The species specificity of the microimmunofluorescence antibody test and comparisons with a time resolved fluoroscopic immunoassay for measuring IgG antibodies against Chlamydia pneumoniae.

A significant difference in seroprevalence between patients and healthy subjects was observed with the LS EIA, while seropositivities in the two study groups appeared equal when the Focus MIF assay was applied. The MC rELISA and MCp sELISA gave statistically significant differences in antibody seroprevalence in patients with two-vessel disease or when the patient group combined individuals with a two-or a three-vessel disease, respectively. The concordance between MIF and other commonly used serological assays for C. pneumoniae IgG antibody detection is good to fair. The choice of serological assay has important implications for C. pneumoniae antibody seroprevalence, as well as for the relationship between C. pneumoniae seropositivity and coronary artery disease.

mentioning

confidence: 99%

Importance of Methodology in Determination of Chlamydia pneumoniae Seropositivity in Healthy Subjects and in Patients with Coronary Atherosclerosis

Hoymans¹,

Bosmans²,

Renterghem³

et al. 2003

“…The microimmunofluorescent (MIF) test is still considered the serologic "gold standard." Although it is claimed to be species specific, cross-reactions between chlamydial species have been reported (37,38). Recently, several enzyme-linked immunosorbent assays (ELISAs) have been commercially developed with Chlamydia recombinant antigens, some of them known to be C. trachomatis specific.…”

mentioning

confidence: 99%

Chlamydial Serology: Comparative Diagnostic Value of Immunoblotting, Microimmunofluorescence Test, and Immunoassays Using Different Recombinant Proteins as Antigens

Bas

Muzzin²,

Ninet

et al. 2001

To improve the reliability of the serodiagnosis of Chlamydia trachomatis infections, an immunoblot analysis, a microimmunofluorescence titration, and different immunoassays using synthetic peptides derived from species-specific epitopes in variable domain IV of the major outer membrane protein or recombinant antigens (heat shock protein 70 [hsp70], hsp60, hsp10, polypeptide encoded by open reading frame 3 of the plasmid [pgp3], macrophage infectivity potentiator, and a fragment of the total lipopolysaccharide) were evaluated. Because cross-reactions between chlamydial species have been reported, the microimmunofluorescence tests were also performed with Chlamydia pneumoniae and Chlamydia psittaci used as antigens, and C. pneumoniaespecific antibodies were also determined by immunoassays. Since the presence of antimicrobial antibodies must be interpreted in light of their prevalence in the general population, responses obtained with serum samples from patients with well-defined infection (i.e., with positive urethral or endocervical C. trachomatis DNA amplification) were compared to those obtained with samples from healthy blood donors. The best sensitivity (86%) with a specificity of 81% was obtained for immunoblotting results, when the number of individuals with >10 immunoglobulin G (IgG) and/or >2 IgM responses to the different C. trachomatis antigens was considered. A 13-kDa antigen was recognized by most of the samples (86% for IgG) from patients with acute urogenital infection but rarely (3%) by those from healthy blood donors (P < 0.0001). The sensitivity and specificity results obtained for serum antibodies to peptides or recombinant antigens were slightly lower than those results obtained for the number of responses to whole C. trachomatis antigens, which were 76 and 77%, respectively, when IgG responses to both recombinant hsp60 and pgp3 were considered.

“…Several studies have already reported that MIF specificity is lower than that generally thought (2)(3)(4)(6)(7)(8)(9). Because MIF tests are detecting anti-bodies against surface protein antigens and because the protein composition of the C. pneumoniae outer membrane complex is similar to those described for C. trachomatis and C. psittaci (5), the detection of cross-reacting antibodies is not surprising.…”

Section: Labsystems Enzyme Immunoassay For Chlamydia Pneumoniae Also mentioning

confidence: 90%

Labsystems Enzyme Immunoassay for Chlamydia pneumoniae Also Detects Chlamydia psittaci Infections

Strålin¹,

Fredlund

Olcén

2001

In a recent article, Bas and collaborators compared different serological methods to detect chlamydial antibodies in patients with Chlamydia trachomatis infections and healthy blood donors (1). Using the Labsystems enzyme immunoassay (EIA) for C. pneumoniae, no cross-reaction between C. trachomatis and C. pneumoniae was found. However, Gnarpe and collaborators recently showed cross-reactions between C. trachomatis and C. pneumoniae, when the Labsystems EIA for C. pneumoniae was used on sera containing high titers of C. trachomatis antibodies documented by the microimmunofluorescence (MIF) test (2). A broader cross-reactivity between the different chlamydial species was suspected. The Labsystems EIA test has previously been shown to have high sensitivity and specificity in the diagnosis of acute infections caused by C. pneumoniae during an epidemic of C. pneumoniae (3).To examine the Labsystems EIA test for C. pneumoniae more extensively, we tested it on paired sera, taken from 43 patients for etiological diagnosis of pneumonia. The immunoglobulin G (IgG) and IgM antibody results for C. pneumoniae, C. psittaci, and C. trachomatis had previously been documented by the MIF tests, and IgG and IgM antibodies were now determined by the Labsystems EIA for C. pneumoniae. Of seven patients who were positive by the MIF test for C. pneumoniae, only three were positive by the EIA for C. pneumoniae, while five out of five patients who were positive by the MIF test for C. psittaci were positive by the EIA for C. pneumoniae. One patient with positive MIF test results for both C. pneumoniae and C. psittaci also tested positive for C. pneumoniae by the EIA. Sera from the remaining 30 patients, who showed no significant IgG or IgM antibody changes with the MIF test, also produced negative results with the EIA.Because infections caused by C. pneumoniae and C. psittaci have important epidemiological differences, it is important to make a correct etiological diagnosis. The study of Gnarpe and collaborators and the present study indicate that cross-reactions between the chlamydial species occur when the Labsystems EIA for C. pneumoniae is used. The EIA could be used for the purpose of screening for chlamydial infections, but in nonepidemic situations we suggest that a method that differentiates between the chlamydial species, such as the MIF test, should be used directly (or, alternatively, as a second step after a screen with the EIA).