Serum complement component levels in human glomerulonephritis.

Abstract

Serum total hemolytic complement (CH50) and complement components Clq, C4, and C3 were measured in patients with several forms of renal disease. The hypocomplementemia that accompanies active lupus nephritis was associated with low levels of all three components measured, whereas the hypocomplementemia associated with chronic membranoproliferative glomerulonephritis was usually related to depression of C3 protein only. Low serum hemolytic complement levels in acute poststreptococcal glomerulonephritis can be associated with depression of the early reacting components, Clq and C4 protein; however, isolated C3 depression also can be seen in this disease. Depression of Clq levels was frequently found in the nephrotic syndrome of childhood, despite normal levels of C4 protein and C3 protein. These results indicate that several disorders of the complement system exist in the diverse forms of renal disease that are associated with lowering of the serum level of one or more of the components of this system.