Interaction of polymorphonuclear leukocytes with immune complexes trapped in rheumatoid articular cartilage.

When rheumatoid articular cartilage samples were incubated with normal polymorphonuclear leukocytes (PMN) in vitro, large numbers of PMN were seen attached to the articular surface. As observed by electron microscopy, significant numbers of these cells invaded the cartilage tissue and phagocytosed amorphous material which presumably contained immune complexes. In control cartilage from osteoarthritic, pyogenic, and normal subjects, only a few PMN were attached to the articular surface after incubation with PMN. These results demonstrate that immune complexes trapped in the superficial region of the rheumatoid articular cartilage may play an important role in the destruction of cartilage by the release of lysosomal enzymes from PMN.