Platelet function in leprosy.

In a group of 50 leprosy patients, platelet function tests were found to be abnormal in 44. More than half the patients showed significant impairment in platelet adhesiveness and aggregation to collagen which correlated best with increase in serum IgM levels. ADP-induced aggregation of platelets was not a major defect and Pf-3 availability was reduced only in a fourth of the patients. In vitro incubation of collagen with plasma from leprosy patients significantly reduced its ability to clump normal platelets. This appears to be the first report of defective platelet function in leprosy, and it is thought that such changes may in part be due to increased IgM globulins in the blood and/or to alterations in the collagen brought about thereby.