To determine whether a small CD3+ lymphocyte population expressing 110-kd CD57 antigens (HNK1) is expanded in patients with rheumatoid arthritis (RA), as it is in patients who have undergone bone marrow transplantation and patients with the acquired immunodeficiency syndrome, and to investigate whether it is involved in the pathogenesis of RA.
The phenotype of CD3+, CD57+ lymphocytes was analyzed by flow cytometry, and correlations between the percentage of these cells in the blood and various clinical and biologic parameters were investigated.
The percentage of CD3+, CD57+ lymphocytes was increased in RA patients compared with controls. These lymphocytes expressed T cell receptor alpha/beta. Eighty percent expressed the CD8 accessory molecule, and 20% expressed the CD4 accessory molecule. The leukocyte common antigen CD45RA isoform was expressed by these CD3+, CD57+ lymphocytes in blood. The HLA-DR antigen was expressed in synovial fluid but not in blood. Finally, the percentage of these lymphocytes in the blood correlated with the duration of RA.
The expansion of the CD3+, CD57+ lymphocyte population and their activation in the synovial fluid of RA patients suggest that these cells are involved in the inflammatory process.