Some patients who had had prior chemotherapy seemed to have deeper nadir counts as well.19, , -22 We evaluated bone marrows in cases of significant thrombocytopenia and these were normal with normal morphology and numbers of megakaryocytes, suggesting peripheral sequestration or destruction, which did not extend beyond completion of IL-2 therapy (J. P. Dutcher, personal observation). This evidence concerns the gene IL2 and Thrombocytopenia.