Immunohistochemical analysis of the membrane attack complex (MAC) and the membrane cofactor protein (MCP) was performed on the tubuli and cortical vessels of 46 kidney biopsies with various types of human glomerulopathies. Irrespective of the type of glomerulopathy, significant correlations between tubular MAC and interstitial lymphomonocyte infiltration (p < 0.001) and interstitial volume (p < 0.02) were found. Tubular MCP was significantly overexpressed at the site of MAC deposition (p < 0.002). There was no correlation between the vascular MAC and MCP and tubulointerstitial lesions. Since tubular MAC is deposited in inflamed areas of tubulointerstitium, we propose that MAC might contribute to the development of tubulointerstitial inflammatory processes in human glomerulopathies. MCP as a regulatory factor in the tubulointerstitium might abrogate further tissue damage and cell-stimulatory effects of the MAC.