Gut microbiome in allogeneic hematopoietic stem cell transplantation and specific changes associated with acute graft vs host disease

Allogeneic hematopoietic stem cell transplantation(aHSCT)is a standard validated therapy for patients suffering from malignant and nonmalignant hematological diseases.However,aHSCT procedures are limited by potentially life-threatening complications,and one of the most serious complications is acute graft-versus-host disease(GVHD).During the last decades,DNA sequencing technologies were used to investigate relationship between composition or function of the gut microbiome and disease states.Even if it remains unclear whether these microbiome alterations are causative or secondary to the presence of the disease,they may be useful for diagnosis,prevention and therapy in aHSCT recipients.Here,we summarized the most recent findings of the association between human gut microbiome changes and acute GVHD in patients receiving aHSCT.

Oral graft vs host disease:An immune system disorder in hematopoietic cell transplantation

Graft vs host disease(GVHD) is a complication of patients who are treated by hematopoietic cell transplantation.National Institutes of Health in 2005 by Working Group on Diagnosis and Staging Consensus Development Project on Criteria for Clinical Trials in Chronic GVHD(cGVHD) established 2 principal categories of oral GVHD, acute and chronic. The oral mucosa may be the first site of manifestation of the disease. Clinical diagnosis needs to be confirmed by a biopsy of oral mucosa and minor salivary glands. Microscopic results have played a major role in the diagnosis and management of acute and chronic oral GVHD. Development of second malignancies is the greatest risk of oral cGVHD patients, mostly regarding squamous cell carcinoma. The focus of oral GVHD therapy is to improve symptoms and maintain oral function. The aim of this review article is to update the information on the oral GVHD in its clinical, microscopic features and their complications.

Immunophenotypic characteristics of multipotent mesenchymal stromal cells that affect the efficacy of their use in the prevention of acute graft vs host disease

BACKGROUND Multipotent mesenchymal stromal cells(MSCs)are widely used in the clinic due to their unique properties,namely,their ability to differentiate in all mesenchymal directions and their immunomodulatory activity.Healthy donor MSCs were used to prevent the development of acute graft vs host disease(GVHD)after allogeneic bone marrow transplantation(allo-BMT).The administration of MSCs to patients was not always effective.The MSCs obtained from different donors have individual characteristics.The differences between MSC samples may affect their clinical efficacy.AIM To study the differences between effective and ineffective MSCs.METHODS MSCs derived from the bone marrow of a hematopoietic stem cells donor were injected intravenously into allo-BMT recipients for GVHD prophylaxis at the moment of blood cell reconstitution.Aliquots of 52 MSC samples that were administered to patients were examined,and the same cells were cultured in the presence of peripheral blood mononuclear cells(PBMCs)from a third-party donor or treated with the pro-inflammatory cytokines IL-1β,IFN and TNF.Flow cytometry revealed the immunophenotype of the nontreated MSCs,the MSCs cocultured with PBMCs for 4 d and the MSCs exposed to cytokines.The proportions of CD25-,CD146-,CD69-,HLA-DR-and PD-1-positive CD4+and CD8+cells and the distribution of various effector and memory cell subpopulations in the PBMCs cocultured with the MSCs were also determined.RESULTS Differences in the immunophenotypes of effective and ineffective MSCs were observed.In the effective samples,the mean fluorescence intensity(MFI)of HLAABC,HLA-DR,CD105,and CD146 was significantly higher.After MSCs were treated with IFN or cocultured with PBMCs,the HLA-ABC,HLA-DR,CD90 and CD54 MFI showed a stronger increase in the effective MSCs,which indicated an increase in the immunomodulatory activity of these cells.When PBMCs were cocultured with effective MSCs,the proportions of CD4+and CD8+central memory cells significantly decreased,and the proportion of CD8+CD146+lymphocytes increased more than in the subpopulations of lymphocytes cocultured with MSC samples that were ineffective in the prevention of GVHD;in addition,the proportion of CD8+effector memory lymphocytes decreased in the PBMCs cocultured with the effective MSC samples but increased in the PBMCs cocultured with the ineffective MSC samples.The proportion of CD4+CD146+lymphocytes increased only when cocultured with the inefficient samples.CONCLUSION For the first time,differences were observed between MSC samples that were effective for GVHD prophylaxis and those that were ineffective.Thus,it was shown that the immunomodulatory activity of MSCs depends on the individual characteristics of the MSC population.

Advantageous tactics with certain probiotics for the treatment of graft-versus-host-disease after hematopoietic stem cell transplantation

Hematopoietic stem cell transplantation(HSCT)becomes a standard form of cellular therapy for patients with malignant diseases.HSCT is the first-choice of immunotherapy,although HSCT can be associated with many complications such as graft-versus-host disease(GVHD)which is a major cause of morbidity and mortality after allogeneic HSCT.It has been shown that certain gut microbiota could exert protective and/or regenerative immunomodulatory effects by the production of short-chain fatty acids(SCFAs)such as butyrate in the experimental models of GVHD after allogeneic HSCT.Loss of gut commensal bacteria which can produce SCFAs may worsen dysbiosis,increasing the risk of GVHD.Expression of G-protein coupled receptors such as GPR41 seems to be upre-gulated in the presence of commensal bacteria,which might be associated with the biology of regulatory T cells(Tregs).Treg cells are a suppressive subset of CD4 positive T lymphocytes implicated in the prevention of GVHD after allogeneic HSCT.Here,we discuss the current findings of the relationship between the modification of gut microbiota and the GVHD-related immunity,which suggested that tactics with certain probiotics for the beneficial symbiosis in gut-immune axis might lead to the elevation of safety in the allogeneic HSCT.

Gene and protein expression of proteinase-activated receptor-1, 2 in a murine model of acute graft vs host disease

Proteinase-activated receptors(PARs)are a novel subclass of seven transmembrane-spanning,G protein-coupled receptors.PAR-1 and PAR-2 are widely expressed in a variety of cells and are found to be involved in many physiological and pathological processes includ-ing inflammation and immune response.However,little is known about the function of PAR-1,2 in acute graft vs host disease(GVHD).In the present study,wefirst detected the expression of PAR-1,2 protein and mRNA in a murine model of acute GVHD using the methods of immunohis-tochemistry,Western blot and quantitative real-time polymerase chain reaction(PCR).Syngeneic hematopoie-tic stem cell transplantation(HSCT)mice served as controls.The relative gene expression level of PAR-1 was significantly increased in the skin,liver,small intestine of allogeneic HSCT mice(in skin:0.039�0.013 vs 0.008�0.002 of controls,P=0.009;in liver:0.165�0.006 vs 0.017�0.006 of controls,P=0.004;in small intestine:0.215�0.009 vs 0.016�0.002 of con-trols,P=0.003),but not in the stomach,lung and kidney of allogeneic HSCT mice(P>0.05).PAR-2 mRNA expression in the liver and small intestine of allogeneic HSCT mice(in liver:0.010�0.002 vs 0.003�0.001 of controls,P=0.008;in small intestine:0.006�0.001 vs 0.003�0.001 of controls,P=0.024)was increased significantly,but PAR-2 mRNA expression in the other organs(P>0.05)was not found to be significantly elevated.PAR-1,2 protein expression was in accordance with the mRNA expression,as shown by Western blot.Using immunohistochemistry the present study demon-strated that there was strong PAR-1,2 immunoreactivity in the epithelial cell and vascular endothelial cell of target organs of acute GVHD.Ourfindings of markedly increased expression of PAR-1,2 in target organs of acute GVHD suggest that PAR-1 and PAR-2 may play an important role in the pathogenesis of acute GVHD.

Noninvasive tools based on immune biomarkers for the diagnosis of central nervous system graft-vs-host disease:Two case reports and a review of the literature

BACKGROUND Central nervous system graft-vs-host disease(CNS-GVHD)is a rare cause of CNS disorders after allogeneic hematopoietic stem cell transplantation.Currently,establishing a diagnosis of CNS-GVHD is challenging because the diagnostic criteria and diagnostic methods are not well defined and many confounding factors need to be ruled out.CASE SUMMARY Here,we present two patients with CNS-GVHD.Both patients with a history of acute GVHD or chronic GVHD developed neurological symptoms that could not be explained by other causes,and had abnormal cerebrospinal fluid(CSF)studies as determined by CSF and blood immune biomarker examinations,suggestive of suspected CNS-GVHD.Due to the lack of specific magnetic resonance imaging abnormalities and the rapid clinical deterioration of the patients,we did not attempt to perform a brain biopsy,but prompted the initiation of empirical immunosuppressive therapy.In view of the rapid and favorable response to local and systematic immunosuppressive treatment and the aforementioned neurologic manifestations together with CSF abnormalities and other negative findings,a final diagnosis of CNS-GVHD was made.CONCLUSION CSF and blood immune biomarker examinations facilitated the diagnosis of CNSGVHD,which are particularly suitable for patients who are critically ill and require urgent treatment and for those who are unsuitable for invasive diagnostic procedures.

Nephrotic syndrome in syngeneic hematopoietic stem cell transplantation recipients: A case report

BACKGROUND Hematopoietic stem cell transplantation(HSCT)is widely used in the treatment of hematological diseases.However,complications after transplantation,such as acute and chronic graft-vs-host disease(GVHD),still seriously affect the quality of life and even threaten the lives of patients.There is evidence that glomerular diseases can manifest as GVHD.However,GVHD should not occur as a result of syngeneic HSCT.CASE SUMMARY A 20-year-old male diagnosed with T lymphoblastic lymphoma(stage IIIA,aaIPI 1)in September 2013 was treated with six cycles of hyper-CVAD and achieved complete remission.He underwent syngeneic HSCT in June 2014,and had no kidney disease history before the transplant.However,nephrotic syndrome occurred 24 mo later in the patient after syngeneic HSCT.Renal biopsy was performed,which led to a diagnosis of atypical membranous nephropathy.After treatment with glucocorticoids combined with cyclophosphamide and cyclosporine,the nephrotic syndrome was completely relieved.CONCLUSION We report a case of delayed nephrotic syndrome after syngeneic HSCT.Antibodymediated autoimmune glomerular disease may be the underlying mechanism.After treatment with immunosuppressive agents,the nephrotic syndrome was completely relieved but further long-term follow-up is still needed.

Influence on the immune function of the human peripheral blood mononuclear cells transfected by retrovirus-mediated HSV-tk gene

Graft-versus-host disease （GVHD） is a severe complication and a major source of morbidity and mortality after allogeneic hematopoietic stem cell transplantation （HSCT）. Although T cell depletion of the allogeneic HSCT can efficiently prevent GVHD, it is associated with increased graft rejection and relapse of the malignant disease. To preserve the beneficial effects of donor T cells and avoid their GVHD effects, some approaches have been explored. One of them is to transfer a special suicide gene into the donor T lymphocytes so that they become more sensitive to a specific drug that is ordinarily not toxic. The most commonly used suicide gene is the thymidine kinase-encoding gene of herpes simplex virus （HSV-tk）.

Black hairy tongue associated with allo peripheral blood hematopoietic stem cell transplantation

Tongue lesions resulting from mucositis are a frequent complication of high-dose chemotherapy and irradiation. They are very common in patients with hematopoiefic stem cell transplantation, and tongue lesions due to other causes have also been reported. Black hairy tongue （BHT） is a special tongue lesion, not rare in the population with tobacco abuse, but so far it has not been reported after allo peripheral blood hematopoietic stern cell transplantation （allo-PBHST）. Here we presented a patient who developed BHT after allo-PBHST and discussed the factors that may cause this condition.