Radio-isotope investigations in primary myeloid metaplasia.

Chromium-51 and iron-59 studies in patients with primary myeloid metaplasia show that the anaemia of the condition is dependent on depression of marrow activity, aggravated in about one-third of cases by accelerated red cell destruction to which the marrow compensatory response is inadequate. Surface measurements of isotope activity assist in assessing dependence on extramedullary sites for erythropoiesis and in diagnosis. The relevance of these findings to the hypotheses of the pathogenesis of the condition is discussed.