STUDY OF PLATELET-FUNCTION IN PATIENTS WITH SICKLE-CELL-ANEMIA DURINGSTEADY-STATE AND VASOOCCLUSIVE CRISIS

Although there are many reports providing evidence for platelet hypera ctivity during acute infarctive crisis in sickle cell disease, little attention has been paid to the study of platelet release reaction in s teady state. Plasma levels of the alpha-granule constituents beta-thro mboglobulin and platelet factor 4 were measured in patients with sickl e cell anemia during steady state and vaso-occlusive crisis in order t o determine in vivo platelet activity. Significantly higher plasma lev els of both proteins were found in steady state and in crisis when com pared with those of normal controls. Platelet hyperactivity was also f ound to be more vigorous in painful crisis, suggesting a possible ther apeutic role for drugs that inhibit platelet function.