Serology of leprosy. I. Indirect hemagglutination test with stabilized sensitized red cells

An indirect hemagglutination (IHA) test has been described for the qualitative and quantitative detection of antibodies specific to Mycobacterium leprae. Aldehyde stabilized red cells were sensitized with a sonicate antigen prepared from M. leprae purified from armadillo liver. These cells were titrated against sera from patients with different types of leprosy, their healthy household contacts and patients with tuberculosis. Specific antibodies were demonstrated in leprous sera by IHA test after absorption of sera with M. tuberculosis and M. vaccae. All advanced forms of leprosy (LL and BL) and a variable number of other forms of leprosy (BB, BT and TT) showed a positive result with an IHA titre of 1 in 32 or above. None of the household contact sera nor sera from tuberculosis patients showed a positive IHA test. The application of the simple hemagglutination test in the immunoepidemiology of leprosy is discussed.