Intraplatelet serotonin (I5HT) in children with the hemolytic uremic syndrome.

I5HT levels were investigated in 14 children with Hemolytic Uremic Syndrome (HUS). Low levels of I5HT were demonstrated in all the children studied during the early phase of the disease, indicating reversible platelet aggregation and recirculation of degranulated platelets. Three months after the onset of HUS, only 2 children with a pathological picture of cortical necrosis and a mild degree of chronic renal failure had low I5HT levels. On the contrary, normal I5HT levels were present in the other children completely recovered from HUS and with a renal biopsy picture of thrombotic microangiopathy with predominant glomerular involvement. We conclude that normal values of I5HT, after the acute stage of HUS, are a good index of complete recovery from the disease. Further observations are required to assess the prognostic value of low I5HT levels in children with chronic renal failure secondary to HUS.