Faculty Bibliography

With a rising incidence of COVID-19-associated morbidity and mortality worldwide, it is critical to elucidate the innate and adaptive immune responses that drive disease severity. We performed longitudinal immune profiling of peripheral blood mononuclear cells from 45 patients and healthy donors. We observed a dynamic immune landscape of innate and adaptive immune cells in disease progression and absolute changes of lymphocyte and myeloid cells in severe versus mild cases or healthy controls. Intubation and death were coupled with selected natural killer cell KIR receptor usage and IgM+ B cells and associated with profound CD4 and CD8 T-cell exhaustion. Pseudo-temporal reconstruction of the hierarchy of disease progression revealed dynamic time changes in the global population recapitulating individual patients and the development of an eight-marker classifier of disease severity. Estimating the effect of clinical progression on the immune response and early assessment of disease progression risks may allow implementation of tailored therapies.

Maximizing the probability of antigen presentation to T cells through diversity in HLAs can enhance immune responsiveness and translate into improved clinical outcomes, as evidenced by the association of heterozygosity and supertypes at HLA class I loci with improved survival in patients with advanced solid tumors treated with immune checkpoint inhibitors. We investigated the impact of HLA heterozygosity, supertypes, and surface expression on outcomes in adult and pediatric patients with acute myeloid leukemia (AML), myelodysplastic syndrome, acute lymphoblastic leukemia, and non-Hodgkin lymphoma who underwent 8/8 HLA-matched, T cell replete, unrelated, allogeneic hematopoietic cell transplant (HCT) from 2000 to 2015 using patient data reported to the Center for International Blood and Marrow Transplant Research. HLA class I heterozygosity and HLA expression were not associated with overall survival, relapse, transplant-related mortality (TRM), disease-free survival (DFS), and acute graft-versus-host disease following HCT. The HLA-B62 supertype was associated with decreased TRM in the entire patient cohort (hazard ratio [HR], 0.79; 95% CI, 0.69 to 0.90; P = .00053). The HLA-B27 supertype was associated with worse DFS in patients with AML (HR = 1.21; 95% CI, 1.10 to 1.32; P = .00005). These findings suggest that the survival benefit of HLA heterozygosity seen in solid tumor patients receiving immune checkpoint inhibitors does not extend to patients undergoing allogeneic HCT. Certain HLA supertypes, however, are associated with TRM and DFS, suggesting that similarities in peptide presentation between supertype members play a role in these outcomes. Beyond implications for prognosis following HCT, these findings support the further investigation of these HLA supertypes and the specific immune peptides important for transplant outcomes.

Alternative donor transplantation with the haplo-cord platform allows the use of a lower-dose single umbilical cord blood unit (CBU) by co-infusion of third-party CD34⁺-selected cells from a haploidentical relative, which provides early transient engraftment while awaiting durable CBU engraftment. In our experience, ~15% of patients lack a suitable haploidentical donor. Here we report 26 patients who underwent haplo-cord transplant using CD34⁺-selected partially matched unrelated donor grafts. Twenty-four were conditioned with fludarabine/melphalan +/- low-dose TBI (n = 16). Twenty-five received ATG and all received posttransplant tacrolimus and mycophenolate mofetil. Median time to neutrophil and platelet recovery was 11 and 18 days. CBU engraftment, with CD33 and CD3 >5% cord chimerism in the myeloid/lymphoid compartment by day +60, occurred in 20 of 24 patients (83%). Incidence of grade 2-4 acute graft-versus-host disease (GVHD) was 27% at day +100, and chronic GVHD was 4% at 1 year. Overall survival at 1 year was 54%. For patients in need of an alternative transplant who lack a haploidentical donor, haplo-cord transplantation using CD34⁺-selected partially matched unrelated donor grafts results in rapid engraftment with no increased rate of cord graft failure or GVHD.

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.

Hematopoietic stem and progenitor cell (HSPC) formation and lineage differentiation involve gene expression programs orchestrated by transcription factors and epigenetic regulators. Genetic disruption of the chromatin remodeler chromodomain-helicase-DNA-binding protein 7 (CHD7) expanded phenotypic HSPCs, erythroid, and myeloid lineages in zebrafish and mouse embryos. CHD7 acts to suppress hematopoietic differentiation. Binding motifs for RUNX and other hematopoietic transcription factors are enriched at sites occupied by CHD7, and decreased RUNX1 occupancy correlated with loss of CHD7 localization. CHD7 physically interacts with RUNX1 and suppresses RUNX1-induced expansion of HSPCs during development through modulation of RUNX1 activity. Consequently, the RUNX1:CHD7 axis provides proper timing and function of HSPCs as they emerge during hematopoietic development or mature in adults, representing a distinct and evolutionarily conserved control mechanism to ensure accurate hematopoietic lineage differentiation.

With a rising incidence of COVID-19-associated morbidity and mortality worldwide, it is critical to elucidate the innate and adaptive immune responses that drive disease severity. We performed longitudinal immune profiling of peripheral blood mononuclear cells from 45 patients and healthy donors. We observed a dynamic immune landscape of innate and adaptive immune cells in disease progression and absolute changes of lymphocyte and myeloid cells in severe versus mild cases or healthy controls. Intubation and death were coupled with selected natural killer cell KIR receptor usage and IgM+ B cells and associated with profound CD4 and CD8 T cell exhaustion. Pseudo-temporal reconstruction of the hierarchy of disease progression revealed dynamic time changes in the global population recapitulating individual patients and the development of an eight-marker classifier of disease severity. Estimating the effect of clinical progression on the immune response and early assessment of disease progression risks may allow implementation of tailored therapies.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Reduced-intensity conditioning (RIC) regimens, improved HLA matching, and better supportive care allow allogeneic stem cell transplant (alloSCT) to be offered to older patients. Only a small percentage of eligible patients between ages 65 and 74 years actually undergo alloSCT, and comprehensive outcome data from the aging population are still lacking. We examined the outcome of older patients who underwent alloSCT using melphalan-based RIC for hematologic malignancies at our institution. We identified 125 patients older than 65 years (median, 69; range, 66 to 77) who underwent matched related donor, matched unrelated donor, or combined haploidentical/umbilical cord alloSCT between 2012 through November, 2017. Among them, 52 (41.6%) and 70 (56%) had, respectively, intermediate and high/very high Center for International Blood and Marrow Transplant Research (CIBMTR) disease risk index (DRI). One hundred six patients (85%) received fludarabine/melphalan-based RIC regimen with either antithymocyte globulin (ATG) or alemtuzumab. The median time to neutrophil engraftment was 13 days (range, 8 to 37) and platelet engraftment 17 days (range, 9 to 169). The cumulative incidence of nonrelapse mortality was 11.5% at 100 days and 30.1% and 34.8% at 1 and 2 years, respectively. The cumulative incidence of relapse was 35% and 40% at 1 and 2 years. The cumulative incidence of grades II to IV acute graft-versus-host disease (GVHD) at day 100 and 6 months was 29.5% and 34.5%, and chronic GVHD at 6, 12, and 24 months was 2.5%, 5.2%, and 6.3%, respectively. With a median follow-up of 32 months, the 1-, 2-, and 3-year progression-free survival (PFS) was 34.6%, 24.4%, and 16.5%, respectively. The graft GVHD-free survival was 24.6%, 16.1%, and 9.3%, respectively. The 1-, 2-, and 3-year overall survival (OS) was 44.5%, 30.7%, and 26.5%, respectively. In multivariable analysis, low albumin was predictive of poor PFS and OS and high hematopoietic cell transplantation-specific comorbidity index, and CIBMTR DRI was predictive of worse graft GVHD-free survival. Among long-term survivors the median Karnofsky performance status was 80. Older patients, even when referred with advanced disease, can benefit from melphalan-based alloSCT with HLA-matched or alternative donor sources without discernible impact of donor source on outcome. Using alemtuzumab- or ATG-based in vivo T cell depletion, the incidence of chronic GVHD is extremely low. Performance status in survivors is excellent. Better predictors for outcome in this patient population need to be identified.