HLA-DRB1 and viral infectious disease: Regarding the HLA mismatch, univariate analysis showed that HLA-C mismatch was associated with a significantly higher incidence of viral infection within 100 days of CBT (mismatched vs. matched; 42.4% vs. 14.3%, HR 3.67 [1.33–10.1], p = 0.01), while HLA-A, B, and DRB1 allele mismatches were not related to a significantly higher incidence of viral infections (Table 2, Fig. 1B–E).