STUDIES OF THE LIFE SPAN AND FATE OF PLATELETS

SUMMARY Chromium‐51 labelling of platelets has been employed to study their life span and to assess the role of the spleen in platelet dynamics in idiopathic thrombocytopenic purpura, congestive splenomegaly and congenital hæmolytic anæmia with splenomegaly. Surface scanning has not provided unequivocal evidence of splenic sequestration in the majority of the patients studied. It may be possible to predict the response to splenectomy in idiopathic thrombocytopenic purpura, but larger numbers of patients require to be studied before a clear pattern can be established. Estimations of platelet yield before and after splenectomy, together with some evidence from surface scanning, suggest that the thrombocytopenia of congestive splenomegaly with short platelet survival may be due to splenic removal of platelets. It is suggested that, in some circumstances, the enlarged spleen may remove many platelets from the circulation. This effect may not be reflected in thrombocytopenia and may be detectable only by studies of platelet dynamics.