Additionally, a significant association was found between MBL levels < 1000 ng/mL in the pre-transplant (before conditioning) and the risk of virus infection after Allo-HSCT, in the early (RR 2.48, 95% CI 1.00–6.13), neutropenic (RR 3.28, 95% CI 1.53–7.06) and intermediate periods (RR 2.37, 95% CI 1.15–4.90). This evidence concerns the gene MBL2 and viral infectious disease.