742 IMPLICATIONS CONCERNING THE COMPLEMENT SYSTEM IN A PATIENT WITH GLOMERULONEPHRITIS AND IMMUNOCHEMICAL FINDINGS OF HEREDITARY ANGIONEUROTIC EDEMA

Abstract

An 11-year-old white female with focal glomerulonephritis was found to have an absence of functional Cl esterase inhibitor, 5% of normal levels of serum C2 and C4, as well as evidence of circulating, active C1 esterase. C1 esterase inhibitor measured by immunochemical means, however, was only reduced by 25%. Several family members had similar findings. Neither the patient nor her family had clinical signs of hereditary angioneurotic edema (HANE) despite continued and persistent complement consumption for at least 18 months. These data suggest that mechanisms controlled by C1 esterase inhibitor, other than those related to complement, might be responsible for the clinical features of HANE. In addition, evidence from immunofluorescent studies of the deposition of IgG and C3 on the kidney of this patient suggests the participation of an immune complex and terminal complement activity in the genesis of the glomerulonephritis. The prolonged and marked depression of C2 and C4, however, precludes any utilization of the classical pathway in that process. Further, it would appear that the hypocomplementemia antedated the onset of the nephritis and, therefore, may be a predisposing factor in the persistence of the immune complex and its presumed activity via the alternative pathway.

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