Intracytoplasmic vacuoles in cervical smears: relationship to chlamydial inclusions--morphology, mucin histochemistry, and immunocytochemistry

Monoclonal antibodies against lipopolysaccharide of Chlamydia trachomatis with cross reactivity to human ApoB

Splenocytes obtained from mice immunized with whole purified elementary bodies of Chlamydia trachomatis were used for hybridoma construction. The resulting clones were screened with ELISA using chlamydial lipopolysaccharide (LPS) and full-length human apolipoprotein B (ApoB). One analyzed clone producing IgG1 (MAb 7B5) showed simultaneous recognition of chlamydial LPS and human ApoB, suggesting the presence of common antigenic epitopes in their structures. MAb 7B5 exhibited agreeable activity in immunoblot analysis conducted using chlamydial extracts or full-length human ApoB as well as in immunofluorescence (IF) detecting typical inclusion bodies of C. trachomatis and C. pneumoniae in the infected eukaryotic host cells. The removal of LPS from chlamydial suspensions with lauroyl sarcosyl led to a complete disappearance of IF associated with the elementary bodies of C. trachomatis. Therefore, immunologic response to chlamydial antigen may be associated with the generation of ApoB-specific antibody. Molecular mimicry and subsequent formation of cross-reactive antibodies might be an essential mechanism explaining the appearance of circulating auto-antibodies against low density lipoproteins (LDL) in patients with atherosclerosis. Moreover, newly generated MAb 7B5 can be a useful tool in the laboratory diagnosis of chlamydial infections.

Reliability of cytology to detect chlamydial infection in asymptomatic women

Chlamydia trachomatis is a frequent sexually transmitted disease. The diagnosis of C. trachomatis infection by cytology is controversial. We compared the ability of Papanicolaou (Pap) smears to detect C. trachomatis infection with antigen detection (enzyme immunoassay; EIA) and polymerase chain reaction (PCR). One hundred sixty-seven women attending a therapeutic abortion clinic were enrolled in the study. Endocervical samples were first collected for EIA and PCR, and then Pap smears were prepared for cytologic evaluation. Eight patients were excluded from the study due to the lack of an endocervical component. The criteria established by Gupta and associates (Diagn Cytopathol 1988;4:224-229; Acta Cytol 1979;23:315-320) were used in this study to assess the specificity and sensitivity of the Pap smear in recognizing C. trachomatis infection. After EIA testing, the remaining sample was subjected to phenol-chloroform extraction to purify the DNA and then tested by PCR. Positive PCR samples were subjected to repeat phenol-chloroform and retested to confirm the positive result. Using a confirmed PCR or a blocked EIA as the extended gold standard, the incidence of C. trachomatis infection was 9.4%. Fifteen of the 159 cases reviewed were positive by extended gold standard. Thirteen (86.7%) of those 15 cases were interpreted as negative by cytology (false-negatives), and two (13.3%) cases were positive. Of the remaining 144 cases, 14 cases (9.7%) were interpreted as positive by cytology (false-positives) but were not confirmed by the extended gold standard. Ten (66.7%) of the 15 cases confirmed by the extended gold standard were interpreted as negative by EIA (false-negatives), and five (33.3%) were positive. There were no false-positives by EIA. In this study, the sensitivity and the specificity for cytology were 13.3% and 90.3%, respectively. The positive predictive value was 12.5%, and the negative predictive value for cytology was 90.9%. The sensitivity and the specificity for EIA were 33.3% and 100%, respectively. The positive predictive value was 100%, and the negative predictive value for EIA was 93.5%. Both EIA and cytology are insensitive methods compared with PCR. Based on these data, cytology should not be used to diagnose C. trachomatis infection in an asymptomatic female population with a moderate risk of C. trachomatis infection.

Cervicovaginal cytology and the diagnosis of Chlamydia trachomatis: a comparison with immunofluorescent results

To evaluate the accuracy of a Chlamydia diagnosis in our laboratory, cytologic Chlamydia diagnoses for the years 1990 and 1991 were compared with immunofluorescent studies for Chlamydia for the same period. Only one of 22 cases diagnosed cytologically as suggestive of Chlamydia had a positive immunofluorescent result. On rescreen of 110 cervicovaginal smears taken within 1 mo of a positive fluorescent antibody test, 11 cases were found to contain criteria suggestive of Chlamydia. These correlations represent a 4.5% specificity and 10% sensitivity rate, suggesting that our current efforts in cytology are not effective in determining the presence of Chlamydia.