Introduction: Stroke is the third most common cause of mortality and the most common disability disorder among adults. We aimed to study the relationship between Chlamydia pneumonia infection and non-cardio Ambulatory ischemic stroke. Methods: This case-control study was performed on 162 patients with non-cardio ambulatory ischemic stroke admitted to Shahid Beheshti Hospital of Kashan in 2019 as the case group and patients with neurological headache and degenerative diseases as the control group. After filling out the questionnaire for all subjects, we took blood samples. We analyzed all three anti-chlamydia pneumonia antibodies (IgM, IgG, IgA) by ELISA method after data were analyzed by Chi-square and Fisher tests. Results: The findings of this study showed that positive IgA in the stroke group was significantly higher than in the control group (p=0.001); it was also found that the risk factors of HTN (p=0.001), HLP (p=0.001), DM (p=0.001), and age (p = 0.049) were significantly higher in the stroke patients' group than the control group. On the other hand, there was not a significant difference in serum IgG level (p = 0.349), IgM (p = 0.745), smoking (p = 0.211) and gender (p = 0.157) in understudied groups. Conclusion: Chlamydia IgA antibodies can be a complementary tool for predicting prognosis and monitoring new therapies for ischemic stroke. This study provides a way for further studies, especially with other markers of acute and chronic systemic Chlamydia pneumonia infection. Antibiotic treatment significantly helps to reduce mortality and stroke complications.

This open-access article distributed under the terms of the Creative Commons Attribution NonCommercial 3.0 License (CC BY-NC 3.0) About 2.5 million people worldwide have Multiple sclerosis, a demyelinating inflammatory disease of the central nervous system (1). Despite the young age of onset, this disease imposes a high social-economic burden on individuals and society (2). Although the exact pathophysiology of MS is unclear, the environmental factors and the immune response are considered to be key factors (3).According to previous studies, MS is more common where the infectious agent is more prevalent. On the other hand, A few studies have linked MS to the health hypothesis, which implies an insufficient immune response in people living in very "clean" environments. (4-5) Several studies have investigated