CD4 and myelodysplastic syndrome: Concerning the T cell subsets, AA patients had a lower frequency of γδ T cells than controls (3.6% vs. 7.6%, p < 0.05), and MDS-h patients presented an increased proportion of activated CD4+ T cells (6.4% vs. 4.0%, p < 0.05), including the HLA-DR+ naive subset (8.2% vs. 4.8%, p < 0.05).