Presence of C1q-reactive immune complexes in patients with leprosy.

Presence of soluble immune complexes was investigated in sera from persons with a well documented clinical diagnosis of leprosy. The complexes were detected by their reactivity with the C1q component of complement. More than 70% of the studied patients with lepromatous-leprosy had immune complexes demonstrable by this method (39/51), while only a small proportion of the healthy control group (1/35 or about 3%) had precipitable complexes. Two out of nine sera from patients with tuberculoid leprosy reacted when tested with C1q component. The presence of free-antibody to mycobacterial antigens was determined as well. The possible relationship between the presence of such immune complexes and the pathology of some reactional states of the disease is discussed.