Further studies on seroreactivity in leprosy by means of a lecithin-free cardiolipin antigen (cardchol) and other antigens ordinarily used in the serodiagnosis of treponematoses.

In a previous study the reactivities of some lipoidal antigens in sera from patients with different types of leprosy were investigated. The present paper is a continuation of this earlier study and relates to an investigation of some 300 sera from leprosy patients in India. In particular, the reactivity of cardchol (a complement-fixing, lecithin-free, cardiolipin antigen) is compared with that of CWRM (an "ordinary" cardiolipin antigen used in routine complement-fixation tests for the serodiagnosis of treponematoses).Cardchol, which is inferior to CWRM in reactivity with treponemal sera, has proved to be more reactive than CWRM in leprosy sera. The use of a lecithin-free cardiolipin antigen in serological investigations has revealed that the antilipoidal antibodies occurring in leprosy are most probably different from those demonstrated in treponematoses. Among the sera of non-syphilitic lepers, the percentage reactivity was significantly higher with cardchol than with CWRM. Thus, by changing the relative proportions of the three components of cardiolipin antigen, it has been possible to produce antigens with reactivities quite different from those of the antigens ordinarily used for the serological demonstration of syphilis.Cardchol is by no means a specific antigen for the demonstration of leprosy, but it has the ability to fix antibodies in certain leprosy sera that are not fixed by the ordinary CWRM antigen.