Compared with mice without HSCT, T1DM mice treated with HSCT have higher serum insulin levels, lower lymphocyte infiltration levels, and a lower percentage of CD8 + T cells, the survival rate of mice was found to be higher, which confirms the role of HSCT in improving islet cell tolerance, effectively treating T1DM, and improving hematopoietic function [179]. The gene discussed is CD8A; the disease is type 1 diabetes mellitus.