CD34-selected stem cell boost was an effective treatment for refractory poor hematopoietic reconstitution after haploidentical hematopoietic stem cell transplantation.

Abstract

Poor hematopoietic reconstitution (PHR), especially poor graft function (PGF) and prolonged isolated thrombocytopenia (PT), is a life-threatening complication after allo- hematopoietic stem cell transplantation (HSCT). Currently, almost no studies have analyzed CD34+-selected stem cells "boost" (SCB) after haplo-HSCT. Hence, in this study, we focused specifically on refractory PHR after haplo-HSCT. To retrospectively evaluate the safety and efficacy of donor- CD34+ SCB for the treatment of refractory PHR after haplo-HSCT. Twenty-seven patients with refractory PHR who received a donor-CD34+ selected SCB at Peking University People's Hospital were retrospectively analyzed. The patients' hematopoietic response, incidence of graft-versus-host disease, and survival after CD34+ cell boost were evaluated. Among the 27 patients with refractory PHR who received a CD34+ SCB, five patients (18.5%) were diagnosed with primary PGF, 17 patients (63%) were diagnosed with secondary PGF, and five patients (18.5%) were diagnosed with PT. The median time to PHR diagnosis was 63 days (range: 42-330 days), and the median time to the donor CD34+ boost was 456 days (range: 58-853 days). The median number of infused CD34+ cells was 2.589 × 10⁶/kg (range: 0.738-16.8 × 10⁶/kg). Among the 27 patients, 15 achieved hematologic response (55.56%). Among the responders, the median time of absolute neutrophil count (ANC) response was 15 days (range: 10-158 days), and the median time of erythroid reconstitution was 18 days (range: 7-158 days). The platelet reconstitution time was 22 days (range: 7-171 days). Patients with acute infection during CD34+ SCB were noted to have a worse hematologic response (1/15 vs. 5/12, P = 0.03). The mortality rate significantly differed between patients who achieved complete hematologic response and those who did not (100% vs. 33.3%, respectively; P < 00.001). Infections were the leading cause of death (n = 5/8, 62.5%). CD34+-selected SCB is a potentially effective treatment for refractory PHR after haploidentical HSCT.