Correlation of Histochemical, Histologic and Biochemical Evaluations of Human Synovium with Clinical Activity

Operative synovial specimens from rheumatoid, osteoarthritic and control joints were assayed for acid phosphatase content histochemically and biochemically; portions of these same specimens were incubated in tissue culture with chick cartilage, the collagen of which was labeled with 3 H, and the protein polysaccharide of which was labeled with 35 S. Activity of the disease process was also evaluated from clinical data and routine histologic examination. A linear relationship was found between the histochemical and biochemical determinations of acid phosphatase. We demonstrated significant associations between acid phosphatase content and histologic activity, between acid phosphatase content and clinical activity and between histologic and clinical activity. Rheumatoid synovia had a significantly higher mean acid phosphatase content than osteoarthritic and normal, but no consistent difference was found between osteoarthritic and normal. Rheumatoid synovia also caused greater cartilage destruction in vitro than osteoarthritic and normal synovia. These findings are interpreted as further evidence for the role of synovial lysosomal enzymes in the pathophysiology of rheumatoid arthritis and provide a rational justification of synovectomy in this disease.