[The abnormalities of the cellular immunity in rheumatoid synovium]

With the technique of immunohistochemical (ABC) method monoclonal antibodies were used to identify the lymphocyte subsets, macrophage and the expression of class II MHC (HLA-DR, HLA-DQ) antigens in the synovium cells from 18 RA patients and 8 patients with osteoarthritis as control. The results showed that the main cellular abnormality at the sublayer of the synovium was the appearance of lymphoid follicles which mainly consisted of the infiltration of T lymphocytes (77.8%).50.6% of them were CD4+, which mainly consisted by of CD45RO+ cells in the rheumatoid synovium on the consecutive sections. The increased ratio of CD4/CD8 in RA patients was significantly higher when compared with that in the controls (2.11 +/- 0.93 vs 0.63 +/- 0.13, P < 0.001). In advanced RA with fibrosis of joints, the ratio tended to decrease and was accompanied with reduction of infiltrated lymphocytes. Compared with T cells CD20+ B lymphocyte not only had a lower percentage (25.2%), but also showed a characteristic picture of locating in the centre of the follicles. The fact that most of the CD4+ T cells was helper memorized lymphocytes with CD4 phenotype of positive TAC(+) (interleukin-2 receptor) and that up to 54.2% was anti-HLA-DR and 54.1% anti-HLA-DQ monoclonal antibodies indicated that these T lymphocytes were activated in vivo. Cells with anti-CD68+ were seen all over the RA synovium. Class II HLA and CD68 molecule were also expressed on the endothelium cells of the small vessels. It is suggested that the activated lymphocytes, macrophages and endothelium cells and their abnormal distribution may indicate the abnormalities of the cellular immunity in rheumatoid synovium.