The investigated polymorphisms were not associated with the progression of the IgA nephropathy, as shown by the similar genotype distribution in group A and group B (slow progressors: TGF-beta1, 92.3%; TNFalpha, 25.6%; IL-6, 74.4%; fast progressors: TGF-beta1, 85.7%; TNFalpha, 22.4%; IL-6: 81.6%, ns).
To clarify whether TGF-beta1 contributes to the progression of IgA nephropathy by activating apoptosis in glomerular cells, we examined the expression of TGF-beta1 gene and apoptotic changes in kidney biopsy samples, and assessed those relations to the severity of nephropathy.
These results suggest that TGF-beta1 gene polymorphisms are specifically associated with heavy proteinuria and mesangial cell proliferation in Japanese patients with IgAN, although they do not confer susceptibility to this disease.