IL-33-ILC2 axis promotes anti-tumor CD8+ T cell responses via OX40 signaling.

Group 2 innate lymphoid cells (ILC2s) are resident cells and participate in innate and adaptive immunity. In the tumor microenvironment (TME), ILC2s contribute to both tumorigenesis and inhibition of tumor growth, but the true role of ILC2s in TME construction remains unclear. We show that IL-33 treatment induces an anti-tumor effect in vivo in a mouse model of melanoma in which ILC2s and CD8+ T cells infiltrate into tumor tissue. This anti-tumor effect is dependent on CD8+ T cells, however, IL-33 does not act directly on CD8+ T cells because the cells lack ST2, the receptor for IL-33. ILC2s and CD8+ T cells in tumors of IL-33-treated mice express OX40 ligand (OX40L) and OX40, respectively, and in vivo blockade of OX40L-OX40 interaction canceled the anti-tumor effect of IL-33. Co-culture of CD8+ T cells expressing OX40 with IL-33-stimulated ILC2 expressing OX40L promoted cell activation and proliferation of CD8+ T cells, which was significantly suppressed by administration of anti-OX40L blocking antibody. Thus, the IL-33-ILC2 axis promotes CD8+ T cell responses via OX40/OX40L interaction and exerts an anti-tumor effect.

Prognostic implication of CTLA-4, PD-1, and PD-L1 expression in aggressive adult T-cell leukemia-lymphoma.

The prognosis of patients with aggressive adult T cell leukemia-lymphoma (ATLL) is dismal even with intensive chemotherapy. Allogeneic hematopoietic stem cell transplantation (HSCT) is a promising option for patients with aggressive ATLL, but the posttransplant outcome remains unsatisfactory. Hence, to further improve clinical outcomes, novel therapeutic approaches are needed. The clinical significance of immune checkpoint protein expression has not been well-established in aggressive ATLL. This study aims to identify the association between the expression profile of immune checkpoint proteins on ATLL cells and clinical outcomes. This retrospective study cohort included 65 patients with aggressive ATLL diagnosed between 2001 and 2015 at the National Cancer Center Hospital, Tokyo, Japan. Formalin-fixed paraffin-embedded tissue was used to immunohistochemically determine the expression of immune checkpoint proteins and assess the impact of expression profile on the probability of overall survival from diagnosis or HSCT. The current analysis shows that cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed death-1 (PD-1), and programmed death-ligand 1 (PD-L1) expressions were adverse prognostic factors in patients with aggressive ATLL. Experiments that assess the efficacy of immune checkpoint inhibitors are warranted to alleviate the adverse impacts associated with negative immune checkpoints.

Association of CD204+ macrophages with poor outcomes of malignant lymphomas not in remission treated by allogeneic HCT.

OBJECTIVE: CD204+ tumor-associated macrophages are associated with adverse outcomes of various malignancies. We performed a study to elucidate the role of CD204+ macrophages in allogeneic hematopoietic cell transplantation (allogeneic HCT). METHODS: In a total of 81 patients who received allogeneic HCT for non-remission malignant lymphoma, immunohistochemical staining of CD204 using specimens preserved before allogeneic HCT was performed. According to the average number of CD204+ macrophages in a high-power field, patients were categorized into three groups: low (<25th percentile), intermediate (≥25th percentile and <50th percentile), and high (≥50th percentile). RESULTS: The B-cell lymphoma proportion was higher in the low group, while T-cell lymphoma and adult T-cell leukemia proportions were higher in the high group. The 3-year overall survival (OS) was poorest in the high group; low vs intermediate vs high = 83.3% vs 43.7% vs 20.2% (P < .01). The 3-year cumulative incidences of relapse were significantly higher in the high group than the intermediate and low groups: 67.0% vs 38.1% vs 18.2% (P < .01). In multivariate analyses, the numbers of CD204+ macrophages were independent risk factors of poorer OS and cumulative incidences of relapse. CONCLUSIONS: CD204+ macrophages might be associated with poorer prognosis in allogeneic HCT for malignant lymphomas.

Double-Expressor Lymphoma Is Associated with Poor Outcomes after Allogeneic Hematopoietic Cell Transplantation.

Double-expressor lymphoma (DEL) is a diffuse large B cell lymphoma that exhibits co-expression of MYC and BCL2 proteins by immunohistochemistry. Patients with double-expressor lymphoma have a poor prognosis after standard chemoimmunotherapy or after high-dose chemotherapy with autologous transplantation, but the prognostic impact of DEL after allogeneic hematopoietic cell transplantation has not been well characterized. We retrospectively analyzed 60 consecutive patients with de novo diffuse large B cell lymphoma or transformed follicular lymphoma who underwent allogeneic transplantation at our center and had available immunohistochemistry data. Thirty-seven patients (62%) had DEL. The 2-year progression-free and overall survival rates were lower in patients with DEL than in those without DEL (20% versus 78%; overall P <.001 and 46% versus 77%; overall P = .016, respectively). The cumulative incidence of disease progression at 2 years was higher in patients with DEL (60% versus 13%; overall P = .005). The cumulative incidence of nonrelapse mortality did not differ statistically in the 2 groups. Even in patients with DEL and chemosensitive disease at transplantation, the 2-year progression-free survival rate was only 27% due to early disease progression. Multivariate analysis showed associations between DEL and increased risks of progression-free survival events (hazard ratio [HR], 4.58; 95% confidence interval [CI], 2.07-10.2; P <.001), overall mortality (HR, 2.29; 95% CI, 1.03-5.09; P = .042) and disease progression (HR, 3.60; 95% CI, 1.38-9.44; P = .009). Patients with DEL had poor outcomes after allogeneic transplantation. Innovative strategies are needed to improve outcomes in this population.

Association of Cumulative Steroid Dose with Risk of Infection after Treatment for Severe Acute Graft-versus-Host Disease.

This study aimed to characterize the incidence and risk factors of invasive fungal disease, cytomegalovirus infection, other viral diseases, and gram-negative rod infection after glucocorticoid treatment for severe acute graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation and to elucidate the associations of cumulative steroid dose with the risks of individual infections. The study cohort included 91 consecutive patients who developed maximum grades III and IV acute GVHD at our center. The mean cumulative prednisolone-equivalent dose was 41 mg/kg during the first 4 weeks. The cumulative incidence rates of fungal disease, cytomegalovirus disease, other viral diseases, and gram-negative rod infection at 6 months after glucocorticoid treatment were remarkably high, at 14%, 21%, 28%, and 20%, respectively. GVHD within 26 days after transplantation and low lymphocyte count at GVHD treatment were associated with increased risks of several infections. Cumulative prednisolone-equivalent steroid doses ≥ 55 mg/kg during the first 4 weeks were associated with an increased risk of fungal disease (hazard ratio, 3.65; P = .03) and cumulative doses ≥ 23 mg/kg were associated with an increased risk of non-cytomegalovirus viral diseases (hazard ratio, 4.14; P = .02). Strategies to reduce the risk of infectious complications are needed, particularly for patients who have risk factors and those who receive high cumulative steroid doses.

Excess generation and activation of naturally arising memory-phenotype CD4+ T lymphocytes are inhibited by regulatory T cells in steady state.

Conventional CD4+ T lymphocytes consist of naïve, foreign antigen-specific memory, and self-antigen-driven memory-phenotype (MP) cell compartments at homeostasis. We recently showed that MP cells tonically proliferate in response to self-antigens and differentiate into the T-bet+ subset in steady state. How excess proliferation and differentiation of MP cells are inhibited remains unclear. Given immunosuppressive function of regulatory T cells (Tregs), it is possible that they are also involved in inhibition of spontaneous MP cell activation. Here we show using Foxp3-diphtheria toxin receptor-transgenic mice that both MP and naïve CD4+ T cells spontaneously proliferate and differentiate into Th1 cells upon acute Treg depletion. At an early time point post Treg depletion, MP as compared to naïve CD4+ T cells are preferentially activated while at a later stage, the response is dominated by activated cells originated from the naïve pool. Moreover, we argue that MP cell proliferation is driven by TCR and CD28 signaling whereas Th1 differentiation mediated by IL-2. Furthermore, our data indicate that such activation of MP and naïve CD4+ T lymphocytes contribute to development of multi-organ inflammation at early and later time points, respectively, after Treg ablation. Together our findings reveal that Tregs tonically inhibit early, spontaneous proliferation and Th1 differentiation of MP CD4+ T lymphocytes as well as late activation of naïve cells, thereby contributing to maintenance of T cell homeostasis.

Successful Cord Blood Transplantation for Myeloid/Natural Killer Precursor Acute Leukemia: A Case Report and Literature Review.

A 21-year-old man was diagnosed with myeloid/natural killer precursor leukemia (MNKPL) with bone marrow infiltration of blasts of cyCD3+, CD7+, CD33+, CD34dim, CD56+/-, HLA-DR+, cyMPO+, and TdT- immunophenotypes. Although hyper-CVAD therapy was unsuccessful, induction treatment with idarubicin and cytarabine resulted in complete remission (CR). The patient subsequently underwent cord blood transplantation with a myeloablative conditioning regimen, which resulted in durable CR and complete donor chimerism. He had been in good health without relapse for over nine months since transplantation. Timely allogeneic hematopoietic stem cell transplantation using an available donor source may be a promising treatment strategy for MNKPL.

Human leukocyte antigen (HLA) haplotype matching in unrelated single HLA allele mismatch bone marrow transplantation.

The role of matching human leukocyte antigen (HLA) haplotypes in unrelated allogeneic bone marrow transplantation (allo-BMT) remains unclear. Here, we imputed the HLA haplotypes of 3657 patients who received unrelated single HLA allele-mismatched allo-BMT, included from the Transplant Registry Unified Management Program (TRUMP) database, the Japanese registry program for hematopoietic transplantation, using mathematical methods. We successfully imputed the HLA haplotypes of both patients and donors in 1365 cases (37.3%) with ≥90% probability. Of the patients, 1326 (97.1%) and 39 (2.9%) were categorized into one-haplotype-matched and no-haplotype-matched groups, respectively. Disease-free survival was significantly worse in the no-haplotype-matched group. Multivariate analyses revealed that no-haplotype-match was an independent risk factor for reducing disease-free survival (hazard ratio, 1.54 [95% confidence interval: 1.01-2.36]; p = 0.047). However, the overall survival did not significantly differ between the groups. The incidence of grade III-IV acute and chronic graft-versus-host disease did not significantly differ between the groups. Furthermore, there were no significant differences in the cumulative incidences of relapse and non-relapse mortality between the groups. Our findings suggest that imputing haplotypes using a mathematical approach can help to avoid transplanting patients with donors who do not share matching haplotypes, thereby improving the outcome of allo-BMT.

Redefining the Foreign Antigen and Self-Driven Memory CD4+ T-Cell Compartments via Transcriptomic, Phenotypic, and Functional Analyses.

Under steady-state conditions, conventional CD4+ T lymphocytes are classically divided into naïve (CD44lo CD62Lhi) and memory (CD44hi CD62Llo) cell compartments. While the latter population is presumed to comprise a mixture of distinct subpopulations of explicit foreign antigen (Ag)-specific "authentic" memory and foreign Ag-independent memory-phenotype (MP) cells, phenotypic markers differentially expressed in these two cell types have yet to be identified. Moreover, while MP cells themselves have been previously described as heterogeneous, it is unknown whether they consist of distinct subsets defined by marker expression. In this study, we demonstrate using combined single-cell RNA sequencing and flow cytometric approaches that self-driven MP CD4+ T lymphocytes are divided into CD127hi Sca1lo, CD127hi Sca1hi, CD127lo Sca1hi, and CD127lo Sca1lo subpopulations that are Bcl2lo, while foreign Ag-specific memory cells are CD127hi Sca1hi Bcl2hi. We further show that among the four MP subsets, CD127hi Sca1hi lymphocytes represent the most mature and cell division-experienced subpopulation derived from peripheral naïve precursors. Finally, we provide evidence arguing that this MP subpopulation exerts the highest responsiveness to Th1-differentiating cytokines and can induce colitis. Together, our findings define MP CD4+ T lymphocytes as a unique, self-driven population consisting of distinct subsets that differ from conventional foreign Ag-specific memory cells in marker expression and establish functional relevance for the mature subset of CD127hi Sca1hi MP cells.

BK Virus-Associated Urothelial Carcinoma in a Patient with Peripheral Blood Stem Cell Transplantation for Acute Lymphoblastic Leukemia: A Case Report.

Bladder tamponade due to hemorrhagic cystitis caused by BK virus in immunocompetent patients is familiar to urologists. BK virus is an important cause of nephropathy and graft loss in kidney transplant recipients. Although urothelial carcinoma of the bladder in kidney transplant recipients with persistent BK viruria is known, BK virus-associated urothelial carcinoma (BKVUC) in peripheral blood stem cell transplantation recipients is not as well known. A 54-year-old man with acute lymphoblastic leukemia was treated in the Department of Hematology of our hospital. After recurrence 25 months later, he received chemotherapy for half a year and underwent peripheral blood stem cell transplantation. He achieved temporarily complete remission, but he developed hematuria with BK virus-positive result 1 month after peripheral blood stem cell transplantation. One month later, he developed bladder tamponade-diagnosed hemorrhagic cystitis due to BK virus in our Urological Department. We performed transurethral coagulation to manage hemorrhage and removed a bleeding lesion in the bladder wall. Pathological examination of the removed bladder wall revealed pT1 stage BKVUC. We found that bladder tamponade could have led to reactivation of BK virus in this immunocompetent patient. This could be the first report of BKVUC of the bladder found in a peripheral blood stem cell transplantation recipient with close urological follow-up for 24 months. Adequate removal of bleeding lesions from the bladder mucosa with appropriate timing during hemorrhagic cystitis due to BKVUC could be essential to achieve good outcomes.

Characterization of readmission after allogeneic hematopoietic cell transplantation.

To elucidate the incidence, causes, and risk factors associated with readmission due to transplant-related complications, we studied 213 consecutive patients who were discharged without progression of primary disease after their first allogeneic hematopoietic cell transplantation at our center between 2013 and 2016. The median patient age was 50 years (range, 18-71 years). Eighty-three patients had AML or MDS, 66 had lymphoma, 28 had ALL, 23 had ATL, and 13 had other diseases. The median duration of hospitalization for transplantation was 56 days (range 27-325 days). The cumulative incidences of readmission due to transplant-related complications were 8% at 30 days, 16% at 100 days, and 25% at 1 year after discharge. The most frequent cause of readmission was infection, followed by graft-versus-host disease throughout the first year. In multivariate analysis, steroid use at discharge was the only risk factor associated with readmission within 30 days, and steroid use at discharge, absolute lymphocyte count < 500/µl at discharge, and documented bacterial infection during admission were risk factors associated with readmission within 1 year. Our results indicated that factors during hospitalization or discharge, but not at transplantation, were associated with readmission. Patients with these risk factors should be monitored carefully after discharge.

Author Correction: Requirements for the differentiation of innate T-bethigh memory-phenotype CD4+ T lymphocytes under steady state.

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

Requirements for the differentiation of innate T-bethigh memory-phenotype CD4+ T lymphocytes under steady state.

CD4+ T lymphocytes consist of naïve, antigen-specific memory, and memory-phenotype (MP) cell compartments at homeostasis. We recently showed that MP cells exert innate-like effector function during host defense, but whether MP CD4+ T cells are functionally heterogeneous and, if so, what signals specify the differentiation of MP cell subpopulations under homeostatic conditions is still unclear. Here we characterize MP lymphocytes as consisting of T-bethigh, T-betlow, and T-bet- subsets, with innate, Th1-like effector activity exclusively associated with T-bethigh cells. We further show that the latter population depends on IL-12 produced by CD8α+ type 1 dendritic cells (DC1) for its differentiation. Finally, our data demonstrate that this tonic IL-12 production requires TLR-MyD88 signaling independent of foreign agonists, and is further enhanced by CD40-CD40L interactions between DC1 and CD4+ T lymphocytes. We propose that optimal differentiation of T-bethigh MP lymphocytes at homeostasis is driven by self-recognition signals at both the DC and Tcell levels.

Kinetics of neutrophil engraftment in allogeneic stem cell transplantation.

Primary graft failure is a lethal complication that occurs after allogeneic stem cell transplantation (allo-SCT) and requires retransplantation. We retrospectively assessed 1,355 patients who underwent allo-SCT at our institute. Following allo-SCT, the cumulative incidence of subsequent neutrophil engraftment was calculated each day after day 5 among patients with white blood cell (WBC) count<100 cells/µL on the respective day. The number of patients with WBC count<100 cells/µL at days 14, 21, and 28 were 372, 55, and 21, respectively. In patients with WBC count<100 cells/µL on day 14, the cumulative incidence of engraftment was lower in recipients of peripheral blood stem cells (PBSCs) and cord blood (CB) compared with recipients of bone marrow (BM) (BM vs. PBSCs vs. CB, 93% vs. 79% vs. 77%, P<0.01). In patients with WBC count<100 cells/µL after day 14, the cumulative incidence of engraftment in recipients of PBSCs became progressively lower (25% at day 21 and 0% at day 28). In patients with WBC count<100 cells/µL on day 28, the cumulative incidence of engraftment was 100% in patients with donor chimerism≥95%, while it was only 13% in those with chimerism<95% (P<0.01). These data provide important information that could be useful in deciding the appropriate time for performing tests in patients with donor chimerism and in those that require retransplantation.