Background: Thin basement membrane nephropathy (TBMN) patients with additional inflammatory diseases and IgA nephropathy (IgAN) have not been reported before. It was unclear that if the prognosis of these patients is better or worse than patients with IgAN and TBMN, or IgAN patients with normal glomerular basement membrane (GBM).
Methods: We first reported five TBMN patients with additional inflammatory diseases and IgAN: three were with rheumatoid arthritis, and two had Crohn's disease. Clinical and laboratory features were analyzed between this group (group 3), IgAN patients with normal GBM (group 1), and patients with TBMN and IgAN (group 2).
Results: Significant differences were observed in serum levels of IgG, IgA, and IgM between groups 1 and 3, p < 0.001, and between groups 2 and 3, p < 0.001. Glomerular filtration rate (GFR) in group 3 was significantly lower than that of groups 1 and 2, p < 0.01, respectively.
Conclusion: The prognosis of these patients is worse than patients with IgAN and TBMN or IgAN patients with normal GBM. Serum immunoglobulin levels and GFR in these patients were different from patients with IgAN and TBMN, or IgAN patients with normal GBM.