Specific serum IgA antibodies in the diagnosis of Chlamydia trachomatis infection

Abstract

Serologic diagnosis in pneumonia or pelvic inflammatory diseases by C. trachomatis was confirmed by demonstration of rising titer of specific serum IgM antibodies. The possiblity that the specific serum IgA antibodies might be a marker of active chlamydial infection had recently been suggested by Sarov. We discussed the usefulness of the serum specific IgA antibodies as a marker of active chlamydial infections.In monkeys inoculated with L2 strain of C. trachomatis, it was recognized that the specific serum IgA antibodies rised in primary infection and reinfection but the IgM antibodies did not appeared in secondary infection.Sera obtained from 17 men with C. trachomatis isolation-positive non-gonococcal urethritis (NGU) and 19 men with C. trachomatis isolation-negative NGU were studied for the presence of C. trachomatis specific IgG and IgA antibodies. The IgA positive-coincidence ratio was 94.1%(16/17) in isolation-positive NGU patients and the IgA negative-coincidence ratio was 78.9%(15/19) in the isolation-negative NGU patients.The specific srum IgA antibodies had been detected in three of four C. trachomatis antigen detected pneumonia infants and these four mothers had high level specific serum IgA and IgG antibodies.It is suggested from our studies that specific serum IgA antibodies may be used as a marker of active C. trachomatis infection.