Harnessing and honing mesenchymal stem/stromal cells for the amelioration of graft-versus-host disease

Allogeneic hematopoietic stem cell transplantation is a deterministic curative procedure for various hematologic disorders and congenital immunodeficiency.Despite its increased use,the mortality rate for patients undergoing this procedure remains high,mainly due to the perceived risk of exacerbating graft-versushost disease(GVHD).However,even with immunosuppressive agents,some patients still develop GVHD.Advanced mesenchymal stem/stromal cell(MSC)strategies have been proposed to achieve better therapeutic outcomes,given their immunosuppressive potential.However,the efficacy and trial designs have varied among the studies,and some research findings appear contradictory due to the challenges in characterizing the in vivo effects of MSCs.This review aims to provide real insights into this clinical entity,emphasizing diagnostic,and therapeutic considerations and generating pathophysiology hypotheses to identify research avenues.The indications and timing for the clinical application of MSCs are still subject to debate.

Pathophysiology of acute graft-versus-host disease from the perspective of hemodynamics determined by dielectric analysis

BACKGROUND Numerous reports have demonstrated that the pathophysiology of graft-versushost disease(GVHD)during hematopoietic stem cell transplantation(HSCT)is closely related to vascular endothelial disorders and coagulation abnormalities.We previously presented the discovery of a principle and the development of a novel instrument for measuring whole blood coagulation.This was achieved by assessing the variations in the dielectric properties of whole blood.AIM To investigate how GVHD affects the changes of dielectric properties of whole blood in patients with HSCT.METHODS We examined the changes of dielectric properties of whole blood and erythrocyte proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis sequentially in patients with HSCT and compared it with clinical symptoms and inflammatory parameters of GVHD.RESULTS During severe GVHD,the dielectric relaxation strength markedly increased and expression of band3 decreased.The dielectric relaxation strength normalized with the improvement of GVHD.In vitro analysis confirmed that the increase of relaxation strength was associated with severe erythrocyte aggregates,but not with decreased expression of band3.CONCLUSION Severe erythrocyte aggregates observed in GVHD may cause coagulation abnormalities and circulatory failure,which,together with the irreversible erythrocyte dysfunction we recently reported,could lead to organ failure.

Cytokines are early diagnostic biomarkers of graft-versus-host disease in liver recipients

BACKGROUND： Graft-versus-host disease （GVHD） is associated with high mortality. Early diagnosis is essential to start treatment and to improve outcomes. Because of the inflammatory nature, we hypothesis that cytokine profile of patients with GVHD may serve as diagnostic markers. The present study was to evaluate the role of cytokine profile in the diagnosis of GVHD. METHODS： An immunoassay was used to detect 29 cytokines simultaneously in the serum; the measuring sensitivity of all cytokines was pg/mL. Healthy subjects undergoing annual routine physical examinations served as negative controls; 23 patients with hepatocellular carcinoma （HCC） who had undergone liver transplantation （the LT group） comprised the test subjects. A total of 22 kidney recipients with biopsyconfirmed GVHD （the RT group） were included for comparison. HCC patients with radical surgery （the HCC group, n=22） served as positive control. The liver contents of the three cytokines, IL-2, IL-18, and IFN-γ, were detected with immunohistochemistry. Serum granzyme B and perforin were measured by flow cytometry.RESULTS： Of the 29 cytokines, the levels of IL-2 and IL-18 were increased significantly in liver recipients with GVHD compared with healthy controls （P〈0.05）. The serum levels of these three cytokines in the healthy, HCC, LT, and RT groups were IL-2： 0.90±0.02, 4.14±0.61, 5.10±0.89, and 1.48±0.09 pg/mL; IL-18： 80.61±9.35, 109.51±10.93, 230.11±12.92, and 61.98±7.88 pg/mL; IFN-γ： 24.06±3.88, 24.84±3.21, 40.37±5.88, and 15.33±4.72 pg/mL, respectively. Immunohistochemistry showed that these 3 cytokines expressions in the liver were parallel to the serum cytokine. After standard anti-GVHD treatment, the expressions of IL-2, IL-18, and IFN-y were de- creased in the liver （P〈0.05）. Serum granzyme B and perforin were significantly increased in GVHD patients （P〈0.05）. CONCLUSIONS： IL-2, IL-18 and IFN-γ were from liver and might serve as biomarkers for monitoring GVHD develop- ment and the effects of anti-GVHD treatment. Granzyme B and perforin may play a role in increasing IL-2, IL-18, and IFN-y levels in GVHD patients.

Umbilical Cord Blood-derived Mesenchymal Stem Cells Ameliorate Graft-Versus-Host Disease Following Allogeneic Hematopoietic Stem Cell Transplantation through Multiple Immunoregulations

Summary： Although mesenchymal stem cells （MSCs） are increasingly used to treat graft-versus-host disease （GVHD）, their immune regulatory mechanism in the process is elusive. The present study aimed to investigate the curative effect of third-party umbilical cord blood-derived human MSCs （UCB-hMSCs） on GVHD patients after allogeneic hematopoietic stem cell transplantation （allo-HSCT） and their immune regulatory mechanism. Twenty-four refractory GVHD patients after allo-HSCT were treated with UCB-hMSCs. Immune cells including T lymphocyte subsets, NK ceils, Treg cells and dendritic cells （DCs） and cytokines including interleukin-17 （IL-17） and tumor necrosis factor-alpha （TNF-α） were monitored before and after MSCs transfusion. The results showed that the symptoms of GVHD were alleviated significantly without increased relapse of primary disease and transplant-related complications after MSCs transfusion. The number of CD3^＋, CD3＋CD4^＋ and CD3＋CD8^＋ cells decreased significantly, and that of NK cells remained unchanged, whereas the number of CD4^＋ and CD8^＋ Tregs increased and reached a peak at 4 weeks; the number of mature DCs, and the levels of TNF-α and IL-17 decreased and reached a trough at 2 weeks. It was concluded that MSCs ameliorate GVHD and spare GVL effect via immunoregulations.

Fulminant gastrointestinal graft-versus-host disease concomitant with cytomegalovirus infection:Case report and literature review

Here,we report a case of fulminant gastrointestinal graft-versus-host disease(GI-GVHD) with cytomegalovirus(CMV) infection in 44-year-old woman.Despite the difficulties associated with the treatment of GIGVHD and GI-CMV disease,the mucosal findings and the clinical course showed marked improvements during long-term clinical observation.The endoscopic findings were remarkable,with diffuse sloughing mucosa in the stomach and highly active inflammation and deep discrete ulcers throughout the colon.Changes in the CMV quantitative polymerase chain reaction results were correlated with the endoscopic mucosal findings and were useful for assessing the efficacy of the treatment.Although a definite diagnosis of GI-GVHD is generally made by endoscopy with biopsy,the gross appearance of this disease can vary depending on the endoscopy.In this paper,we also conduct a literature review of patients with GI-GVHD.

Comparison of the meibomian gland dysfunction in patients with chronic ocular graft-versus-host disease and Sjogren's syndrome

AIM: To investigate the abnormalities in the meibomian gland in patients with dry eye disease(DED) associated with chronic ocular graft-versus-host disease(coGVHD) in comparison with Sj?gren's syndrome(SS), a major form of aqueous deficient DED and meibomian gland dysfunction(MGD), a common cause of evaporative DED.METHODS: A total 135 eyes of 135 subjects included in this study: patients with DED associated with coGVHD(n=30), patients with SS(n=35), patients with MGD(n=35), and normal controls(n=35). All participants completed the Ocular Surface Disease Index(OSDI) questionnaire, ocular surface examination [Schirmer test, tear film breakup time(TFBUT), and ocular surface staining], and meibomian gland assessment [meiboscore(gland dropout detected on meibography using infrared camera of the Keratograph 5 M), meibum expressibility score(MES), meibum quality score(MQS), lid margin abnormality]. In addition, correlations of meibomian gland characteristics with ocular surface parameters as well as disease severity score were investigated in coGVHD group.RESULTS: The coGVHD group showed significantly higher meiboscore, MES, and MQS than the other 3 groups(all P<0.05). In the coGVHD group, parameters of meibomian gland showed a significant correlation each other and those of ocular surface. The correlation between meibomian gland parameters and severity score of co GVHD was also established(meiboscore, r=0.62; MES, r=0.47; MQS, r=0.47; lid margin abnormality score, r=0.55; all P<0.05).CONCLUSION: Patients with DED associated with co GVHD show poorer gland morphology and worse glandfunction than other types of DED. In addition, meibomian gland damage is not only associated with ocular surface damage but also disease severity of coGVHD.

Diagnosis and treatment of acute graft-versus-host disease after liver transplantation:Report of six cases

BACKGROUND Graft-versus-host disease(GVHD)following liver transplantation(LT)is an unpredictable complication with poor outcome.However,consensus regarding the diagnosis and therapeutic regimen for the disease is yet lacking.The present study summarized the clinical experience on the diagnosis and treatment of acute GVHD(aGVHD)following LT and reviewed the pertinent literature.CASE SUMMARY Between January 1^(st),2000 and December 31^(st),2020,a total of 1053 LT were performed in the First Affiliated Hospital of Xi’an Jiaotong University.Six recipients developed aGVHD with clinical symptoms of fever,rash,diarrhea,and pancytopenia.The incidence of aGVHD was 0.57%.The median time from LT to the clinical presentation of aGVHD was 22.17 d.The median time from the beginning of the clinical symptom to histopathological diagnosis was 7.5 d.All six cases underwent treatment of immunosuppressant adjustment,corticosteroids,human normal immunoglobulin,and antithymocyte globulin/IL-2 antagonists.Despite intensive treatment strategies,4 patients were deceased due to sepsis,multiple organ failure,and cerebral hemorrhage.The remaining two cases were discharged as treatment successfully.However,one died because of tuberculosis infection on the 6 th month of follow-up,the other one was alive healthy during 30 mo of follow-up.CONCLUSION The rapid diagnosis of aGVHD is mainly based on the time from the first symptom,histopathological features,and the donor T-lymphocyte chimerism.Our cases report highlights massive corticosteroid therapy and age difference between donors and recipients could accelerate to aGVHD.Moreover,gut microbial interventions and donor-targeted serotherapy may provide novel therapeutics.

Nanoparticle-encapsulated allogeneic T cells mitigate graft-versus-host disease but retain graft-versus-leukemia activity

Aim Allogeneic hematopoietic stem cell transplantation （HSCT） has curable potential for hematopoietic malignancies through graft-versus-leukemia （GVL） effects but is often associated with life-threatening graft-versus-host disease （GVHD）. Donor T cells play an important role in the pathological process of GVHD. In this study, to determinate immunoisolation through encapsulating T cells with biomaterials could be a promising approach to atten- uate GVHD. Methods T cells were isolated from spleens of donor C57B1/6 mice by magnetic cell separation and coated by layer-by-layer in chitosan and alginate. BALB/c recipient mice were established by GVHD mode and leukemia mode. Xenogen IVIS imaging system was used for live animal imaging. Donor BMCs and T cell subsets were analyzed by flow cytometry. Results In this study, we successfully encapsulated T cells of mice in multilay- ers of chitosan and alginate. In vitro studies showed that the encapsulation did not change the phenotype of T cells as defined through the following parameters： size, viability, proliferation, antibody binding, cytokine secretion, and cytotoxicity. Mice transplanted with encapsulated allogeneic T cells exhibited less severe acute GVHD and pro- longed survival. The mice showed a lower GVHD score, less liver damage, a smaller CD8/CD4 T cell ratio, and a higher number of donor BM-derived cells following transplantation with encapsulated donor T cells. When this GVHD model was combined with implantation of A20 lymphoma cells, GVL of encapsulated T cells was not com- promised, while GVHD was still suppressed and the mouse survival also prolonged. Conclusion These studies demonstrate that encapsulation of T cells with bio-degradable materials could attenuate the severity of GVHD but re- taine GVL, which presents a novel and potentially safer and effective approach of allogeneic HSCT for future clini- cal application.

Immune Regulatory Cell Biology and Clinical Applications to Prevent or Treat Acute Graft-Versus-Host Disease

The most common approaches to prevent and treat graft-versus-host disease (GVHD) are intended to deplete or suppress the T cells capable of mediating or supporting alloresponses;however, this renders the recipients functionally T cell deficient and hence highly susceptible to infections and tumor recurrence. Depletion is often accomplished through the use of broadly reactive antibodies, while functional impairment is typically achieved by pharmacological agents that require long-term administration (usually six months or more), have significant side effects, and may not result in tolerance (i.e., nonresponsiveness) of donor T cells to conditioning regimen-resistant host alloantigen-bearing cells. As our knowledge of immune system homeostasis has increased, cell populations with immune regulatory function have been identified and characterized. Although such cell populations are typically present in low frequencies, methods to isolate and expand these cells have permitted their supplementation to the donor graft or infusion late post-transplant in order to stifle GVHD. This review discusses the biology and preclinical proof of concept of GVHD models, along with GVHD outcomes that focus exclusively on immune regulatory cell therapies that have progressed to clinical testing.

Expressions of Tissue Factor and Tissue Factor Pathway Inhibitor in Patients with Acute Graft-versus-host Disease after Allogeneic Hematopoietic Stem Cell Transplantation

This study examined the expressions of human serum tissue factor （TF） and tissue factor pathway inhibitor （TFPI） in patients with acute graft-versus-host disease （aGVHD） after allogeneic hematopoietic stem cell transplantation （allo-HSCT） and their clinical significance. The serum TF and TFPI levels were detected by ELISA in 28 allo-HSCT recipients before and after the transplanta-tion and the changes of TF and TFPI levels were dynamically monitored at different phases of the disease. No significant differences in the serum TF and TFPI levels were found in allo-HSCT recipi-ents in the absence of aGVHD or with gradeⅠaGVHD before and after the transplantation. The lev-els of serum TF and TFPI were substantially increased in the patients with gradeⅡ aGVHD at the peak of aGVHD （P〈0.05） and they were even higher in the patients with grade Ⅲ–Ⅳ aGVHD （P〈0.01）. When the conditions became stable after treatment with immunosuppressive agents, the serum TFPI level was decreased to the baseline level （P〉0.05） and the TF level was lowered but still higher than the baseline level （P〈0.05）. It was concluded that the levels of serum TF and TFPI were increased significantly in the patients with grade Ⅱ–Ⅳ aGVHD after allo-HSCT and decreased markedly after the treatment. Monitoring the levels of serum TF and TFPI in the patients with allo-HSCT is important to predict the occurrence, outcome and prognosis of aGVHD.

Oral granuloma in a pediatric patient with chronic graft-versus-host disease:A case report

BACKGROUND Oral mucositis is often observed with graft-versus-host disease(GVHD);however,the occurrence of oral granuloma is rare.The rapid increase in granulomatous lesions should be distinguished from malignant tumors in patients with GVHD because malignant diseases can develop in those patients.This case is the youngest pediatric patient with granuloma associated with GVHD.CASE SUMMARY The patient was a 1-year and 5-mo-old girl who presented to our department for the management of oral nodules.At the age of 5 mo,she was diagnosed with primary immunodeficiency disease,cord blood transplant was performed at 11 mo and bone marrow transplant at 1 year of age.After transplantation,GVHD and oral mucositis developed,and tacrolimus was administered.Interestingly,nodules appeared on the lower lip and buccal mucosa,which spontaneously disappeared.Then,a new nodule appeared on the left lateral border of the tongue.Resection was performed and the histopathological diagnosis was granuloma.The origin of these nodules were considered to be the fibroblasts activated under inflammation caused by GVHD because the calcineurin inhibitor tacrolimus acted on their proliferation.CONCLUSION It is very important to distinguish oral granulomatous lesions from malignancies if GVHD is present at the base and if immunosuppressive agents and steroids are being administered.

Modified Vecchietti’s vaginoplasty with Remeex^(■) system in patient with chronic graft-versus-host disease

We present a case report of a chronic graft-versus-host disease manifestation in 33-year-old patient with an unusual complication of vaginal stenosis with complete obstruction after allogeneic bone marrow transplantation for myelocytic leukemia. The patient complained on a progressive dyspareunia and sexual intercourse inability. She has received hormone replacement therapy due to the ovarian failure after the chemotherapy treatment. The hormonal treatment was used in continuous combined manner and hematocolpos wasn’t seen during an abdominal ultrasound examination. The reconstructive surgery was performed by the modified Vecchietti’s neovagina technique with a Remeex&reg;system after histological confirmation of main diagnosis. The immediate postoperative course was uneventful with gradual normalization of sexual function.

Severe graft-versus-host disease post allogeneic hematopoietic stem cell transplantation due to loss of HLA heterozygosity in recipient lymphocytes after full graft rejection

Germ cell tumors complicated by hematological malignancy(HM)are a rare clinical phenomenon.Allogeneic hematopoietic stem cell transplantation(allo-HSCT)is a potentially effective therapy,but graft-versus-host disease(GVHD)is a life-threatening complication.We report a case of a 13-year-old female patient diagnosed with germ cell tumors followed by acute lymphoblastic leukemia.After chemotherapy,she received allo-HSCT and her chimerism rate decreased rapidly to near zero by 6 months without evidence of HM recurrence.However,she developed severe,multiorgan GVHD-like manifestations.DNA analysis revealed the pathogenesis of GVHD to be loss of HLA heterozygosity in recipient hematopoietic cells.

Risk factors for chronic graft-versus-host disease after anti-thymocyte globulin-based haploidentical hematopoietic stem cell transplantation in acute myeloid leukemia

Chronic graft-versus-host disease(cGVHD)is a major complication following unmanipulated haploidentical hematopoietic stem cell transplantation(haplo-HSCT).We aimed to identify the risk factors for cGVHD in patients who underwent anti-thymocyte globulin-based haplo-HSCT for acute myeloid leukemia(n=280).The diagnosis of cGVHD was in accordance with the National Institutes of Health consensus criteria.A total of 169 patients suffered from cGVHD.The patients who had 3 loci mismatched had a higher 8-year incidence of cGVHD(total,66.0%vs.53.7%,P=0.031;moderate to severe,42.4%vs.30.1%,P=0.036)than the patients who had 1 to 2 loci mismatched.The patients who had maternal donors had a higher 8-year incidence of moderate to severe cGVHD(49.2%vs.32.9%,P=0.024)compared with the patients who had other donors.The patients who had grades III to IV acute GVHD(aGVHD)had higher 8-year incidence of cGVHD(total,88.0%vs.50.4%,P<0.001;moderate to severe,68.0%vs.27.0%,P<0.001)compared with the patients without aGVHD.In multivariate analysis,grades III to IV aGVHD was the only independent risk factor for cGVHD.Thus,further interventions should be considered in patients with severe aGVHD to prevent cGVHD.

Hemorrhagic cystitis following hematopoietic stem cell transplantation:incidence,risk factors and association with CMV reactivation and graft-versus-host disease

Background The definite pathogenesis of hemorrhagic cystitis （HC） after allogenic hematopoietic stem cell transplantation （allo-HSCT） has not been well elucidated. The role of cytomegalovirus （CMV） reactivation and graft-versus-host disease （GVHD） in the development of HC remains obscure. This study determined the incidence and risk factors for HC after alIo-HSCT and analyzed its association with CMV reactivation and GVHD. Methods We retrospectively studied 250 patients at high risk for CMV disease who underwent alIo-HSCT all based on busulfan/cyclophosphamide （BU/CY） myloablative regimens. The incidence, etiology, risk factors and clinical management of HC were investigated. Results HC developed within 180 days of transplant in 72 patients, with an overall incidence of 28.8% and an incidence of 12.6% in patients with HLA-matched related donors （MRD）, 34.38% in those with HLA-matched unrelated donors （MUD）, 49.45% in those with mismatched related donors （MMRD）. CMV-viremia significantly increased the incidence of later onset HC （LOHC）; however, only 9 out of 15 patients with CMV viruria actually developed LOHC. Multiple regression analysis identified grade II-IV acute GVHD （RR=2.75; 95% CI 1.63-4.66; P〈0.01） and grafts from MUD or MMRD （RR=2.60; 95% CI 1.52-5.20; P〈0.01） as independent risk factors for HC. Event sequence analysis indicated a majority of HC episodes began around GVHD initiation. Conclusions CMV-viremia is a high risk factor for LOHC. Our data also showed a correlation between acute GVHD and HC, which suggested that alloimmunity may be involved in the pathogenesis of HC.

Arsenic trioxide alleviates acute graft-versus-host disease by modulating macrophage polarization

This study aimed to explore macrophage polarization in acute graft-versus-host disease after hematopoietic stem cell transplantation, and investigated if arsenic trioxide(ATO) could correct this imbalance. In the colon of GVHD mice, we found that the number of F4/80+iNOS+ cells as well as the expression intensity of TNF-α and IL-1β was greater in the GVHD group than in the BM group, whereas the number of F4/80+CD206+ cells and the expression intensity of IL-10 and TGF-β was greater in the BM group than in the GVHD group. We investigated the effect of ATO on GVHD mice, and found that ATO treatment clearly improved the survival of the mice and reduced the severity of GVHD. In addition, ATO reduced the number of F4/80+iNOS+ cells, and increased the number of F4/80+CD206+ cells in the colon of GVHD mice. Furthermore, ATO sharply decreased CD86 and CD80 expression, and increased CD163 and CD206 expression in macrophages induced from aGVHD patients. Therefore,ATO can modulate the M1 and M2 phenotype in GVHD mice or in macrophages from aGVHD patients. Our data suggest that macrophage polarization is involved in the pathogenesis of aGVHD, and ATO treatment modulates macrophage polarization toward an M2 phenotype.

Immunosuppression for 6-8 weeks after modified donor lymphocyte infusion reduced acute graft-versus-host disease without influencing graft-versus-leukemia effect in haploidentical transplant

Background In haploidentical hematopoietic stem cell transplantation （HSCT）, the duration of graft-versus-host disease （GVHD） prophylaxis after modified donor lymphocyte infusion （DLI） was the only risk factor of DLI-associated grades 3-4 acute GVHD. However, the successful application of modified DLI depended not only on the reduction of severe GVHD, but also on the preservation of graft-versus-leukemia （GVL） effect. Therefore, this study was performed to compare the impact of prophylaxis for 6-8 weeks and prophylaxis for 〈6 weeks on GVL effect after modified DLI in haploidentical HSCT. Methods A total of 103 consecutive patients developing hematological relapse or minimal residual disease （MRD）-positive status after haploidentical HSCT and receiving modified DLI were investigated retrospectively. Fifty-two patients received prophylaxis for 6-8 weeks after modified DLI; the remaining 51 patients received prophylaxis for 〈6 weeks. Results First, compared with prophylaxis for 〈6 weeks, prophylaxis for 6-8 weeks reduced incidence of relapse in total patients （26.6% vs. 69.0%, P 〈0.001）. Besides, prophylaxis for 6-8 weeks also reduced incidence of relapse in 54 patients developing hematological relapse post-transplant （P=0.018） and in 49 patients developing MRD-positive status post-transplant （P 〈0.001）. Second, prophylaxis for 6-8 weeks reduced incidence of acute GVHD （P 〈0.05）, reduced the therapeutic application of immunosuppressive agents （P=0.019）, but increased the incidence of chronic GVHD （P〈0.05）. Third, prophylaxis for 6-8 weeks improved overall survival and disease-free survival in total patients, as well as in patients developing hematological relapse post-transplant and in patients developing MRD-positive status post-transplant （P 〈0.05）. Conclusions In haploidentical HSCT, prophylaxis for 6-8 weeks after modified DLI does not reduce GVL effect, but reduces the incidence of DLI-associated acute GVHD compared with prophylaxis for 〈6 weeks. This strategy will probably improve the safety and efficacy of modified DLI further.

TLR4 inactivation protects from graft-versus-host disease after allogeneic hematopoietic stem cell transplantation

Graft-versus-host disease （GVHD） is the most common complication after hematopoietic stem cell transplantation. To clarify the role of Toll-like receptor 4 （TLR4）, which is a major receptor for bacterial lipopolysaccharides （LPS）, in the development of acute GVHD, we used a TLR4-knockout （TLR4-/-） mouse GVHD model and analyzed the underlying immunological mechanisms. When TLR4-/- mice were used as bone marrow and splenocyte cell graft donors or recipients, GVHD symptom occurrence and mortality were delayed compared to wild-type （TLR4＋/＋） mice. In addition, histopathological analyses revealed that in TLR4-/-→BALB/c chimeras, liver and small intestine tissue damage was reduced with minimal lymphocytic infiltration. In contrast to TLR4＋/＋, TLR4-/- mice dendritic cells did not express CD80, CD86, CD40, MHC-II or IL-12 during LPS induction and remained in an immature state. Furthermore, the ability of TLR4-/- mice spleen dendritic cells to promote allogeneic T-cell proliferation and, in particular, T-helper cell 1 （Th 1） development was obviously attenuated compared with TLR4＋/＋ mice dendritic cells, and the levels of interferon-T （IFN-γ） and IL-IO, Th2-cell specific cytokines, were significantly higher in the serum of TLR4-/-→BALB/c than in TLR4＋/＋→BALB/c chimeric mice. Overall, our data revealed that TLR4 may play a role in the pathogenesis of GVHD and that targeted TLR4 gene therapy might provide a new treatment approach to reduce the risk of GVHD.

Health related quality of life among patients with chronic graft-versus-host disease in China

Background Chronic graft-versus-host disease （GVHD）,the commonest long-term complication after allogeneic hematopoietic stem cell transplantation （HSCT）,has a negative impact on patients＇ health related quality of life （HRQoL）.This study was designed to investigate the HRQoL in patients with chronic GVHD in China.Methods Two hundred and sixty-four patients with chronic GVHD who were ＞24 months post-HSCT and had been in continuous complete remission since HSCT were enrolled in this retrospective study.HRQoL was evaluated using an SF-36 questionnaire.Multivariate analysis was used to identify the factors that affect HRQoL in patients with chronic GVHD.Results HRQoL in patients categorized as having mild and moderate chronic GVHD was significantly better than in those in the severe category.In the moderate chronic GVHD category,markedly poorer HRQoL was observed in patients with both multiple organ involvement and more severe organ impairment than in those without these factors.According to multivariate analysis,chronic GVHD severity had the greatest significant negative impact on patients＇ HRQoL; whereas being female was associated with a negative impact on psychological health.Conclusion Chronic GVHD severity strongly correlates with negative impacts on patients＇ HRQoL.

Loss of Lkb1 impairs Treg function and stability to aggravate graft-versus-host disease after bone marrow transplantation

Accumulating evidence suggests that a reduction in the number of Foxp3^(+) regulatory T cells(Tregs)contributes to the pathogenesis of acute graft-versus-host disease(aGVHD),which is a major adverse complication that can occur after allogeneic hematopoietic stem cell transplantation(allo-HSCT).However,the precise features and mechanism underlying the defects in Tregs remain largely unknown.In this study,we demonstrated that Tregs were more dramatically decreased in bone marrow compared with those in peripheral blood from aGVHD patients and that bone marrow Treg defects were negatively associated with hematopoietic reconstitution.Tregs from aGVHD patients exhibited multiple defects,including the instability of Foxp3 expression,especially in response to IL-12,impaired suppressor function,decreased migratory capacity,and increased apoptosis.Transcriptional profiling revealed the downregulation of Lkb1,a previously identified critical regulator of murine Treg identity and metabolism,and murine Lkb1-regulated genes in Tregs from aGVHD patients.Foxp3 expression in human Tregs could be decreased and increased by the knockdown and overexpression of the Lkb1 gene,respectively.Furthermore,a loss-of-function assay in an aGVHD murine model confirmed that Lkb1 deficiency could impair Tregs and aggravate disease severity.These findings reveal that Lkb1 downregulation contributes to multiple defects in Tregs in human aGVHD and highlight the Lkb1-related pathways that could serve as therapeutic targets that may potentially be manipulated to mitigate aGVHD.