EFFECTS OF RENAL-FAILURE ON COMPLEMENT C3D LEVELS

Elevated plasma concentrations of complement split product C3d have been reported to represent activation of the complement system. In the present study the effect of renal function on C3d concentrations was investigated in patients with various degrees of renal impairment, in patients with chronic renal failure and in CAPD patients. It appeared that elevated plasma C3d concentrations were present in patients with plasma creatinine concentrations in excess of 200-mu-mol/l regardless of the type of kidney disease. It is very likely that this can be attributed to renal handling (i.e. glomerular filtration, tubular reabsorption and renal catabolism) of C3d in a similar way as has been demonstrated for other low molecular weight proteins. The peritoneal permeability to C3d was slightly less than could be expected on the basis of its molecular weight without evidence of local production of C3d. Renal function should be taken into account in the interpretation of elevated plasma concentrations of C3d.