Inhibition of Jak1/Jak2 Is More Effective Than Inhibition of Jak3 in Protecting Mice From Acute Graft-Versus-Host Disease (aGvHD) by Significantly Decreasing Alloreactive CD4+ T-Cells.

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 2997-2997
Author(s):  
Cristiana Carniti ◽  
Silvia Gimondi ◽  
Raffaella Vaccaroli ◽  
Antonio Vendramin ◽  
Anisa Bermema ◽  
...  
Keyword(s):  
Weight Loss ◽  
T Cells ◽  
Mouse Model ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
Acute Gvhd ◽  
Janus Kinase ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host

Abstract Abstract 2997 Background: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative treatment for patients with hematological malignancies. However, its success is limited by a life-threatening complication: the graft-versus-host disease (GvHD). Although numerous studies have described immunosuppression protocols to mitigate acute GVHD (aGvHD), novel approaches are needed. Chemokines are well known inducers of leukocyte trafficking and activation. Stimulation of the chemokine receptor signaling pathway leads to initiation of the Janus Kinase (JAK)/Signal Transducer and Activator of Transcription (STAT) pathway that contributes to the pathogenesis of GvHD. The key role of JAK signaling in normal and abnormal lymphocyte development and function, along with the cytotoxic effects of its inhibitor INCB18424 (Ruxolitinib) on leukemia cells, prompted us to hypothesize that this selective JAK1 and 2 inhibitor could be useful as anti-GvHD agent while maintaining antitumor activity. Since CP-690550, a more selective JAK3 inhibitor, was recently shown to protect against GvHD in mouse models, we also tested whether blocking the JAK1/JAK2 pathway could be more effective in preventing GvHD. Methods: To assess the therapeutic effect of pharmacologic modulation of JAK1 and 2 on GvHD, a major histocompatibility complex (MHC) mismatched HSCT mouse model was used. Recipient BALB/c mice were lethally irradiated and treated either with spleen and bone marrow (BM) cells from C57BL/6 (B6) donors (GvHD cohort, n=8), or with spleen and BM cells from B6 donors along with INCB18424 90mg/kg/day at days -1 to 13 (INCB18424 cohort, n=10) or with CP-690550 15mg/kg/day (CP-690550 cohort, n=8) at days -1 to 13. Syngeneic transplants (B6-B6, n=6) and BALB/c recipients treated with B6 BM cells only (control cohort, n=8) were also included as controls. Mice were characterized for GvHD by monitoring overall survival and weight loss. Recipient mice were sacrificed and tissues harvested on day 14 and 30 post transplant and GvHD confirmed by histology. Results: All mice in the GvHD cohort had clinical evidence of GvHD (weight loss, generalized erythema of the skin and poor fur quality) by day 14. The INCB18424 treated mice showed markedly reduced weight loss along the time of observation when compared to the GvHD cohort. Animals in the CP-690550 cohort tended to gain weight during the time of treatment (day-1 to 13), but thereafter they exhibited reduced body weight similar to that observed in the GvHD cohort. The histological examination of the stomach, liver, skin and intestine obtained at day 14 revealed no sign of GvHD in the control group as well as in the INCB18424 group. On the other hand, mild to moderate signs of GvHD were present in the tissues of CP-690550 treated mice and extensive inflammation and disruption of the normal architecture of the tissues was observed in the GvHD group. To determine whether INCB18424 treatment affected alloreactive CD4+ T cells, total spleen T cells were harvested at day 14 from the GvHD cohort and from recipients either of INCB18424 or CP-690550. Total spleen T cells were co-cultured with BM derived BALB/c (recipient-derived) or C57BL/6 (donor-derived) dendritic cells (DCs). After 24h, T cells alloreactivity was determined by IFN-γ production assessed by intracellular staining. As expected, T cells from GvHD mice showed significantly higher alloreactivity against BALB/c DCs compared to the reactivity observed against syngeneic B6 DCs (5.24% and 0.84% respectively, p<0.05). The alloreactivity observed when T cells from INCB18424 treated mice were stimulated with allogeneic BALB/c DCs was significantly lower than that in the GvHD group (0.64% and 5.24% respectively, p<0.05) and eas also lower than that of the CP-690550 group (1.43%). STAT phosphorylation analysis demonstrated that INCB18424 treatment was effective in vitro. Conclusions: The inhibition of Jak/STAT signaling using the sensitive and specific inhibitor of Jak1/Jak2, INCB18424, conferred effective protection from aGvHD in a HSCT mouse model. INCB18424 treatment was more effective than the targeting of JAK3 with CP-690550. In fact, CP-690550 administered during GvHD induction was not completely sufficient to restore the normal weight and to prevent the histological appearance of GvHD whereas INCB18424 was. INCB18424 protected mice against acute GvHD by significantly decreasing alloreactive CD4 T cells. Disclosures: No relevant conflicts of interest to declare.

Recipient CD4+ T cells that survive irradiation regulate chronic graft-versus-host disease

Blood ◽  
2004 ◽  
Vol 104 (5) ◽  
pp. 1565-1573 ◽  
Author(s):  
Britt E. Anderson ◽  
Jennifer M. McNiff ◽  
Catherine Matte ◽  
Ionna Athanasiadis ◽  
Warren D. Shlomchik ◽  
...  
Keyword(s):  
T Cells ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
Acute Gvhd ◽  
Cell Receptor ◽  
Host Disease ◽  
Graft Versus Host ◽  
Pathologic Features ◽  
Radiation Resistant ◽  
Tcr Diversity

Abstract Chronic graft-versus-host disease (cGVHD) is an increasingly common cause of morbidity and mortality in allogeneic stem cell transplantation (alloSCT). Relative to acute GVHD (aGVHD), much less is understood about cGVHD. Using the B10.D2 → BALB/c murine cGVHD model, which shares critical pathologic features with human cGVHD, we find that radiation-resistant host T cells regulate cGVHD. We initially observed that recipients lacking all lymphocytes developed accelerated and more severe cGVHD. Using genetically deficient recipients, we determined that αβ+CD4+ T cells were required to regulate cGVHD. Increased cGVHD severity was not due to the absence of T cells per se. Rather, the potency of regulation was proportional to host T-cell receptor (TCR) diversity. Only CD4+CD25+, and not CD4+CD25-, host T cells ameliorated cGVHD when added back, indicating that host T cells acted not via host-versus-graft activity or by reducing homeostatic proliferation but by an undefined regulatory mechanism. Thus, preparative regimens that spare host CD4+CD25+ T cells may reduce cGVHD. Donor CD4+CD25+ T cells also reduced cGVHD. Depletion of CD4+CD25+ cells from the inoculum exacerbated disease, whereas transplantation of additional CD4+CD25+ cells protected against severe cGVHD. Additional CD4+CD25+ cells also promoted healing of established lesions, suggesting that their effects persist during the evolution of cGVHD.

Cell Autonomous Role of TGFβ and IL-2 Receptor in the In Vivo Generation of CD4 and CD8 Inducible Regulatory T Cells During Graft-Versus-Host Disease,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4015-4015
Author(s):  
Atsushi Satake ◽  
Norifumi Sawamukai ◽  
Taku Kambayashi
Keyword(s):  
Weight Loss ◽  
T Cells ◽  
Regulatory T Cells ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Receptor Expression ◽  
Host Disease ◽  
Graft Versus Host ◽  
Tgfβ Receptor

Abstract Abstract 4015 FoxP3+ regulatory T cells (Tregs) suppress graft-versus-host disease (GVHD) while preserving graft-versus-tumor effects, making them an attractive target for GVHD therapy. The donor-derived Treg pool can potentially be derived from expansion of pre-existing natural Tregs (nTregs) or from de novo generation of inducible Tregs (iTregs) from donor conventional T cells (Tconvs) in the transplant recipient. Although the co-adoptive transfer of nTregs or in vitro -derived iTregs has been shown to prevent the development of GVHD, the relative contribution of these two Treg subsets in protection against GVHD has been unclear. To investigate the contribution of the different FoxP3+ Treg subsets, we used a MHC-mismatched mouse model of acute GVHD. Lethally irradiated (500cGy × 2) B6D2F1.SJL (H-2bxd) host mice were injected with T cell-depleted bone marrow cells and FACS-sorted Tconvs (WT or Foxp3-deficient) with or without FACS-sorted Tregs of C57BL/6 (H-2b) mouse origin. Weight loss in mice receiving Foxp3-deficient Tconvs alone was significantly more pronounced compared to other groups. The presence of either donor-derived nTregs or iTregs alone protected against GVHD-induced weight loss but was suboptimal compared to the presence of both donor-derived nTregs and iTregs. Next, we sought to determine how the donor-derived Treg pool was established during acute GVHD and tracked the appearance of Tregs in the secondary lymphoid organs at different time points post transplant. On Day 8 post GVHD induction, ∼5% of the donor-derived CD4+ T cells in the spleen were FoxP3+. We found that the Treg pool was comprised equally of donor-derived nTregs and iTregs. Unexpectedly, we found a significant fraction of CD8+FoxP3+ T cells (1–3% of all CD8+ T cells) in the spleen and in the lymph nodes. These CD8+FoxP3+ T cells representing ∼70% of the iTreg pool on Day 8 post GVHD induction. These CD8+FoxP3+ T cells shared phenotypic markers with their CD4+ counterparts and displayed suppressive activity, suggesting that they were bona fide iTregs. Both CD4+ and CD8+ Tregs expanded in vivo with IL-2 treatment and required IL-2 and TGFβ receptor expression for their generation. In summary, we found that donor derived-iTregs are generated during GVHD and contribute to suppression of acute GVHD induced-weight loss. Surprisingly, CD8+Foxp3+T cells were a major contributor to the donor derived-iTreg pool after transplantation. The generation of CD8+ and CD4+ iTregs occurred at least in part by a cell autonomous IL-2 and TGFβ receptor-dependent mechanism. Thus, our data suggest that in addition to increasing nTregs, concomitant strategies aimed at enhancing the conversion of donor-derived Tconvs to iTregs for example by engaging the IL-2 and TGFβ signaling pathways might be beneficial for the treatment of GVHD. Disclosures: No relevant conflicts of interest to declare.

MiR-146a Regulates the TRAF6/TNF-Axis in Donor T Cells during Graft-Versus-Host Disease

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 843-843
Author(s):  
Natalie Stickel ◽  
Gabriele Prinz ◽  
Dietmar Pfeifer ◽  
Annette Schmitt-Graeff ◽  
Marie Follo ◽  
...  
Keyword(s):  
T Cells ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Negative Regulator ◽  
Snp Analysis ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host ◽  
Donor T Cells

Abstract Introduction: Acute graft-versus-host disease (GvHD) arises from the attack of recipient tissues by donor allogeneic T cells and represents one of the major limitations of allogeneic hematopoietic cell transplantation (allo-HCT). In spite of many clinical trials, the standard immunosuppressive regimens for prevention of acute GvHD have improved little in the last two decades. Hence, a better understanding of the biology of acute GvHD may improve therapeutic options. MicroRNA-146a (miR-146a) was found to be increased in the sera of patients with GvHD. Therefore, we aimed to decipher the role of miR-146a in allogeneic donor T cells during GvHD by functional studies and in patients undergoing allo-HCT by single nucleotide polymorphism (SNP) analysis. Methods: We used two different murine major MHC mismatch models for acute GvHD. Recipient mice were conditioned with irradiation before transplantation of bone marrow and either wildtype or miR-146a deficient T cells from allogeneic donor mice. Furthermore, genomic DNA from 289 patients that underwent allo-HCT and their respective hematopoietic stem cell donors was isolated in order to determine their miR-146a rs2910164genotype. Results: We observed miR-146a upregulation in T cells of mice developing acute GvHD compared to untreated mice in a major MHC and a minor histocompatibility antigen mismatch model. Transfer of miR-146a deficient T cells caused increased GvHD severity, elevated TNF serum levels and reduced survival. Conversely, the phytochemical induction of miR-146a or its overexpression in donor T cells using a specific miR-146a mimic reduced GvHD severity. TNF receptor-associated factor 6 (TRAF6), a verified target of miR-146a, was upregulated in miR-146a-/- T cells following alloantigen stimulation. Higher TRAF6 levels translated into increased NF-κB activity and TNF production in miR-146a-/- T cells, while other pro-inflammatory cytokine levels were unaffected. The detrimental effect of miR-146a deficiency in T cells could be antagonized by TNF blockade in vivo. Moreover, in contrast to WT T cells, over expression of miR-146a in Tnf deficient T cells had no effect on their alloreactivity. In the human system, the minor genotype of the SNP rs2910164, which causes reduced miR-146a expression, was more frequent in patients developing acute GvHD grade III/IV compared to all other allo-HCT recipients (n=289). Conclusions: Taken together we show that miR-146a functions as a negative regulator of the TRAF6/TNF-axis in allogeneic donor T cells during GvHD, leading to reduced TNF transcription. Given our observation on the predictive role of the SNP leading to decreased miR-146a expression in acute GvHD in patients and the possibility to exogenously enhance miR-146a expression, we provide a novel and targeted molecular approach to mitigate GvHD. Disclosures No relevant conflicts of interest to declare.

scholarly journals LYG1 Deficiency Attenuates the Severity of Acute Graft-Versus-Host Disease Via Skewing T Cells Polarization Towards Treg Cells

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 4-4
Author(s):  
Huihui Liu ◽  
Zhengyu Yu ◽  
Bo Tang ◽  
Shengchao Miao ◽  
Chenchen Qin ◽  
...  
Keyword(s):  
T Cells ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
Bone Marrow Cells ◽  
Conflicts Of Interest ◽  
Treg Cells ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host ◽  
Acute Graft

Acute graft-versus-host disease (aGVHD) is a lethal complication after allogeneic hematopoietic stem cell transplantation (allo-HSCT). As a complex immunopathology, aGVHD depends on the recognition of host antigens by donor T cells and induces augmented response of alloreactive T cells. Despite considerable achievements in the treatment of aGVHD, it remains a major clinical problem for the patients undergoing allo-HSCT. Therefore, it is necessary to further illustrate new mechanisms and develop novel therapeutic strategies of aGVHD. Previously we reported LYG1 (Lysozyme G-like 1) as a novel classical secretory protein promoted antitumor function of T cell. In this study, the role of LYG1 in aGVHD was investigated. Firstly, we examined whether LYG1 affected the alloreactivity of CD4+ T cells in vitro by MLR assay and discovered that LYG1 deficiency reduced the activation of CD4+ T cells and Th1 ratio, but increased Treg ratio. Then we confirmed these observations using a major MHC mismatched aGVHD model by transferring T cells sorting from WT B6 or Lyg1-/- mice with bone marrow cells from WT B6 mice into lethally irradiated BALB/c mice. The alloreactive CD4+ T cells and the proportions of Th1 cells decreased whereas the proportions of Treg cells increased in spleens and livers in mice receiving Lyg1-/- T cells. LYG1-deficient T cells attenuated aGVHD severity, inhibited the expression of CXCL9 and CXCL10 and restrained CD4+ T cells infiltrating in livers. Furthermore, administration of recombinant LYG1 protein intraperitoneally aggravated aGVHD by promoting IFN-γ production. More importantly, LYG1 deficiency did not affect GVT (graft-versus-tumor) effects. In summary, we demonstrate LYG1 regulates aGVHD via modulating the alloreactivity of CD4+ T cells and differentiation of Th1/Treg cells. Our study indicates that LYG1 may be a novel target in aGVHD by mitigating aGVHD without impairing GVT function. The therapeutic effect of targeting LYG1 is required in future investigations. Funding This study was supported by grant from The National Natural Science Foundation of China (NSFC) (Grant Number 81600144) and grant from Research Foundation of Peking University First Hospital. Disclosures No relevant conflicts of interest to declare.

Prevention of Graft-Versus-Host Disease in Mouse Model Using Anti-Mouse C5 Antibody.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3245-3245
Author(s):  
Jun-ichi Nishimura ◽  
Divino DeOliveira ◽  
Benny J. Chen ◽  
Yuzuru Kanakura ◽  
Russell P. Rother ◽  
...  
Keyword(s):  
Bone Marrow ◽  
T Cells ◽  
Mouse Model ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Host Cells ◽  
Average Weight ◽  
Similar Data ◽  
Host Disease ◽  
Graft Versus Host

Abstract Graft versus-host disease (GVHD) is a major cause of morbidity and mortality after bone marrow transplantation (BMT). An allogeneic GVH reaction is a response of donor lymphoid cells to host minor or major histocompatibility antigens. Donor T cells can be activated through the innate and the adaptive immune mechanisms. Donor B cells produce antibodies directed to host cells. These mechanisms may activate complement pathways. Thus, complement may have a crucial role in inflammation during a GVH reaction, but direct evidence for this has not been shown. In this study, we investigated the possibility of complement inhibitor, anti-mouse C5 antibody (BB5.1), to ameliorate the symptoms of GVHD using an acute GVHD mouse model: C57BL/6 (H2b) →BALB/c (H2d). One million T cells were injected together with 1 x 107 T-cell-depleted bone marrow (TCD BM) cells via tail vein into lethally irradiated BALB/c (8.5 Gy) recipients. Anti-mouse C5 antibody or its isotype matched control was administered intraperitoneally at a dose of 1 mg/mouse, 3 doses/week, for 4 weeks. Recipients were weighed weekly, and their survival was monitored daily. Average body weight of C5 antibody treated mice was 15.8 g at day 84 (19.2 g at day 0, N=12), whereas average weight of control mice was 13.3 g (19.2 g at day 0, N=12) (P=0.05, Student’s t-test). Kaplan-Meier survival curves were also compared as shown in the Figure. Eight of 12 mice were alive at day 84 in the treated group, as compared to only 2 of 12 in the control group (P=0.03, Logrank test). A second experiment showed similar data. We, thus, observed the effect of anti-mouse C5 antibody to reduce the symptoms of GVHD using an acute GVHD mouse model. These results might open a new window for the prevention of acute GVHD. Further experiments are currently ongoing to clarify the exact mechanism between complement and GVHD. Figure Figure

Tregs In Graft-Versus-Host Disease: A Task Force In Trouble?.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3748-3748
Author(s):  
Sya N. Ukena ◽  
Jens Grosse ◽  
Stefanie Buchholz ◽  
Michael Stadler ◽  
Arnold Ganser ◽  
...  
Keyword(s):  
T Cells ◽  
Graft Versus Host Disease ◽  
Peripheral Blood ◽  
Acute Gvhd ◽  
Chronic Gvhd ◽  
Peripheral Tolerance ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host ◽  
The Impact

Abstract Abstract 3748 Graft-versus-host disease (GvHD) remains the major clinical complication in hematopoietic stem cell transplantation (SCT) resulting in severe morbidity and significant mortality. This alloreactive immune response is mainly induced by donor T cells transplanted with the graft. Regulatory T cells (Tregs) play an essential role in the induction and maintenance of peripheral tolerance. In addition, data from murine models have shown that Tregs can prevent GvHD while preserving the graft-versus-leukemia effect. In order to functionally and dynamically characterize human Tregs after allogeneic SCT, we analyzed CD4+CD25highCD127dim T cells isolated from the peripheral blood of more than 80 patients with hematological malignancies every 30 days over half a year following SCT. Patients were divided into the following clinical groups: (A) no signs of acute or chronic GvHD, (B) acute GvHD, (C) chronic GvHD and (D) acute GvHD passed into chronic GvHD. Human peripheral blood lymphocytes were separated by Ficoll gradient and CD4+CD14−CD25highCD127dim T cells were isolated by MoFlow cell sorting. Isolated RNA was pooled and microarray analysis was performed by using Affymetrix HG_U133_Plus2.0 Arrays. Results were verified by using quantitative realtime RT-PCR. Additionally, Tregs were phenotypically analyzed by FACS. We monitored a continous but slower recovery of Tregs in GvHD within the first 6 months following PBSCT. Manifestation of acute and chronic GvHD correlated with significantly reduced frequencies of peripheral Tregs in the first month after PBSCT compared to patients without GvHD. Microarray data revealed a high stability of the Treg transcriptome in the first half year representing the most sensitive time window for tolerance induction. Moreover, comparison of the Treg gene expression profiles from patients with and without GvHD point to a reduced suppressive function of Tregs with diminished migration capacity to the target organs likely contributing to the development of GvHD. Our findings corroborate the impact of human Tregs in the pathophysiology of GvHD and identify novel targets for the manipulation of Tregs to optimize strategies for prophylaxis and treatment of life-threatening GvHD. Disclosures: No relevant conflicts of interest to declare.

Naturally occurring regulatory dendritic cells regulate murine cutaneous chronic graft-versus-host disease

Blood ◽  
2009 ◽  
Vol 113 (19) ◽  
pp. 4780-4789 ◽  
Author(s):  
Kaori Sato ◽  
Kawori Eizumi ◽  
Tomohiro Fukaya ◽  
Shigeharu Fujita ◽  
Yumiko Sato ◽  
...  
Keyword(s):  
T Cells ◽  
Dendritic Cells ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
T Cell Response ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host ◽  
Naturally Occurring ◽  
Regulatory Dendritic Cells

Abstract Chronic graft-versus-host disease (cGVHD) is a limiting factor in allogeneic hematopoietic stem cell transplantation (alloHSCT) for the treatment of leukemia and other malignancies. Relative to the process that initiates and promotes cGVHD, the regulation is poorly understood. In this study, we examined the role of naturally occurring regulatory dendritic cells (DCregs) in murine major histocompatibility complex (MHC)-compatible and multiple minor histocompatibility antigen (miHAg)–incompatible model of cGVHD in alloHSCT. DCregs generated from bone marrow in vitro (BM-DCregs) exclusively expressed CD200 receptor 3 (CD200R3), which exerted a suppressive function in the Ag-specific CD4+ T-cell response. CD49+CD200R3+ cells showed similarities in phenotype and function to BM-DCregs, which formally distinguishes them from other leukocytes, suggesting that they are the natural counterpart of BM-DCregs. Treatment of the recipient mice after alloHSCT with the recipient-type CD49+CD200R3+ cells as well as BM-DCregs protected against cGVHD, and the protection was associated with the generation of Ag-specific anergic CD4+ T cells as well as CD4+CD25+Foxp3+ regulatory T cells (Tregs) from donor-derived alloreactive CD4+CD25−Foxp3− T cells. In addition, the depletion of CD49+CD200R3+ cells before alloHSCT enhanced the progression of cGVHD. In conclusion, CD49+CD200R3+ cells act as naturally occurring DCregs to regulate the pathogenesis of cGVHD in alloHSCT mediated through the control of the transplanted alloreactive CD4+ T cells.

scholarly journals T-Cell Costimulatory Molecules in Acute-Graft-Versus Host Disease: Therapeutic Implications

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Javier Briones ◽  
Silvana Novelli ◽  
Jorge Sierra
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Acute Gvhd ◽  
Critical Role ◽  
Costimulatory Molecules ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host ◽  
Acute Graft

Acute Graft-versus-host disease (GVHD) is a major complication after allogeneic hematopoietic stem cell transplantation. Although this process is thought to consist of several phases, T-cell activation plays a critical role in the pathogenesis of acute GVHD. To become efficient effectors, T-cells require additional costimulation after T-cell receptor signaling. A number of molecules are involved in costimulation of T-cells such as CD28, CD40L, CD30, OX40, 4-1BB, ICOS, and LIGHT. The system is regulated by inhibitory molecules, CTLA-4, and PD-1. There is experimental evidence that those molecules are implicated in the pathogenesis of GHVD. We describe how these molecules are involved in acute GVHD and how the blockade of costimulatory molecules may have potential implications for the treatment of patients with acute GVHD.

scholarly journals Somatic Mutations in Clonally Expanded T-lymphocytes in Patients with Chronic Graft-Versus-Host Disease

2019 ◽  
Author(s):  
Giljun Park ◽  
Daehong Kim ◽  
Jani Huuhtanen ◽  
Sofie Lundgren ◽  
Rajiv K. Khajuria ◽  
...  
Keyword(s):  
T Cells ◽  
T Cell ◽  
Graft Versus Host Disease ◽  
Cd4 T Cells ◽  
Somatic Mutations ◽  
Chronic Gvhd ◽  
Sensitivity Testing ◽  
Hematopoietic Stem ◽  
Host Disease ◽  
Graft Versus Host

ABSTRACTGraft-versus-host-disease (GvHD) is the main complication of allogeneic hematopoietic stem cell transplantation. GvHD patients have aberrant T cell expansions, which are thought to drive pathological immune activation. Here we report mechanistic insights that somatic mutations may account for persistent clonal T cell expansions in chronic GvHD (cGvHD). In an index patient suffering from cGVHD, we discovered persisting somatic MTOR, NFKB2, and TLR2 mutations in an expanded CD4+ T clone. In the screening cohort (n=135), the MTOR P2229R kinase domain mutation was detected in two additional cGvHD patients, but not in controls. Functional analysis of the discovered MTOR mutation indicated a gain-of-function alteration in translational regulation yielding in up-regulation of phosphorylated S6K1, S6, and AKT. Paired single-cell RNA and T cell receptor alpha and beta sequencing strongly supported cytotoxicity and abnormal proliferation of the clonally expanded CD4+ T cells. Real-time impedance measurements indicated increased cytotoxicity of mutated CD4 + T cells against the patient’s fibroblasts. High throughput drug-sensitivity testing suggested that mutations induce resistance to mTOR inhibitors but increase sensitivity for HSP90 inhibitors. Our findings suggest a novel explanation for the aberrant, persistent T cell activation in cGvHD, and pave the way for novel targeted therapies.

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