IFNA2 and graft versus host disease: During the same period, 11 patients with MRD failed to receive preemptive IFN-α therapy because of following reasons: active GVHD (n = 3), severe myelosuppression (n = 1), active infection: (n = 1), and MRD turned negative without interventions (n = 6) (Supplementary Table 8 and Figure 1).