The correlation between human parvovirus B19 infection and certain immunological markers increases the likelihood of rheumatoid arthritis in individuals with joint issues.

Rheumatoid arthritis (RA) is a common autoimmune disease, hallmarked by persistent inflammation of joints. It is mediated by genetic, environmental, and microbial triggers. Human parvovirus B19 (HPV B19) has been identified as one of the virus infections that potentially induces immunological responses in the pathogenesis of arthritis. This study included 60 samples of blood from RA patients, who were attending hospitals in Al-Najaf-Province during the period from October 2023 until March 2024. Diagnosis had been established using the rheumatoid factor (RF) test, and 54 patients were shown to have RA by a more specific ACCPA-test. Especially, ESR was elevated in most of the patients with a mean of 45 mm/h, and had positive CRP values. The most common age group affected was 41–53 years, and males outnumbered females slightly (33:27). Presence of HPV B19 infection was studied by ELISA IgG, showing 55 positive patients, with a concentration average (mean) of 0.986 compared to 0.12 in the negative group and control group. The viral DNA was verified in 42 of the 60 patients using RT-PCR. A Phylogenetic tree was constructed comparing 8 viral strains sequenced in this study with GenBank references. Patients were classified into 4groups according to the status of RA and HPV B19. IL-32 levels were changed significantly , and no significant changes were observed in IL-37. These results indicate a potential involvement of HPV B19 and certain cytokines in the pathogenesis of RA.