Cyclic thrombocytopenia: a thrombopoietin deficiency?

Severe cyclic thrombocytopenia is reported in a young woman. This rare phenomenon is of considerable theoretical interest in relation to platelet kinetics. In this patient platelet and fibrinogen survival times exclude the possibility of excessive peripheral platelet destruction. Serial plasma thrombopoietin levels suggest that a deficiency of this protein may be the underlying factor. As a result platelet production may fall to a very low level. The megakaryocyte, however, remains responsive and the hypothesis advanced is that under these circumstances the intermenstrual platelet increase, normally caused by the interplay of the sex hormones, becomes grossly exaggerated.