Persistence of Australia antigen in leprosy--a frustrating puzzle in immunology.

This paper deals with the relationship of Australia antigen (Au) to various sub-groups of leprosy, in a total of 200 cases. Au was found to be present up to 4% in lepromatous leprosy, 2% in tuberculoid leprosy and lepra reaction, and 3% of antibody in lepromatous leprosy. Presence of antibody denotes past antigenemia. The quantitation of the antigen is done using the new technique of Electro-immuno-diffusion (EID) of Laurell, synonymous with rocket technique. The persistence of the antigen is explained in the light of deranged immunological mechanisms.