Selective control of transposable element expression during T cell exhaustion and anti-PD-1 treatment.

In chronic infections and cancer, T cells are exposed to prolonged antigen stimulation, resulting in loss of function (or exhaustion) and impairment of effective immunological protection. Exhausted T cells are heterogeneous and include early progenitors (Tpex) and terminally exhausted cells (Tex). Here, we used bulk and single-cell transcriptomics to analyze expression of transposable elements (TEs) in subpopulations of mouse and human CD8+ tumor-infiltrating T lymphocytes (TILs). We show that in mice, members of the virus-like murine VL30 TE family (mostly intact, evolutionary young ERV1s) are strongly repressed in terminally exhausted CD8+ T cells in both tumor and viral models of exhaustion. Tpex expression of these VL30s, which are mainly intergenic and transcribed independently of their closest gene neighbors, was driven by Fli1, a transcription factor involved in progression from Tpex to Tex. Immune checkpoint blockade (ICB) in both mice and patients with cancer increased TE expression (including VL30 in mice), demonstrating that TEs may be applicable as ICB response biomarkers. We conclude that expression of TEs is tightly regulated in TILs during establishment of exhaustion and reprogramming by ICB. Analyses of TE expression on single cells and bulk populations open opportunities for understanding immune cell identity and heterogeneity, as well as for defining cellular gene expression signatures and disease biomarkers.

Ambivalent role of FasL in murine acute graft-versus-host-disease.

Fas ligand is increased in several immune-mediated diseases, including acute graft-versus-host disease, a donor cell-mediated disorder post-hematopoietic stem cell transplantation. In this disease, Fas ligand is involved in T-cell-mediated damage to host tissues. However, the role of its expression on donor non-T cells has, so far, never been addressed. Using a well-established CD4- and CD8-mediated graft-versus-host disease murine model, we found that precocious gut damage and mice mortality are increased with a graft of donor T- and B-depleted bone marrow cells devoid of Fas ligand as compared with their wild-type counterparts. Interestingly, serum levels of both soluble Fas ligand and IL-18 are drastically reduced in the recipients of Fas ligand-deficient grafts, indicating that soluble Fas ligand stems from donor bone marrow-derived cells. In addition, the correlation between the concentrations of these 2 cytokines suggests that IL-18 production arises through a soluble Fas ligand-driven mechanism. These data highlight the importance of Fas ligand-dependent production in IL-18 production and in mitigating acute graft-versus-host disease. Overall, our data reveal the functional duality of Fas ligand according to its source.

Prospective external validation of biomarkers to predict acute graft-versus-host disease severity.

Acute graft-versus-host disease (GVHD) is still the major contributor to comorbidities and mortality after allogeneic hematopoietic stem cell transplantation. The use of plasmatic biomarkers to predict early outcomes has been advocated in the past decade. The purpose of this prospective noninterventional study was to test the ability of panels including 7 biomarkers (Elafin, HGF, IL2RA, IL8, REG3, ST2, and TNFRI), to predict day 28 (D28) complete response to steroid, D180 overall survival, and D180 nonrelapse mortality (NRM). Using previous algorithms developed by the Ann Arbor/MAGIC consortium, 204 patients with acute GVHD were prospectively included and biomarkers were measured at GVHD onset for all of them. Initial GVHD grade and bilirubin level were significantly associated with all those outcomes. After adjustment on clinical variables, biomarkers were associated with survival and NRM. In addition to clinical variables, biomarkers slightly improved the prediction of overall survival and NRM (concordance and net reclassification indexes). The potential benefit of adding biomarkers panel to clinical parameters was also investigated by decision curve analyses. The benefit of adding biomarkers to clinical parameters was however marginal for the D28 nonresponse and mortality endpoints.

In vivo genome-wide CRISPR screens identify SOCS1 as intrinsic checkpoint of CD4+ TH1 cell response.

Although CD8+ T cells undergo autonomous clonal proliferation after antigen stimulation in vivo, the expansion of activated CD4+ T cells is limited by intrinsic factors that are poorly characterized. Using genome-wide CRISPR-Cas9 screens and an in vivo system modeling of antigen-experienced CD4+ T cell recruitment and proliferation during a localized immune response, we identified suppressor of cytokine signaling 1 (SOCS1) as a major nonredundant checkpoint imposing a brake on CD4+ T cell proliferation. Using anti­interleukin-2 receptor (IL-2R) blocking antibodies, interferon-γ receptor (IFN-γR) knockout mice, and transcriptomic analysis, we show that SOCS1 is a critical node integrating both IL-2 and IFN-γ signals to block multiple downstream signaling pathways abrogating CD4+ T helper 1 (TH1) cell response. Inactivation of SOCS1 in both murine and human CD4+ T cell antitumor adoptive therapies restored intratumor accumulation, proliferation/survival, persistence, and polyfunctionality and promoted rejection of established tumors. However, in CD8+ T cells, SOCS1 deletion did not affect the proliferation but rather improved survival and effector functions, which allowed for optimal therapeutic outcome when associated with SOCS1 inactivation in CD4+ T cells. Together, these findings identify SOCS1 as a major intracellular negative checkpoint of adoptive T cell response, opening new possibilities to optimize CAR-T cell therapy composition and efficacy.

Epstein-Barr virus induced post-transplant lymphoproliferative disorder presenting with unilateral retinal involvement.

PURPOSE: Post-transplant lymphoproliferative disorder (PTLD) represents a spectrum of disorders associated with Epstein Barr Virus infection in up to 80% of cases in the setting of pharmacologic immunosuppression following hematopoietic stem cell or solid organ transplantation. Ocular involvement is a rare finding in PTLD. OBSERVATION: We report the case of a 38-year-old man who presented with unilateral retinal infiltrates as first manifestation of PTLD relapse. Diagnosis relied on the presence of EBV DNA in anterior chamber fluids and vitrectomy that showed the presence of a B cell clone. Systemic relapse of PTLD was detected 12 weeks after retinal findings. Treatment of ocular disease included systemic injections of rituximab and intravitreal injections of methotrexate, halting the extension of retinal infiltrates. CONCLUSION: Ocular involvement in PTLD is rare and needs to be acknowledged because it can precede a systemic relapse of the hematological condition.

Long-term outcomes and risk factor analysis of steroid-refractory graft versus host disease after hematopoietic stem cell transplantation.

Steroid-refractory graft versus host disease (GVHD) represents a fearsome complication after allogeneic hematopoietic stem cell transplantation (HSCT). We conducted a retrospective study on outcomes and risk factors associated with acute and chronic steroid-refractory GVHD in a large cohort of 1207 patients receiving HSCT in Saint Louis Hospital between 2007 and 2017. Among patients who developed an acute and/or a chronic GVHD, the cumulative incidences of acute and chronic steroid-refractory disease were 31% and 48%, respectively, at day +100 and 1-year post-HSCT. Through a multivariable analysis we selected several risk factors associated with the development of a steroid-refractory disease. For acute GVHD steroid refractoriness, we identified (1) a very high disease risk index, (2) an unrelated donor, (3) the absence of in vivo T-depletion as GVHD prophylaxis, and (4) a reduced intensity conditioning regimen. For chronic GVHD, (1) the use of peripheral blood stem cells, (2) unrelated donors, and (3) absence of in vivo T-depletion were more likely associated with a steroid-refractory disease. After the construction of a multistate dynamic model, we found that the probability of being alive without relapse after the resolution of all GVHD episodes was about 36% in the long term.

Elastography improves accuracy of early hepato-biliary complications diagnosis after allogeneic stem cell transplantation.

Significant morbidity and mortality have been associated with liver complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Causes and consequences of these hepato-biliary complications are various and might be life-threatening. A high misdiagnosis rate has been reported because of a weak correlation between clinical, laboratory and imaging data. Liver elastography, a liver stiffness measure, is able to assess liver fibrosis and portal hypertension in most liver diseases, but data after allo-HSCT are scarce. Our aim was to determine the interest of sequential liver stiffness measurements for the diagnosis of early hepatic complications after allo-HSCT. Over a two years period of time, 161 consecutive adult patients were included and 146 were analyzed. Ultrasonography and elastography measurements were performed before transplantation, at day+7 and day+14 by three different experienced radiologists unaware of patients'clinical status. Eighty-one (55%) patients had liver involvements within the first 100 days after allo-HSCT. Baseline elastography was not predictive for the occurrence of overall liver abnormalities. A significant increase in 2D real-time shearwave elastography (2D-SWE) was found in patients with sinusoidal obstruction syndrome (SOS). Fifteen patients (10%) fulfilled EBMT score criteria and twelve (8%) reached Baltimore criteria for SOS diagnosis, but only six (4%) had a confirmed SOS. 2D-SWE at day+14 allowed early detection of SOS (AUROC=0.84, p=0.004) and improved sensibility (75%), specificity (99%) and positive predictive value (60%) over the Seattle, Baltimore or EBMT scores. A 2D-SWE measurement above 8.1kPa at day+14 after allo-HSCT seems a promising, non-invasive, and reproducible tool for early and accurate diagnosis of SOS.

Human-Derived α1-Antitrypsin is Still Efficacious in Heavily Pretreated Patients with Steroid-Resistant Gastrointestinal Graft-versus-Host Disease.

Almost one-half of patients developing graft-versus-host disease (GVHD) will not respond to standard first-line steroid treatment. Alpha-1 antitrypsin (AAT) is able to induce tolerance in preclinical models of GVHD. AAT alters the cytokine milieu, promotes a tolerogenic shift of dendritic cells, and skews effector T cells toward regulatory T cells. Gastrointestinal steroid-refractory (SR)-GVHD is a protein-losing enteropathy that might represent the optimal setting in which to use AAT. Here we analyze the outcomes of 16 patients treated with human-derived AAT in advanced-stage gut SR-GVHD, with two-thirds of the patients having failed at least 1 treatment for SR-GVHD. The overall response rate (ORR) was 44%, with a complete response (CR) rate of 27%. Gastrointestinal response was observed in 61% of patients. The median time to best response was 21 days (range, 6 to 26 days). At day 56 after AAT treatment, all CRs were maintained, and the ORR was 39%. The 1-year overall survival was 48% (95% confidence interval, 26% to 74%). Ancillary studies showed that AAT serum levels were in the normal range at the beginning of treatment, whereas fecal loss was elevated. AAT levels consistently rose after exogenous administration, but no correlation was found between serum levels and response. REG3α and IL-33 levels were associated with response while, in contrast to previous reports, regulatory T cells decreased during AAT treatment. This retrospective analysis supports a previous report of AAT as a promising agent in the management of gut SR-GVHD and should prompt its evaluation at an earlier stage.

A monocentric study of steroid-refractory acute graft-versus-host disease treatment with tacrolimus and mTOR inhibitor.

Acute graft-versus-host disease (aGVHD) remains one of the leading causes of morbidity and mortality after allogeneic hematopoietic stem cell transplantation. No consensus exists on the best second-line treatment of steroid-refractory acute GVHD (SR-aGVHD). Previously published smaller studies on the use of sirolimus in SR-aGVHD treatment report a response rate of 57 to 86%, with 40% overall survival. The association of tacrolimus and mTOR inhibitor is supported by pre-clinical data and has been used as GVHD prophylaxis. We report 42 patients who received tacrolimus and mTOR inhibitor as a second- or third-line treatment of SR-aGVHD. Thirty-one patients were treated in second-line, with an overall response rate of 48.5% (complete response: 42%). Eleven patients were treated in third-line, with an overall response rate of 27%. Thirty-eight patients had at least one episode of infection, due to bacteria, viruses, fungi and parasites in 61, 42, 12 and two episodes, respectively. For patients treated in second-line, six-month and one-year survival were 61% and 42%, respectively. None of the patients treated in third-line survived. These results were not promising enough to initiate a phase three randomized clinical trial, but tacrolimus and mTOR inhibitor can be discussed among other options for patients with SR-aGVHD.

Quantitative chimerism in CD3-negative mononuclear cells predicts prognosis in acute myeloid leukemia patients after hematopoietic stem cell transplantation.

Relapse is a major complication of acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (SCT). The objective of our study was to evaluate chimerism monitoring on the CD3-negative mononuclear cells by RQ-PCR to predict relapse of patients allografted for AML and to compare its performance with WT1 quantification. A cohort of 100 patients undergoing allogenic SCT for AML was retrospectively analyzed in a single institution. Patients without complete chimerism, defined as less than 0.01% of recipient's DNA in CD3-negative cells, had a significantly higher risk of relapse and a lower overall survival (p < 0.001). An increase in the percentage of recipient DNA in CD3-negative cells was associated with an increased risk of relapse (p < 0.001) but not with overall survival. Comparable performances between monitoring of CD3-negative cell chimerism and WT1 expression to predict relapse was observed up to more than 90 days before hematological relapse, with sensitivity of 82% and 78%, respectively, and specificity of 100% for both approaches. Quantitative specific chimerism of the CD3-negative mononuclear fraction, enriched in blastic cells, is a new and powerful tool for monitoring measurable residual disease and could be used for AML patients without available molecular markers.

Allogeneic reactivity-mediated endothelial cell complications after HSCT: a plea for consensual definitions.

Endothelial cell (EC) activation has been suspected of triggering a group of rare and dismal complications that can occur after allogeneic hematopoietic stem cell transplantation (HSCT). Capillary leak syndrome, engraftment syndrome, transplant-associated microangiopathy, diffuse alveolar hemorrhage, and idiopathic pneumonia syndrome are the main nosological entities. Post-HSCT endotheliitis can be triggered by chemotherapy, infections, and calcineurin inhibitors, but allogeneic reactivity is claimed to be the common denominator. Endothelial damages are thought to activate several deleterious pathways (proapoptotic, procoagulant, proinflammatory) and can lead to multiorgan failure; however, clinical manifestations of each syndrome overlap, and their relationship with graft-versus-host disease could be minimal. The lack of well-defined diagnostic criteria does not allow for a clear-cut comparison in the current literature. Therapeutic efforts have been made to intercept the pathogenic mechanisms leading to EC dysfunction, but remission rates and survival remain mostly unsatisfactory. In this article, we have reviewed the incidence, clinical features, and treatment approaches of EC activation syndromes, and we plead for the development of internationally accepted standard definitions.

Impact of front line relative dose intensity for methotrexate and comorbidities in immunocompetent elderly patients with primary central nervous system lymphoma.

Primary central nervous system lymphomas (PCNSL) are non-Hodgkin lymphomas strictly localized to the CNS, occurring mainly in elderly patients with comorbidities. Current treatment in fit patients relies on high-dose methotrexate and high-dose cytarabine. The aim of this study was to evaluate the efficacy and feasibility of this treatment in elderly patients and to assess potential prognostic factors associated with survival. We conducted a retrospective study in two centers between January 2008 and September 2015 including 35 elderly immunocompetent patients who received first-line treatment with high-dose methotrexate. With a median follow-up of 19.8 months (range: 1.7-73.4 months), median overall survival (OS) was 39.5 months (95% confidence interval (95% CI): 18.3-60.7) and median progression-free survival (PFS) was 25.8 months (95% CI: 5.2-46.4). In univariate analysis, administration of high-dose cytarabine and achieving a relative dose intensity for methotrexate > 75% were associated with increased OS (p = 0.006 and p = 0.003, respectively) and PFS (p = 0.003 and p = 0.04, respectively) whereas comorbidities, defined by a CIRS-G score ≥ 8, were associated with decreased OS and PFS (p = 0.02 and p = 0.04, respectively). A high MSKCC score was associated with decreased OS (p = 0.02). In multivariate analysis, administration of high-dose cytarabine was associated with increased OS and PFS (p = 0.02 and p = 0.007, respectively). Comorbidities and relative dose intensity for methotrexate are important for the prognosis of elderly patients with PCNSL. These results must be confirmed in prospective trials.

[Acquired Pelger-Huët anomaly/abnormal chromatin clumping of granulocytes after allogeneic hematopoietic stem cell transplantation for acute myeloid leukaemia: medication or relapse? ]. / Anomalie de Pelger-Huët acquise/condensation anormale de la chromatine des granulocytes après allogreffe médullaire pour leucémie aiguë myéloïde : iatrogène ou signe de rechute ?

An acute myeloid leukemia was diagnosed in a 53-year-old female patient. She received an allogeneic stem cell transplant. After this transplant, some neutrophils with hyposegmented nucleus and abnormal chromatin clumping appeared in the peripheral blood, and their number gradually increased. The hypothesis of early relapse after transplant was ruled out and drug-related anomaly was suspected. The authors discuss about morphological features of constitutional and acquired Pelger-Huët anomaly. In the patient reported here, ciclosporine seemed to be involved in the phenomenon, as the morphological anomaly of the neutrophils gradually decreased after the drug was discontinued.