A casuistic immunologic response in primary and repeated Chlamydophila pneumoniae infections in an immunocompetent individual.

A casuistic immunologic response in primary and repeated Chlamydophila pneumoniae infection is described. The primary C pneumoniae infection was documented as laboratory accident in late 1990. The immunologic response was mediated mainly through production of IgM antibodies with only a marginal IgG and IgA increase near the cut-off value. The second episode of respiratory illness in the summer of 1999 that was clinically compatible with acute C. pneumoniae infection was characterised by only increase of specific IgM antibodies detected by microimmunofluorescence, EIA and Western blot analysis. Remarkably, in the first episode of C. pneumoniae infection IgM antibodies were predominantly to 60 kDA and LPS antigens, whereas in the second episode they were to a 40 kDA protein and LPS. Non-specific polyclonal B-cell activation by Epstein Barr virus infection as well as other possible common causes of acute respiratory illness were excluded by routine serology. Noteworthy, the patient was able to respond adequately to other pathogens (e.g. cytomegalovirus) as determined by IgG EIA. The reason for the observed uncommon immunological reaction remains enigmatic. However, quick therapeutic interventions (due to awareness) or massive infection load in the primary infection might have had some suppressive impact on the maturation of the immunity.