Adoptive Immunotherapy with Cord Blood for the Treatment of Refractory Acute Myelogenous Leukemia: Feasibility, Safety, and Preliminary Outcomes.

Adoptive immunotherapy has shown efficacy in patients with relapsed/refractory acute myelogenous leukemia (AML). We conducted a prospective evaluation of cord blood (CB)-based adoptive cell therapy following salvage chemotherapy in patients with AML or myelodysplastic syndrome (MDS) and describe the safety and early outcomes of this approach. To enhance the antileukemic effect, we selected CB units (CBUs) with a shared inherited paternal antigen (IPA) and/or noninherited maternal antigen (NIMA) match with the recipients. Furthermore, the CBUs had total nucleated cell (TNC) dose <2.5 × 107/kg and were at least 4/6 HLA-matched with the patients; a higher allele-level match was preferred. Heavily pretreated adult patients with AML/MDS were enrolled. CBU searches were performed for 50 patients. CBUs with shared IPA targets were identified for all, and CBUs with NIMA matches were found for 80%. Twenty-one patients underwent treatment (AML, primary induction failure, n = 8; refractory relapse, n = 10, including 7 recipients of previous allogeneic HSCT; blast crisis chronic myelogenous leukemia, n = 1; MDS, n = 2). Most received combination chemotherapy; those not fit for intensive treatment received a hypomethylating agent. Response was defined as <10% residual blasts in hypocellular bone marrow at approximately 2 weeks after treatment. Ten of the 19 evaluable patients responded, including 5 of the 7 recipients of previous transplant. Response was seen in 4 of 4 patients with full CBU-derived chimerism, 2 of 2 of those with partial, low-level chimerism and 4 of 12 of the recipients with no detectable CBU chimerism. The most common adverse events were infections (bacterial, n = 5; viral, n = 2; fungal, n = 5). Grade IV acute graft-versus-host disease (GVHD) developed in 2 patients with full CBU chimerism; 2 other patients had grade 1 skin GVHD. A total of 11 patients died, 7 from disease recurrence and 4 from infections (1 early death; the other 3 in remission at the time of death). Overall, 12 patients proceeded to allogeneic HSCT; of those, 7 had responded to treatment, 3 had not (and had received additional therapy), and 2 had persistent minimal residual disease. In conclusion, the use of CB as adoptive immunotherapy in combination with salvage chemotherapy for patients with refractory AML/MDS is feasible, can induce disease control, can serve as a bridge to allogeneic HSCT, and has an acceptable incidence of adverse events. Alloreactivity was enhanced through the selection of CBUs targeting a shared IPA and/or NIMA match with the patients. CBUs with lower cell doses, already available in the CB bank and unlikely to be adequate grafts for adult transplants, can be used for cell therapy within a short time frame.

Impact of delayed umbilical cord clamping on public cord blood donations: can we help future patients and benefit infant donors?

BACKGROUND: Cord blood (CB) is a widely accepted stem cell source and its clinical utilization depends, to a great extent, on its cell content. Birth-to-clamping (BTC) time of umbilical cord determines placental transfusion to the newborn, and the remaining blood that can be collected and banked. The 2017 Committee Opinion of the American College of Obstetrics and Gynecologists (ACOG) recommends a delay of "at least 30-60 seconds" before clamping the cord for all newborns to ensure adequate iron stores. The impact of delayed cord clamping (DCC) on public CB banking can be substantial. STUDY DESIGN AND METHODS: Cord blood units (CBUs) collected from 1210 mothers at one hospital were evaluated for total nucleated cells (TNCs) and weight/volume based on time to clamping. Bank staff recorded BTC time in seconds as reported by obstetricians; collections were performed ex utero. Immediate clamping was defined as BTC of less than 30 seconds, whereas DCC was defined as BTC of 30 seconds or more. RESULTS: Cord clamping was immediate in 903 (75%) and delayed in 307 (25%) deliveries. Successful recovery (% clinical CBUs) decreased 10-fold with DCC of more than 60 seconds (22% vs. 2.4%, p < 0.001). CBUs collected after DCC of more than 60 seconds had significantly lower TNC counts than those after DCC of less than 60 seconds (p < 0.0001). Furthermore, 38% to 46% of CBUs after DCC of more than 60 seconds had volume of less than 40 mL. CONCLUSION: Our study indicates that DCC of 30 to 60 seconds has a small negative impact on collection of high-TNC-count CBUs. However, increasing BTC to more than 60 seconds decreases significantly both TNC content and volume, reducing drastically the chances of obtaining clinically useful CBUs.

Cytomegalovirus viral load in cord blood and impact of congenital infection on markers of hematopoietic progenitor cell potency.

BACKGROUND: The low incidence of cytomegalovirus (CMV) infection in neonates decreases the risk of viral transmission with cord blood transplantation. Cord blood donors are screened by testing the maternal sample for total antibodies to CMV. Some cord blood banks also screen cord blood for CMV-DNA. The aim of this study was to develop and validate a multiplex real-time polymerase chain reaction assay to measure CMV viral load in cord blood from asymptomatic infants with congenital CMV infection and to assess the impact of CMV infection on cord blood hematopoietic progenitor cell concentrations and colony-forming unit functionality. STUDY DESIGN AND METHODS: CMV infection was evaluated in two groups of cord blood donors: 1) 30,308 neonates prospectively screened by saliva culture, including 41 positive cases (0.14%), all from mothers with total antibodies to CMV; and 2) 4712 newborns from mothers with total antibodies to CMV who were screened retrospectively by polymerase chain reaction, including 18 positive cases (0.38%). All 59 infants with CMV were asymptomatic at birth. RESULTS: Among the 59 positive cases, the average CMV viral load in cord blood was 20.6 × 104 viral copies (vc)/mL; seven of 59 mothers (12%) had CMV-DNA detected, however, with no association to their newborns' CMV viral load. Levels of colony-forming units, CD34+ /CD45+ cells, and total nucleated cells measured in a cohort of CMV-positive cord blood samples were higher than those in the matched control group. CONCLUSION: We developed and validated a multiplex real-time polymerase chain reaction assay to detect CMV-DNA in cord blood. In our study, maternal total antibodies to CMV or CMV-DNA at birth were poor predictors of infection in cord blood donors. Furthermore, our results suggest that CMV congenital infection impacts CD34+ /CD45+ cells and some hematopoietic progenitor cells toward higher proliferation.

Isolation and characterization of mesenchymal stem cells from human umbilical cord blood: reevaluation of critical factors for successful isolation and high ability to proliferate and differentiate to chondrocytes as compared to mesenchymal stem cells from bone marrow and adipose tissue.

Human umbilical cord blood (CB) is a potential source for mesenchymal stem cells (MSC) capable of forming specific tissues, for example, bone, cartilage, or muscle. However, difficulty isolating MSC from CB (CB-MSC) has impeded their clinical application. Using more than 450 CB units donated to two public CB banks, we found that successful cell recovery fits a hyper-exponential function of time since birth with very high fidelity. Additionally, significant improvement in the isolation of CB-MSC was achieved by selecting cord blood units having a volume ≥90 ml and time ≤2 h after donor's birth. This resulted in 90% success in isolation of CB-MSC by density gradient purification and without a requirement for immunoaffinity methods as previously reported. Using MSC isolated from bone marrow (BM-MSC) and adipose tissue (AT-MSC) as reference controls, we observed that CB-MSC exhibited a higher proliferation rate and expanded to the order of the 1 × 10(9) cells required for cell therapies. CB-MSC showed karyotype stability after prolonged expansion. Functionally, CB-MSC could be more readily induced to differentiate into chondrocytes than could BM-MSC and AT-MSC. CB-MSC showed immunosuppressive activity equal to that of BM-MSC and AT-MSC. Collectively, our data indicate that viable CB-MSC could be obtained consistently and that CB should be reconsidered as a practical source of MSC for cell therapy and regenerative medicine using the well established CB banking system.

Adoptive immunotherapy with CB following chemotherapy for patients with refractory myeloid malignancy: chimerism and response.

We conducted a prospective evaluation of cord blood (CB)-derived adoptive cell therapy, after salvage chemotherapy, for patients with advanced myeloid malignancies and poor prognosis. Previously, we reported safety, feasibility, and preliminary efficacy of this approach. We present updated results in 31 patients who received intensive chemotherapy followed by CB infusion and identify predictors of response. To enhance the antileukemic effect, we selected CB units (CBU) with shared inherited paternal antigens and/or noninherited maternal antigens with the recipients. Twenty-eight patients with acute myeloid leukemia (AML), 2 with myelodysplastic syndrome, and 1 in chronic myeloid leukemia myeloid blast crisis were enrolled; 9 had relapsed after allogeneic transplant. Response was defined as <5% blasts in hypocellular bone marrow at 2 weeks after treatment. Thirteen patients (42%) responded; a rate higher than historical data with chemotherapy only. Twelve had CBU-derived chimerism detected; chimerism was a powerful predictor of response (P < .001). CBU lymphocyte content and a prior transplant were associated with chimerism (P < .01). Safety was acceptable: 3 patients developed mild cytokine release syndrome, 2 had grade 1 and 2 had grade 4 graft-versus-host disease. Seven responders and 6 nonresponders (after additional therapy) received subsequent transplant; 5 are alive (follow-up, 5-47 months). The most common cause of death for nonresponders was disease progression, whereas for responders it was infection. CB-derived adoptive cell therapy is feasible and efficacious for refractory AML. Banked CBU are readily available for treatment. Response depends on chimerism, highlighting the graft-versus-leukemia effect of CB cell therapy. This trial was registered at www.clinicaltrials.gov as #NCT02508324.

Umbilical cord blood transplantation and cytomegalovirus: Posttransplantation infection and donor screening.

This study assessed the incidence of cytomegalovirus (CMV) infection after transplantation of cord blood (CB) from unrelated donors and evaluated strategies for screening CB donors. Posttransplantation CMV infection, reported in 23% of 1221 CB recipients, was associated with patient pretransplantation CMV serology (P < .001), but not with CMV serology in CB donors or their mothers. A total of 26 988 infant CB donors were evaluated by viral culture of saliva. Subgroups were evaluated by polymerase chain reaction in CB (CB-PCR) in 2 case-control studies. In the first study, 33 of 47 saliva culture-positive CB donors were confirmed by CB-PCR. All mothers of the 33 infants with confirmed CMV infection were CMV-total antibody positive, but only 1 of 3 had CMV-IgM antibody. The second study evaluated infants born to mothers with CMV-IgM antibody. Of these, 5 of 170 saliva culture-negative infants were positive by CB-PCR. The incidence of congenital CMV infection in CB donors was low (0.12%). Maternal serology had poor predictive value for CMV infection in their infant CB donors and bore no detected relationship to CMV infection in CB recipients. Saliva culture for CMV had both false-positive and -negative results. CB-PCR was a useful alternative for detecting CMV in CB donors.