Response to mucosal antigen challenge in IgA nephropathy.

While IgA nephropathy (IgAN) is characterized by the deposition of glomerular IgA, the source of the deposited IgA is not known, with both the mucosal and systemic IgA systems being implicated. In order to investigate mucosal and systemic antibody production to mucosal antigen challenge in IgAN, 9 patients and 11 controls were immunized intranasally with tetanus toxoid (TT). There was no significant difference in the serum or saliva IgG, IgA, IgA1, or IgA2 antibody production to TT. However, in IgAN there was an increase of in vitro IgA anti-TT production in Epstein-Barr virus transformed cultures of peripheral blood lymphocytes taken after mucosal immunization. This increase in traffic of immunocompetent cells between the systemic and mucosal systems could play a role in the link between the mucosa and glomerulus in IgAN. Systemic immunization with TT following mucosal priming did not result in any difference in the antibody response between patients and controls. There was no evidence from this study that mucosal immunization results in an enhanced antibody response in IgAN or that mucosal priming alters the subsequent systemic antibody response.