Serodiagnostic tests for leprosy.

All of the specific serodiagnostic tests developed by now only are able to detect advanced stages of the disease. None of these tests can efficiently diagnose leprosy at a ver, early stage of the disease including TT/BT cases. However, 35 kD based SACT and/or PGL-1 (ND-O/NT-P) based ELISA could be applied for confirmation in doubtful situations wherein cardinal signs of leprosy are not fulfilled. In addition, both of these tests can also be applied for efficiently monitoring patients on chemotherapy.The reason for any of the specific tests not becoming useful for detection of early cases of leprosy might be due to the presence of insignificant level of antibody even below the background level of the population. It has been noted by us that majority of tuberculoid leprosy cases have a low level of antibody against the specific and wholeM.leprae antigens (unpublished data). Therefore, attempts have been made to look for the presence of local antibody in the lesions of leprosy patients. It is expected that these studies would lead to the understanding into the mechanism of antibody secretion in early stages of the disease and would help in development of a specific serological test for early leprosy.