Abstract
The pathogenesis of IgA nephropathy (IGA N) is unclear. We have previously shown the glomerular deposition of Haemophilus parainfluenzae (HP) antigens and the presence of IgA antidody against HP antigens in patients with IgA N. We examined the immune response to HP antigens in tonsillar lymphocytes from patients with IgA N.
We used tonsillar lymphocytes isolated from the palatine tonsils of 13 patients with IgA N and 16 patients with chronic tonsillitis but without renal disease as controls. We examined lymphocyte proliferation and production of IgA antibody against HP antigens by measuring thymidine uptake and IgA antibody in culture supernatants after lymphocyte incubation with HP antigens.
Patients with IgA N showed a significantly higher stimulation index to HP antigens (thymidine incorporation in tonsillar lymphocytes with HP/thymidine incorporation in unstimulated tonsillar lymphocytes) than controls (P<0.002). Lymphocytes from patients with IgA N also showed a significantly higher level of IgA antibody and IgAl antibody against HP antigens in culture supernatants than lymphocytes from controls (P=0.0002 and P=0.004; respectively).
Our results suggest that HP antigens stimulate tonsillar T-and B-lymphocytes in patients with IgA N and that an immune response to HP antigens may play a role in the pathogenesis of this disease in some cases.
