Background The studies of the last few years demonstrated that parvovirus B19 (B19) genome not only persists in latent state in host’s tissues, but it may be also expressed in cells of healthy immunocompetent persons (1, 2). The sustained T cell response reflects the level of antigen exposure in human organism. At the same time chemotherapy may lead to deficiency of cellular immune responses.
Objectives To study T lymphocytes’ response to B19 antigens in rheumatoid arthritis patients and possible changes in immune response due to chemotherapy.
Methods Serum/plasma and blood samples from 52 RA patients and 25 sex and age-matched practically healthy individuals were studied. Virus specific IgG and IgM class antibodies were determined using recomLine Parvovirus B19 IgG and IgM test, the presence of B19 genomic sequences - using B19 VP1 and B19 NS1 nested PCRs. The proliferative activity of T lymphocytes was estimated at the 3rd and 6th day of cultivation in the presence of B19 (the final concentration 106viral genomes/ml) or B19 peptide VP1/VP2 (LASEESAFYVLEHSSFQLLG - in the final concentration 10μg/ml (Caslo Laboratory ApS, Denmark) using 3H-thmidine incorporation technique.
Results In our previous study we had shown that B19 infection markers are frequently presented in the RA patients. In this study the RA patients’ lymphocytes were cultivated in the presence of B19 or B19 peptides VP1/VP2 and their proliferative response to the antigens measured on the 3rd and 6th day. The lymphocytes of RA patients responded with the proliferative reaction to B19 antigens more frequently and more quickly than lymphocytes of apparently healthy individuals. At the 3rd day the proliferation of lymphocytes was observed in 50% (26/52) of RA patient samples and only in 8.0% (2/25) samples (p=0.0003) of healthy individuals, at the 6 day - in 73.1% (38/52) and 36% (9/25) samples of RA patients and healthy individual, respectively (p=0.0027). The analysis of the RA patients group, in which the lack of T cell response to B19 antigens was observed, showed that all these patients had received DMARDs therapy. The lack of T cell responses in the whole was associated with the course of Methotrexate treatment. The lymphocytes of patients, not treated using DMARDs, responded to B19 antigens in 84.6% (11/13) cases at the 3rd day and in 100% (13/13) cases at the 6th day, while the lymphocytes of patients taking Methotrexate had responded only in 32.0% (8/25) cases (p=0.0051) at 3rd day and in 56.0% (14/25) cases (p=0.0026) at the 6th day. It should be note that in patients treated by Methotrexate virus specific IgM class antibodies were revealed more frequently than in the RA patients without this drug treatment (13/25 versus 4/27, p=0.0026).
Conclusions The higher detection rate of B19 infection markers in RA patients is confirmed by more frequent and quicker T lymphocyte proliferative response to B19 antigens. The treatment of RA patients by Methotrexate inhibits T cells’ response to B19 antigens and possibly influences the formation of virus-specific IgM.
Lefrere J-J et al., Blood 2005, 106: 2890-2895.
Lindblom A et al., Clin Infect Dis 2005, 41: 1201-1203.
Disclosure of Interest None Declared