Ochronotic arthropathy and lysosomes: a clinical and electron microscopic study

In order to understand better the time dependency of the arthritic manifestations of ochronosis, as well as its relationship with lysosomal activities, we sampled a small series of various arthropathies (11 joints). The joint fluid, serum, and urine lysosomal activity levels were measured. The lysosomal enzyme level was elevated in patients with acutely symptomatic, chronically involved ochronotic joints. The enzyme activity level in the other joints (chronically involved) was less. Postulated clinical manifestations of increased levels of intraarticular lysozymes seem to apply to ochronosis as well. Further studies with larger series of patients are warranted.