Abstract
Haploidentical hematopoietic cell transplantation (HHCT) using CD3/CD19 depleted grafts may lead to faster engraftment and immune reconstitution since grafts contain also graft-facilitating-cells, CD34− progenitors, NK cells, and dendritic cells. Reduced intensity conditioning may also have a positive impact on immune reconstitution following HHCT. 26 adults received CD3/CD19 depleted HHCT after RIC (150–200 mg/m2 fludarabine, 10mg/kg thiothepa, 120 mg/m2 melphalan and 5mg/day OKT-3 (day −5 to +14)) at our institution between 2005–2008. We prospectively evaluated engraftment and immune reconstitution. B-, NK-, T- and T-cell subsets (CD3/8, CD4/8, CD4/45RA/RO), TCR-Vβ repertoire and NK-cell receptors (NKP30, NKP44, NKP46, NKG2D, CD158a/b/e, CD85j, NKG2A, CD161) were analyzed by FACS. Grafts contained 8.8×106 CD34+ (range, 4.3–18.0 ×106), 2.9×104 CD3+ (range, 1.2–9.2×104) and 3.6×107 CD56+ (range, 0.02–23.0 ×107) cells/kg. Engraftment was rapid with a median time to >500 granulocytes/μl of 11 days (range, 9–15) and a median time to >20 000 platelets/μl of 11 days (range, 8–23). Full chimerism was reached on day 14 (median; range, 6–26). NK-cell engraftment was rapid, reaching normal values on day 20 (median of 247 CD16+CD56+CD3− cells/μl (range, 1–886)) with NK cells comprising up to 70% of lymphocytes. B-cell reconstitution was delayed with 81 (range, 0–280) and 335 (range, 11–452) CD19+20+ cells/μl on days 150 and 400, respectively. T-cell reconstitution was impaired with 49 (range, 0–586) and 364 (range, 35–536) CD3+ cells/μl on day 60 and day 150, respectively. We observed an increase of CD3+CD8+ cells in contrast to CD3+CD4+ cells early after HHCT with a median of 24 (range, 0–399) vs 16 (range, 0–257) and 159 (range, 1–402) vs 96 (range, 18–289) cells/μl on day 50 and day 200, respectively. CD4+CD45RA+ T cells increased slowly while CD4+CD45RO+ T cells reconstituted faster with a median of 61 CD4+CD45RO+ cells/μl (range, 0–310) vs 24 CD4+CD45RA+ (range, 0 to 152) on day 100. Within the CD4+CD25+ regulatory T cells there was a slow regeneration with median of 14 CD4+CD25+ cells/μl (range, 0–96) on day 100 and 28 CD4+CD25+ cells/μl (range, 19–160) on day 200. CD14+CD45+ monocytes did not reach normal values within the time of observation with 7 CD14+CD45+ cells/μl (range, 0–21) on day 120 and 7 CD14+CD45+ cells (range, 2–381) on day 400. TCR-Vβ repertoire and NK-cell receptor reconstitution was analyzed so far in 7 and 8 patients, respectively. We found a skewed T-cell repertoire with oligoclonal T-cell expansions to day 100 and normalization after day 200. An increased natural cytotoxicity receptor (NKP30, NKP44, NKP46) and NKG2A, but decreased NKG2D and KIR-expression was observed on NK-cells until day 100. In conclusion, T- and B-cell reconstitution is delayed after HHCT using CD3/CD19 depleted grafts and RIC. However, T-cell reconstitution is faster compared to data published with CD34 selected grafts and myeloablative conditioning. A fast NK-cell reconstitution early after HHCT was observed. Thus a combination of reduced intensity conditioning with CD3/CD19 depleted grafts appears to accelerate the immune recovery after haploidentical stem cell transplantation.
Use of Myeloablative or Reduced Intensity Conditioning with Haploidentical Hematopoietic Cell Transplantation for Acute Leukemia and MDS is Associated with Similar Outcomes
