Hematopoietic Stem Cell Transplantation (HSCT) for Malignancies Using Plasma Depleted Umbilical Cord Blood (UCB) That Were Not Red Blood Cell Depleted.

Cell dosage is a limiting factor for UCB HSCT, especially for adult patients. Most UCB banks practice red cell depletion (RCD) techniques to save storage space, which incur significant nucleated cell loss after processing. One method to minimize cell loss and still reduce volume after processing is to deplete plasma (PD), but not the red blood cells. Not washing UCB (NW) after thawing also minimizes cell loss. A large racially diverse PD UCB inventory of over 25,000 units is now available on stem cell registries. There were 70 ALL, 54 AML, 19 CML, and 45 others transplanted for malignant indications. A retrospective audited analysis was performed on 170 patients with engraftment and/or survival information. Of the ALL/AML/CML cases with available information, there were 32 1CR/CP, 33 2CR, and 13 3CR/CP. The median age of patients was 13 years old (range 05–59); median weight 50 kg (range 5–137); male 45%. Transplant characteristics indicated a median # HLA ABDR matches of 4.0; median pre-freeze TNC dose 4.1 × 10⁷/kg; median post-thaw TNC dose as reported by TC 3.7 × 10⁷/kg; median pre-freeze CD34 dose 1.4 × 10⁵/kg; transplants outside of U.S. 34%; double unit transplant 30%; non-myeloablative 16%. Sixty-one percent of the transplanted UCB were washed post-thaw (W), 39% were infused without post-thaw wash (NW), with 20% of the units without available post-thaw data. Kaplan-Meier estimates of 3-month ANC500 and 6-month platelet 20K and 50K engraftment are 89±3%, 81±5%, and 73±5% respectively. Median time to engraftment for ANC 500, platelet 20K, and 50K were 22 days (range 7–69 days), 52.5 days (range 12–181 days), and 64 days (range 25–374 days) respectively. Median time to engraftment for post-thaw washed units (W) versus PD CBU not washed and infused directly after thawing (NW) were 24 vs. 22 days for ANC500, and 57 vs. 48 days for platelet 20K respectively. The incidence of reported grade II-IV and III-IV acute GVHD were 32% and 14% respectively. Twelve percent developed limited chronic GVHD and 14% developed extensive chronic GVHD. With a median follow-up of 170 days (range 4–1402 days), the Kaplan-Meier estimates of 1-year TRM, OS and relapse-free survival were 31±4%, 51±4% and 47±4% respectively. These results demonstrate that HSCT using unrelated PD UCB can be performed safely and effectively in patients with malignancies, and post-thaw wash may not be necessary.