Chlamydia pneumoniae seropositivity in Iranian patients with multiple sclerosis: a pilot study

Background and purpose: Multiple sclerosis (MS) is a chronic inflammatory autoimmune disease of the central nervous system. Genetic and environmental factors could not completely explain the pathogenesis of the disease. Among environmental factors, infectious agents are of more interest than other candidates, so Chlamydia pneumoniae (C pneumoniae) may have a role in MS development or progression. This study aimed to evaluate C. pneumoniae seropositivity in MS patients. Material and methods: Serum samples obtained from a cohort of 85 patients with MS and from 50 age- and sex-matched controls were assessed for the presence of antibodies. IgM and IgG concentration for C pneumoniae were determined with enzyme-linked immunosorbent assay (ELISA). Results: The mean age was 33.8 (9.96) years in the MS group and 33.9 (10.7) years in controls. Female/male ratio was 3.5 : 1 in the MS group; 69 patients (81%) had relapsing-remitting course (RRMS) and 16 patients (19%) had secondary progressive course (SPMS). The median concentration of C pneumoniae IgM in the MS group was 0.5 RU/mL (0.25-1) versus 0.5 RU/mL (0.3-0.8) in the control group (p = 0.66); likewise, the median concentration of C. pneumoniae IgG in MS patients was 57.3 RU/mL (17.05-95.1) compared with 56.15 RU/mL (6.85-102.5) in the control group (p = 0.85).Regarding the clinical course, C. pneumoniae IgG was 55.1 RU/mL (20.7-88.6) in RRMS and 59.1 RU/mL (5.35-112) in SPMS (p = 0.8). Conclusion: No association was observed between MS and C pneumoniae in Iranian MS patients.