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Objective: To explore the effect of Caspase 1 inhibitor Ac-YVAD-CMK on acute graft-versus-host disease (aGVHD) after allogeneic hematopoietic stem cell transplantation(allo-HSCT) and its mechanism., Methods: Experiments were divided randomly into 3 groups: allogeneic hematopoietic stem cell transplantation combined with splenic cell infusion group (TS group, n=12), allogeneic hematopoietic stem cell transplantation combined with splenic cell infusion plus injection of low dose Caspase 1 inhibitor group (TS+low dose of C group, n=16) and plus high dose Caspase1 inhibitor (TS+high dose of C group, n=19). The body weight of mice in each group was dynamically detected, and the clinical manifestation of GVHD and score of aGVHD were determined, and the chimerism rate of mice was detected after transplantation for 14 days. Th1, Th2 and Th17 cells in peripheral blood were examined by flow cytometry. Peripheral proinflammatory cytokines IL-1β, IFN-γ, IL-1α and IL-18 were examined by enzyme-linked immunosorbent assay(ELISA). The tissues sections of GVHD target organs (liver, lung, colon and skin) were stained with HE for histopathologic examination and histopathologic score., Results: Ac-YVAD-CMK could alleviate murine aGVHD and pathological injury, decreare the incidence and severity of aGVHD in recipient mice. The detection of Th cell subsets in peripheral blood by flow cytometry showed that compared with TS group, the Th1 cell ratio in TS+low dose of C and TS+high dose of C groups was significantly reduced (P<0.05), while the Th2 and Th17 cell ratio was significantly enhanced (P<0.05) in TS+low dose of high dose of C groups. The detection of peripheral inflamematory cytokines by ELISA demonstrated that the inflammatory cytokines including IL-1β,IFN-γ,IL-18 and IL-1α were reduced significantly (P<0.05)., Conclusion: Ac-YVAD-CMK can improve aGVHD by inhibiting Caspase 1 and reducing the release of some inflammatory cytokines, thereby alleviated the aGVHD pathological damage.

Recently there are increasing evidence of the existence of an immune-mediated endothelial-cell injury in the acute graft-versus-host disease (aGVHD). Endothelial cells are an important target in the process of GVHD immune attacking, and vascular end thelial injure is an early event of tissue injury caused by aGVHD after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Biomarkers for endothelial damage were consisted with endothelia injury, which may be considered a valuable marker to confirm GVHD diagnosis. The endothelial cell phenotype differs between organs, which results in organ-dependent differences for the involved organs when GVHD occurring. Although the endothelial cells play an impartant tole in process of aGVHD occurence, a further research to better characterize its role in allo-HSCT is needed. This review focusses on the research progress of aGVHD after allo-HSCT and endothelial-cell injury, as well as is markers so as to provide corresponding strategies and targets for the prevent and treatment of a GVHD.

Numerous previous studies have suggested that cytotoxic T lymphocyte antigen-4 (CTLA-4) plays an important role in acute graft-versus-host disease (GVHD). How CTLA-4 acts in regulating acute GVHD remains unknown, however. In the present study, we found that, compared with healthy controls, CTLA-4 plasma and relative mRNA levels in patients with acute GVHD were initially decreased and then markedly elevated after 28 days of treatment. CTLA-4 levels were higher in patients with grade I-II acute GVHD compared with those with grade III-IV acute GVHD both before and after treatment. Up-regulation of CTLA-4 significantly increased the luciferase activity and degree of phosphorylation of signal transducer and activator of transcription 3 (STAT3). Meanwhile, T cell activation was significantly inhibited, and levels of IFN-γ, IL-17, and IL-22 decreased. These findings suggest that CTLA-4 might be involved in the pathogenesis of acute GVHD, and may down-regulate T helper 1 cells by increasing STAT3 expression in acute GVHD., (Copyright © 2016 American Society for Blood and Marrow Transplantation. Published by Elsevier Inc. All rights reserved.)

Objective: To investigate the effects of Th1/Th17 cell imbalance on the pathogenesis of acute graft-versus-host disease (GVHD) in mice., Methods: In a murine GVHD model of C57BL/6 (H-2(b)), a low dose of halofuginone (HF) was applied for treating the recipients in order to result in Th1/Th17 imbalance. Rechipient mice were divided into GVHD group (without HF intervention) and GVHD plus HF group (treated by HF). The recipients were monitored for survival rate, clinical scores of acute GVHD, contents of circulatory Th1 and Th17 cells, Th1/Th17 ratio and serum level of IFN-γ and IL-17A. Expression levels of IFN-γ and IL-17A in target organs were analyzed by using real-time PCR, and the target organs were delivered for histological examinations., Results: Recipients treated with HF showed that all the mortality, circulatory Th1/Th17 ratio and clinical score were higher than those in the mice without HF intervention (P < 0.05). Circulatory Th1/Th17 ratio positively correlates with clinical score (P < 0.001). HF administration reduces the expression level of intestinal IL-17A and increases intrahepatic and intestinal IFN-γ level (P < 0.05), HF treatment aggravates GVHD in liver and small intestine with augmented hepatic and intestinal inflammation., Conclusion: Th1/Th17 imbalance contributes to the pathogenesis of acute GVHD.

Acute graft-versus-host disease (aGVHD) has become the important complication post-allogeneic hematopoietic stem cell transplantation. Abnormally activated T cells might play an important role in the pathogenesis of aGVHD. But its exact mechanism remains poorly understood. T cell immune response cDNA 7 (TIRC7) has been identified to be essential in T cell activation; however, the role of TIRC7 in aGVHD remains unclear. The purpose of this study was to measure the expression of TIRC7 and T helper (Th) cells in patients with aGVHD before and after treatment. We showed that TIRC7 levels in aGVHD patients were higher than those of healthy controls and markedly declined after treatment. The levels of IFN-γ (Th1), IL-17 (Th17), and IL-22 (Th22) were in accordance with the grade of aGVHD. In addition, TIRC7 levels were also associated with the severity of aGVHD. In conclusion, TIRC7 might be involved in the pathogenesis of aGVHD and TIRC7 level might be an indicator to evaluate the response of patients with aGVHD to treatment.

This study was purposed to explore the cellular source of IL-22 in graft versus host disease (GVHD) mouse following allo-genetic bone marrow transplantation. BALB/c and C57BL/6 mice were used as recipients and donors, respectively. GVHD model was established by irradiated BABL/c mice inoculated with mixed suspension of C57BL/6 bone marrow cells and splenic lymphocytes. The mice were divided into normal group (normal), total body irradiated group (TBI), bone marrow cell-transplanted group (BMT), and the combination of bone marrow cell and splenic lymphocytes-induced GVHD group (BS). The level of IL-22 in plasma was detected by ELISA. The cellular source of IL-22 and IL-22(+) subsets were detected by flow cytometry. The results showed that compared with normal mice, the level of IL-22 in plasma from BS mice was the highest (P < 0.01). All the lymphocytes of spleen, lymph nodes and peripheral blood from BS mice could produce IL-22, in which the percentage of IL-22(+)CD4(+) T cell was higher than that of IL-22(+)CD8(+) T cells. Not only Th22 cells but also Th1 and Th17 cells were the cellular source of IL-22 in GVHD mice. It is concluded that the high level of IL-22 has been found in mice with GVHD, which mainly originates from IFN-γ(-)IL-17(-)IL-22(+) Th22 cells.

Objective: To explore the effects of p38MAPK inhibitor SB203580 (SB) on the occurrence of acute GVHD and intestine damage after allogeneic hematopoietic stem cell transplantation (allo-HSCT) in mice., Methods: Sixty BALB/c mice, as recipients, were randomized to control group, irradiation group, model group and intervention group. C57BL/6 mice, as donors, were raised to prepare the bone marrow cells (BMCs) and spleen cells (SCs), which were injected into irradiated recipients mice by tail vein. Except control group, other groups accepted 7.5Gy total body irradiation. Model group and intervention group were infused with BMCs 5×10⁶ and SCs 5×10⁵ by less than 4 h after irradiation. SB was injected into intervention group by intraperitoneally, but only DMSO for model group. The general status and survival rate of each group were evaluated. The expression of p-p38MAPK, Fas and FasL in intestine were determined by RT-PCR, Western blot and immunohistochemistry (IHC)., Results: The weight changes of intervention group (13.00±0.50)% was significantly lighter than that of model group (25.00±0.75)% (P<0.05). The clinical score of acute GVHD in the intervention group (3.33±0.82) was significantly lower than that of model group (6.33±1.36) (P<0.05). The expression levels of p-p38MAPK, Fas and FasL in small intestine of intervention group (1.43±0.02, 0.81±0.03, 0.97±0.03) were lower than those of model group (1.76±0.05, 1.52±0.04, 1.48±0.04)., Conclusion: SB inhibited the activation of p38MAPK and Fas/ FasL signal pathway and alleviated the apoptosis of small intestine. And SB could relieve small intestine damages induced by allogeneic T lymphocytes.

Objective: To study the role of Th17 cells in acute intestine graft-versus-host disease following allogenetic bone marrow transplantation(allo-BMT)., Methods: Mice were split randomly into five groups: normal control, irradiated, allo-BMT, allo-BMT + DMSO and allo-BMT + Halofuginone (HF) groups. HF was given intraperitoneally at a dose of 5 µg per mouse from -1 d to 10 d after allo-BMT. aGVHD symptoms were followed-up to perform clinical and pathogenic scores. The levels of Th1/Th17, interleukin-17 and interferon-γ were measured by flow cytometry at day 7 d. mRNA expressions of T-bet, RORγT, CXCL9, CXCL10, CXCL11 and CCL20 in intestine were evaluated by real-time PCR., Results: Intestinal damages in allo-BMT-HF mice was more serious than in normal control and allo-BMT groups at day 14 after transplantation. At day 7, Th17 ratio in allo-BMT + HF group was significantly lower than in allo-BMT group. IL-17A was not detected, but Th1 ratio was higher in allo-BMT + HF. There was a similar increment in the relative expressions of T-bet in both allo-BMT and allo-BMT + HF groups. Expressions of CXCL9 and CXCL10 elevated in allo-BMT + HF group, which were significantly higher than those in allo-BMT group (P < 0.01). CCL20 expression significantly increased in allo-BMT group, but it was not detected in allo-BMT + HF group., Conclusion: Blockage of th17 cells differentiation exacerbated acute intestine graft versus-host disease.

This study was aimed to explore the influence of recipient age on the occurrence of acute graft-versus-host disease (aGVHD) in mice. 8 - 10 weeks aged C57BL/6 (H-2K(b)) mice were selected as donors, 18 - 20 weeks aged and 8 - 10 weeks aged BALB/c (H-2K(d)) mice were served as recipients. 18 - 20 weeks and 8 - 10 weeks aged mice were all randomly divided into three groups: normal control group (without any treatment); irradiation alone group [administered a total body irradiation (TBI) without bone marrow transplantation] and model group [infused with bone marrow mononuclear cells 5 × 10(6) and splenocytes 5 × 10(5) from donor C57BL/6 (H-2K(b)) mice through caudal vein no more than 4 h after TBI]. The general state and survival rate of all mice were observed everyday. The factors (the chimerism in peripheral blood, T lymphocyte and their subsets, the percentage of Th1 cells) of mice in model groups were measured by flow cytometry on day 5, 10, 15, 20, 25, 30 after TBI, the leukocytes in peripheral blood were also calculated by direct microscopic counting. The histological examinations of liver, intestine and skin were done by hematoxylin and eosin staining on day 5, 15, and 25 after TBI. All above data were compared between model groups. The results indicated that murine model with aGVHD was established in two model groups. Compared with 8 - 10 weeks aged mice, the 18 - 20 weeks aged mice showed higher survival rate and lower clinical scores (P < 0.05); the reconstitution time of leukocyte and chimerism in peripheral blood were delayed (P < 0.05); The ratio of CD8(+)T lymphocytes and Th1 cells in peripheral blood were lower (P < 0.05); the histological changes of liver, intestine and skin were little. It is concluded that 18 - 20 weeks aged recipient mice exhibited a lower incidence of aGVHD than 8 - 10 weeks aged recipient mice.

Objective: To investigate the effect of immature dendritic cells (inDC) genetically modified to express sTNFR I on acute graft-versus-host disease (aGVHD) and the graft-versus-leukemia (GVL) effect ofter allogeneic bone marrow transplantation (allo-BMT) in leukemic mice and its mechanism., Methods: An EL4 leukemia allo-BMT model was established with the BALB/c (H-2d) donor mice (DM)and C57BL/6 (H-2b) recipient mice (RM). The RM received DM bone marrow (BM) cells at a 1:1 ratio with spleen cells intravenously via tail vein at 4 h after TBI. Fifty DM were separated randomly into five groups: (1) Group A: total body irradiation (TBI) group, (2) Group B: lymphoma cell leukemia group, (3) Group C: allo-BMT group, (4) Group D: pXZ9-DC group, (5) Group E: sTNFR I-DC group. Acute GVHD scores, incidence of leukemic cell infiltration, histopathological analysis, survival rate, and survival rate of the recipients were estimated after allo-BMT. Enzyme-linked immunosorbent assay (ELISA) method was used to detect cytokines (INF-gamma and IL-4 ) production. Flow cytometry (FCM) analysis was used to detect allogeneic chimerism., Results: (1) The mice in group A and group B all died of the BM failure and lymphoma cell leukemia, respectively. The mice in group C developed typical clinical signs of a GVHD after BMT with an average survival time(AST) of (11.50 +/- 3.50) d. The signs of aGVHD were less evident in the group D and E, and their AST (21.70 +/- 5.80 and 25.80 +/- 5.20 days, respectively) were all longer than that in group C (P < 0.05). AST of group E was the longest (P < 0.05). The mice in group B all died of leukemia within 18 days after engraftment of EL4 cells. There was was no significant difference in groups C, D and E in the incidence of leukemia (P > 0.05). (2) Serum IFN-gamma level reached peak value. At + 12 d, then decreased gradually in group C, D, and E, and then reached the nadir at +18 d post-BMT, with the lowest in group E (P < 0.05), and the level was significantly lower in group D than in group C (P < 0.05). After BMT, serum IL-4 level slightly decreased in group C, but gradually elevated in group D and E and reached their peak at +12 d, and even more significantly increased in group E (P < 0.05). There was no statistical significance in the pair wise comparison among three group (P < 0.05). (3) The average proportion of H-2d positive cells in RM was 95%-100% on day 30 post-BMT, with complete donor-type implantation., Conclusion: Immature DC can induce immuno tolerance. Immature DC genetically modified to express sTNFR I has been shown to prevent acute GVHD in lethally irradiated mice reconstituted with allogeneic bone marrow grafts while maintaining the GVL response.

Objective: To explore the functions of TH17 cell in cutaneous graft-versus-host disease (GVHD)., Methods: A model of acute GVHD (aGVHD) was established with a major histocompatibility complex class I/II-disparate allogeneic bone marrow transplantation (BMT). Bone marrow monocytes and splenic T cells from donor C57/BL6 were enriched. The recipient BABL mice were irradiated ((60)Co source) with 7.5 Gy total body irradiation (TBI) and injected with 5 × 10(6) marrow monocytes and 5 × 10(5) T cells. The experimental mice were divided into 3 groups: lethal total body irradiation (TBI); allogeneic bone marrow transplantation (BMT) and recipients of halofuginone (HF). The symptoms of aGVHD were observed daily and detailed histopathologic analyses of recipient skin were performed at Day 6 post-transplantation. And Tri-color flow cytometry (FCM) was performed at Day 6 post-transplantation to measure the levels of interleukin (IL)-17, interferon (IFN)-γ and TH1/TH17., Results: Clinical GVHD symptoms were observed in recipient mice. The administration of HF to lethally irradiated recipients led to very modest GVHD-induced cutaneous changes manifested predominantly by fur loss. However, the experimental animals receiving only allogeneic BMT showed significant fur loss and pathologic skin conditions. Consistent with the clinical evaluations, the histopathologic results demonstrated significantly increased pathologic cutaneous lesions in recipients undergoing only BMT. The median ratios of TH1/TH17 cells were 17.57 and 5.31 in the HF and BMT groups respectively. The difference had statistical significance (P < 0.05). The serum levels of IL-17 were(1.47 ± 0.18) and (2.81 ± 0.19) pg/ml in the TBI and BMT groups respectively (P < 0.05). But IL-17 could not be detected in the HF group. The serum levels of IFN-γ were (3.86 ± 0.32), (42.97 ± 0.42) and (9.89 ± 0.51) pg/ml in the TBI, BMT and HF groups respectively. The inter-group differences had statistical significance (P < 0.05)., Conclusion: An absence of TH17 cell may alleviate the cutaneous GVHD but exacerbate the systemic GVHD.

Objective: To explore the role of Th17 cells in early onset of acute graft-versus-host disease (aGVHD) and its mechanism., Methods: Mice aGVHD model was established by irradiated BABL/c mice inoculated with mixed suspension of C57BL/6 bone marrow cells and splenocytes. The mice were divided into 4 groups: (1) normal control, (2) irradiated group, (3) allo-BMT + DMSO group, (4) allo-BMT + halofuginone (HF) group. HF was given intraperitoneally at 5 µg per mouse from -1 d to +10 d after allogeneic bone marrow transplantation(allo-BMT).Mice aGVHD symptoms and survival were observed. Th1/Th17 cells ratio was evaluated by flow cytometry., Results: All the experimental groups (3) and (4) developed aGVHD after transplantation. More severe aGVHD was observed in group (4) than in group (3). HF prevented cutaneous aGVHD in all the mice, but augmented hepatic and small intestine GVHD. The percentage of Th17 cells and the ratio of Th1/Th17 were significantly higher while the percentage of Th1 cells was significantly lower in group (4) at day +6 (P < 0.05)., Conclusion: Early blockage of Th17 cell results in increase of Th1 cell percentage, which exacerbates aGVHD.

Objective: To explore the influence of the lentiviral vector mediated mouse genetic engineering regulatory T cells (Treg) infusion on post-allogeneic bone marrow transplantation (allo-BMT) acute graft-versus-host disease (GVHD) in mice., Methods: Lentivirus-mediated Forkhead box P3 (Foxp3) gene was transduced into BALB/c mice CD4(+)CD25(-) T cells (Treg) to construct engineered Tregs in vitro. An allo-BMT model of BALB/c to C57BL/6 mice was established. After irradiation, the recipients were injected with donor cells plus the genetic engineering Tregs. Survival time, clinical GVHD score, histopathological findings, activation of donor T cells or serum levels of inflammatory cytokines were observed after allo-BMT., Results: The mean survival times for radiation alone group (Gp I), transplantation control group (Gp II), engineering Treg infusion group (Gp III) and empty vector control group (Gp IV) were (8.8 ± 0.6) d, (36.7 ± 2.5) d, (51.6 ± 4.0) d and (34.1 ± 2.3) d, respectively. The survival time was significantly longer in Gp III than in other groups (P < 0.05). Histopathological finding in several target organs (skin, liver and small intestine) confirmed the presence of severe GVHD in Gp II and Gp IV, while no histological signs of GVHD were observed in long survival recipients in Gp III, and clinical GVHD scores in Gp III were significantly lower than that in Gps II and IV. The numbers of donor T cells and the percentage of IFN-producing donor T cells in the spleen of recipients in Gp III were significant lower than those in Gps II and IV at days 3 and 4, and at day 3 after transplantation, respectively (P < 0.05). The serum levels of IFN-γ, IL-2 and TNF-α were increased at day 21 to 28 after transplantation in all groups. The peak concentrations of IFN-γ, IL-2 and TNF-α in Gp III were significantly lower than those in Gps II and IV control groups at day 21 (P < 0.05)., Conclusion: Co-injection of genetic engineering Treg can efficiently prevent recipients from lethal GVHD after allo-BMT in mice by inhibiting the early activation and expansion of donor T cells and reducing the serum levels of inflammatory cytokines.

In order to explore the influence of purified donor regulatory T cells (Treg) infused after allogeneic bone marrow transplantation (allo-BMT) on GVHD and GVL effect in mice, an EL4 leukemia allo-BMT model of BALB/c-->C57BL/6 mice was established. The CD4(+)CD25(+)T cells were purified by positive selection using MACS. The recipients were injected with CD4(+)CD25(+)T cells or CD4(+)CD25(-)T cells within 4 hours respectively along with allo-BMT. Survival time, clinical GVHD score or histopathological features were observed after allo-BMT. The results showed that the mean survival time in leukemia control group was (17.9 +/- 0.7) days and all mice died of leukemia. The mean survival times in transplantation control group and CD4(+)CD25(-)T group were (23.2 +/- 1.6) and (22.3 +/- 1.9) days. Histopathological analysis in several target organs (skin, liver and small intestine) confirmed the presence of severe GVHD. The mean survival time in Treg group was (47.3 +/- 6.5) days. 70% of recipients were alive until day 60 without features of GVHD or tumor progression. Clinical GVHD scores in Treg group significantly decreased as compared to transplantation control group and CD4(+)CD25(-)T group (p < 0.05). It is concluded that allo-BMT combined with injection of donor CD4(+)CD25(+)Treg cells can efficiently prevent recipients from lethal GVHD with preserving GVL effect during allo-BMT.