The local production of complement in the pathogenesis of renal inflammation.

The deposition of complement components is a feature of many immune mediated human glomerular diseases. Experimental models provide evidence that complement activation within the glomerulus has a pathogenic role in immune complex and antibody mediated glomerulonephritis. It was thought that the complement components deposited within the kidney were derived from the systemic circulating pool. However, recent work has shown that the kidney is able to produce many of the components of the complement cascade. In vitro work has shown that cells of glomerular and tubular origin can produce complement, as can inflammatory cells present within the kidney during inflammation. Analysis of human biopsy material has shown that expression of complement genes is increased during inflammatory renal disease implicating local complement synthesis as a potential source of complement components. At present no direct evidence for a pathogenic role of local complement synthesis exists. In this review we consider the current experimental evidence which suggests that local production of complement may be contributing to renal injury in a variety of diseases.