Compartmental localization of complement component transcripts in the normal human kidney

Local synthesis of complement components may play a crucial role in the pathogenesis of renal disease. Previous reports have shown that a number of complement components are produced by renal tissue both in vitro and in disease states. In the present study, we focused on the topographical distribution of components of the alternative and classical activation pathways in normal human kidney. As a whole, the normal renal cortex has the capacity to express the genes corresponding to most components of both complement pathways. There appears to be relatively high expression of transcripts for factor D and properdin in glomeruli, whilst factor B expression is greater within the medulla. Components C2, C3, and C4 and factor H are expressed predominantly in cortical tubule-rich fractions, and C1q is similarly expressed in all fractions. These results suggest that there may be differing emphasis on the alternative and classical pathways of complement activation in different regions within normal kidney.