Clinical Characteristics of Chlamydia pneumoniae Infection

Abstract

The symptoms of Chlamydia pneumoniae infection are mostly derived from case reports and descriptions of outbreaks in which the diagnosis of infection has been made from the results of serological tests showing either high or rising titers of antibody to C. pneumoniae, suggesting that the patients had suffered from an acute or an asymptomatic form of respiratory infection. The micro-immunofluorescence test showing IgM and IgG antibodies is considered the golden standard in the serology of these infections. A fourfold rise in IgM antibody titers or a single titer of 1:16 or greater are considered evidence of recent infection as it is a single IgG titer > 1:512. If the IgM antibody titer is negative and the IgG titer is between 1:16 and 1:512 it is generally supposed that the patient has had an infection with C. pneumoniae in the past [3]. If the relatively insensitive complement fixation test (CFT) technique has been used with the non-specific genus antigen then an infection is assumed if there is a fourfold rise in serum antibody titer in the course of a period of 10 days to 4 weeks, and certainly if the CFT titer is greater than 1:64 Sometimes the patients fail completely to mount any form of complement fixing antibody response [8].