Abstract

Antibody titres were measured in patients with clinical syphilis, and the effect of treatment on the results of the Treponema pallidum immune adherence (TPIA) test is reported. In the Treponema pallidum haemagglutination (TPHA) test little change in antibody titre occurred after treatment while in the fluorescent treponemal antibody-absorbed (FTA-ABS) test only a slight decrease occurred. The decrease in the antibody titre in the TPIA test was similar to that in the glass plate test, but the findings were different. From the results of gel filtration of sera obtained from patients with syphilis at different intervals after treatment it was apparent that the decrease in antibody titre after treatment mainly concerned the IgM antibody; thus, because of the high sensitivity of the TPIA test to IgM antibody the test is useful in evaluating the effect of treatment.