Large granular lymphocytic proliferation-associated cyclic thrombocytopenia.

Cyclic thrombocytopenia is a rare condition characterized by regular fluctuations in the platelet count, resulting in bleeding at the time of platelet count nadir. We evaluated a male patient whose platelet count cycled between <10x10(9)/L and a maximum of >1300x10(9)/L over a median of every 42 days (range, 28-57 days). Antiplatelet antibodies were present at highest titer just prior to platelet nadirs.