Chikungunya virus and autoimmunity

Purpose of review Chikungunya virus (CHIKV) is a mosquito-borne alphavirus. Fever, rash and severe arthralgia are the hallmarks of chikungunya fever (CHIKF), the disease caused by this virus. The acute course of the disease usually lasts few weeks to months. Chronic, relapsing or persistent arthralgia and arthritis have been described mimicking rheumatoid arthritis (RA), requiring immunosuppressive drugs. The purpose of this review is to characterize both the chronic clinical course of CHIKF-associated arthritis and the immunological pathogenic mechanisms involved. Recent findings The effect of postepidemic chronic persistent rheumatic course on the functional status of affected individuals, affecting large populations, has been studied. One-third of affected individuals had persistent pain months to years postepidemic and the identified risk factors for functional disability were identified. Inflammatory biomarkers associated with disease severity of RA such as interleukin 6 (IL6), and relevant chemokines have been found to correlate with the severity of postepidemic chronic disease. There are conflicting reports on antinuclear antibodies (ANAs) as well as rheumatoid factor and anti-citrullinated peptide antibody (ACPA) sero-positivity during infections. According to a recent study, eight out of 10 infected individuals developed chronic persistent rheumatic course and met classification criteria for seronegative RA. In a flow cytology analyses, these eight patients, similar to a group of RA patients, had a greater percentage of activated and effector CD4(+) and CD8(+) T cells than healthy controls. Summary Patients with CHKV infections may have a chronic persistent course of musculoskeletal disease, overlapping clinical and immunologic features with RA patients. In the appropriate setting and awareness, CHIKV infection should be considered when a patient is evaluated with a new symmetric polyarthritis. The question to be raised: Is it possible that in genetic prone individuals and in a particular environmental and infectious setting, such as CHIKF outbreak, an autoimmune disease will emerge?