Fluorescent treponemal antibody absorption (FTA-ABS) test in yaws.

The pathogenic treponemes, T. pertenue and T. pallidum, produce similar antibodies in the serum of a person infected with either organism. Thus sera from patients with yaws react similarly to sera from syphilitic patients in the conventional tests for syphilis and in the Treponema pallidum immobilization (TPI) test. The most recent test developed for the detection of syphilis is the fluorescent treponemal antibody absorption (FTA-ABS) test of Hunter, Deacon, and Meyer (1964). This was introduced as a simpler, less costly procedure than the TPI test, which could be performed in a non-specialized laboratory and was as specific as the TPI test for treponemal infection. The FTA-ABS test was a refinement of the less specific fluorescent treponemal antibody (FTA-200) test, which detects both group and specific antibodies in syphilitic sera. The non-pathogenic and the pathogenic treponemes all share common or group antigens which can cause the production of group antibody. Thus false reactive FTA-200 test results can be due to the presence in the serum of group antibody to non-pathogenic treponemes. The pathogenic treponemes have group and specific antigens, the specific antigens being shared by the pathogenic treponemes alone. In the FTA-ABS test, sorbent, an extract of the non-pathogenic Reiter treponeme, is used to remove group antibody from the serum and leave only specific antibody. This specific antibody is theoretically the one detected in the FTA-ABS test. The FTA-ABS test has been compared by various laboratories with the TPI test, an established specific test for syphilis, and has shown reasonable agreement (Johnston and Wilkinson, 1968; Garner, Grantham, Collins, and Roeder, 1968). The present study has been undertaken to compare the results of the FTA-ABS test with those of the TPI test in sera from persons living in areas where yaws is a common treponemal infection.