T and B cell responses following immunization with tetanus toxoid in IgA nephropathy

Abstract

SUMMARY The B and T cell responses were investigated in IgA nephropathy before and after immunization with tetanus toxoid (TT). Both IgA and IgG anti-tetanus toxoid antibodies were elicited, but the IgA ntibodies were significantly greater in patients (92·6 ± 11·7 ELISA units) than in the controls (49·2 ± 7·5 ELISA units). This was associated with a significantly greater proportion of IgA+ B cells in patients than controls before immunization. However, a significant increase in the proportion of IgA 1 binding CD4 and CD8 cells was also found. The proportion of CD3 cells with γδ T cell receptors (CD3+TCRγδ+), was significantly greater before immunization in the IgA nephropathy patients 37·0%± 2·4), compared with controls (100%± 2·3; P < 0·001). Immunization with TT further enhanced the CD3+TCRγδ5+ cells in patients to 45·8%± 7·2 compared with controls (16·3%± 4·5), with a corresponding decrease in CD3+TCRαβ+ cells in the patients (P < 0·001). CD3+TCRγδ+ cells are upregulated by common microbial antigens and clinical exacerbations of IgA nephropathy are frequently associated with mucosal infections and a rise in serum IgA concentration. The increased TCRγδ (5 expression may be responsible for the enhanced IgA antibody response in IgA nephropathy. The increase in IgA antibodies may then exert a controlling effect by binding to augmenting T cells and thereby inhibiting their function.