Proposal of criteria for dyserythropoiesis in the diagnosis of myelodysplastic syndromes.

The percentage manifesting dysplasia in bone marrow needed to qualify as significant is ≥10 % in each lineage. However, detailed analyses of this threshold have not been reported. Here, we analyzed dyserythropoiesis (dysE) in 109 myelodysplastic syndromes (MDS) patients with 21 immune thrombocytopenia (ITP)/12 hemolytic anemia (HA) patients as a control. In present study, mild megaloblastic erythroblasts were specifically named 'red cell with abnormal chromatin clumping (RCACC)'. RCACC ≥10 % in erythroblasts was observed in 29 % of ITP patients and 58 % of HA patients. The numbers of MDS patients with RCACC in erythroblasts <10, 10-19 and ≥20 % were 1, 3, and 105, respectively. We analyzed dysE criteria according to the WHO classification (original WHO dysE). Most of our MDS patients (98 %) had original WHO dysE ≥20 %. The ITP patients with original WHO dysE ≥10 % was 48 %, and there were no ITP patients had original WHO dysE ≥20 %. Sixty-seven percent of HA patients had original WHO dysE ≥10 %, and three patients (25 %) had original WHO dysE ≥20 %. Raising the threshold of the original WHO dysE from 10 to 20 or 30 % may provide more suitable criteria. If RCACC is not included in dysE criteria, we think that '10 %' is a suitable threshold for the determination of dyserythropoiesis.