CAN HYDROXYAPATITE DEPOSITION IN THE EYE CAUSE A NEUTROPHIL-RELATED INFLAMMATORY REACTION

Patients with chronic renal failure on intermittent dialysis sometimes develop an acute diffuse conjunctival and episcleral hyperaemia. Tn t his study the hypothesis was tested whether the precipitation of hydro xyapatite crystals could result in an inflammatory reaction mediated b y enzymes liberated from polymorphonuclear leucocytes (PMN). Ingestion of the crystals by PMN's can result in cell death and membranolysis a nd subsequent release of intracellular enzymes into the surrounding ti ssues. This 'suicide sac' hypothesis for the inflammatory reactions of the conjunctiva and episclera was rejected after histopathological ex amination of conjunctival biopsies failed to show complement activatio n or crystal ingestion by PMN's despite the presence of small subepith elial hydroxyapatite crystals.