergic children using tritiated thymidine incorporation and UniCAP, respectively. We also investigated the corresponding tetanus toxoid specific responses in both groups. Results We found that tetanus-specific IgG did not correlate with lymphocyte proliferation (Spearman rank correlation coefficient r' = 0.08, P = 0.74) nor with tetanus-specific cytokine production (IFN-gamma: r' = 0.198, P = 0.285; TNF-alpha: r' = 0.274, P = 0.146; IL-4: r' = -0.007, P = 0.96; P = 0.221; IL-13: r' = 0.363, P = 0.056). Conversely, in peanut-allergic donors, peanut-specific IgE (average 21 kU/L, median 2.27 kU/L, range 0.34-100 kU/L) but not peanut-specific IgG was positively correlated with proliferation (r' = 0.751, P = 0.003). In these donors, specific IgE was positively correlated with peanut-specific Th2 cytokines production: r' = 0.635, P = 0.02 for IL-4 and r' = 0.641, P = 0.025 for IL-13 and negatively correlated with Th1 cytokines (r' = -0.71, P = 0.007 for IFN-gamma and r' = -0.746, P = 0.005 for TNF-alpha, respectively). However, peanut-specific IgE was not correlated with T cell proliferation or cytokine production in non-allergic individuals. In conclusion, in allergic individuals, B and T cell responses to peanut antigens are correlated whereas normal immune responses B and T cell responses are uncoupled. Conclusion Our results support the view that B cell responses to allergens but not those to non-allergenic proteins are correlated with specific T cell responses and therefore specific immunotherapy targeting of such T cells would inhibit allergen-specific B cells