Cord Blood Hematopoietic Cells Research Articles

Identifying the Optimal Conditioning Intensity of Hematopoietic Stem Cell Transplantation in Patients with Acute Myeloid Leukemia in Complete Remission

Background Allogeneic hematopoietic stem cell transplantation (HSCT) as consolidation therapy is considered a curative option for acute myeloid leukemia (AML) in complete remission (CR) to prevent relapse. Many studies have investigated the optimal conditioning intensity, comparing reduced-intensity conditioning regimen (RIC) and myeloablative conditioning regimen (MAC) for patients with AML in CR. However, inconsistent results have been observed, possibly due to selection biases and significant heterogeneous treatment effects when focusing on average treatment effect. Some studies have attempted to assess treatment effects in specific subgroups, highlighting the heterogeneity conditioning intensity's impact. However, these analyses typically examined one factor at a time, overlooking potential multiple-factor combinations that might contribute to such heterogeneity.To address these limitations and surpass conventional comparison studies and subgroup analyses, machine-learning methods for group identification have been developed. In this study, we aimed to identify patient groups in which MAC or RIC had a superior PFS in patients with AML in CR using a machine-learning approach. Methods Our study included 3273 patients aged 40-69 years with AML in CR from the TRUMP2. These patients were divided into training (N=2020) and validation cohorts (N=1253). In the training cohort, we employed a group identification model to identify patient subsets. Preprocessing of variables was performed to ensure the ease of use in clinical practice. We modeled the magnitude of interaction between treatment and covariates without the main effect of covariates, thus leading to the construction of a scoring system that measures the individualized-treatment effect. The objective variable was set as 1-year PFS, and the interaction effects between treatment and covariates were estimated using a regression model with propensity score weight and LASSO regularization. The sum of the interaction term between treatment and covariates was defined as the “Conditioning Intensity Score”. Patients were categorized into high-score and low-score groups using a cut-off level of median in patients who received RIC. Subsequently, in the validation cohort, we estimated the average treatment effect of RIC compared to MAC for each group with hazard ratios (HR) using inverse treatment probability weight analysis. Results In the training cohort, the median age was 55 years (IQR, 48-61 years), with 1110 (55%) male patients. Among them, 666 (33%) received RIC, while the others underwent MAC. Conditioning Intensity Model was developed and consistent with followings; age over 49 (1.4 points), age over 49 and male (0.8 points), age over 49 and poor karyotype (0.5 point), age over 49 and cord blood transplantation (0.9 points), poor karyotype (-1.6 points), poor karyotype and primary induction failure (8.0 points), poor karyotype and bone marrow transplantation (-5.3 points), cord blood transplantation and hematopoietic cell transplant comorbidity index over 2 (2.1 points) and cord blood transplantation and extra bone marrow involvement (-8.6 points). The cut-off level was set as 2.2. The weighted HR of RIC on 1-year PFS was 0.56 (95%CI; 0.40-0.79, p < 0.001) in the high-score group and 1.23 (95%CI: 0.97- 1.57, p=0.094) in the low-score group. In the entire validation cohort, there were no significant differences in PFS between the RIC and MAC (67.7% [95% CI: 62.1-70.3%] in the RIC group vs. 70.3% [95% CI: 67.2-73.1%] in the MAC group, P=0.318). Patients were divided into two groups based on Conditioning Intensity Score. In the high-score group, the 1-year PFS was 73.9% (95% CI: 65.0-80.9%) in the RIC group vs. 66.2% (95% CI: 58.3-73.0%) in the MAC group ( P=0.181), with a weighted HR of 0.69 (95% CI: 0.43-1.11) for PFS in the RIC group compared to that the MAC group ( P=0.125) (Figure left). Conversely, in the low-score group, the 1-year PFS was 63.7% (95% CI: 56.3-70.2%) in the RIC group vs. 71.2% (95% CI: 67.8-74.2%) in the MAC group ( P=0.031), with a weighted HR of 1.35 (95% CI: 0.96-1.89) in the RIC group compared to the MAC group (log-rank P=0.086) (Figure right). Conclusion In conclusion, we have demonstrated the feasibility of utilizing a machine learning method for subgroup identification of conditioning regimens in patients with AML in CR. This established model holds promise for designing patient-specific regimens.

Hematopoiesis in the spleen after engraftment in unrelated cord blood transplantation evaluated by 18F-FLT PET imaging.

Cord blood is an important donor source for allogeneic hematopoietic stem cell transplantation (allo-HSCT), with its unique composition and quality of hematopoietic cells. The proliferation site and potency of infused hematopoietic stem cells in humans may vary between stem cell sources. We investigated this possibility in a prospective, exploratory study to assess hematopoietic dynamics using the radiopharmaceutical 3'-deoxy-3'-18F-fluorothymidine (18F-FLT), a thymidine analog used in positron emission tomography imaging, before allo-HSCT and on days 50 and 180 after allo-HSCT. We evaluated 11 patients with hematological malignancies who underwent allo-HSCT [five with peripheral blood stem cell transplantation (PBSCT) and six with unrelated cord blood transplantation (UCBT)]. Before allo-HSCT, 18F-FLT uptake did not differ between the two groups. At day 50, 18F-FLT uptake in the spleen was significantly greater in the UCBT group than in the PBSCT group (p = 0.0043), with no difference in whole-body bone marrow. At day 180, the differences in spleen uptake had diminished, and there were no differences between groups in whole-body bone marrow or the spleen, except for the sternum. The persistence of splenic hematopoiesis after engraftment in the UCBT group may reflect the complex systemic homing and proliferation mechanisms of cord blood hematopoietic cells.

Transient regulation of RNA methylation in human hematopoietic stem cells promotes their homing and engraftment

Enhancing the efficiency of hematopoietic stem cell (HSC) homing and engraftment is critical for cord blood (CB) hematopoietic cell transplantation (HCT). Recent studies indicate that N6-methyladenosine (m6A) modulates the expression of mRNAs that are critical for stem cell function by influencing their stability. Here, we demonstrate that inhibition of RNA decay by regulation of RNA methylation, enhances the expression of the homing receptor chemokine C-X-C receptor-4 (CXCR4) in HSCs. We show that YTH N6-methyladenosine RNA binding protein 2 (YTHDF2), a m6A reader and FTO α-ketoglutarate dependent dioxygenase (FTO), a m6A eraser play an opposite role in this process. Through screening, we identified several FDA-approved compounds that regulate the expression of YTHDF2 and FTO in CB CD34+ cells. We show that transient downregulation of YTHDF2 or activation of FTO by using these compounds inhibits CXCR4 decay in CB HSCs and promotes their homing and engraftment. Our results demonstrate a novel regulation strategy to enhance the function of CB HSCs and provide a translational approach to enhance the clinical efficacy of HCT.

Engineering human mini-bones for the standardized modeling of healthy hematopoiesis, leukemia, and solid tumor metastasis.

The bone marrow microenvironment provides indispensable factors to sustain blood production throughout life. It is also a hotspot for the progression of hematologic disorders and the most frequent site of solid tumor metastasis. Preclinical research relies on xenograft mouse models, but these models preclude the human-specific functional interactions of stem cells with their bone marrow microenvironment. Instead, human mesenchymal cells can be exploited for the in vivo engineering of humanized niches, which confer robust engraftment of human healthy and malignant blood samples. However, mesenchymal cells are associated with major reproducibility issues in tissue formation. Here, we report the fast and standardized generation of human mini-bones by a custom-designed human mesenchymal cell line. These resulting humanized ossicles (hOss) consist of fully mature bone and bone marrow structures hosting a human mesenchymal niche with retained stem cell properties. As compared to mouse bones, we demonstrate superior engraftment of human cord blood hematopoietic cells and primary acute myeloid leukemia samples and also validate hOss as a metastatic site for breast cancer cells. We further report the engraftment of neuroblastoma patient-derived xenograft cells in a humanized model, recapitulating clinically described osteolytic lesions. Collectively, our human mini-bones constitute a powerful preclinical platform to model bone-developing tumors using patient-derived materials.

Natural Killer Cell Alloreactivity Predicted By Killer Cell Immunoglobulin-Like Receptor Ligand Mismatch Does Not Impact Engraftment in Umbilical Cord Blood and Haploidentical Stem Cell Transplantation

Natural killer cell alloreactivity is determined by killer cell immunoglobulin-like receptor (KIR) ligands in donor and recipient pairs. A small, single institution study suggested that the risk of primary graft failure after cord blood hematopoietic cell transplantation (CBT) can be predicted by host-versus-graft (HvG)–directed natural killer cell alloreactivity. In the haploidentical transplantation (Haplo HCT) cohort, graft failures were observed only in graft-versus-host (GvH) KIR ligand mismatched pairs. A subsequent study was designed to explore the association between HvG and GvH KIR ligand mismatching and engraftment in both CBT and Haplo HCT using the large, multicenter transplant population of the Center for International Blood and Transplant Research database. Nine hundred single CBT (sCBT), 954 double CBT (dCBT), and 671 Haplo HCT performed between 2008 and 2017 for acute leukemias and myelodysplastic syndrome were examined. Several models of KIR-L interactions were analyzed by multiple regression analyses for their association with engraftment, overall survival (OS), and transplant-related mortality (TRM). In sCBT, although HvG or bidirectional KIR ligand mismatch (KIR-L-MM) was initially associated with higher TRM in the first 6 months after transplantation, this effect was nullified after 6 months such that long-term survival was not different compared to GvH KIR-L-MM or KIR-L matched (KIR-L-M) pairs. There was no significant difference in neutrophil and platelet engraftment. In dCBT, no significant differences were seen in engraftment, OS and TRM. In the Haplo cohort there was faster platelet recovery in the GvH KIR-L-MM/KIR-L-M pairs versus HvG KIR-L-MM or bidirectional mismatch (HR 1.23, P= .0116). There was no significant association with OS, TRM, or neutrophil engraftment. In this large registry study, KIR-L mismatching did not significantly impact engraftment, TRM, or survival in CBT and Haplo HCT, although an association with platelet engraftment in Haplo HCT was demonstrated.

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs.

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns. A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34+ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34+ cells. Maternal triglycerides (TG) showed a significant positive association with BW and CD34+ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34+ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34+ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively). We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

Frequent Eczematous Dermatitis in Unrelated Cord Blood Hematopoietic Cell Transplant Recipients Compared With Other Donor Types

We have consistently noticed in our clinical practice eczematous dermatitis (EcD) without other pathologic findings of graft-versus-host disease (GVHD) in recipients of unrelated cord blood transplantation (CBT). We hypothesized that the incidence of EcD was higher in CBT compared with other donor types, and our objective in this study was to compare the frequency, clinical course, and response to therapy of EcD between CBT and non-CBT recipients. We conducted a retrospective study of 720 consecutive adult recipients of allogeneic hematopoietic cell transplants from 2010 to 2016 from any donor type and with follow-up for at least 1 year after transplantation. After using keyword-based automated scanning to identify "eczema," "dermatitis," or "spongiosis" terms in medical records, we retrieved 217 cases for manual record review. We identified 23 EcD cases (12 in CBT recipients and 11 in patients with other types of donors) with a median onset at 8 months after transplantation. The 2-year cumulative incidence of EcD was 20% (95% confidence interval [CI], 11.2% to 31.5%) after CBT and 1.7% (95% CI, .90% to 2.90%) with other types of donors (P < .0001). Fifteen cases had a skin biopsy without distinctive pathologic features of GVHD. The most common EcD-involved sites in CBT recipients were face (75%), neck (50%), and antecubital fossae (50%). Compared with patients with other types of donors, EcD after CBT was more likely to involve three or more sites (10 of 12 vs. 2 of 10; P=.008) and had a more protracted course (lasting >6 months in 6 of 58 vs. 1 of 661; P < .0001). In both groups, EcD responded to topical therapy, and only a few cases required systemic therapy. EcD is a relatively frequent skin condition among recipients of unrelated CBT. Irrespective of donor type, most cases of EcD can be successfully managed with only topical therapy. These findings will help providers recognize EcD, avoid potentially harmful systemic therapy, and better counsel transplant recipients.

Transfusion- Related Iron Overload (TRIO) Is Associated with Delayed Engraftment and Increased Non Relapse Mortality (NRM) in Patients Undergoing Umbilical Cord Blood (UCB) Hematopoietic Cell Transplantation (HCT)

▪TRIO has been shown to be associate with higher risk of morbidity (infections, venocclusive disease and hepatic dysfunction) and mortality after allogeneic HCT. A high transplant iron score (>25 red cell unit transfused prior to HCT, serum ferritin > 1000 ng/ml and a bone marrow (BM) iron stain of +6) was associated with 50% decrease in survival at one year (Storey J. Hem & Oncol 2009). TRIO in BM macrophages can generate free radicals resulting in oxidant stress thereby altering the hematopoietic microenvironment. This could have adverse effects on hematopoiesis and affect engraftment after HCT. To date, limited data are available on the effect of TRIO on outcomes of UCB HCT. We examined whether TRIO quantified based on serum ferritin (sF) and BM iron score (MIS) impact outcomes of UCB HCT, particularly with regards to engraftment.We reviewed 150 consecutive patients (pts) who underwent UCB HCT between March 2006 and September 2015 at City of Hope. Median age at time of HCT was 33.5 years (yrs) (range: 0-70 years) with 55% male and 23% < 18 yrs of age. sF was available within 30 days before HCT for 65%, and MIS was assessed on the pre-HCT BM biopsy for 40% of pts. HCT indications included bone marrow failure (n=13), hemoglobinopathies (n=2), lymphoma (n=23), acute leukemia (n=104), and chronic leukemia (n=8). Disease risk index (DRI) was high/very-high in 38% and 20% of pts had HCT comorbidity index of more than 2. One cord graft was received for 20% of pts. Median TNC of 4.9X10^7/kg (range: 1.8-26.6) and median CD34 count of 1.8X10^5/kg (range: 0.2-122.4). HLA match status was 4/6, 5/6, 6/6 in 93, 48, and 9 pts. Almost 60% of pts received myeloablative conditioning regimen (MAC) and 80% had calcineurin inhibitor/mycophenolate mofetil for graft versus host disease (GVHD) prophylaxis.With a median follow-up of 48.1 months (range: 5.8- 119.6), 2- and 5-yrs progression free survival (PFS) were 41% and 35.5% while 2- and 5-yrs OS were 47% and 36%, respectively. Cumulative incidence (CI) of NRM at 2 and 5 yrs were 35.7 and 40.6% and CI of relapse at 2- and 5-yrs were 23 and 24%, respectively. Day 100 grade II-IV and grade III/IV aGvHD were 56.7% and 28.7%. 2 yrs CI of cGvHD was 51.7% with 38.8% extensive cGvHD. DRI was found to be significant factor for relapse (HR 1.74 95%CI 0.88-3.45 p<0.001) and conditioning regimen significantly affect OS (HR= 1.92 95%CI 1.24-2.96; p=0.003), PFS (HR= 2.12 CI 1.39-3.24; p<0.001) and relapse rate (HR= 4.07 CI 1.95-8.49; p<0.001) when non-myeloablative/reduced intensity conditioning was compared with MAC. However, day 100 grade II-IV and III/IV aGVHD was increased in pts with MAC (65.1% vs 45.3%; p=0.006 and 37.2% vs 17.2%; p=0.005; respectively) with no significant effect seen on the NRM (p=0.9).In multivariable analysis, sF <1000 ng/ml independently predicted for shorter OS (HR=0.49; CI 0.27-0.88 p=0.015). When the impact of sF was examined by quartiles, pts in the highest sF quartile (>1948 ng/ml) had shorter OS (HR=3.05, 95%CI: 1.40-6.66; p=0.03) and higher NRM (HR=2.79, 95%CI: 1.16-6.72; p=0.03) compared to those in the lowest quartile (<530 ng/ml) (Fig 1a and b). There was no statistically significant difference in regards to disease relapse, or incidence of acute or chronic GVHD across sF groups.Patients in the highest sF quartile had delayed platelet engraftment compared to those in the lowest quartile (HR=0.46, 95%CI: 0.24-0.89, p=0.03). A trend towards delayed neutrophil engraftment was also observed between these 2 groups (HR=0.57, 95%CI: 0.33-0.99; p=0.055) (Fig 1c and d). No significant difference was seen in neutrophil (p=0.67) or platelet engraftment (p=0.92) based on MIS. But there was a statistically significant increase of grade II-IV aGVHD in pts with MIS of 3-4 (63.8% vs 30.8% at day 100; p=0.04). This however did not translate into worse OS, NRM or relapse.In conclusion, TRIO measured by sF has an adverse impact on OS and NRM in recipients of UCB HCT. Elevated sF is also associated with delay in platelet and neutrophil engraftment after UCB HCT. MIS was not associated with time to engraftment, however, this value was available in only 40% of pts. Therefore, TRIO should be considered as a risk factor for adverse outcome and poor graft function after UCB HCT. [Display omitted] DisclosuresNademanee:seattle Genetics: Speakers Bureau.

Prophylactic Foscarnet for Human Herpesvirus 6: Effect on Hematopoietic Engraftment after Reduced-Intensity Conditioning Umbilical Cord Blood Transplantation

The high incidence of human herpesvirus-6 (HHV-6) reactivation, potentially interfering with engraftment after umbilical cord blood (UCB) hematopoietic cell transplantation (HCT), remains a major challenge. To potentially address this problem, we evaluated the effect of prophylactic foscarnet administered twice daily beginning on day +7 and continuing through engraftment in 25 patients. To determine the impact of foscarnet on HHV-6, engraftment, and other transplantation outcomes, we compared results in 61 identically treated patients with hematologic malignancies. Treatment and control groups underwent reduced-intensity conditioning UCB HCT with a conditioning regimen of fludarabine, cyclophosphamide, and total body irradiation 200 cGy with or without antithymocyte globulin (ATG), using sirolimus plus mycophenolate mofetil immune suppression. The treatment and control groups were similar in terms of age, disease risk, use of ATG, Hematopoietic Cell Transplantation Comorbidity Index, and graft CD34 cell dose; however, foscarnet-treated patients were less likely to receive a double UCB graft and to be treated more recently (2016 to 2018). The cumulative incidence of HHV-6 reactivation by day +100 was 63% for all patients (95% confidence interval [CI], 51% to 75%) and was not significantly different between the 2 groups. HHV-6 reactivation occurred at a median of 34 days in the foscarnet group and 25.5 days in the control group. The incidence of neutrophil engraftment at day 42 was higher in the foscarnet group compared with the control group (96%; [95% CI, 83% to 100%] versus 75% [95% CI, 64% to 85%]; P< .01). The cumulative incidence of platelet engraftment by 6 months was 92% (95% CI, 69% to 100%) for the foscarnet group versus 75% (95% CI, 60% to 90%) for the control group (P= .08), and multivariate analysis identified the use of foscarnet as an independent predictor of better platelet engraftment. No patients died as a result of graft failure in recipients of foscarnet, whereas 5 patients died from graft failure in the control group. Six-month overall survival (OS) and nonrelapse mortality (NRM) were better in the foscarnet group (96% versus 72% [P= .02] and 4% versus 18% [P= .07], respectively). Even though foscarnet prophylaxis did not prevent HHV-6 viremia, we observed a delay in time to HHV-6 reactivation, a trend toward differences in engraftment, NRM, and OS compared with historical controls.

Human cord blood hematopoietic cells acquire neural features when cultured in the presence of neurogenic cytokines

In vitro growth of hematopoietic cells depends on the presence of hematopoietic cytokines. To date, it is unclear if these cells would be able to respond to non-hematopoietic cytokines. In the present study, we have explored this by culturing human hematopoietic cells in presence of neurogenic cytokines. Lineage-negative (Lin−) umbilical cord blood (UCB)-derived cells -enriched for hematopoietic stem and progenitor cells- were cultured in presence of different combinations of hematopoietic cytokines, neurotrophins, epidermal growth factor, fibroblast growth factor, and neurogenic culture media, in a 3-phase culture system. A proportion (1–22%) of Lin− UCB hematopoietic cells normally express neural markers and are capable of responding to neural cytokines. Neural cytokines did not have effects on hematopoietic cell proliferation; however, we observed generation of neural-like cells, assessed by morphology, and a significant increase in the proportion of cells expressing neural markers. Such neural-like cells, however, retained expression of hematopoietic markers. It seems that under our culture conditions, no actual transdifferentiation of hematopoietic cells into neural cells occurred; instead, the cells generated in culture seem to be hematopoietic cells that acquired neural features upon contact with neurogenic factors. The identity of UCB cells that acquired a neural phenotype is still unclear.

Chains of Iron in Umbilical Cord Blood Hematopoietic Stem Cell Transplantation: Comment on "Iron Overload Is Associated with Delayed Engraftment and Increased Nonrelapse Mortality in Recipients of Umbilical Cord Blood Hematopoietic Cell Transplantation" by Al Malki et al, 2020.

Abstract Comment on “Iron Overload is Associated with Delayed Engraftment and Increased Non-Relapse Mortality in Recipients of Umbilical Cord Blood Hematopoietic Cell Transplantation” by Al Malki et al. 2020

Iron Overload Is Associated with Delayed Engraftment and Increased Nonrelapse Mortality in Recipients of Umbilical Cord Blood Hematopoietic Cell Transplantation.

The negative impact of iron overload (IO) on outcomes of allogeneic hematopoietic cell transplantation (HCT) is well recognized, but its impact on umbilical cord blood (UCB) transplant outcome is unknown. We retrospectively analyzed outcomes of 150 patients who received UCB-HCT at our institution, stratified by pre-HCT serum ferritin (SF) level of 2000 ng/mL. Two-year overall survival rate among patients with SF >2000 and ≤2000 ng/mL was 26.1% (95% CI, 10.6% to 44.7%) and 52.1% (95% CI, 40.1% to 62.8%), respectively; hazard ratio (HR)=2.26 (95% CI, 1.28 to 4.00, P=.005). Two-year nonrelapse mortality rate was higher among patients with SF >2000 ng/mL (56.5%; 95% CI, 33.3% to 74.4%) compared to SF ≤2000 ng/mL (30.1%; 95% CI, 20.0% to 40.9%); HR=2.18 (95% CI, 1.10 to 4.31, P=.025). Neutrophil engraftment at 42 days was 78.3% (95% CI, 53.5% to 90.8%) in patients with SF >2000 ng/mL versus 91.8% (95% CI, 82.1% to 96.4%) in patients with SF ≤2000 ng/mL; HR=0.58 (95% CI, 0.35 to 0.96, P=.034). A significant difference in platelet engraftment at 3 months was also observed: 52.2% (95% CI, 29.4% to 70.8%) for SF >2000 ng/mL versus 80.8% (95% CI, 69.5% to 88.3%) for SF ≤2000 ng/mL; HR=0.48 (95% CI, 0.23 to 0.98, P=.044). In conclusion, IO defined by SF of 2000 ng/mL is a strong adverse prognostic factor for UCB-HCT and should be considered when UCB is chosen as the graft source for patients without a fully matched donor.

High Incidence of Herpes Zoster After Cord Blood Hematopoietic Cell Transplant Despite Longer Duration of Antiviral Prophylaxis.

Cord blood transplant (CBT) recipients have a high incidence of herpes zoster (HZ) in the context of short-term peritransplant antiviral prophylaxis. In 2009, international guidelines recommended HZ prophylaxis for at least 1 year after hematopoietic cell transplant. The impact of longer-term antiviral prophylaxis on HZ incidence after CBT is unknown. We retrospectively analyzed varicella zoster virus (VZV)-seropositive CBT recipients who were transplanted between 2006 and 2016. We abstracted HZ events and other variables for up to 5 years post-CBT. We calculated the cumulative incidence of HZ and used Cox proportional hazards regression to identify variables associated with HZ. The study cohort consisted of 227 patients. Among 1-year survivors, 91% were still receiving prophylaxis, for a median duration of 20.6 months. HZ occurred in 44 patients (19%) at a median of 23.6 months. The cumulative incidence of HZ by 1 year after CBT was 1.8% (95% confidence interval [CI], .1%-4%), but increased to 26% (95% CI, 19%-33%) by 5 years. In a multivariable analysis, acute graft-vs-host disease was associated with increased risk, whereas antiviral prophylaxis was associated with reduced risk for HZ (adjusted hazard ratio, 0.19 [95% CI, .09-.4]). There was no association between CD4+ T-cell counts at 1 year post-CBT and subsequent risk for HZ. We found a high incidence of HZ after CBT despite antiviral prophylaxis for > 1 year. Based on these findings, we suggest longer duration of prophylaxis for HZ after CBT. Compliance with antiviral prophylaxis, VZV-specific immune monitoring, and vaccination to mitigate HZ after CBT also require further study.

Nonmyeloablative Alternative Donor Transplantation for Hodgkin and Non-Hodgkin Lymphoma: From the LWP-EBMT, Eurocord, and CIBMTR.

To compare the outcomes of patients with Hodgkin or non-Hodgkin lymphoma undergoing nonmyeloablative haploidentical or unrelated cord blood (UCB) hematopoietic cell transplantation. We retrospectively studied 740 patients with Hodgkin lymphoma (n = 283, 38%) and non-Hodgkin lymphoma (n = 457, 62%) age 18-75 years who received transplantations from 2009 to 2016. Data were reported to the Lymphoma Working Party of the European Society for Blood and Marrow Transplantation, Eurocord, or Center for International Blood and Marrow Transplant Research. Of the 526 patients who received haploidentical transplantation, 68% received bone marrow and 32% received peripheral blood. All patients received a uniform transplantation conditioning regimen (2 Gy of total-body irradiation, cyclophosphamide, and fludarabine) and graft-versus-host disease prophylaxis (calcineurin inhibitor and mycophenolate). In addition, patients who received a haploidentical transplantation received posttransplantation cyclophosphamide. Compared with haploidentical bone marrow and peripheral-blood transplantations and adjusted for age, lymphoma subtype, and disease status, survival was lower after UCB transplantation (hazard ratio [HR], 1.55; P = .001; and HR, 1.59; P = .005, respectively). Similarly, progression-free survival was lower after UCB transplantations compared with haploidentical bone marrow and peripheral-blood transplantations (HR, 1.44; P = .002; and HR, 1.86; P < .0001), respectively. The 4-year overall and progression-free survival rates after UCB transplantation were 49% and 36%, respectively, compared with 58% and 46% after haploidentical bone marrow transplantation and 59% and 52% after peripheral-blood transplantation, respectively. Lower survival was attributed to higher transplantation-related mortality after UCB transplantation compared with haploidentical bone marrow and peripheral-blood transplantation (HR, 1.91; P = .0001; and HR, 2.27; P = .0002, respectively). When considering HLA-mismatched transplantation for Hodgkin or non-Hodgkin lymphoma, the data support haploidentical related donor transplantation over UCB transplantation.

An Autosomal Dominant SCID Form Due to a Gain of Function Mutation in the RAC2 Gene

Severe combined immunodeficiencies (SCIDs) form a heterogeneous group of life-threatening genetic disorders defined by the absence of autologous T cells and an intrinsic or extrinsic defect in the B-cell compartment. In our cohort, three newborn patients with bone-marrow hypoplasia associated with clinical and biological features of SCID received allogenic hematopoietic stem cell transplantation in the first weeks of life. To identify the molecular defect involved in this life threatening SCID form, we performed whole-genome sequencing on patient's fibroblasts. The same heterozygous, dominant missense mutation was found in the RAC2gene encoding for the RAC2 GTPase (p.G12R). By biochemical analyses we demonstrated that arginine substitution at position 12 leads to sustained activation of the RAC2 signalling pathway; the G12R mutation is therefore a gain of function mutation. In cord blood hematopoietic cells, we observed that the mutation disrupts mitochondrial activity and blocks hematopoietic stem/progenitor cells (HSPCs) differentiation toward the myeloid and lymphoid lineages. Altogether, our data emphasize the involvement of the RAC2 signalling pathway during hematopoeisis and might thus explain the severity of the patients' clinical and immunological phenotype. The present study is the first to report an autosomal dominant form of SCID and suggest that RAC2 gene sequencing should be considered for patients with SCID clinical presentation. Disclosures Cavazzana: Smartimmune: Other: Founder of Smartimmune.

High Incidence of Herpes Zoster after Cord Blood Hematopoietic Cell Transplant Despite Longer Duration of Antiviral Prophylaxis

Introduction Herpes zoster (HZ) after hematopoietic cell transplant (HCT) is a well-known complication with a peak incidence during the first year post-HCT. Cord blood transplant (CBT) recipients are at increased risk for viral infections and historically have a cumulative incidence of HZ approaching 80% by 2.5 years in the context of short-term peri-HCT antiviral prophylaxis. In 2009, international guidelines for prevention of infections after HCT recommended maintaining HZ prophylaxis for at least 1 year after HCT. We retrospectively studied the impact of longer-term antiviral prophylaxis on the incidence of HZ after CBT. Methods Between 2006 and 2016, we performed 360 CBT at our Institution. Patients who were seronegative for varicella zoster virus (VZV) or received the live varicella vaccine (i.e. Varivax®) pre-CBT without a history of chickenpox or HZ were excluded. From 2006-2008, CBT recipients received acyclovir (ACV) 800 mg BID or valacyclovir (VACV) 500 mg BID for HSV and VZV prophylaxis. From 2008-2016, patients who were CMV seropositive received higher-dose prophylaxis with VACV 2g TID through day +100. Before 2009, institutional guidelines recommended to continue prophylaxis until the end of immunosuppression; after 2009, prophylaxis was recommended for at least 1 year and until 8 months after immunosuppression ends. For patients discharged from our center, data were collected through standardized questionnaires and medical records. We abstracted HZ events and other variables for up to 5 years post-CBT. We calculated the cumulative incidence of HZ after CBT, treating death and second HCT as competing risk events. Variables were evaluated for an association with development of HZ using Cox proportional hazards regression; those of biological interest and with a P value ≤ 0.3 in univariable analyses were considerate for multivariable model. Results The study cohort consisted of 227 CBT recipients with a median follow up of 25.4 months (interquartile range [IQR], 6.8 - 49). Follow up time was truncated at the time of death (n=113), second HCT (n=13) or last available records (n=32). Cohort characteristics are shown in Table 1. Among 1-year survivors, 91% were still receiving prophylaxis for a median duration of 20.6 months post-CBT (IQR, 14.1 - 29.4). HZ occurred in 44 patients (19%) at a median of 23.6 months (IQR, 16.1 - 30.3). Most patients (n=31/44, 70%) were not taking antiviral prophylaxis when HZ developed. The cumulative incidence of HZ by 1-year post-CBT was low (1.8%; 95% CI, 0.1%-4%) but increased starting from the second year and reached 26% (95% CI, 19%-33%) by 5 years (Figure 1). Disseminated HZ occurred in 5 cases (11%), and post-herpetic neuralgia occurred in 14 cases (31.8%). Of the 13 HZ episodes that occurred in patients reportedly taking antiviral prophylaxis, 6/13 had clear documentation of ongoing antiviral prophylaxis and 5/13 were still receiving immunosuppressive treatment for graft-versus-host disease (GvHD). All patients responded to antiviral treatment, which consisted of ACV (n=18), VACV (n=16), and famciclovir (n=1). In a multivariable analysis, patients who received myeloablative conditioning or had acute GvHD grades 2-4 had a higher risk of HZ, whereas the use of antiviral prophylaxis was associated with a lower risk of HZ (Table 2). Among 35 patients who discontinued prophylaxis before completing immunosuppressive therapy, 28.5% developed HZ. We found no association between CD4+ T cell counts at 1-year after-CBT and HZ risk. Conclusions In this cohort of 227 CBT recipients with up to 5 years of follow up, the cumulative incidence of HZ was 26% at 5 years, despite antiviral prophylaxis for &amp;gt;1 year in the majority of patients. Furthermore, these patients had high rates of post-herpetic neuralgia and disseminated VZV. Antiviral prophylaxis protected against HZ but there were breakthrough cases. Given that a high number of patients interrupted prophylaxis while still receiving immunosuppressants, adherence to antiviral prophylaxis should be emphasized by health care providers. Based on our findings, the lack of alternative prophylactic strategies at this time, and the safety of ACV/VACV, longer duration of prophylaxis should be considered, especially in patients with ongoing immunosuppression. Recent data demonstrating the safety and efficacy of the HZ subunit vaccine after autologous HCT support future study of HZ vaccination after allogeneic HCT. Disclosures Delaney: Nohla Therapeutics: Employment, Equity Ownership; Biolife Solutions: Membership on an entity's Board of Directors or advisory committees. Boeckh:Chimerix: Research Funding; GSK: Other: Personal fees; GSK: Research Funding; Merck: Research Funding; Merck: Other: Personal fees; Clinigen: Other: Personal fees. Milano:ExCellThera: Research Funding; Amgen: Research Funding. Hill:Takeda: Other: research support; Karius: Other: research support; Amplyx: Consultancy; Nohla Therapeutics: Consultancy, Other: research support.

Past, present, and future efforts to enhance the efficacy of cord blood hematopoietic cell transplantation.

Cord blood (CB) has been used as a viable source of hematopoietic stem cells (HSCs) and hematopoietic progenitor cells (HPCs) in over 35,000 clinical hematopoietic cell transplantation (HCT) efforts to treat the same variety of malignant and non-malignant disorders treated by bone marrow (BM) and mobilized peripheral blood (mPB) using HLA-matched or partially HLA-disparate related or unrelated donor cells for adult and children recipients. This review documents the beginning of this clinical effort that started in the 1980’s, the pros and cons of CB HCT compared to BM and mPB HCT, and recent experimental and clinical efforts to enhance the efficacy of CB HCT. These efforts include means for increasing HSC numbers in single CB collections, expanding functional HSCs ex vivo, and improving CB HSC homing and engraftment, all with the goal of clinical translation. Concluding remarks highlight the need for phase I/II clinical trials to test the experimental procedures that are described, either alone or in combination.

Maternal lipid profiles vs. fetal growth and cord blood hematopoietic cells: weak associations in healthy Korean newborn-mother pairs

We aimed to define the maternal lipid profiles that are associated with fetal growth and cord blood (CB) hematopoietic cells in healthy Korean full-term newborns. A total of 608 fetal-maternal pairs were enrolled; mothers voluntarily donated CB with informed consent. We analyzed birth weight (BW) as a marker of fetal growth, and we examined total nucleated cells (TNCs) and CD34+ cell concentrations of CB as markers of hematopoietic progenitor cell (HPC) contents. We also analyzed maternal lipid levels and investigated their associations with BW, TNCs and CD34+ cells. Maternal triglycerides (TG) showed a significant positive association with BW and CD34+ cells, and low-density lipoprotein (LDL) showed a negative association with BW and CD34+ cells. Though not statistically significant, higher maternal TG showed a tendency toward higher levels of TNCs. Maternal TG was independently and positively correlated with BW, and maternal LDL was independently and negatively correlated with CD34+ cells, although the impacts were not as strong, as indicated by small beta coefficients (0.157 and -0.226, respectively). We were able to investigate the association of maternal lipid profiles with BW and CB HPCs in healthy Korean newborn-mother pairs in this study. Both BW and the HPC contents showed independent associations with maternal TG and LDL, although the effect of maternal lipid levels on fetal growth and HPCs was not strong in the normal healthy population. Because maternal lipid levels were assessed once in the healthy fetal-maternal pairs, we could not investigate those associations across pregnancy.

An Approach to the Cure of HIV using Cord Blood Hematopoietic Cell Transplantation

An Approach to the Cure of HIV using Cord Blood Hematopoietic Cell Transplantation

Donor KIR3DL1/Receptor HLA-Bw4-80I Combination Reduce Acute Leukemia Relapse after Umbilical Cord Blood Transplantation without in Vitro T-Cell Depletion

Objective: How to reduce relapse is still a puzzle in the treatment of acute leukemia patients with allogeneic umbilical cord blood hematopoietic cell transplantation (UCBT). Donor natural killer (NK) cell alloreactivity in UCBT can control leukemic relapse, However, NK cell function is calibrated through education, that is governed by human leukocyte antigens (HLAs), our study aim to investigate the Graft-resistant leukemia effect after transplantation of KIR3DL1 and its different ligand HLA-B subtypes(BW6, Bw4-80T, Bw4-80I).Design and method: we retrospectivly analysed single center of 232 acute leukemia patients who underwent UCBT(myeloablative conditioning without ATG). The killer immunoglobulin-like receptor (KIR) genotype of cord blood donors was detected by SSP method, they all contains KIR3DL1. There were 104 cases of acute lymphoblastic leukemia, 112 cases of acute myeloid leukemia, 16 cases of myelodysplastic syndrome. 168 cases of transplant patients in remission period, and 64 cases of non-remission. There were 122 males and 110 females with a median age of 13 years (2-45 years). The patients were divided into three groups according to HLA-B locus, 1.patients had BW6 in both two HLA-B locus(group 1, N=86) , which means uneducated; 2.patients had HLA-Bw4-80T in the HLA-B locus(group 2, N=68), which means educated; 3.patients had HLA- Bw4-80I in the HLA-B locus(group 3, N=77), which means highly educated. The receptors were followed-up from July 31, 2012 to December 30,2017, in graft failure, neutrophil engraftment, platelet engraftment, acute graft-versus-host disease (aGVHD), chronic graft-versus-host disease (cGVHD), relapse, overall survival (OS), and leukemia free survival (LFS).Results: In group 3 patients, donor KIR3DL1 and receptor HLA-Bw4-80I combinations that were predictive of highly educated were associated with significantly lower relapse (hazard ratio [HR], HR = 0.49; P =0 .004) and better LFS (HR = 0.68, p = 0.014), compared with the educated(group2) and uneducated (group3) group, with no significant increase in aGVHD and cGVHD incidence. While no difference was observed in the other index in the three group.Conclusion : Alloreactivity of NK cells demonstrated reproducible patterns of strong or weak graft-versus-leukemia (GVL) effect against leukemia blast, which is depend on donor KIR3DL1/receptor HLA-B subtype combinations. Our data suggests that donor KIR3DL1/receptor HLA-Bw4-80I combination in UCBT may achieve superior graft versus leukemia effects, lower risk for relapse among patients with acute leukemia.Keywords: KIR, Umbilical Cord Blood Transplantation, UCBT, GVL DisclosuresNo relevant conflicts of interest to declare.