[Antibodies against Chlamydia trachomatis in patients with non-gonococcal urethritis and in the healthy Italian population]

The Authors report the results of a study on the prevalence of serum antibodies against Chlamydia trachomatis among patients with non-gonococcal urethritis caused by Chlamydia trachomatis and diagnosed on the basis of the isolation of the microorganism in cell cultures, among patients with non-gonococcal urethritis of unknown etiology and in groups of healthy population, in Italy. The search for antibodies was performed both with complement-fixation tests in micro-titer system, using an antigen prepared from chicken embryo yolk sacs infected with the 6BC strain of Chlamydia psittaci, and with indirect immunofluorescence tests. The indirect immunofluorescence tests were carried out using as antigen the whole chlamydial inclusion developed in IUDR pre-treated McCoy cell cultures, grown on coverslips, and infected with the BU/434 strain of the LGV2 immunotype of Chlamydia trachomatis. The immunofluorescence tests proved to be much more sensitive than the complement fixation tests in detecting the presence of anti-chlamydial antibody both in patients with non-gonococcal urethritis and in the healthy population groups. The percentage of subjects possessing anti-chlamydial antibodies among the healthy population suggests a diffuse circulation of Chlamydia trachomatis infection. The possibility of employing the serological data in the diagnosis of the etiology of non-gonococcal urethritis is briefly discussed.