The Microimmunofluorescence Test forChlamydia pneumoniaeInfection: Technique and Interpretation

A brief description of current procedures for the Chlamydia microimmunofluorescence (MIF) test is presented.To date, use of MIF serology with Chlamydia pneumoniae (TWAR) antigen has provided the most sensitive and specific method for diagnosis of acute TWAR infection.In primary infections, the TWAR IgM antibody response is longer lasting and IgG antibody is slower to develop 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 infection, rheumatoid factor often causes falsepositive reactions.Persistent TWAR IgG antibody has been useful for seroepidemiologic studies and an association of TWAR IgG antibody and atherosclerotic diseases has been observed.IgA antibody may not be a useful marker for chronic TWAR infection or for acute infection.The complement-fixation (CF) test is the time-honored serologic method for diagnosis of psittacosis and lymphogranuloma venereum [1].The CF test measures Chlamydia genus antibody.It is also useful for primary infection with Chlamydia pneumoniae (TWAR) infection.It was for use with Chlamydia trachomatis infection that we developed the microimmunofluorescence (MIF) test [2, 3], which works well with TWAR as antigen.It was essential to the discovery of the clinical disease caused by and to the description of its epidemiology [8][9][10][11][12].Here I briefly describe the MIF method [13] and some characteristic features of TWAR MIF serology.