Stable Long-Term Donor Engraftment following Reduced-Intensity Hematopoietic Cell Transplantation for Sickle Cell Disease

Recovery of (A) neutrophils and platelets, and (B) hemoglobin levels during the first 100 days following HCT in patients 1-7. Median duration of neutropenia (defined as ANC <0.5 × 10⁹/L) was 13 days (range: 8-17 days). Median duration thrombocytopenia requiring transfusion (platelet count <50 × 10⁹/L) was 17 days. Median duration of days during which platelet and PRBC transfusions were needed are indicated by the shaded gray regions.

Lineage-specific peripheral blood donor chimerism at 1 year after HCT. Chimerism was examined in the mononuclear (dark gray bars), CD3⁺ lymphoid chimerism (light gray), and RBC precursor (black bars) compartments. ∗Sample unavailable for analysis.

At 1-year post-HCT, transplanted SCD patients with stable engraftment demonstrate percentage of hemoglobin S (Hb S) in peripheral blood of a similar level to their donors. Patients 1, 3, and 5 received HCT from donors with sickle cell trait, wheres the donors of patients 2, 4, and 6 were normal nonsickle trait (AA) donors.

Lineage-specific peripheral blood donor chimerism at the time of last contact (2-8.5 years post-HCT). Chimerism was examined in the mononuclear (dark gray bars), CD3⁺ lymphoid chimerism (light gray), and red blood cell precursor (black bars) compartments.