Serum Complement Component Levels in

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, despit