Clinical impact and characteristics of erythroid dysplasia in adult aplastic anaemia: Results from a multicentre registry

Morphological dysplasia in haematopoietic cells, defined by a 10% threshold in each lineage, is one of the diagnostic criteria for myelodysplastic neoplasms. Dysplasia limited to the erythroid lineage has also been reported in some cases of aplastic anaemia (AA); however, its significance remains unclear. We herein examined the impact of erythroid dysplasia on immunosuppressive therapy responses and survival in AA patients. The present study included 100 eligible AA patients without ring sideroblasts. Among them, 32 had dysplasia in the erythroid lineage (AA with minimal dysplasia [mini-D]). No significant sex or age differences were observed between AA groups with and without erythroid dysplasia. In severe/very severe AA and non-severe AA patients, a response to anti-thymocyte globulin + ciclosporin within 12 months was observed in 80.0% and 60.0% of AA with mini-D and 42.9% and 90.0% of those without dysplasia, with no significant difference (p = 0.29 and p = 0.24 respectively). Overall survival and leukaemia-free survival did not significantly differ between the groups. Collectively, the present results indicate that the presence of erythroid dysplasia did not significantly affect clinical characteristics or outcomes in AA patients, suggesting that its presence in AA is acceptable. Therefore, erythroid dysplasia should not exclude an AA diagnosis. It is difficult to distinguish between MDS and AA in clinical practice, especially when only erythroid dysplasia is present in patients who have bone marrow hypoplasia without an increase in blasts. In the morphological diagnosis of MDS and AA, the central review team in Japan distinguishes between the two diseases by especially focusing on the number of MgK. In this study, we found that erythroid dysplasia is also observed in AA and does not significantly affect the clinical features or impact the outcome of patients with AA. In conclusion, the finding of erythroid dysplasia alone should not exclude a diagnosis of AA. AA, aplastic anaemia; MDS, myelodysplastic neoplasms; MgK, megakaryocytes; OS, overall survival.image