Background:
Several studies have assessed the association between chlamydia pneumoniae infection and thrombotic ischemic strokes. This study was designed to investigate the association between this organism and ischemic strokes in Iranian patients.

Methods:
Antibodies to Chlamydia pneumoniae(CP IgA and IgG) were measured in 81 patients with stroke and 43 controls. CP IgG and CP IgA titers more than 1.1 Immune Status Response (ISR) were considered as positive.

Findings:
We found that 9.3% of controls and 13.6% of cases were CP IgA seropositive. Although the difference between these two groups was prominent but it was not statistically significant (p=0.25). The mean CP IgA titer was significantly higher in the case than in the control group (0.6 ± 0.3 vs. 0.47 ± 0.3 ISR, respectively, p=0.03). This difference was not significant for CP IgG titer.

Conclusion:
The higher titer of CP IgA in patients with ischemic stroke than in controls might suggest the co-existence of this infection with ischemic stroke. Assessment of this association needs longitudinal studies.

Key words:
Ischemic stroke, chlamydia pneumoniae, serum antibody