Over-expression of PD-1 Does Not Predict Leukemic Relapse after Allogeneic Stem Cell Transplantation.

Blockade of the T-cell exhaustion marker PD-1 to re-energize the immune response is emerging as a promising cancer treatment. Relapse of hematologic malignancy after allogeneic stem cell transplantation limits the success of this approach, and PD-1 blockade may hold therapeutic promise. However, PD-1 expression and its relationship with post-transplant relapse is poorly described. Because the donor immunity is activated by alloresponses, PD-1 expression may differ from nontransplanted individuals, and PD-1 blockade could risk graft-versus-host disease. Here we analyzed T-cell exhaustion marker kinetics and their relationship with leukemia relapse in 85 patients undergoing myeloablative T-cell-depleted HLA-matched stem cell transplantation. At a median follow-up of 3.5 years, 35 (44%) patients relapsed. PD-1 expression in CD4 and CD8 T cells was comparably elevated in relapsed and nonrelapsed cohorts. Helios+ regulatory T cells and CD8 effector memory cells at day 30 emerged as independent predictors of relapse. Although leukemia antigen-specific T cells did not overexpress PD-1, single-cell analysis revealed LAG3 and TIM3 overexpression at relapse. These findings indicate that PD-1 is an unreliable marker for leukemia-specific T-cell exhaustion in relapsing patients but implies other exhaustion markers and suppressor cells as relapse biomarkers.

Distinct Biomarker Profiles in Ex Vivo T Cell Depletion Graft Manipulation Strategies: CD34+ Selection versus CD3+/19+ Depletion in Matched Sibling Allogeneic Peripheral Blood Stem Cell Transplantation.

Various approaches have been developed for ex vivo T cell depletion in allogeneic stem cell transplantation to prevent graft-versus-host disease (GVHD). Direct comparisons of T cell depletion strategies have not been well studied, however. We evaluated cellular and plasma biomarkers in 2 different graft manipulation strategies, CD3+CD19+ cell depletion (CD3/19D) versus CD34+ selection (CD34S), and their associations with clinical outcomes. Identical conditions, including the myeloablative preparative regimen, HLA-identical sibling donor, GVHD prophylaxis, and graft source, were used in the 2 cohorts. Major clinical outcomes were similar in the 2 groups in terms of overall survival, nonrelapse mortality, and cumulative incidence of relapse; however, the cumulative incidence of acute GVHD trended to be higher in the CD3/19D cohort compared with the CD34S cohort. A distinct biomarker profile was noted in the CD3/19D cohort: higher levels of ST2, impaired Helios- FoxP3+Treg reconstitution, and rapid reconstitution of naïve, Th2, and Th17 CD4 cells in the early post-transplantation period. In vitro graft replication studies confirmed that CD3/19D disproportionately depleted Tregs and other CD4 subset repertoires in the graft. This study confirms the utility of biomarker monitoring, which can be directly correlated with biological consequences and possible future therapeutic indications.

Epigenetic landscape of the TERT promoter: a potential biomarker for high risk AML/MDS.

Although recent observations implicate the importance of telomerase activity in acute myeloid leukaemia (AML), the roles of epigenetic regulations of the TERT gene in leukaemogenesis, drug resistance and clinical prognosis in AML are not fully understood. We developed a quantitative pyrosequencing-based methylation assay covering the TERT proximal promoter and a partial exon 1 (TERTpro/Ex1) region and tested both cell lines and primary leukaemia cells derived from AML and AML with preceding myelodysplastic syndrome (AML/MDS) patients (n = 43). Prognostic impact of methylation status of the upstream TERT promoter region was assessed by the Kaplan-Meier method. The activity of the telomerase inhibitor, imetelstat, was measured using leukaemia cell lines. The TERTpro/Ex1 region was highly methylated in all cell lines and primary leukaemia cells showed diverse methylation profiles. Most cases showed hypermethylated regions at the upstream TERTpro/Ex1 region, which were associated with inferior patient survival. TERTpro/Ex1 methylation status was correlated with the cytotoxicity to imetelstat and its combination with hypomethylating agent enhanced the cytotoxicity of imetelstat. AML cell lines and primary blasts harbour distinct TERTpro/Ex1 methylation profiles that could serve as a prognostic biomarker of AML. However, validation in a large cohort of patients is necessary to confirm our findings.

Immune Response Following Quadrivalent Human Papillomavirus Vaccination in Women After Hematopoietic Allogeneic Stem Cell Transplant: A Nonrandomized Clinical Trial.

Importance: Human papillomavirus (HPV) infection is found in about 40% of women who survive allogeneic hematopoietic stem cell transplant and can induce subsequent neoplasms. Objective: To determine the safety and immunogenicity of the quadrivalent HPV vaccine (HPV-6, -11, -16, and -18) in clinically stable women post-allogeneic transplant compared with female healthy volunteers. Interventions: Participants received the quadrivalent HPV vaccine in intramuscular injections on days 1 and 2 and then 6 months later. Design, Setting, and Participants: This prospective, open-label phase-1 study was conducted in a government clinical research hospital and included clinically stable women posttransplant who were or were not receiving immunosuppressive therapy compared with healthy female volunteers age 18 to 50 years who were followed up or a year after first receiving quadrivalent HPV vaccination. The study was conducted from June 2, 2010, until July 19, 2016. After all of the results of the study assays were completed and available in early 2018, the analysis took place from February 2018 to May 2019. Main Outcomes and Measures: Anti-HPV-6, -11, -16, and -18-specific antibody responses using L1 virus-like particle enzyme-linked immunosorbent assay were measured in serum before (day 1) and at months 7 and 12 postvaccination. Anti-HPV-16 and -18 neutralization titers were determined using a pseudovirion-based neutralization assay. Results: Of 64 vaccinated women, 23 (35.9%) were receiving immunosuppressive therapy (median age, 34 years [range, 18-48 years]; median 1.2 years posttransplant), 21 (32.8%) were not receiving immunosuppression (median age, 32 years [range, 18-49 years]; median 2.5 years posttransplant), and 20 (31.3%) were healthy volunteers (median age, 32 years [range, 23-45 years]). After vaccine series completion, 18 of 23 patients receiving immunosuppression (78.3%), 20 of 21 not receiving immunosuppression (95.2%), and all 20 volunteers developed antibody responses to all quadrivalent HPV vaccine types (P = .04, comparing the 3 groups). Geometric mean antibody levels for each HPV type were higher at months 7 and 12 than at baseline in each group (all geometric mean ratios >1; P < .001) but not significantly different across groups. Antibody and neutralization titers for anti-HPV-16 and anti-HPV-18 correlated at month 7 (Spearman ρ = 0.92; P < .001 for both). Adverse events were mild and not different across groups. Conclusions and Relevance: Treatment with the HPV vaccination was followed by strong, functionally active antibody responses against vaccine-related HPV types and no serious adverse events. These findings suggest that HPV vaccination may be safely administered to women posttransplant to potentially reduce HPV infection and related neoplasia. Trial Registration: ClinicalTrials.gov Identifier: NCT01092195.