Maybe the donor and the recipient both get leronlimab for 10 weeks prior to BMT to saturate all their CCR 5 receptors before transplant. Then the donor marrow is blocked from HIV infection immediately upon transplant to the recipient. Otherwise saturating all the CCR5 receptors in the new donor marrow may take a few weeks once in the recipient which may give the residual virus enough time to infect the new marrow prior to full CCR5 saturation.