Disturbances of prostacyclin metabolism in children with hemolytic-uremic syndrome and in first degree relatives

Plasma from 24 children with hemolytic uremic syndrome (HUS) (10 in acute, 14 in remission phase), 42 first degree relatives and 24 controls were studied for PGI2 supporting activity (PSA) from human umbilical arterial rings and the concentration of PGI2 metabolite (PGI2m). HUS patients in acute phase showed very low or absent level of plasma PSA, which remained depressed 3 months following presentation. Plasma from 2 out of 5 acute HUS patients showed inhibition against PGI2-like activity, and depressed preservation of PGI2 effect. The mean value of PGI2m in acute phase of HUS patients was elevated initially, but fell below control range by the day 14 and remained decreased at the end of 3rd month. Patients on long term remission showed a significantly lower concentration of plasma PGI2m. Eight of 14 HUS patients in remission and 18 of 42 family members had lower PSA levels than the controls. These studies confirmed a decreased PSA in HUS and suggest that persistently low PSA levels may reflect an inherited predisposition.