In patients with hematological disorders receiving aHSCT, a low BC count is observed in the first months after aHSCT with an increase over 3–18 months and CD4 TC remain low for at least a year or longer, whereas CD8 + TC return sooner, i.e. 3–18 months after aHSCT [24, 25]. The gene discussed is CD8A; the disease is hematologic disorder.