Platelet-derived TGF-ß1 induces functional reprogramming of myeloid-derived suppressor cells in immune thrombocytopenia.

ABSTRACT: Platelet α-granules are rich in transforming growth factor ß1 (TGF-ß1), which is associated with myeloid-derived suppressor cell (MDSC) biology. Responders to thrombopoietin receptor agonists (TPO-RAs) revealed a parallel increase in the number of both platelets and MDSCs. Here, anti-CD61 immune-sensitized splenocytes were transferred into severe combined immunodeficient mice to establish an active murine model of immune thrombocytopenia (ITP). Subsequently, we demonstrated that TPO-RAs augmented the inhibitory activities of MDSCs by arresting plasma cells differentiation, reducing Fas ligand expression on cytotoxic T cells, and rebalancing T-cell subsets. Mechanistically, transcriptome analysis confirmed the participation of TGF-ß/Smad pathways in TPO-RA-corrected MDSCs, which was offset by Smad2/3 knockdown. In platelet TGF-ß1-deficient mice, TPO-RA-induced amplification and enhanced suppressive capacity of MDSCs was waived. Furthermore, our retrospective data revealed that patients with ITP achieving complete platelet response showed superior long-term outcomes compared with those who only reach partial response. In conclusion, we demonstrate that platelet TGF-ß1 induces the expansion and functional reprogramming of MDSCs via the TGF-ß/Smad pathway. These data indicate that platelet recovery not only serves as an end point of treatment response but also paves the way for immune homeostasis in immune-mediated thrombocytopenia.

Low-dose decitabine modulates myeloid-derived suppressor cell fitness via LKB1 in immune thrombocytopenia.

Myeloid-derived suppressor cells (MDSCs) are heterogeneous immature cells and natural inhibitors of adaptive immunity. Metabolic fitness of MDSCs is fundamental for its suppressive activity toward effector T cells. Our previous studies showed that the number and inhibitory function of MDSCs were impaired in patients with immune thrombocytopenia (ITP) compared with healthy controls. In this study, we analyzed the effects of decitabine on MDSCs from patients with ITP, both in vitro and in vivo. We found that low-dose decitabine promoted the generation of MDSCs and enhanced their aerobic metabolism and immunosuppressive functions. Lower expression of liver kinase 1 (LKB1) was found in MDSCs from patients with ITP, which was corrected by decitabine therapy. LKB1 short hairpin RNA (shRNA) transfection effectively blocked the function of MDSCs and almost offset the enhanced effect of decitabine on impaired MDSCs. Subsequently, anti-CD61 immune-sensitized splenocytes were transferred into severe combined immunodeficient (SCID) mice to induce ITP in murine models. Passive transfer of decitabine-modulated MDSCs significantly raised platelet counts compared with that of phosphate buffered saline-modulated MDSCs. However, when LKB1 shRNA-transfected MDSCs were transferred into SCID mice, the therapeutic effect of decitabine in alleviating thrombocytopenia was quenched. In conclusion, our study suggests that the impaired aerobic metabolism of MDSCs is involved in the pathogenesis of ITP, and the modulatory effect of decitabine on MDSC metabolism contributes to the improvement of its immunosuppressive function. This provides a possible mechanism for sustained remission elicited by low-dose decitabine in patients with ITP.

Atorvastatin restores imbalance of cluster of differentiation 4 (CD4)+ T cells in immune thrombocytopenia in vivo and in vitro.

Immune thrombocytopenia (ITP) is an autoimmune haemorrhagic disease, in which the overactivation of T cells is crucial in the pathogenesis. Atorvastatin (AT), a lipid-lowering medicine, has shown promising immunomodulatory effects in certain inflammatory conditions. However, the immunoregulatory role of AT in ITP remains elusive. To investigate the effect of AT in the treatment of ITP, cluster of differentiation 4 (CD4)+ T cells were isolated from patients with ITP and cultured with different dosages of AT. We found that AT significantly inhibited cell proliferation, led to cell cycle arrest, induced apoptosis, and repressed the activation of CD4+ T cells in vitro. ITP murine models were then established, and results showed that AT treatment led to faster recovery of the platelet count to normal and exhibited comparable immunomodulatory function. Furthermore, we found the phosphorylation of mammalian target of rapamycin (mTOR), protein kinase B (AKT) and extracellular signal-regulated kinase (ERK), as well as activation of rat sarcoma virus (RAS) were all reduced dramatically after AT treatment in vitro. In conclusion, our present study demonstrated that AT could reinstate the functions of CD4+ T cells by inhibiting the excessive activation, proliferation, and survival of CD4+ T cells in ITP via the RAS/mitogen-activated protein kinase kinase (MEK)/ERK and the mTOR/phosphatidylinositol-3 kinase (PI3K)/AKT pathway. Therefore, we propose that AT could be used as a potential therapeutic option for ITP by restoring the over-activated cellular immunity.

Enhancing regulatory T-cell function via inhibition of high mobility group box 1 protein signaling in immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is the most common acquired autoimmune bleeding disorder. Abnormally increased levels of High Mobility Group Box 1 (HMGB1) protein associate with thrombocytopenia and therapeutic outcome in ITP. Previous studies proposed that a natural inhibitor of HMGB1, 18ß-glycyrrhetinic acid (18ß-GA), could be used for its anti-inflammatory and immune-modulatory effects, although its ability to correct immune balance in ITP is unclear. In this study, we showed that plasma HMGB1 correlated negatively with platelet counts in ITP patients, and confirmed that 18ß-GA stimulated the production of regulatory T cells (Treg), restored the balance of CD4+ T-cell subsets and enhanced the suppressive function of Treg through blocking the effect on HMGB1 in patients with ITP. HMGB1 short hairpin RNA interference masked the effect of 18ß-GA in Treg of ITP patients. Furthermore, we found that 18ß-GA alleviated thrombocytopenia in mice with ITP. Briefly, anti-CD61 immune-sensitized splenocytes were transferred into severe combined immunodeficient mice to induce a murine model of severe ITP. The proportion of circulating Treg increased significantly, while the level of plasma HMGB1 and serum antiplatelet antibodies decreased significantly in ITP mice along 18ß-GA treatment. In addition, 18ß-GA reduced phagocytic activity of macrophages towards platelets both in ITP patients and ITP mice. These results indicate that 18ß-GA has the potential to restore immune balance in ITP via inhibition of HMGB1 signaling. In short, this study reveals the role of HMGB1 in ITP, which may serve as a potential target for thrombocytopenia therapy.

Significance of anti-HBc serological status in primary immune thrombocytopenia.

The association of previous hepatitis B virus (HBV) exposure [hepatitis B surface antigen (HBsAg) negative, hepatitis B core antibody (anti-HBc/HBcAb) positive] with disease severity and decision on treatment option in primary immune thrombocytopenia (ITP) patients remains unclear. Data from 725 patients diagnosed with ITP were analyzed to elucidate the association between anti-HBc serological status and disease severity. Data from a published prospective study [high-dose dexamethasone (HD-DXM), HD-DXM plus recombinant human thrombopoietin, NCT01734044] and two retrospective studies (standard-dose and low-dose rituximab) were rearranged to evaluate the impact of anti-HBc serological status on the response and outcome to ITP-specific treatments and the risk of HBV reactivation related to these treatments. The prevalence of HBsAg- HBcAb+ and HBsAg- HBcAb- in ITP patients was 51·03% and 48·97% respectively. Compared to the HBsAg- HBcAb- group, patients in the HBsAg- HBcAb+ group had lower platelet count, higher bleeding score, and longer hospitalization (P = 0·002, 0·033, and 0·008 respectively). Moreover, the initial complete response rate of HBsAg- HBcAb+ patients was lower than that of HBsAg- HBcAb- patients (45·2% vs 59·8%, P = 0·027). In conclusion, previous HBV exposure was correlated with disease severity and hospitalization in ITP patients. Anti-HBc positivity may be considered as a predictor for poor response to ITP-specific treatments.

Single-dose versus low-dose rituximab in corticosteroid-resistant or relapsed ITP: A multicenter, randomized, controlled study.

Primary immune thrombocytopenia (ITP) is an autoimmune bleeding disorder, in which rituximab (RTX) induces the best long-term effect among recommended second-line treatments. Nevertheless, the optimal regimen of RTX remains unclear. We herein conducted a prospective, multicenter, open-label, randomized controlled trial to compare the efficacy and safety of RTX at two different dosage regimens in patients with corticosteroid-resistant or relapsed ITP. Recruited patients were randomly assigned (1:1) to receive either RTX at a repeated low dose (100 mg weekly for 4 weeks, LD-RTX) or at a single dose (375 mg/m2 , S-RTX). Overall response was achieved in 64.3% of patients who received LD-RTX versus 67.4% of those receiving S-RTX (p = .759). The complete response (CR) rate was 23.8% after LD-RTX and 28.3% after S-RTX (p = .635). In health-related quality of life, S-RTX improved patients' psychological status, quality of life, social activities, and work compared with LD-RTX. Furthermore, S-RTX significantly reduced physician visits without compromising efficacy. Our findings demonstrate that a S-RTX is comparable to LD-RTX in effectiveness and safety for treatment of corticosteroid-resistant or relapsed ITP. The single-dosage regimen optimizes the use of medical resources, improves the cost-effectiveness of RTX, and represents a promising and more convenient replacement for LD-RTX in ITP. This study has been completed and is registered with ClinicalTrials.gov, number NCT03258866.

Interleukin-37 reduces inflammation and impairs phagocytosis of platelets in immune thrombocytopenia (ITP).

Immune thrombocytopenia (ITP) is an autoimmune disease characterized by low platelet count with heterogeneous bleeding manifestations. Severe bleeding in ITP is not completely related with low platelet count. Fcγ receptor (FcγR)-mediated platelet destruction is one of the major mechanisms of ITP. Interleukin-37 (IL-37) is a fundamental natural suppressor of innate immunity and inflammatory responses in several autoimmune diseases. However, the role of IL-37 in the pathogenesis of ITP is unknown. In the present study, we identified that IL-37 expression was elevated in ITP patients, which was correlated with platelet count and the severity of bleeding in ITP, indicating that IL-37 could be a candidate in evaluating disease severity of ITP. In the in vitro study, IL-37 initiated an anti-inflammatory effect on monocytes/macrophages from ITP patients by down-regulating the phosphorylation of MAPK, AKT, and NF-κB signaling pathways. Moreover, IL-37 restored the balance of activating and inhibitory FcγRs and decreased antibody-mediated platelet phagocytosis by monocytes/macrophages. Our findings suggest that IL-37 may be a promising indicator of the disease severity and supplementation of IL-37 may be therapeutically beneficial for ITP patients.

Glucocorticoid receptor modulates myeloid-derived suppressor cell function via mitochondrial metabolism in immune thrombocytopenia.

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature cells and natural inhibitors of adaptive immunity. Intracellular metabolic changes in MDSCs exert a direct immunological influence on their suppressive activity. Our previous study demonstrated that high-dose dexamethasone (HD-DXM) corrected the functional impairment of MDSCs in immune thrombocytopenia (ITP); however, the MDSC population was not restored in nonresponders, and the mechanism remained unclear. In this study, altered mitochondrial physiology and reduced mitochondrial gene transcription were detected in MDSCs from HD-DXM nonresponders, accompanied by decreased levels of carnitine palmitoyltransferase-1 (CPT-1), a rate-limiting enzyme in fatty acid oxidation (FAO). Blockade of FAO with a CPT-1 inhibitor abolished the immunosuppressive function of MDSCs in HD-DXM responders. We also report that MDSCs from ITP patients had lower expression of the glucocorticoid receptor (GR), which can translocate into mitochondria to regulate the transcription of mitochondrial DNA (mtDNA) as well as the level of oxidative phosphorylation. It was confirmed that the expression of CPT-1 and mtDNA-encoded genes was downregulated in GR-siRNA-treated murine MDSCs. Finally, by establishing murine models of active and passive ITP via adoptive transfer of DXM-modulated MDSCs, we confirmed that GR-silenced MDSCs failed to alleviate thrombocytopenia in mice with ITP. In conclusion, our study indicated that impaired aerobic metabolism in MDSCs participates in the pathogenesis of glucocorticoid resistance in ITP and that intact control of MDSC metabolism by GR contributes to the homeostatic regulation of immunosuppressive cell function.

Abnormalities of bone marrow B cells and plasma cells in primary immune thrombocytopenia.

Primary immune thrombocytopenia (ITP) is an autoantibody-mediated hemorrhagic disorder in which B cells play an essential role. Previous studies have focused on peripheral blood (PB), but B cells in bone marrow (BM) have not been well characterized. We aimed to explore the profile of B-cell subsets and their cytokine environments in the BM of patients with ITP to further clarify the pathogenesis of the disease. B-cell subpopulations and their cytokine/chemokine receptors were detected by using flow cytometry. Plasma concentrations of cytokines/chemokines were measured by using enzyme-linked immunosorbent assay. Messenger RNA levels of B cell-related transcription factors were determined by using quantitative polymerase chain reaction. Regulatory B cell (Breg) function was assessed by quantifying their inhibitory effects on monocytes and T cells in vitro. Decreased proportions of total B cells, naive B cells, and defective Bregs were observed in patients with ITP compared with healthy controls (HCs), whereas an elevated frequency of long-lived plasma cells was found in BM of autoantibody-positive patients. No statistical difference was observed in plasmablasts or in short-lived plasma cells between patients with ITP and HCs. The immunosuppressive capacity of BM Bregs from patients with ITP was considerably weaker than HCs. An in vivo study using an active ITP murine model revealed that Breg transfusion could significantly alleviate thrombocytopenia. Moreover, overactivation of CXCL13-CXCR5 and BAFF/APRIL systems were found in ITP patient BM. Taken together, B-cell subsets in BM were skewed toward a proinflammatory profile in patients with ITP, suggesting the involvement of dysregulated BM B cells in the development of the disease.

The safety and efficacy of anti-PD-1/anti-PD-L1 antibody therapy in the treatment of previously treated, advanced gastric or gastro-oesophageal junction cancer: A meta-analysis of prospective clinical trials.

INTRODUCTION: So far, anti-PD-1/anti-PD-L1 antibody therapy is reportedly in treating gastric cancer or gastro-oesophageal junction cancer (GC/GEJC) in a number of clinical trials. Based on this, we conducted current meta-analysis to assess the safety and efficacy of anti-PD-1/anti-PD-L1 antibody for previously treated advanced GC/GEJC patients. METHODS: We searched five electronic databases for eligible records. Outcomes were presented and analyzed by objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and adverse effects (AEs). RESULTS: Nine records involving 1388 participants were selected in our study. The pooled ORR, DCR, OS rate (6 month), PFS rate (6 month), OS rate (12 month) and PFS rate (12 month) were 10% (95% confidence interval [CI]: 6%-14%), 32% (95%CI: 25%-38%), 52% (95%CI: 44%-61%), 18% (95%CI: 13%-24%), 40% (95%CI: 31%-48%) and 8% (95%CI: 5%-10%), respectively. Meanwhile, grade≥3 AEs rate was 12% (95% CI: 10%-15%). Programmed death ligand 1 (PD-L1) positive cases had higher rate of ORR (odds ratio [OR]: 3.75, 95%CI: 2.09-6.74, P=0.58) compared with negative cases. CONCLUSION: The results indicated that anti-PD-1/anti-PD-L1 antibody therapy has an effectual anti-tumor activity and controllable AEs in advanced GC/GEJC patients. Furthermore, overexpression of PD-L1 in advanced GC/GEJC patients had better ORR from anti-PD-1/anti-PD-L1 antibody therapy (PROSPERO registration number: CRD42018116480).

The efficacy and safety of enhanced recovery after surgery (ERAS) program in laparoscopic digestive system surgery: A meta-analysis of randomized controlled trials.

BACKGROUND: The enhanced recovery after surgery (ERAS) program has been applied to a variety of surgeries. However, the efficacy and safety of the ERAS program in laparoscopic digestive system surgery remain unclear. We conducted a meta-analysis to evaluate the ERAS program and traditional perioperative care (TPC) in laparoscopic digestive system surgery. METHODS: We searched five electronic databases for eligible trials. STATA version 14.0 and Revman version 5.3 were used to analyze the data. The results were presented and analyzed by weighted mean difference (WMD) and risk ratio (RR) at their 95% confidence interval (CI). RESULTS: Twenty-five randomized controlled trials (RCTs) of 2219 patients were included in our meta-analysis. The results revealed that the postoperative hospital stay (PHS) (WMD: 2.13 day, 95% CI: 2.56 to -1.70, p = 0.000), time to first flatus (WMD: 12.68 h, 95% CI: 15.95 to -9.41, p = 0.000), and time to defecation (WMD: 34.35 h, 95% CI: 46.82 to -21.88, p = 0.000) were significantly shorter in the ERAS group compared to the TPC group. Additionally, the overall postoperative complication rate (RR: 0.66, 95% CI: 0.49 to 0.88, p = 0.000) was markedly lower in patients using the ERAS program. CONCLUSION: The results indicated that the ERAS program is associated with faster postoperative rehabilitation, shorter PHS, and better postoperative complication rates. The use of the ERAS program for laparoscopic digestive system surgery is more effective and safe than TPC, and it should be recommended. (PROSPERO registration number:CRD42018118551).

Is the Enhanced Recovery After Surgery (ERAS) Program Effective and Safe in Laparoscopic Colorectal Cancer Surgery? A Meta-Analysis of Randomized Controlled Trials.

BACKGROUND: Enhanced recovery after surgery (ERAS) program has shown a few advantages in colorectal cancer surgery. However, the effectiveness of the ERAS program in laparoscopic colorectal cancer surgery is still unclear. We performed a meta-analysis of randomized controlled trials (RCTs) to evaluate the effect of ERAS program in laparoscopic colorectal cancer surgery compared with traditional perioperative care (TC). METHODS: PubMed, EMBASE, Web of Science, The Cochrane Library, and ClinicalTrials.gov were searched for eligible RCTs comparing ERAS program with TC in laparoscopic colorectal cancer surgery. The main outcomes included the average length of postoperative hospital stay (PHS), time to first flatus and defecation, overall complication, readmission, and mortality rates were undertaken. RESULTS: Thirteen RCTs involving 1298 patients were included in our study (639 in ERAS group and 659 in TC group). ERAS group had shorter average length of PHS (weighted mean difference [WMD] - 2.00 day, 95% confidence interval [CI] - 2.52 to - 1.48, p = 0.00), time to first flatus (WMD - 12.18 h, 95%CI - 16.69 to - 7.67, p = 0.00), and time to first defecation (WMD - 32.93 h, 95%CI - 45.36 to - 20.50, p = 0.00) than TC group. In addition, the overall complication rates (risk ratio [RR] 0.59, 95%CI 0.40 to 0.86, p < 0.01) were significantly lower in ERAS group compared with TC group. CONCLUSIONS: The results indicated that ERAS program is a much better effective and safe protocol for laparoscopic colorectal cancer surgery compared with TC. Hence, ERAS program should be recommended in laparoscopic colorectal cancer surgery.