SERUM COMPLEMENT PROFILE IN HUMAN LEPROSY AND ITS COMPARISON WITH IMMUNE-COMPLEX DISEASES

Abstract

The serum levels of early, middle and distal complement [c] components, e.g., Clq, C3, C4, C5, C8 and C9, along with Cl-inactivator and CH50 [total hemolytic complement level] in patients with tuberculoid and lepromatous leprosy were estimated and compared with the levels in healthy subjects and patients with other immune complex diseases. The cryoglobulins present in the sera of these patients were also analyzed; they consisted of a single or mixed Ig[immunoglobulin]G, IgA, IgM or fibrinogen in most instances. C3 was found in only 1 sample. Unlike lupus nephritis in which C is activated by direct path in about 30-50% of leprosy patients, significant C3 consumption probably takes place primarily via the alternate pathway and is probably initiated by the aggregated Ig represented in cryoprecipitates. This is further supported by the study of serum factor B and its breakdown product (Ba) in these patients. The role of the middle and distal C components, such as C5, C8 and C9, during total hemolytic C and C3 consumption in leprosy is unknown.