To the Editor.
—Gilbert et al (Blood 1979;54[suppl]:84) reported low cholesterol levels in 24 patients with polycythemia vera or myeloid metaplasia. In a previous study, we examined the records of 20 patients who had agnogenic myelofibrosis and myeloid metaplasia. We found that 17 of these patients had total plasma cholesterol values substantially lower than normal. In the present study, we extended these observations to include patients with other myeloproliferative disorders. We examined the records of 27 patients who had either chronic myelogenous leukemia or polycythemia vera. Our aim was twofold—to measure the serum cholesterol levels in each of these patients and to determine the degree of marrow fibrosis to define the relationship, ifany, between marrow fibrosis and serum cholesterol levels.There were 19 men aged 16 to 84 years and eight women aged 38 to 76 years, all without diseases known to alter plasma cholesterol levels. Six patients, all men, had total