Uroporphyrinogen I synthase assay as an evaluation of the in vitro development of human BFU-E and CFU-E

We describe a simple spectrophotometric microassay to quantify the proliferation and the differentiation of human bone marrow or blood erythroid progenitor cells CFU-E and BFU-E. These precursors give rise, in culture, to colonies and bursts with markedly variations in size and hemoglobinization, which cannot be accurately evaluated by the usual method of scoring. We then developed a sensitive biochemical microassay to measure the uroporphyrinogen I synthase activity of progenitors grown in small wells. This assay is a valuable index of erythroid differentiation in vitro. This method can offer the opportunity to test the efficiency in vitro of various therapeutic agents in patients with hemopoietic disorders.