[Deciphering Hypoplastic Myelodysplastic Syndrome and Aplastic Anemia via In-Depth Analysis of Lymphocyte Subsets]

To explore the difference of lymphocyte subsets in peripheral blood (PB) between aplastic anemia (AA) and hypoplastic myelodysplastic syndrome (hypo-MDS) patients, meanwhile to compare the clinical parameters obtained from PB and bone marrow (BM).

The lymphocyte subsets in hypo-MDS (n=25) and AA (n=33) patients were investigated by flow cytometry. Meanwhile, the differences in PB cell counts, biochemical indicators, BM cell counts and abnormal chromosomes between the two groups were analyzed.

The percentage of CD8⁺T cells in AA group was significantly higher than that in hypo-MDS group (P=0.001), while the percentage of CD4⁺ T cells and the CD4⁺/CD8⁺ ratio in AA group were obviously lower than those in hypo-MDS group (P=0.015 and 0.001, respectively). Furthermore, the proportion of CD4⁺ and CD8⁺ activated T (TA) cells, and memory Tregs in AA group was distinctly lower than those in hypo-MDS group (P=0.043, 0.015 and 0.024, respectively). Nevertheless, the percentage of CD8⁺ naive T (TN) cells in AA patients was remarkably higher (P=0.044). And hypo-MDS patients had declined lymphocyte counts (P=0.025), increased levels of total bilirubin (TBil), lactate dehydrogenase (LDH), vitamin B12 and proportion of BM blasts than AA patients (P=0.019, 0.023, 0.027 and 0.045, respectively).

In this study it was confirmed that the percentages of CD4⁺ and CD8⁺ TA cells, memory Tregs and CD8⁺ TN cells were significantly different between AA and hypo-MDS patients, which provide an essential basis for the identification of these two diseases.