We treated a female patient suffering from immunoglobulin A (IgA) nephropathy and congenital deficiency of the ninth component of the complement system (C9). She was admitted with hematuria and proteinuria, and the C9 deficiency was diagnosed based on the low hemolytic activity of 50 % of the hemolytic unit of the complements (CH50) and the normal C3 level in the plasma. Renal biopsy revealed m...

C3 glomerulopathy is a recently described form of CKD. C3GN is a subtype of C3 glomerulopathy characterized by predominant C3 deposits in the glomeruli and is commonly the result of acquired or genetic abnormalities in the alternative pathway (AP) of the complement system. We identified and characterized the first mutation of the C3 gene (p. I734T) in two related individuals diagnosed with C3GN...

Decay-accelerating factor (DAF) and complement receptor 1-related gene/protein y (Crry) are two membrane-anchored complement regulatory proteins in rodent. Although both proteins are broadly distributed and exert complement regulation at the same steps of the complement cascade, DAF knockout mice are viable whereas Crry knockout mice die in utero as a result of maternal complement attack. The l...

BACKGROUND C5 blockade by eculizumab prevents complement-mediated intravascular hemolysis in paroxysmal nocturnal hemoglobinuria (PNH). However, C3-bound PNH red blood cells (RBCs), arising in almost all treated patients, may undergo extravascular hemolysis reducing clinical benefits. Despite the uniform deficiency of CD55 and of CD59, there are always two distinct populations of PNH RBCs, with...

Complement activation and tissue deposition of complement fragments occur during disease progression in lupus nephritis. Genetic deficiency of some complement components (e.g., Factor B) and infusion of complement inhibitors (e.g., Crry, anti-C5 Ab) protect against inflammatory renal disease. Paradoxically, genetic deficiencies of early components of the classical complement pathway (e.g., C1q,...

Antibody to the polysaccharide capsule of type III group B streptococci (GBS) and complement are essential to host defense against systemic infection in neonates. Interactions between C3 degradation products and specific neutrophil receptors mediate the attachment and ingestion of these organisms. To evaluate the influence of capsule on C3 disposition, we compared the C3 fragments released from...