The lack of standardization in chlamydia serology has made interpretation of published data difficult. This study was initiated to determine the extent of interlaboratory variation of microimmunofluorescence (MIF) test results for the serodiagnosis of Chlamydia pneumoniae infections. Identical panels of 22 sera were sent to 14 laboratories in eight countries for the determination of IgG and IgM antibodies by MIF. Although there was extensive variation in the numeric titer values, the overall percentage agreement with the reference standard titers from the University of Washington was 80%. For results by serodiagnostic category, the best agreement was for four-fold rise in IgG titers, while the lowest agreement was for negative or low IgG titers. Agreement for IgM titers was 50%-95%. Four laboratories failed to discern false-positive IgM titers possibly because of the presence of rheumatoid factor. Further studies are underway to determine the source of interlaboratory variation for the MIF test.

Thirty-six ruminant isolates of Chlamydia psittaci, previously classified as invasive or non-invasive in a mouse model of virulence, were compared by analysing A h 1 restriction patterns of the major outer-membrane protein (MOMP) gene after DNA amplification by the polymerase chain reaction. The 24 invasive isolates, although from various origins, all belonged to serotype 1 and represented a strictly homogeneous group sharing a specific MOMP-gene restriction'pattern that was not observed in the non-invasive strains. On the other hand, the 12 noninvasive strains, although all belonging to serotype 2, constituted a heterogeneous group with eight distinct MOMP-gene restriction patterns. However, all eight patterns shared a 180 bp fragment or the corresponding restricted fragments of 110 and 70 bp. MOMP-gene restriction patterns also clearly distinguished the ruminant strains from an avian C.psi#uciisolate, a Cpneumoniae isolate and two C. truchomatis isolates which were studied for comparison. The homogeneous character of the invasive C. psiffuci strains argues strongly for their genetic relatedness. Our results illustrate the usefulness of the MOMP-gene restriction mapping in typing chlamydiae.

Twenty one Chlamydia trachomatis reference strains and 40 clinical isolates belonging to the lymphogranuloma venerum (LGV) and trachoma biovars were genotyped by differential restriction mapping of the major-outer-membrane-protein gene (MOMP) obtained by the polymerase-chain reaction (PCR). AluI digestion of the PCR product distinguishes eight MOMP-genotypes corresponding to 8 serovars. Six additional enzymes (NlaIII, CfoI, EcoRI, HinfI, DdeI and FokI) further permit the discrimination of 10 MOMP-genotypes corresponding to the 10 remaining serovars of the species. AluI alone allows direct typing of 78% of the clinical isolates. AluI digestion patterns of mouse C. trachomatis biovar, a C. pneumoniae and two C. psittaci strains, studied for comparison, were clearly distinguishable from one another and from the C. trachomatis LGV and trachoma strains. These results indicate that MOMP genotyping by PCR is a valuable molecular tool for studying C. trachomatis epidemiology.

Case-control studies of cervical intra-epithelial neoplasia grade III (CIN III) and of invasive cervical cancer were carried out in Spain and Colombia to assess the relationship between cervical cancer and 6 common sexually transmitted agents (STAs). The CIN-III studies included 525 cases and 512 controls matched for age and for the place of recruitment; the invasive-cancer studies included 373 histologically confirmed cases of squamous-cell carcinoma and 387 age-stratified controls selected randomly from the populations that generated the cases. Antibodies to Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, herpes simplex virus type II (HSV-2) and cytomegalovirus (CMV) were tested in 88% of the women. Cervical scrapes were examined for HPV DNA in 63% of the women using a polymerase-chain-reaction assay (PCR). Among controls, the highest antibody prevalence was to CMV (96.5%), followed by HSV-2 (31.4%) and C. trachomatis (23.3%). For all STAs, the sero-prevalence was markedly higher in Colombia than in Spain both for cases and for controls. After adjustment for the presence of HPV DNA, C. trachomatis was the only STA associated with CIN III in both countries; Spain and Colombia. In both countries, the risk of CIN III increased with increasing of C. trachomatis antibody titers. Among Spanish women, an increase in risk of invasive carcinoma was found for those with antibodies to N. gonorrhoeae; those with antibodies to HSV-2 and those with antibodies to C. trachomatis. These associations were present only in HPV-DNA-negative women. Among HPV-DNA-positive women, none of the STAs considered were associated with cervical neoplasia. Our findings could be interpreted as indicating that past infections with HSV-2, N. gonorrhoeae and C. trachomatis are surrogate markers of HPV, but because HPV DNA may have escaped detection, we cannot exclude that these STAs are also of separate etiological significance.

Aims-To examine the species specificity of the microimmunofluorescence test (MIF) and assess a time resolved fluoroscopic immunoassay (TRIA) for measuring IgG antibodies to C pneumoniae. Methods-Sera from 1020 subjects were tested by MIF for IgG, IgM, and IgA antibodies to C pneumoniae, C trachomatis, and C psittaci; 501 serum samples were also tested by TRIA for IgG antibodies to C pneumoniae. Results-C pneumoniae antibody titres as measured by MIF were correlated with those for C psittaci and C trachomatis. It was estimated that on average, one third of the twofold dilution steps that make up the final C pneumoniae antibody titre may be due to cross reacting genus specific antibody. The results of TRIA correlated well with those of MIF. In 75% of cases, the TRIA result predicted a three titre range within which the actual MIF result would fall. Conclusions-MIF does not appear to be as species specific as claimed. TRIA is unlikely to be as specific but as it is completely objective, easier to perform, amenable to automation, and gives reproducible results, it is a rapid and useful method for comparing populations. (J Clin Pathol 1999;52:99-102)