Hydroxyapatite associated arthritis in a patient undergoing chronic haemodialysis.

A patient with uraemia undergoing chronic haemodialysis developed a unilateral effusion of the elbow joint. The chalky-white synovial fluid obtained from the joint contained many crystals that were identified as hydroxyapatite by infrared spectroscopy. The joint effusion showed chemotactic activity for healthy human neutrophils. Chemotactic activity of the lipopolysaccharide(LPS)-activated patient's serum was low compared to that of pooled healthy human sera, but the patient's serum did not have the inhibitor for the chemotactic factor. These findings suggest that the production of chemotactic factor in this patient's serum was decreased. The possible combined effects of the uraemic state and crystal-induced inflammation on the chemotaxis of neutrophil leukocytes are discussed.