Arthritis induced in rabbits by lysates of granulocyte lysosomes

From rabbit heterophile leukocytes, granules were prepared which had a high specific activity of acid hydrolases. When lysates of such granules were injected into the skin and joints of other rabbits, acute inflammation was regularly produced. Repeated intraarticular injections led to hypertrophy and hyperplasia of synovial lining cells, round cell infiltration of synovium in the vicinity of blood vessels, pannus formation, and cartilage degradation. The data suggest that escape of granule contents from lysosomes into the joint cavity is sufficient to account for proliferative and degradative changes observed in several forms of clinical and experimental arthritis.