Figure 1. Curve of hemoglobin and reticulocytes values, and response to treatment with daratumumab. Changes in hemoglobin concentration (blue line, right y-axis) and absolute reticulocyte count (orange line, left y-axis) in a patient after allogeneic hematopoietic cell transplantation with ABO major incompatibility (case 2). The x-axis indicates days after transplantation. The black arrow marks the initiation of rituximab treatment, and the red arrow marks the initiation of daratumumab treatment. A marked increase in reticulocyte count and gradual recovery of hemoglobin were observed following daratumumab administration.