The myelodysplastic syndrome: analysis of laboratory characteristics in relation to the FAB classification.

A detailed study of 43 newly diagnosed cases of myelodysplastic syndrome (MDS) shows that many of the morphological features of blood and bone marrow are common to the different FAB groups. In addition, there is no clear distinction between the groups with regard to CFU-E, BFU-E or CFU-GM colony growth in vitro or ferrokinetic assessment of erythropoiesis in vivo. The interrelationships between all the parameters we have studied have been examined and there is little correlation between erythroid colony formation in vitro, the percentage erythroblasts in the bone marrow, erythroid output measured by ferrokinetics and the peripheral blood reticulocyte count, all of which appear to measure different aspects of erythropoiesis. Reduced erythroid colony growth and a high degree of ineffective erythropoiesis in vivo are common in all groups and appear to be an early manifestation of abnormal function. Decreasing marrow iron turnover is more closely related to increasing numbers of marrow blast cells than any other index of erythropoiesis.