Increased circulating immune complexes in acute stroke: the triggering role of Chlamydia pneumoniae and cytomegalovirus.

BACKGROUND AND PURPOSE The mechanisms of immune reaction involved in the pathogenesis and clinical course of acute vascular incidents are still not completely understood. The aim of this study was to examine the presence of immune complexes (IC) in the acute stroke setting and the first month thereafter and to characterize IC by analyzing the contents of chlamydial lipopolysaccharide and anti-cytomegalovirus (CMV) antibodies in IC. METHODS Serum concentration of IC was investigated in 179 stroke patients, 122 "old" controls and 112 "young" controls, by the precipitation method. The presence of chlamydial lipopolisaccharyde and anti-CMV antibodies was investigated in some IC preparations by the ELISA method after earlier dissociation of IC into components by high pH treatment. RESULTS Significantly increased serum IC concentration in stroke patients was noticed. Increased serum IC concentration was revealed as an independent strong stroke risk factor and was connected with significantly worse neurological status and increased 30-day mortality rate. A significantly larger proportion of stroke patients than controls had Chlamydia pneumoniae antigen and anti-CMV antibodies in IC. CONCLUSIONS This study provides the first evidence of an association between increased serum level of IC and the clinical course of cerebral ischemia and identifies a potentially important association of C pneumoniae and CMV-specific IC with stroke incidence.