Human retinoic acid-regulated CD161+ regulatory T cells support wound repair in intestinal mucosa.

Repair of tissue damaged during inflammatory processes is key to the return of local homeostasis and restoration of epithelial integrity. Here we describe CD161+ regulatory T (Treg) cells as a distinct, highly suppressive population of Treg cells that mediate wound healing. These Treg cells were enriched in intestinal lamina propria, particularly in Crohn's disease. CD161+ Treg cells had an all-trans retinoic acid (ATRA)-regulated gene signature, and CD161 expression on Treg cells was induced by ATRA, which directly regulated the CD161 gene. CD161 was co-stimulatory, and ligation with the T cell antigen receptor induced cytokines that accelerated the wound healing of intestinal epithelial cells. We identified a transcription-factor network, including BACH2, RORγt, FOSL2, AP-1 and RUNX1, that controlled expression of the wound-healing program, and found a CD161+ Treg cell signature in Crohn's disease mucosa associated with reduced inflammation. These findings identify CD161+ Treg cells as a population involved in controlling the balance between inflammation and epithelial barrier healing in the gut.

Treg sensitivity to FasL and relative IL-2 deprivation drive idiopathic aplastic anemia immune dysfunction.

Idiopathic aplastic anemia (AA) has 2 key characteristics: an autoimmune response against hematopoietic stem/progenitor cells and regulatory T-cells (Tregs) deficiency. We have previously demonstrated reduction in a specific subpopulation of Treg in AA, which predicts response to immunosuppression. The aims of the present study were to define mechanisms of Treg subpopulation imbalance and identify potential for therapeutic intervention. We have identified 2 mechanisms that lead to skewed Treg composition in AA: first, FasL-mediated apoptosis on ligand interaction; and, second, relative interleukin-2 (IL-2) deprivation. We have shown that IL-2 augmentation can overcome these mechanisms. Interestingly, when high concentrations of IL-2 were used for in vitro Treg expansion cultures, AA Tregs were able to expand. The expanded populations expressed a high level of p-BCL-2, which makes them resistant to apoptosis. Using a xenograft mouse model, the function and stability of expanded AA Tregs were tested. We have shown that these Tregs were able to suppress the macroscopic clinical features and tissue manifestations of T-cell-mediated graft-versus-host disease. These Tregs maintained their suppressive properties as well as their phenotype in a highly inflammatory environment. Our findings provide an insight into the mechanisms of Treg reduction in AA. We have identified novel targets with potential for therapeutic interventions. Supplementation of ex vivo expansion cultures of Tregs with high concentrations of IL-2 or delivery of IL-2 directly to patients could improve clinical outcomes in addition to standard immunosuppressive therapy.

Immunomodulatory Effects of Tyrosine Kinase Inhibitor In Vitro and In Vivo Study.

Pathogenesis of chronic graft-versus-host disease (cGVHD) is incompletely defined, involving donor-derived CD4 and CD8-positive T lymphocytes as well as B cells. Standard treatment is lacking for steroid-dependent/refractory cases; therefore, the potential usefulness of tyrosine kinase inhibitors (TKIs) has been suggested, based on their potent antifibrotic effect. However, TKIs seem to have pleiotropic activity. We sought to evaluate the in vitro and in vivo impact of different TKIs on lymphocyte phenotype and function. Peripheral blood mononuclear cells (PBMCs) from healthy donors were cultured in the presence of increasing concentrations of nilotinib, imatinib, dasatinib, and ponatinib; in parallel, 44 PBMC samples from 15 patients with steroid-dependent/refractory cGVHD treated with nilotinib in the setting of a phase I/II trial were analyzed at baseline, after 90, and after 180 days of therapy. Flow cytometry was performed after labeling lymphocytes with a panel of monoclonal antibodies (CD3, CD4, CD16, CD56, CD25, CD19, CD45RA, FoxP3, CD127, and 7-amino actinomycin D). Cytokine production was assessed in supernatants of purified CD3+ T cells and in plasma samples from nilotinib-treated patients. Main T lymphocyte subpopulations were not significantly affected by therapeutic concentrations of TKIs in vitro, whereas proinflammatory cytokine (in particular, IL-2, IFN-γ, tumor necrosis factor-α, and IL-10) and IL-17 production showed a sharp decline. Frequency of T regulatory, B, and natural killer (NK) cells decreased progressively in presence of therapeutic concentrations of all TKIs tested in vitro, except for nilotinib, which showed little effect on these subsets. Of note, naive T regulatory cell (Treg) subset accumulated after exposure to TKIs. Results obtained in vivo on nilotinib-treated patients were largely comparable, both on lymphocyte subset kinetics and on cytokine production by CD3-positive cells. This study underlines the anti-inflammatory and immunomodulatory effects of TKIs and supports their potential usefulness as treatment for patients with steroid-dependent/refractory cGVHD. In addition, both in vitro and in vivo data point out that compared with other TKIs, nilotinib could better preserve the integrity of some important regulatory subsets, such as Treg and NK cells.

Deep phenotyping of Tregs identifies an immune signature for idiopathic aplastic anemia and predicts response to treatment.

Idiopathic aplastic anemia (AA) is an immune-mediated and serious form of bone marrow failure. Akin to other autoimmune diseases, we have previously shown that in AA regulatory T cells (Tregs) are reduced in number and function. The aim of this study was to further characterize Treg subpopulations in AA and investigate the potential correlation between specific Treg subsets and response to immunosuppressive therapy (IST) as well as their in vitro expandability for potential clinical use. Using mass cytometry and an unbiased multidimensional analytical approach, we identified 2 specific human Treg subpopulations (Treg A and Treg B) with distinct phenotypes, gene expression, expandability, and function. Treg B predominates in IST responder patients, has a memory/activated phenotype (with higher expression of CD95, CCR4, and CD45RO within FOXP3(hi), CD127(lo) Tregs), expresses the interleukin-2 (IL-2)/STAT5 pathway and cell-cycle commitment genes. Furthermore, in vitro-expanded Tregs become functional and take on the characteristics of Treg B. Collectively, this study identifies human Treg subpopulations that can be used as predictive biomarkers for response to IST in AA and potentially other autoimmune diseases. We also show that Tregs from AA patients are IL-2-sensitive and expandable in vitro, suggesting novel therapeutic approaches such as low-dose IL-2 therapy and/or expanded autologous Tregs and meriting further exploration.

Functional characterization of CD4+ T cells in aplastic anemia.

The role of CD4(+) T cells in the pathogenesis of aplastic anemia (AA) is not well characterized. We investigate CD4(+) T-cell subsets in AA. Sixty-three patients with acquired AA were studied. Th1 and Th2 cells were significantly higher in AA patients than in healthy donors (HDs; P = .03 and P = .006). Tregs were significantly lower in patients with severe AA than in HDs (P < .001) and patients with non-severe AA (P = .01). Th17 cells were increased in severe AA (P = .02) but normal in non-severe AA. Activated and resting Tregs were reduced in AA (P = .004; P = .01), whereas cytokine-secreting non-Tregs were increased (P = .003). Tregs from AA patients were unable to suppress normal effector T cells. In contrast, AA effector T cells were suppressible by Tregs from HDs. Th1 clonality in AA, investigated by high-throughput sequencing, was greater than in HDs (P = .03). Our results confirm that Th1 and Th2 cells are expanded and Tregs are functionally abnormal in AA. The clonally restricted expansion of Th1 cells is most likely to be antigen-driven, and induces an inflammatory environment, that exacerbate the functional impairment of Tregs, which are reduced in number.

The effects of 5-azacytidine on the function and number of regulatory T cells and T-effectors in myelodysplastic syndrome.

Expansion of regulatory T cells occurs in high-risk myelodysplastic syndrome and correlates with a poor prognosis. DNA methyltransferase inhibitors, particularly 5-azacytidine, have been shown to increase the survival of patients with high-risk myelodysplastic syndrome. It is not entirely clear whether this improvement in patients' survival is related to the effects of DNA methyltransferase inhibitors on the immune system and/or the direct effect of these drugs on the dysplastic clone. In this study we investigated the effect of 5-azacytidine on the function and proliferation capability of regulatory T cells and T-helper cells. The number and function of CD4(+) T-cell subsets in 68 patients with intermediate-2/high-risk myelodysplastic syndrome were serially assessed at diagnosis and following treatment. The in-vitro effects of 5-azacytidine on CD4(+) T-cell subsets isolated from both healthy donors and patients with myelodysplastic syndrome were also investigated. The number of peripheral blood regulatory T cells was significantly higher in myelodysplastic syndrome patients than in healthy donors and responders to treatment (P=0.01). The absolute numbers of T-helper 1 and T-helper 2, but not T-helper 17, cells were significantly reduced following 12 months of treatment (P=0.03, P=0.03). The in vitro addition of 5-azacytidine to CD4(+) T cells reduced the proliferative capacity of regulatory T cells (P=0.03). In addition, the 5-azacytidine-treated regulatory T cells had reduced suppressive function and produced larger amounts of interleukin-17. The FOXP3 expression in 5-azacyti-dine-treated T-effectors was also increased. Interestingly, these FOXP3(+)/interleukin-17(+) cells originated mainly from effector T cells rather than regulatory T cells. Our data suggest that 5-azacytidine has profound effects on CD4(+) T cells, which correlate with disease status after treatment. Furthermore, despite the demethylation of the FOXP3 promoter and increased FOXP3 expression following 5-azacytidine treatment, these phenotypic regulatory T cell-like cells lack the regulatory function and cytokine profile of regulatory T cells. These findings are important in correlating the clinically relevant immunomodulatory effects of 5-azacytidine.

Prognostic role of immunohistochemical analysis of 5 mc in myelodysplastic syndromes.

BACKGROUND: Aberrant DNA methylation at CpG islands within promoters is increasingly recognised as a common event in human cancers and has been associated with the silencing of important tumour suppressor genes. Epigenetic therapy using hypomethylating agents has demonstrated clinical effectiveness; the drugs azacitidine and decitabine have been approved for the treatment of MDS. METHOD: We investigated the association between global DNA methylation and clinical outcome in MDS. We evaluated 134 MDS bone marrow trephine biopsies (BMTB) by immunohistochemistry and compared the results with those from an age-matched group of normal BMTB. Immunohistochemistry was performed on paraffin-embedded sections using the anti-5-methylcytosine (5mc) antibody. RESULTS: Our results showed that the 5mc immunostaining score (M-score) of patients with MDS was higher than those of normal controls and that overall survival significantly correlated with global DNA methylation, age and IPSS score. Therefore, we found that patients with high levels of methylation had a shorter median overall survival (OS) compared with patients with lower levels. These immunohistochemistry results were confirmed by analysing global DNA methylation on LINE-1 sequences using the COBRA method and pyrosequencing. CONCLUSION: This study reports that global DNA methylation detected by immunohistochemistry predicts OS in MDS.

Gene expression profile of cytokines in patients with chronic graft-versus-host disease after allogeneic hematopoietic stem cell transplantation with reduced conditioning.

There are no reliable markers useful to predict the onset or the evolution of chronic graft-versus-host disease (cGVHD) after allogeneic hematopoietic stem cell transplantation (HSCT), although several candidate biomarkers have been identified from limited hypothesis-driven studies. In this study we evaluated 14 patients who received a reduced intensity conditioning HSCT. Seven patients had cGVHD, whereas 7 never developed cGVHD during the period of observation. The expression of 114 cytokines in immunoselected cell populations was explored by microarray analysis and 11 cytokines were selected for further evaluation by real-time PCR. Differential gene expression measurements showed a significant up-regulation for INFγ (interferon, gamma) in CD8+ and for TNFSF3 (tumor necrosis factor superfamily, member 3) and for TNFSF10 (tumor necrosis factor superfamily, member 10) in CD14+ cell population when comparing cGVHD with control samples. The expression levels were significantly decreased for TNFSF10 in CD8+ cell population and for TNFSF12 (tumor necrosis factor superfamily, member 12) and for PDGFß (platelet-derived growth factor, beta) in CD4+. Our data seem to suggest that different immune populations can play a role in cGVHD pathogenesis and the early detection of gene expression profile in these patients could be useful in the monitoring of GVHD. We hypothesized that PDGFß down-regulation could represent a negative feedback to compensate for enhanced expression of its receptor recently reported.

Unusual presentation of primary myelofibrosis with spontaneous bleeding after laparoscopic adrenalectomy: A case report.

INTRODUCTION: We described unusual presentation of primary myelofibrosis with spontaneous bleeding after laparoscopic adrenalectomy. This case is written following the SCARE criteria. PRESENTATION OF CASE: A 73 years old Caucasian man underwent laparoscopic right adrenalectomy for a rapidly increasing expansive mass (3.5 × 2.5 cm) of the right adrenal gland. The night of intervention, patient underwent urgent explorative laparotomy, that highlighted massive haemoperitoneum, clots in the abdomen, on the splenic side, on Morrison's space, and at the confluence between right renal vein and inferior vena cava. Surgical specimen examination showed extra-medullary myeloid proliferation of the right periadrenal tissue. DISCUSSION: Bone marrow biopsy was performed. The list of differential diagnoses included: chronic myelomonocitic leukaemia, atypical CML and primary myelofibrosis (PMF). After discharge, several results became available: conventional cytogenetics was normal, PDGFR-α, PDGFR-ß and FGFR1 mutations were negative but V617 F mutation of the JAK2 gene was positive. Therefore, the final diagnosis was pre-fibrotic primary myelofibrosis according to the 2016 WHO classification, Dynamic International Prognostic Scoring System (DIPSS) plus 2 (intermediate-2). CONCLUSION: To our knowledge, we report uncommon case of primary myelofibrosis associated with extra-medullary myeloid proliferation of the right periadrenal tissue.

Developments in consolidation and maintenance strategies in post-remission multiple myeloma.

Introduction: Multiple Myeloma (MM) is a very heterogeneous clonal plasma cell hematological malignancy for which new therapies and transplantation effectively improve Progression-free survival (PFS) and overall survival (OS). Maintenance seems to have made a significant contribution in achieving these advances, whereas the real role of consolidation is still controversial. Despite lenalidomide having been approved as maintenance therapy after autologous stem cell transplantation (ASCT), the optimal maintenance agent, drug combinations, schedules, and duration are still under investigation.Areas covered: This review summarizes data regarding maintenance and consolidation therapies for transplant-eligible patients, updating on the ongoing developments in this area. Papers published on PubMed and abstracts presented at the ASCO, ASH, and EHA meetings up to December 2019 were used.Expert opinion: The available studies demonstrate that maintenance therapy is very effective although results from ongoing clinical trials suggest that disease features and minimal residual disease (MRD) status may optimize the selection of agents, schedule, and duration of maintenance therapy. Consolidation with last-generation drugs seems to be more effective and it could replace transplantation in some subgroups of patients.

Expansion of myeloid derived suppressor cells correlates with number of T regulatory cells and disease progression in myelodysplastic syndrome.

Although the role of CD4+ T cells and in particular Tregs and Th17 cells is established in myelodysplastic syndrome(MDS), the contribution of other components of immune system is yet to be elucidated fully. In this study we investigated the number and function of myeloid derived suppressor cells (MDSCs) in fresh peripheral blood and matched bone marrow samples from 42 MDS patients and the potential correlation with risk of disease progression to acute myeloid leukemia (AML). In peripheral blood, very low-/low risk patients had significantly lower median MDSC number (0.16×109/L(0.03-0.40)) compared to intermediate-/high-/very high risk patients, in whom median MDSC counts was 0.52×109/L(0.10-1.78), p < 0.005. When co-cultured with CD4+ effector T-cells (T-effectors), MDSCs suppress Teffector proliferation in both allogeneic and autologous settings. There was a positive correlation between the number of Tregs and MDSCs (Spearman R = 0.825, p < 0.005) in high risk and not low risk patients. We also investigated MDSCs' expression of bone marrow-homing chemokine receptors, and our data shows that MDSCs from MDS patients express both CXCR4 and CX3CR1 which might facilitate migration of MDSCs to bone marrow. Monocytic MDSCs(M-MDSCs) which are more frequent in the peripheral blood express higher levels of CX3CR1 and CXCR4 than the granulocytic subtype (G-MDSCs), and circulating M-MDSCs had significantly higher CX3CR1 expression compared to bone-marrow M-MDSCs in intermediate-/high-/very high risk MDS. Our results suggest that MDSCs contribute significantly to the dysregulation of immune surveillance in MDS, which is different between low and high risk disease. It further points at mechanisms of MDSCs recruitment and contribution to the bone marrow microenvironment.

Valproic acid for the treatment of low-risk myelodysplastic syndromes: A case report and a review of the literature.

Myelodysplastic syndromes are heterogeneous myeloid neoplasms ranging from indolent conditions with a near-normal life expectancy to forms approaching acute myeloid leukemia. Here we report a 51-year-old woman with depression and severe obesity who was diagnosed with an International Prognostic Scoring System low-risk myelodysplastic syndrome, presenting mainly with thrombocytopenia, treated with escalating dose of valproic acid as a single agent. After two years of treatment her platelet count is almost normal and the tolerance to therapy is good. It is already known that valproic acid could be used in high-risk myelodysplastic syndromes and acute myeloid leukemia, mainly in association with other drugs, but its role in low-risk myelodysplastic syndrome is not well established yet.

Telomere length, c-myc and mad-1 expression could represent prognosis markers of myelodysplastic syndrome.

Telomere dysfunction might generate genomic instability leading to the progression of myelodysplastic syndromes (MDS) into acute myeloid leukemia (AML). We investigated telomere length (TL), telomerase activity (TA) and hTERT, c-myc, mad1, and p53 expression in the bone marrow of patients with MDS (n=109), AML (n=47) and in controls (n=24). TL was lower in MDS patients than in controls (p<0.001) and higher in L-MDS (low, intermediate-1 IPSS, p<0.01) respect H-MDS (high, intermediate-2 IPSS, p<0.01) patients. Mad-1 expression was higher in MDS patients than in controls (p<0.01), c-myc expression was highest in AML and in H-MDS patients. Our results show that the telomere dynamics might be useful for stratifying patients according to a risk scoring system.

Human mesenchymal stem cells from chorionic villi and amniotic fluid are not susceptible to transformation after extensive in vitro expansion.

Mesenchymal stem cells (MSCs) are promising candidates for cell therapy and tissue engineering. Increasing evidence suggests that MSCs isolated from fetal tissues are more plastic and grow faster than adult MSCs. In this study, we characterized human mesenchymal progenitor cells from chorionic villi (CV) and amniotic fluid (AF) isolated during the first and second trimesters, respectively, and compared them with adult bone marrow-derived MSCs (BM). We evaluated 10 CV, 10 AF, and 6 BM samples expanded until the MSCs reached senescence. We used discarded cells from prenatal analyses for all the experiments. To evaluate the replicative stability of these cells, we studied the telomerase activity, hTERT gene transcription, and telomere length in these cells. Spontaneous chromosomal alterations were excluded by cytogenetic analysis. We studied the expression of c-myc and p53, tumor-associated genes, at different passage in culture and the capacity of these cells to grow in an anchorage-independent manner by using soft agar assay. We isolated homogeneous populations of spindle-shaped CV, AF, and BM cells expressing mesenchymal immunophenotypic markers throughout the period of expansion. CV cells achieved 14 ± 0.9 logs of expansion in 118 days and AF cells achieved 21 ± 0.9 logs in 118 days, while BM cells achieved 11 × 0.4 logs in 84 days. Despite their high proliferation capacity, fetal MSCs showed no telomerase activity, no hTERT and c-myc transcriptions, and maintained long, stable telomeres. A constant expression level of p53 and a normal karyotype were preserved throughout long-term expansion, suggesting the safety of fetal MSCs. In conclusion, our results indicate that fetal MSCs could be an alternative, more accessible resource for cell therapy and regenerative medicine.