Reactivity of a lecithin-free cardiolipin preparation (cardchol) in leprosy sera.

Previous experiments have shown that a mixture of cardiolipin and cholesterol in absolute ethanol (named "cardchol") might be used as an antigen in complement-fixation tests. The reactivity in the complement-fixation test of CWRM (an "ordinary" cardiolipin antigen) was compared with that of cardchol in several experiments, and it could be demonstrated that the reactivity of cardchol was especially pronounced in sera from false-positive reactors. In about 50% of such cases, quantitative determination of the antibody content showed that cardchol was more reactive than CWRM, whereas in syphilitic cases the reactivity of cardchol was inferior to that of CWRM. An exception was primary syphilis, which showed a reactivity level with cardchol equal to or even superior to that of CWRM.Examinations of a certain number of sera from leprosy patients had shown them to be highly reactive with cardchol and non-reactive or weakly reactive with CWRM; this observation is fully confirmed by examination of a larger number of leprosy sera, on which this paper reports. These sera were examined with a battery of tests using lipoidal antigens and with the TPI test. Testing with cardchol proved to give the highest reactivity with these sera, which were mostly non-treponemal.Subdivision of the material according to the clinical stage of leprosy showed that the highest reactivity of cardchol occurred in patients with lepromatous leprosy, particularly in those with leprosy of relatively short duration.Electrophoretic fractionation of these sera demonstrated that the substances reacting with cardchol were situated in the gamma-globulin or gamma- and beta-globulin serum fractions.