Abstract
Rheumatoid arthritis (RA) is a chronic autoimmune disease that affects the joints and many factors are involved in the emergence and progression of the disease, including genetics and environmental factors, among the latter factors are the infectious agents, which have not been proven accurately to date, which necessitated this study to identify the role of some different pathogens in the occurrence of the disease. Seventy-five serum samples (62 females, 13 males) were taken for patients suffering from rheumatoid arthritis, 30 of whom were receiving methotrexate (MTX) therapy, in addition to some auxiliary medications, and 45 others who had not received any treatment except pain relievers, from Al-Sadr Teaching Hospital in Najaf Governorate / Iraq. The ages of patients ranged 26 -73 years, in addition to 23 healthy people (15 females, 13 males) within the control group, collected from separate areas of the same governorate and the ages ranged 32-64 years. Serological investigation of IgM and IgG antibody was performed using TORCH Panel Rapid Test which includes Toxoplasma gondii, Rubella virus (RV) Cytomegalovirus (CMV), Herpes simplex virus 1 (HSV-1), and Herpes simplex virus 2 (HSV-2). The results showed that there was significant increase in the prevalence of IgG antibody for both RV and CMV in rheumatoid arthritis patients, and the proportion was 70.6% and 48%, respectively, compared to the healthy group which was 34.7% and 0%, respectively. The prevalence rate of IgM seropositive antibody was 0% for all above pathogens except for one case for HSV-1 in RA patients. Statistical analysis of Chi-Square also showed significant differences in the prevalence of IgG antibody for only both the RV and CMV between the three study groups (the group of patients receiving MTX treatment and the group of patients without treatment and the control group). The IgG positive antibody ratio for both Rv and CMV was higher for females than males, while no significant differences were seen in other pathogens. As a final outcome of our study, it found a positive relationship between presence of serum IgG, which represents chronic infection of rubella, and Cytomegalovirus with rheumatoid arthritis, which proves the role of infection factors in the emergence of autoimmune diseases.

Key words: Rheumatoid Arthritis, Torch Test, Microbial Pathogens, Cytomegalovirus, Methotrexate.