Transformation of the capillary wall elements in synovial tissue in rheumatoid arthritis.

1. The morphologically comprehensible starting point of rheumatoid arthritis is a permeability change of the synovial capillaries. 2. In the context of rheumatoid arthritis all three building elements of the blood capillaries undergo a transformation. 3. In the endothelial cells and the pericytes the endoplasmatic reticulum, the Golgi-apparatus, as well as the mitochondria can be multiplied (progressive transformation). The cell structures can, however, be subject to a degeneration (regressive transformation). The basement membrane as a secretion product, in contrast, undergoes exclusively quantitative changes. 4. The transformation possibilities of the capillary elements will be treated and classified on a graph under general pathological aspects. 5. As an element of the connective tissue the endothelial cell, as are lining cell and stroma cell in rheumatoid arthritis, is subject to transforming influences which, however, at the synovial capillary will be the starter of fibrin exudation into the joint cavity.