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Comparison of Five Serologic Tests for Diagnosis of Acute Infections by Chlamydia pneumoniae

Comparison of Five Serologic Tests for Diagnosis of Acute Infections by Chlamydia pneumoniae,10.1128/CDLI.7.5.739-744.2000,Clinical and Vaccine Immuno

Comparison of Five Serologic Tests for Diagnosis of Acute Infections by Chlamydia pneumoniae   (Citations: 32)
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Serology is often used to diagnose acute infections by Chlamydia pneumoniae. In this study paired sera from patients with acute respiratory tract infection during an epidemic of C. pneumoniae infections were examined by five different antibody tests. These tests were the complement fixation (CF) test, the microimmunofluores- cence (MIF) test, a recombinant enzyme immunoassay (rEIA) (Medac) based on a recombinant lipopolysac- charide of chlamydia and measuring antibodies to a common chlamydial antigen, and two tests that utilize preparations of C. pneumoniae organisms, the SeroCp-EIA (Savyon) (with preserved lipopolysaccharide) and the LOY-EIA (Labsystems) (without this antigen). Both of the last two tests should measure specific antibodies to C. pneumoniae, although cross-reacting antibodies may also be detected by the SeroCp-EIA. Acute infection of C. pneumoniae was serologically confirmed in 44% of the cases by at least two different tests. Using an expanded "gold standard," i.e., the presence of significant reactions in at least two tests, the sensitivity of the CF test was 69%, that of the MIF test was 88%, that of the rEIA was 89%, that of the LOY-EIA was 96%, and that of the SeroCp-EIA was 92%. Specificity was high for all methods, but adjustments of diagnostic criteria were made to several of the tests. The basis for these adjustments and supportive data are presented. Infections of C. pneumoniae were detected in patients from 8 to 83 years of age. Two peaks in the incidence of such infections were observed: one among young teenagers and a second in adults 30 to 45 years of age, corre- sponding to parents of young teen-agers. The tests were equally sensitive in different age groups. Reinfections seemed to be rare. Serological diagnosis has been important to unravel the clin- ical manifestations of acute infections by Chlamydia pneu- moniae. Isolation of the organism or detection of its nucleic acid by PCR has extended the diagnostic arsenal. These meth- ods can provide early diagnosis, which might be helpful for accurate treatment. Serology based on analysis of paired sera will detect acute infection even after antibiotic treatment has been started and might be useful to discriminate between in- fections by C. pneumoniae and Chlamydia psittaci. The complement fixation (CF) test based on the common lipopolysaccharide (LPS) antigen of chlamydia has been used for many years to detect acute infections by C. psittaci. After C. pneumoniae was recognized and infection by this new agent could be confidently diagnosed by the microimmunofluores- cence (MIF) test, many cases previously detected by the CF test and thought to be cases of ornithosis were found to in fact be infections by C. pneumoniae (12, 18). Although the CF test can detect acute infections by C. pneumoniae, its sensitivity has been considered low for such infections, especially in reinfec- tion (13). The MIF test has been of paramount importance to detect acute infections by C. pneumoniae and to describe the prevalence of such infections. The performance of the test depends on several factors, including the antigen preparations used and the experience of the person reading the test. The test has been questioned for different reasons. Some have found it unspecific during acute infections due to cross-reactive antibodies (5, 17). Others have questioned its ability to dis- criminate acute infections, either by being nonreactive where other tests suggest infection (3, 7, 9) or by identifying cases which cannot be confirmed by other means or which seem unlikely for other reasons (10, 11, 14, 15). Serological tests in an enzyme-linked immunoassay (ELISA) format might over- come some of the potential problems with the MIF test. Three new tests have been evaluated in this study and com- pared to the MIF and CF tests for the serological diagnosis of acute infections by C. pneumoniae. One of the new tests is based on an acylated recombinant lipopolysaccharide from chlamydia (recombinant enzyme immunoassay (rEIA)) and has been previously evaluated using the same diagnostic crite- ria (19). The other tests utilize preparations of C. pneumoniae organisms with (SeroCp-EIA) or without (LOY-EIA) LPS. MATERIALS AND METHODS Patients. During an epidemic of infections by C. pneumoniae, 261 consecutive patients with cases of acute respiratory tract infection were chosen for the study. Patients were eligible if paired sera were available and the symptoms indicated respiratory tract infection. Most patients were treated as outpatients. Twenty- one cases were excluded from the final assessment, as all tests could not be performed due to lack of serum. Therefore, 240 cases were finally studied. The study group consisted of 103 males and 137 females. The median age for the males was 31 years, with a range of 1 to 90 years, and that of the females was 40 years, with a range of 6 to 75 years. The sera were collected from late 1994 to the first months of 1996. Initially, the CF and MIF tests were used to detect cases of acute infection. Later the sera were also examined by rEIA, LOY-EIA, and SeroCp-EIA. CF test. The CF test was performed by standard procedures. The chlamydial antigen for this test was obtained from the State Serum Institute (Copenhagen, Denmark). A fourfold titer rise or a titer of 64 or higher was considered diag- nostically significant. MIF test. The MIF test was performed by previously described methods (4, 23). Slides with antigens of Chlamydia trachomatis, C. psittaci, and C. pneumoniae were obtained from Labsystems OY (Helsinki, Finland). In this test the C. pneumoniae and C. trachomatis antigens have been treated to remove the LPS antigen, which is, however, retained in the C. psittaci antigen. Chlamydial im- munoglobulin G (IgG), IgA, and IgM antibodies were determined. All IgM reactions were confirmed after the IgG antibodies had been removed with RF
Journal: Clinical and Vaccine Immunology - CLIN VACCINE IMMUNOL , vol. 7, no. 5, pp. 739-744, 2000
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    • ...Correspondingly, a Chlamydia pneumoniae etiology was diagnosed in seven patients, in all cases by EIA and confirmed in three cases by microimmunofluorescence (MIF) [26, 27]...

    Massimiliano Donet al. Hyponatremia in pediatric community-acquired pneumonia

    • ...In the present study, we evaluated the MySet test for the accuracy of diagnosis of C. pneumoniae infection and compared it with the results obtained with conventional serological tests, the AniLab C. pneumoniae enzyme immunoassay (EIA; Ani Labsystems [AniLab] Ltd., Oy, Vantaa, Finland) (10) and a microimmunofluorescence (MIF) test, which is the current “gold standard” for serological testing for C. pneumoniae infections worldwide (2, 4)...
    • ...The test also contains an integrated control system, and a red control line indicates the proper functioning of the test (Fig. 1). The antigen used is same as that used in the AniLab EIA (10) and comprises elementary bodies (EBs) of a European isolate of C. pneumoniae...
    • ...The results for IgA and IgG are expressed as enzyme immunounits (EIU), which are calculated as follows: [(Asample Ablank)/(Acalibrator Ablank)] n, where A is the absorbance and n is the number of samples (10)...
    • ...by on February 1, 2010 cvi.asm.org Downloaded from ratio of more than 1.1 are considered positive (10)...
    • ...Several studies have demonstrated good agreement between the rEIA and the MIF test for the serodiagnosis of acute C. pneumoniae infection (10)...

    Naoyuki Miyashitaet al. Rapid and Simple Diagnosis of Chlamydophila pneumoniae Pneumonia by an...

    • ...The performance of ELISA assays for anti-Cpn antibodies have been compared relative to the results of the MIF test, considered the standard method for the diagnosis of Cpn infections [25,28-30]...

    Olfa Frikha-Gargouriet al. Evaluation and optimization of a commercial enzyme linked immunosorben...

    • ...Especially in the older age group, the IgA EIA test overestimated the prevalence (62% versus 26%) and the persistence (63% versus 17%) of IgA antibodies compared to the in-house MIF (Table 1). The sensitivities of EIAs and enzyme-linked immunosorbent assays are higher than the sensitivity of MIF in acute-phase sera, and high C. pneumoniae-specific IgG titers are common in healthy individuals (18, 32, 36)...

    Mika Paldaniuset al. Prevalence and Persistence of Chlamydia pneumoniae Antibodies in Healt...

    • ...There is still discussion concerning the diagnostic “gold standard” of C. pneumoniae infection, and the choice of diagnostic tests is of utmost importance when evaluating a possible relationship between C. pneumoniae and a particular disease (7, 12)...

    T. Tenenbaumet al. Acute Hemorrhagic Pericarditis in a Child with Pneumonia Due to Chlamy...

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