The tissue architecture of synovial membranes in inflammatory and non-inflammatory joint diseases. II. The localization of mononuclear cells as detected by monoclonal antibodies directed against T-lymphocyte subsets and natural killer cells.

Tissue specimens of synovial membranes from patients with rheumatoid arthritis (RA) and non-inflammatory joint diseases were analyzed with a panel of monoclonal antibodies directed towards T-lymphocyte subsets and natural killer (NK) cells. In the RA group, mononuclear cell infiltrations in the synovium presented a distinguished pattern as compared to the non-RA group. Inflammatory synovial membranes displayed an increased level of cells recognized by the monoclonal antibodies OKT4 and OKT8, especially attributable to the broadened layer of synoviocytes and to the fibrous synovial tissue. No significant difference in the RA patients was observed with regard to the percentage of OKT4 and OKT8 positive cells in different investigated compartments of the synovium, e.g., diffuse inflamed synovial tissue, fibrous synovial tissue, and perivascular infiltrations. OKT4 and OKT8 positive staining was additionally observed on spindle-shaped cells present in the fibrous and diffuse inflamed synovium. OKT10 binding cells were located in the deeper layers of synoviocytes, in the inflamed synovial tissue, and in one case in perivascular areas, whereas HNK 1 positive cells were scattered in the fibrous synovial and perivascular cells, as well as in lymphocyte clusters of synovium in RA patients.