Immunophenotype in erythroleukemia secondary to myelodysplastic syndrome.

In the August 1,1991 issue ofBlood, San Miguel et all published a report of 41 acute leukemia cases secondary to a myelodysplastic syndrome (MDS). Two were classified as M6 French-AmericanBritish (FAB) subtype on morphologic aspect, but the only erythroid immunologic marker tested, ie, glycophorin A, was negative. This characteristic, owing to the fact that glycophorin A is a relatively mature erythroid marker,2 may be responsible for an underestimation of this type of MDS transformation. We report two cases of M6 acute myeloid leukemia (AML) after MDS in which we tested glycophorin A (Immunotech, Marseille, France) and more immature erythroid markers such as CD71 (Ortho Diagnostic Systems, Raritan, NJ), CD34 (Sera-Lab, Biosys, France), and HLA-DR (Ortho). Immunologic phenotyping was performed on separated cells from bone marrow aspirate by an indirect immunofluorescent method and analyzed by flow cytometry (FACScan; Becton Dickinson, Mountain View, CA). The expression of glycophorin A, CD34, and HLA-DR on a few cells from our patients is presented in Table 1. In both cases, CD71 is more expressed than any other marker. This phenotype corresponds to the last level of normal erythroblastic precursors differentiation (PIV) described by Terstappen et al,3 ie, decreased CD34 and increased CD71 expressions. Glycophorin A is expressed on more mature erythroblasts present in bone Table 1. Results of lmmunophenotyping Observed in Two Cases of M6 AML Secondary to MDS