Involvement of latent/persistent parvovirus B19, HHV-6 and HHV-7 infections in ethiopathogenesis of rheumatoid arthritis and relationship with clinical and radiological findings

By comparing RA patients with OA patients and healthy control group individuals, to confirm or reject the role of B19V, HHV-6 and -7 infections in development of RA, as well as to evaluate the impact of different stages of activity of B19V, HHV-6 and -7 infections the clinical and laboratory activity, aggressiveness and radiological stage of RA. The prospective study includes patients from the Linezers Clinic and the Gaiļezers Clinic of the Riga East Clinical University Hospital, and the Hospital of Traumatology and Orthopaedics, who were treated there from 2010 to 2016. Inclusion criteria included primary or remotely diagnosed RA or OA in these clinics. All RA patients met the RA classification criteria set by the American College of Rheumatology in 1987 (Arnett et al., 1988) or early RA classification criteria set by the American College of Rheumatology and the European League Against Rheumatism in 2010 (Aletaha et al., 2010). The exclusion criteria included pregnant women, alcoholics and patients with other inflammatory diseases. OA patients corresponded to the OA classification criteria set by the American College of Rheumatology (Altman et al., 1986., Altman et al., 1990., Altman et al., 1991). Potentially healthy individuals without known chronic inflammatory diseases were included in the study as a control group. Samples of peripheral blood, synovial tissues and fluid of RA and OA patients (when possible based on indications), surgical material of cartilage tissues and bone tissues were obtained simultaneously. Peripheral blood samples were taken from healthy control group individuals.