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Chlamydia trachomatis species specific serology: ImmunoComb Chlamydia bivalent versus microimmunofluorescence (MIF)
A Clad1, H Freidank, J Plünnecke
1Universitäts-Frauenklinik, Freiburg, Germany.
Insights
The ImmunoComb Bivalent IgG/IgA test shows high agreement with the gold standard for Chlamydia trachomatis IgG detection. This new serologic test offers valuable insights for diagnosing genital chlamydial infections.
Area of Science:
- Medical Diagnostics
- Immunology
- Microbiology
Background:
- Chlamydia trachomatis infections are a significant public health concern, often diagnosed through antigen detection or serologic methods.
- Current serologic methods, like microimmunofluorescence (MIF), serve as the gold standard but can be complex.
- There is a need for accessible and reliable serologic tests for diagnosing genital chlamydial infections.
Purpose of the Study:
- To evaluate the ImmunoComb Chlamydia Bivalent IgG/IgA test as a quantitative serologic diagnostic tool.
- To compare the performance of the Bivalent test against the microimmunofluorescence (MIF) assay for Chlamydia trachomatis IgG and IgA detection.
- To assess the clinical utility of the Bivalent test in various patient populations, including blood donors, obstetric patients, and women with positive cervical smears.
Main Methods:
- The ImmunoComb Chlamydia Bivalent IgG/IgA test utilizes extracted LPS from Chlamydia trachomatis L2 and Chlamydia pneumoniae.
- Test results were quantitatively compared with the established microimmunofluorescence (MIF) method.
- The study involved diverse cohorts: blood donors, obstetric patients, sterile women with open/occluded tubes, and women with positive cervical smears.
Main Results:
- The Bivalent test demonstrated high concordance with MIF for Chlamydia trachomatis IgG detection across all studied groups.
- A significant difference was observed in IgA prevalence between the Bivalent test and MIF, with Bivalent IgA appearing more sensitive.
- Bivalent IgA showed a stronger correlation with positive cervical smears and tubal occlusion compared to MIF IgA.
Conclusions:
- The ImmunoComb Bivalent IgG/IgA test is a valuable tool for routine diagnosis of genital chlamydial infections.
- Its ease of performance complements antigen detection methods, especially when antigen detection is challenging.
- The Bivalent test offers a promising alternative or adjunctive method for Chlamydia trachomatis serology.
Abstract:
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.