A new microimmunofluorescence test for the detection of Chlamydia pneumoniae specific antibodies.

To evaluate a microimmunofluorescence (MIF) test (Chlamydia pneumoniae IgG, Vircell, Spain) that detects IgG against Chlamydophila pneumoniae (Cp), MRL Diagnostics MIF was used as reference test. Cross-reactivity against Chlamydia trachomatis (Ct) and Chlamydophila psittaci (Cps) was investigated. Eighty sera were analysed from 22 subjects with vascular disease, 38 with multiple sclerosis and 20 healthy individuals. Vircell and MRL MIF tests assessed 58.75% and 60% of the samples as positive, respectively, and their results coincided (positive/negative) in 98.75% of samples. One major (>1 IgG titre) and 32 minor (1 titre) discrepancies were observed. Correlation between tests was significant. Vircell MIF test demonstrated 97.9% sensitivity and 100% specificity. Differences in simultaneous reactivity to Ct and Cps between the tests were not significant. Vircell MIF test showed a good performance to detect the IgG against Cp.