Very late activation antigen on synovial fluid T cells from patients with rheumatoid arthritis and other rheumatic diseases.

We used flow cytometry and immunoprecipitation techniques to study the expression of the activation molecules transferrin receptor, interleukin-2 receptor, HLA-DR, and very late activation antigen 1 (VLA-1) on purified T lymphocytes from peripheral blood and synovial fluid of 9 patients with rheumatoid arthritis and 7 patients with other rheumatic diseases. We found a T cell subset bearing VLA-1 in synovial fluid from 8 rheumatoid arthritis patients and 4 patients with other rheumatic diseases. VLA-1 was not found in peripheral blood T lymphocytes from either group.