Immune Complex Glomerulonephritis in a Pregnant Woman with Congenital C9 Deficiency.

Abstract

A 27-year-old womandeveloped proteinuria, hypertension, and peripheral edema during the ninth monthof her first pregnancy. The clinical and serological features were compatible with a diagnosis of toxemia of pregnancy, except for the presence of hypocomplementemia. The patient had glomerulonephritis characterized by large electron-dense deposits, predominantly in the mesangium. Immunofluorescence studies revealed striking accumulations of Clq and C3, and the presence of small amounts of IgG and IgM in the mesangium. Serum and plasma levels of complement components were normal, except for the C9 component. Family studies demonstrated that the C9 deficiency was inherited. (Internal Medicine 32: 806-809, 1993)

Membranoproliferative pattern of glomerular injury associated with complement component 9 deficiency due to Arg95Stop mutation

“…Indeed, the percentage of C9D among patients with mesangial proliferation and duplication of GBM in this study was 5.1%, which is higher than the estimated frequencies of C9D in the general population in Japan (0.12%). In addition to the two cases in this study, previously reported adult C9D cases with IgAN also exhibited partial membranoproliferative lesions [4]. Some investigators suggested that complement deficiency predisposes the individual to chronic infections and subsequent immune complex formation, and impairs the solubilization, disaggregation and clearance of deposited immune complexes [16].…”

“…In contrast, several case reports have described patients with C9D and glomerulonephritis including IgAN [4][5][6][7]. Alexopoulos et al [10] showed no correlation among glomerular T cells, monocytes/macrophages and the deposition of C5b-9.…”

“…Among them, 696 patients underwent renal biopsy, and their diagnoses were as follows: IgAN (433), membranous nephropathy (81), nonIgAN (67), lupus nephritis (31), minimal-change disease (26), diabetic nephropathy (22), membranoproliferative glomerulonephritis (MPGN; 20), purpura nephritis (12) and nephrosclerosis (4). The ethics committee of each institute gave approval for the study.…”

“…There have been several reports of C9D in patients with glomerulonephritis [4][5][6][7]. These cases of glomerulonephritis include IgA nephropathy (IgAN), poststreptococcal glomerulonephritis and immune complex glomerulonephritis.…”