Membranoproliferative glomerulonephritis in a patient with X-linked agammaglobulinemia.

Immune complex and complement systems play an important role in membranoproliferative glomerulonephritis (MPGN). X-linked agammaglobulinemia (XLA) is a primary immunodeficiency characterized by severe hypogammaglobulinemia. We report the case of an XLA patient who developed MPGN during an intravenous immunoglobulin (IVIG) treatment. In this patient, the serum IgG level was maintained at more than 400 mg/dl of regular IVIG administration (2.5 g/dose/month). The patient presented with microscopic hematuria, proteinuria (U-pro/Cr: 4.0-4.2) and low serum complement levels (C3: 57.8 mg/dl) 3 years after IVIG treatment and was diagnosed histopathologically as having MPGN type III. Both hematuria and proteinuria significantly improved, and the serum complement level returned to a normal level following methylprednisolone pulse therapy. To our knowledge, this is the first case report of MPGN associated with XLA. Although it is unclear how MPGN occurred in this XLA patient, we suggest that residual humoral immunity in the patient could be associated with the development of MPGN.