[Changes in the cover layer of the synovial membrane in the early stage of rheumatoid synovitis (based on light and electron microscopic data)].

In the early stage of rheumatoid synovitis, changes in synoviocytes of the cover layer in the joints with clinical manifestations of arthritis differ from stereotype reactions of these cells in the advanced stage of the disease. Fibrin, IgG and C3-fraction of complement are found on the surface and in the depth of the cover layer. Light and electron microscopy revealed the features of type B synoviocytes prevalent in the cover layer in the early stage of the disease: polymorphism and rounding of the nuclei of synoviocytes, mitoses, fragmentation and degeneration of the nucleolus, loosening of the chromatin network and appearance of interchromatin granules, nuclear bodies, formation of multinucleated synoviocytes and symplasts, destruction of organelles, activation of lysosomal apparatus of the cells. These changes may be interpreted as simultaneous manifestations of cell activation and cytopathologic effect. They are likely to be due to the effect of the etiological factor and immunocomplex mechanism. The detection of dystrophically altered chrondrocytes in the cover layer confirms the opinion of simultaneous participation of the synovial and cartilage components of the joint in the rheumatoid process.