PERIPHERAL BLOOD MONONUCLEAR CELLS’ PROLIFERATIVE RESPONSE TO HUMAN PARVOVIRUS B19 ANTIGENS IN PATIENTS WITH RHEUMATOID ARTHRITIS

This study aimed to determine peripheral blood mononuclear cells’ (PBMC) proliferative response to parvovirus B19 (B19) antigens in rheumatoid arthritis (RA) patients and possible changes in proliferative response due to chemotherapy. Serum and blood samples of 52 RA patients and 25 sex and age matched healthy individuals were examined for the presence of anti-B19 IgG and IgM class antibodies and virus specific DNA sequence by the recomLine B19 test and nested polymerase chain reaction, respectively. The PBMC proliferative activity was estimated on the 3rd and 6th day of PBMC cultivation in the presence of virus and B19 VP1/VP2 peptide, using thymidine incorporation assay. On the 3^rd day, PBMC response to B19 antigens was detected in 74.1% RA patients with active, in 44.8% — with remote and in 40% — with latent stage of persistent B19 infection, while in the control group the response was observed only in two individuals with active viral infection. On the 6^th day, the response was found in 50% RA patients with active, 68.9% — with remote and in 80% — with latent stage of latent persistent infection as well as in 41.1% remotely infected control individuals. The highest PBMC mean stimulation indices were detected in the RA patients and control persons with active infection as well as in RA patients with latent stage of persistent viral infection. On the 3^rd and 6^th day, strong proliferative response was significantly more frequently observed in RA patients not receiving methotrexate treatment, compared to the patients receiving methotrexate treatment in different combinations with other drugs. RA patients had more frequent and faster response to B19 antigens than apparently healthy persons.