In multivariate analysis (Table 3), stratification of patients into low and high groups based on the proportion of CD3+CD4+CD161+ T cells by ROC curve analysis revealed a significant protective role for the proportion of pretransplant CD3+CD4+CD161+ cells against the occurrence of mucositis (≥grade 3) (cutoff of 3.72%, relative risk (RR) of 0.19, P = 0.020). The gene discussed is KLRB1; the disease is mucositis.