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A seroepidemiologic study of Chlamydia pneumoniae in Rhode Island. Evidence of serologic cross-reactivity
D G Kern1, M A Neill, J Schachter
1Division of General Internal Medicine, Memorial Hospital, Providence, RI 01860.
Objective:
Although Chlamydia pneumoniae is considered a common cause of pneumonia worldwide, the evidence is mainly serologic. Therefore, we examined whether the currently used chlamydial microimmunofluorescence (MIF) antibody test is specific for C pneumoniae infection.
Design And Setting:
Secondary analysis of data from a cohort study of sarcoidosis among the graduates of ten consecutive apprenticeship classes of firefighters and police officers.
Participants:
One hundred forty-seven young adult men.
Measurements:
Immunoglobulin G and M antibodies to C pneumoniae, 15 serovars of C trachomatis, and 2 strains of C psittaci as measured by MIF.
Results:
Evidence of previous C pneumoniae and C trachomatis infection (IgG > or = 1:16 yet < 1:512) was present in 108 (73 percent) and 59 (40 percent) subjects, respectively. Serologic evidence of recent C pneumoniae and C trachomatis infection (IgM > or = 1:16 or IgG > or = 1:512) was present in 19 (13 percent) and 14 (10 percent) subjects, respectively. Chlamydia pneumoniae and C trachomatis IgM titers were highly correlated (r = 0.80; 95 percent CI, 0.73 to 0.85) while C pneumoniae and C trachomatis IgG titers were fairly correlated (r = 0.44; 95 percent CI, 0.30 to 0.56).
Conclusions:
The C pneumoniae seroprevalence of 86 percent is the highest yet reported. The correlations between C pneumoniae and C trachomatis antibody titers suggest that chlamydial MIF may be less specific than is generally appreciated. Moreover, the observed 13 percent seroprevalence of recent C pneumoniae infection in a healthy working population challenges the serologically based belief that this agent accounts for 6 to 10 percent of community-acquired pneumonia. A more objective, more specific test is needed in the serodiagnosis of C pneumoniae infection.
Insights
The microimmunofluorescence (MIF) antibody test for Chlamydia pneumoniae may not be specific, as antibody titers correlated with Chlamydia trachomatis. Further research is needed for accurate C. pneumoniae infection diagnosis.
Area of Science:
- Infectious Diseases
- Immunology
- Microbiology
Background:
- Chlamydia pneumoniae is a common cause of pneumonia globally, with diagnosis primarily relying on serological evidence.
- The specificity of current serological tests for C. pneumoniae infection has been questioned due to cross-reactivity with other Chlamydia species.
Purpose of the Study:
- To evaluate the specificity of the microimmunofluorescence (MIF) antibody test for diagnosing Chlamydia pneumoniae infection.
- To investigate the correlation between antibody titers for C. pneumoniae and other Chlamydia species.
Main Methods:
- A secondary analysis of data from a cohort study involving 147 young adult men.
- Measurement of Immunoglobulin G (IgG) and M (IgM) antibodies against C. pneumoniae, 15 serovars of C. trachomatis, and 2 strains of C. psittaci using the MIF test.
Main Results:
- High seroprevalence was observed for C. pneumoniae (86%) and C. trachomatis (73%) infections.
- Significant correlations were found between IgM titers for C. pneumoniae and C. trachomatis (r=0.80), and moderate correlations for IgG titers (r=0.44).
- A 13% seroprevalence of recent C. pneumoniae infection was noted in a healthy working population.
Conclusions:
- The high correlation between C. pneumoniae and C. trachomatis antibody titers suggests that the MIF test may lack specificity.
- The findings challenge the established understanding of C. pneumoniae's role in community-acquired pneumonia based on serological data.
- There is a need for more objective and specific diagnostic tests for C. pneumoniae infections.