The microimmunofluorescence test for Chlamydia pneumoniae infection: Technique and interpretation

A brief description of current procedures for the Chlamydia microimmunofluo rescence (MIF) test is presented. To date, use of MIF serology with Chlamyd ia pneumoniae (TWAR) antigen has provided the most sensitive and specific m ethod for diagnosis of acute TWAR infection. In primary infections, the TWA R IgM antibody response is longer lasting and IgG antibody is slower to dev elop compared with Chlamydia trachomatis infection. Unlike other Chlamydia species, only a single serovar for C. pneumoniae has been recognized in the MIF system and cross-reaction with other species is negligible. While IgM antibody response is an important marker for serodiagnosis of acute infecti on, rheumatoid factor often causes false-positive reactions. Persistent TWA R IgG antibody has been useful for seroepidemiologic studies and an associa tion of TWAR IgG antibody and atherosclerotic diseases has been observed. I gA antibody may not be a useful marker for chronic TWAR infection or for ac ute infection.