ABSTRACT
A study was made of immunity in seronegative spondylarthritis. In ankylosing spondylarthritis, reactive arthritides and psoriatic arthritis, the decrease of T cells, T helpers and T suppressors was identified. Patients with ankylosing spondylarthritis and reactive arthritides manifested an increase of the B-lymphocyte count. Patients with ankylosing spondylarthritis were demonstrated to be sensitive to Klebsiella (52%), those with reactive arthritides to intestinal yersinia (44%). The phenotype of antigen-binding cells was examined. Of these, 39% appeared to be T lymphocytes, 29% B lymphocytes. The presence of Fc receptors in an appreciable portion of those cells suggests their functional maturity. The inhibition test demonstrated the participation of HLA-B27 in reception of Klebsiella antigens in ankylosing spondylarthritis.