QUANTITATIVE AND QUALITATIVE CHARACTERISTICS OF COLONY-FORMING UNIT-ERYTHROID COLONIES IN MYELODYSPLASTIC SYNDROME PATIENTS

The microcytofluorometrical method was applied to determine the relati ve hemoglobin (Hb) content in the bone marrow colony-forming unit-eryt hroid (CFU-E) colonies from 6 patients with myelodysplastic syndromes (MDS) and 10 healthy subjects. This method relies on a photochemical r eaction, by which intracellular Hb is converted into fluorescent porph yrin using a 0.2 M mercaptoethylamine solution (an SH donor) and viole t light (lambda = 405 nm). The relative Hb content was determined as a function of the intensity of emitted porphyrin fluorescence. The numb er of colonies identified by porphyrin fluorescence was smaller in MDS patients than in normal subjects. The relative Hb content was also lo wer in MDS patients than in normal subjects. In addition, the coeffici ent of variation of the relative Hb content in the CFU-E colonies was larger in MDS patients than in normal subjects. These findings suggest that colonies with low relative Hb content undergo impaired erythropo iesis and that the CFU-E colonies undergoing the impaired erythropoies is are mixed with CFU-E colonies showing normal erythropoiesis in the bone marrow of MDS patients.