Chlamydial serology in genital infections: ImmunoComb versus Ipazyme

Detection of Antibodies to Chlamydia trachomatis With Peptide-Based Species-Specific Enzyme Immunoassay

OBJECTIVE

We have evaluated the sensitivity and specificity of a new synthetic peptide-based species-specific enzyme immunoassay (EIA) for detection of Chlamydia trachomatis IgG and IgA antibodies.

METHODS

Synthetic peptides derived from variable domain IV of major outer membrane protein (MOMP) were used as antigen in indirect EIA. IgG and IgA antibodies were measured in parallel with serum samples from C. trachomatis culture positive, culture negative, and antigen positive patients, and women with suspected C. trachomatis infection and blood donors. Sera from children under 15 years of age were used as controls.

RESULTS

Culture positive women, culture positive men, and antigen positive women had positive peptide serology in 84.2%, 61.3%, and 93.1% of the cases, respectively. Among C. trachomatis suspected women, the antibody prevalence was 63.6%. Randomly collected blood donors showed a prevalence of 21.5%. Children with C. pneumoniae antibodies determined with the microimmuno-fluorescence (MIF) method did not show any reactivity in the C. trachomatis peptide EIA.

CONCLUSIONS

The results suggest that the new EIA test is highly specific for C. trachomatis, and C. pneumoniae antibodies do not interfere. Both IgG and IgA antibodies appear within at least 2 weeks in acute phase of infection among both culture positive and culture negative patients.

Can serology diagnose upper genital tract Chlamydia trachomatis infections? Studies on women with pelvic pain, with or without chlamydial plasmid DNA in endometrial biopsy tissue

BACKGROUND

Upper genital tract chlamydial infections in women are on the increase, and serology might be a convenient tool for diagnosis. Evaluations of this approach are needed in women with or without microbiologic evidence of organisms in the upper genital tract.

GOALS

To compare the results of antibody assays with cervical culture and upper genital tract histopathology in women with pelvic pain and chlamydial plasmid DNA in endometrial biopsies.

STUDY DESIGN

Chlamydia trachomatis plasmid DNA was detected by polymerase chain reaction (PCR) on extracted deparaffinized endometrial biopsy tissue. Five antichlamydial antibody assays were performed measuring total antibodies or immunoglobulin G (IgG), IgM, and IgA classes on sera from 14 women with plasmid DNA as well as 31 without plasmid DNA.

RESULTS

Accepting the presence of plasmid DNA as the gold standard, no single test had total diagnostic accuracy. The best sensitivity and specificity occurred with the following assays: whole inclusion fluorescence (WIF) (100% and 80.6%); microimmunofluorescence IgM (MIF IgM) (78.6% and 93.6%); and heatshock protein-60 enzyme immunoassay (42.9% and 100%). Although recombinant anti-lipopolysaccharide enzyme-linked immunosorbent assays measured anti-chlamydial antibodies in a large proportion of these women, specificity was low. The sensitivity and specificity of cervical culture was 28.6% and 100% and of endometrial histopathology was 71.4% and 48.4%. Analysis of patient serological profiles suggested that and 6 women without plasmid DNA may have been cases that were missed by PCR.

CONCLUSIONS

Evaluations of assays to diagnosis Chlamydia trachomatis upper genital tract infections could use the presence of organisms or their markers in the upper genital tract as a standard of comparison. Some of these serological assays, such as WIF or MIF IgM, may be helpful in diagnosis, but more studies are needed.

Chlamydia trachomatis species specific serology: ImmunoComb Chlamydia bivalent versus microimmunofluorescence (MIF)

The ImmunoComb Chlamydia Bivalent IgG/IgA (Orgenics, Israel) is a new quantitative serologic test that employs LPS extracted Chlamydia trachomatis L2 and LPS extracted Chlamydia pneumoniae elementary bodies on two separate antigenic spots. The Bivalent C. trachomatis specific test results were compared with microimmunofluorescence (MIF), the gold standard of chlamydial species specific serology. For C. trachomatis IgG the Bivalent was highly concordant with the MIF: the rate of positive titres (IgG > or = 1:8) was 10% vs. 11% in 100 blood donors, 18% vs. 16% in 111 obstetric patients (6% antigen prevalence), 26% vs. 22% in sterile women with open (n = 54) and 86% vs. 84% with occluded (n = 51) tubes, and 88% vs. 85% in 103 women with C. trachomatis positive cervical smears. Surprisingly, the Bivalent differed considerably from the MIF in IgA prevalence: in obstetric patients (8% vs. 4%), sterile women with open (13% vs. 6%) and occluded (71% vs. 20%) tubes, and women with positive cervical smears (78% vs. 24%). Bivalent IgA appeared to be more sensitive than MIF IgA and showed a stronger correlation with positive cervical smears in obstetric patients (sensitivity 67% vs. 0%, specificity 95% vs. 96%, positive prediction 44% vs. 0%, negative prediction 98% vs. 94%) and with tubal occlusion in sterile women (sensitivity 71% vs. 20%, specificity 87% vs. 94%, positive prediction 84% vs. 77%, negative prediction 76% vs. 55%). MIF IgM was of little diagnostic help. Supplemental to the often difficult C. trachomatis antigen detection, the easily performed Bivalent IgG/IgA appears to be of great value in routine diagnosis of genital chlamydial infections.