Identification of molecular markers for pre-engraftment immune reactions after cord blood transplantation by SELDI-TOF MS

Umbilical cord blood transplantation: Still growing and improving

Umbilical cord blood transplantation (UCBT) has been performed in the clinic for over 30 years. The biological and immunological characteristics of umbilical cord blood (UCB) have been re-recognized in recent years. UCB, previously considered medical waste, is rich in hematopoietic stem cells (HSCs), which are naïve and more energetic and more easily expanded than other stem cells. UCB has been identified as a reliable source of HSCs for allogeneic hematopoietic stem cell transplantation (allo-HSCT). UCBT has several advantages over other methods, including no harm to mothers and donors, an off-the-shelf product for urgent use, less stringent HLA match, lower incidence and severity of chronic graft-vs-host disease (GVHD), and probably a stronger graft-vs-leukemia effect, especially for minimal residual disease-positive patients before transplant. Recent studies have shown that the outcome of UCBT has been improved and is comparable to other types of allo-HSCT. Currently, UCBT is widely used in malignant, nonmalignant, hematological, congenital and metabolic diseases. The number of UCB banks and transplantation procedures increased exponentially before 2013. However, the number of UCBTs increased steadily in Asia and China but decreased in the United States and Europe year-on-year from 2013 to 2019. In this review, we focus on the development of UCBT over the past 30 years, the challenges it faces and the strategies for future improvement, including increasing UCB numbers, cord blood unit selection, conditioning regimens and GVHD prophylaxis for UCBT, and management of complications of UCBT.

Pre-engraftment syndrome after myeloablative dual umbilical cord blood transplantation: risk factors and response to treatment

High fevers and/or rashes prior to neutrophil engraftment are frequently observed after umbilical cord blood (UCB) transplantation, and the condition is referred to as pre-engraftment syndrome (PES). Few studies have evaluated the risk factors for and treatment response to PES. Therefore, we retrospectively characterized PES in 57 consecutive engrafted patients (≥ 12 years old) who received myeloablative dual UCB transplantation. All patients received TBI (≥ 13.2 Gy)-based myeloablative conditioning. Tacrolimus (n=35) or CYA (n=22) combined with mycophenolate mofetil was used as GVHD prophylaxis. PES was defined as the presence of non-infectious fever (≥ 38.5 °C) and/or rash prior to or on the day of neutrophil engraftment. The incidence (95% confidence interval) of PES was 77% (66-88%). The incidence of PES was significantly higher in patients who received CYA as a GVHD prophylaxis than those who received tacrolimus (P<0.001), and this association was confirmed in the multivariate analysis. The occurrence of PES did not impact OS or tumor relapse, although it may have increased non-relapse mortality (P=0.071). The incidence of acute GHVD or treatment-related mortality was not influenced by the choice to use corticosteroids to treat PES. This study suggests that use of CYA for GVHD prophylaxis increases the risk of PES following dual UCB transplantation.

Pre-engraftment syndrome after unrelated donor umbilical cord blood transplantation in patients with hematologic malignancies

Pre-engraftment syndrome (PES) after umbilical cord blood transplantation (CBT) remains poorly characterized, and the prognosis and appropriate management are unclear. Therefore, we retrospectively analyzed the incidence, risk factors, manifestations, and clinical outcomes of PES in CBT recipients, who had been treated for hematologic malignancies at our transplantation center. PES was defined as unexplained fever higher than 38.3°C that is not associated with documented infection and unresponsive to antimicrobial manipulations and/or unexplained erythematous skin rash occurring prior to neutrophil engraftment. A total of 81 patients (median 18 yr, range 3-48) received either myeloablative (n=72) or non-myeloablative (n=9) conditioning. Neutrophil engraftment was achieved in 69 of the 81 cases [86.2%, 95% confidence interval (CI)=78.9-94.1%], and the median time to more than 0.5 × 10(9) /L ANC was 19 d (range, 12-39). Fifty-one patients (63.0%) developed PES at a median of 7d (range 3-15) post-transplant: 46 patients had both rash and unexplained fever; one patient had unexplained fever alone; and four patients had rash only. Forty-seven patients (92.2%) received IV methylprednisolone (MP) at a median dose of 1 mg/kg (range 0.4-3). All patients treated with MP responded as evidenced by fever resolution combined with resolution of rash. All patients with PES had high serum levels of C-reactive protein (CRP), which were significantly reduced after effective steroid treatment. Univariate analysis identified myeloablative conditioning and younger age as significant risk factors for developing PES. Cumulative incidence of grade II-IV acute graft-versus-host disease (aGVHD) in the PES+ and PES- groups was 51.5% (95% CI=38.0-70.0%) and 17.0% (95% CI=6.9-41.7%), respectively. In a multivariate analysis, we found significantly increased risk of grade II-IV aGVHD among PES patients (P=0.041). However, PES was not associated with sustained donor engraftment, the day to neutrophil recovery, chronic graft-versus-host disease, transplant-related mortality at day 180, and overall survival. Despite of the inherent limitations of this small retrospective study, PES seemed to be common after CBT and associated with high incidence of aGVHD.