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-γ: r′=0.198, P=0.285; TNF-α: 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-γ and r′=−0.746, P=0.005 for TNF-α, 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. [ABSTRACT FROM AUTHOR]