Articular cartilage from thirteen patients with rheumatoid arthritis was
studied by both light and electron microscopy using recently developed
staining techniques for proteoglycan. Normally proteoglycan is concentrated
about active chondrocytes, but in the cartilage from these patients it was
found to be diminished about most of the chondrocytes while it was
increased around a few. Fragmentation of collagen and phagocytosis of the
fragments by chondrocytes were also noted. This dissolution of collagen was
associated with loss of proteoglycan in the matrix. These findings are
consistent with the variable nature of the rheumatoid destructive process
and appear to be morphological reflections of biochemical changes which
formerly were thought to occur in this disease only at the cartilage-pannus
junction.