Complement determinations in the synovial fluid and serum of a patient with Erythema nodosum leprosum.

Simultaneous serum and synovial fluid CH50, C1, C4, C2, C1 esterase inhibitor and C3 protein were determined in a patient with acute erythema nodosum leprosum. The pattern of synovial fluid complement activity coupled with the demonstration of multiple lepra bacilli free and within histiocytes is more consistent with an infectious than an immune complex induced synovitis.