Germline variants of DNA repair and immune genes in lymphoma from lymphoma-cancer families.

The genetic predisposition to lymphoma is not fully understood. We identified 13 lymphoma-cancer families (2011-2021), in which 27 individuals developed lymphomas and 26 individuals had cancers. Notably, male is the predominant gender in lymphoma patients, whereas female is the predominant gender in cancer patients (p = .019; OR = 4.72, 95% CI, 1.30-14.33). We collected samples from 18 lymphoma patients, and detected germline variants through exome sequencing. We found that germline protein truncating variants (PTVs) were enriched in DNA repair and immune genes. Totally, we identified 31 heterozygous germline mutations (including 12 PTVs) of 25 DNA repair genes and 19 heterozygous germline variants (including 7 PTVs) of 14 immune genes. PTVs of ATM and PNKP were found in two families, respectively. We performed whole genome sequencing of diffuse large B cell lymphomas (DLBCLs), translocations at IGH locus and activation of oncogenes (BCL6 and MYC) were verified, and homologous recombination deficiency was detected. In DLBCLs with germline PTVs of ATM, deletion and insertion in CD58 were further revealed. Thus, in lymphoma-cancer families, we identified germline defects of both DNA repair and immune genes in lymphoma patients.

Camrelizumab plus gemcitabine and oxaliplatin for relapsed or refractory classical Hodgkin lymphoma: a phase II trial.

BACKGROUND: Classical Hodgkin lymphoma (cHL) is a highly curable disease, while novel therapy is needed for refractory or relapsed (R/R) patients. This phase II trial aimed to evaluate the role of camrelizumab plus gemcitabine and oxaliplatin (GEMOX) in R/R cHL patients. METHODS: Transplant-eligible patients with R/R cHL were enrolled and received two 14-day cycles of camrelizumab 200 mg intravenously (IV) and two 28-day cycles of camrelizumab 200 mg IV, gemcitabine 1000 mg/m2 IV, and oxaliplatin 100 mg/m2 IV on days 1 and 15. Patients with partial response (PR) or stable disease received an additional cycle of combination therapy. Those who achieved complete response (CR) or PR proceeded to autologous stem cell transplantation (ASCT). The primary endpoint was the CR rate at the end of protocol therapy before ASCT. RESULTS: Forty-two patients were enrolled. At the end of protocol therapy, the objective response rate and CR rate were 94.9% (37/39) and 69.2% (27/39) in the evaluable set, and 88.1% (37/42) and 64.3% (27/42) in the full analysis set, respectively. Twenty-nine patients (69.0%) proceeded to ASCT, and 4 of 5 patients with PR achieved CR after ASCT. After a median follow-up of 20.7 months, the 12-month progression-free survival rate was 96.6% and the 12-month overall survival rate was 100%. Grade 3 or higher treatment emergent adverse events occurred in 28.6% of patients (12/42), mainly hematological toxicity. CONCLUSIONS: Camrelizumab combined with GEMOX constitutes an effective salvage therapy for R/R cHL, proving to be relatively well-tolerated and facilitating ASCT in most patients, thus promoting sustained remission. TRIAL REGISTRATION: ClinicalTrials.gov NCT04239170. Registered on January 1, 2020.

HCMV modulates c-Mpl/IEX-1 pathway-mediated megakaryo/thrombopoiesis via PDGFRα and αvß3 receptors after allo-HSCT.

Thrombocytopenia is a common complication of human cytomegalovirus (HCMV) infection in immunocompromised hosts, which contributes to poor prognosis even in patients receiving antiviral treatment. Here, we investigated the megakaryo/thrombopoiesis process, including the involvement of the c-Mpl/IEX-1 pathway, after HCMV infection, identified receptors mediating the interaction between megakaryocytes (MKs) and HCMV, and explored novel therapeutic targets. Our data shows that HCMV directly infects megakaryocytes in patients with HCMV DNAemia and influences megakaryopoiesis via the c-Mpl/IEX-1 pathway throughout megakaryocyte maturation, apoptosis, and platelet generation in vivo and in vitro. After treatment with inhibitors of PDGFRα and αvß3, the HCMV infection rate in MKs was significantly reduced, suggesting that IMC-3G3 and anti-αvß3 are potential therapeutic alternatives for viral infection. In summary, our study proposes a possible mechanism and potential treatments for thrombocytopenia caused by HCMV infection and other viral diseases associated with abnormal hemostasis.

Distribution of chimeric antigen receptor-modified T cells against CD19 in B-cell malignancies.

BACKGROUND: The unprecedented efficacy of chimeric antigen receptor T (CAR-T) cell immunotherapy of CD19+ B-cell malignancies has opened a new and useful way for the treatment of malignant tumors. Nonetheless, there are still formidable challenges in the field of CAR-T cell therapy, such as the biodistribution of CAR-T cells in vivo. METHODS: NALM-6, a human B-cell acute lymphoblastic leukemia (B-ALL) cell line, was used as target cells. CAR-T cells were injected into a mice model with or without target cells. Then we measured the distribution of CAR-T cells in mice. In addition, an exploratory clinical trial was conducted in 13 r/r B-cell non-Hodgkin lymphoma (B-NHL) patients, who received CAR-T cell infusion. The dynamic changes in patient blood parameters over time after infusion were detected by qPCR and flow cytometry. RESULTS: CAR-T cells still proliferated over time after being infused into the mice without target cells within 2 weeks. However, CAR-T cells did not increase significantly in the presence of target cells within 2 weeks after infusion, but expanded at week 6. In the clinical trial, we found that CAR-T cells peaked at 7-21 days after infusion and lasted for 420 days in peripheral blood of patients. Simultaneously, mild side effects were observed, which could be effectively controlled within 2 months in these patients. CONCLUSIONS: CAR-T cells can expand themselves with or without target cells in mice, and persist for a long time in NHL patients without serious side effects. TRIAL REGISTRATION: The registration date of the clinical trial is May 17, 2018 and the trial registration numbers is NCT03528421 .

Mesenchymal stem cell deficiency influences megakaryocytopoiesis through the TNFAIP3/NF-κB/SMAD pathway in patients with immune thrombocytopenia.

Immune thrombocytopenia (ITP) is an autoimmune disease. Mesenchymal stem cells (MSCs) play important roles in the physiology and homeostasis of the haematopoietic system, including supporting megakaryocytic differentiation from CD34+ haematopoietic progenitor cells. Tumour necrosis factor alpha-induced protein 3 (TNFAIP3, also termed A20) plays a key role in terminating NF-κB signalling. Human genetic studies showed that the polymorphisms of the TNFAIP3 gene may contribute to ITP susceptibility. In this study, we showed a significant decrease in TNFAIP3 and increase in NF-κB/SMAD7 in ITP-MSCs. In co-cultures with CD34+ cells, NF-κB was overexpressed in MSCs from healthy controls (HC-MSCs) after transfection with NFKBIA (IκB)-specific short hairpin (sh)RNAs, resulting in MSC deficiency and a reduction in megakaryocytic differentiation and thrombopoiesis. Knockdown of TNFAIP3 expression using TNFAIP3-specific shRNAs in HC-MSCs affected megakaryocytopoiesis. However, IKBKB knockdown corrected megakaryocytopoiesis inhibition in the ITP-MSCs by decreasing NF-κB expression. Amplified TNFAIP3 expression in ITP-MSCs by TNFAIP3 cDNA can facilitate megakaryocyte differentiation. shRNA-mediated knockdown of SMAD7 expression rescued the impaired MSC function in ITP patients. Therefore, we demonstrate that a pathological reduction in TNFAIP3 levels induced NF-κB/SMAD7 pathway activation, causing a deficiency in MSCs in ITP patients. The ability of ITP-MSCs to support megakaryocytic differentiation and thrombopoiesis of CD34+ cells was impaired.

Helicobacter pylori infection influences the severity of thrombocytopenia and its treatment response in chronic hepatitis B patients with compensatory cirrhosis: A multicenter, observational study.

The role of Helicobacter pylori (H. pylori) infection on thrombocytopenia in chronic hepatitis B (CHB) related compensatory cirrhotic patients is unknown. We conducted an observational study to determine whether H. pylori plays a role in these patients. A total of 255 patients from three centers in China were enrolled in the study. All patients received nucleoside analogs (NA) therapy and were screened for H. pylori infection. Patients were divided into three groups based on their H. pylori infection status and the therapy administered: patients without H. pylori infection who received NA therapy alone (N = 146); patients with H. pylori infection who received NA therapy alone (n = 48); and patients with H. pylori infection who received H. pylori eradication combined with NA therapy (N = 61). We observed that in CHB compensatory cirrhotic patients with H. pylori infection, the platelets count was significantly lower relative to uninfected patients (31 versus 60 × 10(9)/L, p < 0.01). During a 2-year follow-up, the elevation in platelet count was significantly higher in HBV/H. pylori co-infected patients who received the NA and H. pylori eradication treatment compared to the other two groups (p < 0.01). It suggested that H. pylori infection and eradication treatment combined with NA were independent risk factors associated with platelets response during treatment of thrombocytopenia in CHB compensatory cirrhosis (p < 0.01). In conclusion, H. pylori infection may associate with thrombocytopenia in CHB compensatory cirrhosis. H. pylori eradication combined with NA treatment may prove to be beneficial to CHB compensatory cirrhotic patients with thrombocytopenia who are infected with H. pylori.

Reduced IL-35 levels are associated with increased platelet aggregation and activation in patients with acute graft-versus-host disease after allogeneic hematopoietic stem cell transplantation.

Acute graft-versus-host disease (aGVHD) is a major complication associated with allogeneic hematopoietic stem cell transplantation (allo-HSCT). Interleukin (IL)-35 is a novel anti-inflammatory cytokine that suppresses the immune response. This prospective study explored IL-35 plasma levels in 65 patients after HSCT. The results revealed that the peripheral blood of patients with grades III-IV aGVHD (23.46 ng/ml) had reduced IL-35 compared to transplanted patients with grades I-II aGVHD (40.26 ng/ml, p < 0.01) or patients without aGVHD (41.40 ng/ml, p < 0.05). Allografts, including granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cell (PBPC) and G-CSF-primed bone marrow (GBM), from 38 patients were analyzed for IL-35 levels with respect to aGVHD. The patients who received lower levels of IL-35 cells in the GBM (28.0 ng/ml, p = 0.551) or lower levels of IL-35 in PBPC (53.46 ng/ml, p = 0.03) exhibited a higher incidence of aGVHD. Patients with aGVHD have increased platelet aggregation. IL-35 was added to patient blood in vitro, and platelet aggregation was inhibited by IL-35 in a dose-dependent manner. The markers of platelet activation (CD62P/PAC-1) can also be inhibited by IL-35. The results indicate that IL-35 may affect the development of aGVHD by inhibiting platelet activation and aggregation. Our data suggests that IL-35 represents a potentially effective therapeutic agent against aGVHD after allo-HSCT.

Management and clinical outcomes of follicular lymphoma across continuous lines of treatments: a retrospective analysis in China.

Background: Follicular lymphoma (FL) is characterized by an incurable course that frequently necessitates multiple lines of treatment. While a range of new approaches have broadened therapeutic options for patients in later lines, data regarding treatment patterns and outcomes of Chinese patients with relapsed/refractory(R/R) FL was scarcely reported. Methods: This retrospective single-center study included patients diagnosed with FL grades 1-3a at our institution between January 2002 and December 2019. Endpoints of interest were analyzed according to lines and types of interventions. The endpoints mainly included overall response rate (ORR), progression-free survival (PFS), and overall survival (OS). Results: The study enrolled 566 biopsy-proven patients. Among them, 544 patients initiated the first line of treatment, followed by 240 initiating the second line, 146 initiating the third line, 88 initiating the fourth line, 47 initiating the fifth line, and 28 initiating the sixth line. In terms of treatment patterns, anti-CD20 chemotherapy was a major modality in the first and second lines. However, for patients in the third line and subsequent lines, treatment approaches were diverse, and participation in clinical trials for new medications was common, which correlated with a survival benefit. The study also revealed that clinical indicators (such as ORR, PFS, and OS) gradually decreased with each subsequent line of treatment. The ORR at the first line was 86.6%, but decreased to 48.6% at the third line and 40.4% at the sixth line, respectively. Similarly, median OS and PFS decreased to 88.8 and 7.1 months at the third line and further reduced to 21.7 and 2.8 months at the sixth line, respectively. A total of 133 patients developed progression within 24 months from the initiation of first line anti-CD20 chemotherapy (POD24), and these patients exhibited poorer response rates and outcomes in subsequent lines of therapycompared to the non-POD24 group. Conclusion: This study revealed the clinical routine practices and prognosis of R/R FL patients within the Chinese population. It underscored the unmet need for optimal strategies to improve survival and also served as a benchmark for future trials.

Efficacy and safety of relmacabtagene autoleucel, an anti-CD19 chimeric antigen receptor T cell, in relapsed/refractory B-cell non-Hodgkin's lymphoma: 2-year results of a phase 1 trial.

This study reported 2-year efficacy and safety of relma-cel in Chinese patients with relapsed/refractory (R/R) B-cell non-Hodgkin's lymphoma (B-NHL). In this phase 1 dose-escalating trial, patients received lymphodepleting chemotherapy for 3 days, followed by relma-cel as a single infusion in escalating dose levels (25 × 106, 50 × 106, 100 × 106, and 150 × 106 CAR-T cells). The endpoints included best objective response rate (ORR), best complete response rate (CRR), duration of response (DOR), progression-free survival (PFS), overall survival (OS), and safety. A total of 23 patients were enrolled, including 60.9% with diffuse large B-cell lymphoma and 26.1% with follicular lymphoma. Twenty patients were evaluable for efficacy, and the best ORR was 85.0% and the best CRR was 75.0%. With a median follow-up of 24.2 months, 6 patients died and 2 had progressive disease, the median DOR, PFS, and OS were all not reached. The 2-year PFS and OS rates were 60.0% and 70.0%, respectively. Any grade and grade ≥ 2 cytokine release syndrome occurred in 18.2% and 13.6% of patients, respectively. Only 1(4.5%) patient had grade 3 CRS lasting 13 days, which was resolved by tocilizumab. No grade ≥ 2 neurotoxicity events or treatment-related deaths occurred. Patients with R/R B-NHL treated with relma-cel achieved durable response with favorable safety profile.

Autologous hematopoietic stem cell transplantation with inadequate stem cell dose in patients with non-Hodgkin lymphoma.

Little is known regarding the outcome of lymphoma patients undergoing autologous hematopoietic stem cell transplantation (AHSCT) using inadequate hematopoietic stem cell (HSC) doses. Fifty-six patients were enrolled in the study, and the cohort was subdivided into two groups according to the infusion dose: < 1 × 106/kg (poor HSC group) and 1-2 × 106/kg (unfavorable HSC group). Compared with the unfavorable group, the poor HSC group had a longer median time to neutrophil (13 vs. 11 days, p = .007) and platelet engraftment (17 vs. 13 days, p = .024). CD34+ cell infusion dose of < 1 × 106/kg was the only risk factor for neutrophil and platelet engraftment. The expected 3-year progression-free survival and overall survival rates for the whole cohort were 53% and 66%, and no statistical difference was observed between two groups. In conclusion, inadequate HSC infusion dose did not negatively impact AHSCT patient survival but significantly prolonged the time to hematopoietic engraftment.

The Synergistic Anti-Tumor Activity of EZH2 Inhibitor SHR2554 and HDAC Inhibitor Chidamide through ORC1 Reduction of DNA Replication Process in Diffuse Large B Cell Lymphoma.

BACKGROUND: Upregulation of H3K27me3 induced by EZH2 overexpression or somatic heterozygous mutations were implicated in lymphomagenesis. It has been demonstrated that several EZH2-target agents have notable therapeutic effects in EZH2-mutant B-cell lymphoma patients. Here we present a novel highly selective EZH2 inhibitor SHR2554 and possible combination strategy in diffuse large B-cell lymphoma (DLBCL). METHODS: Cell proliferation, cell cycle and apoptosis were analyzed by CellTiter-Glo Luminescent Cell Viability Assay and flow cytometry. Western Blot was used to detect the expression of related proteins. The gene expression profiling post combination treatment was analyzed by RNA-Seq. Finally, CDX and PDX models were used to evaluate the synergistic anti-tumor effects of the combination treatment in vivo. RESULTS: The novel EZH2 inhibitor SHR2554 inhibited proliferation and induced G1 phase arrest in EZH2-mutant DLBCL cell lines. The combination of EZH2 inhibitor SHR2554 with histone deacetylase (HDAC) inhibitor chidamide (hereafter referred to as HBI8000) exerted synergistic anti-proliferative activity in vitro and in vivo. Gene expression profile analysis revealed dramatic inhibition of the DNA replication process in combined treatment. CONCLUSIONS: SHR2554, a potent, highly selective small molecule inhibitor of EZH2, inhibited EZH2-mutant DLBCL more significantly in vitro and in vivo. The combination of HDAC inhibitor HBI8000 with EZH2 inhibitor SHR2554 exhibited dramatic anti-tumor activity in both mutant and wild-type DLBCL, which may become a potential therapeutic modality for the treatment of DLBCL patients.

Improving survival of 3760 patients with lymphoma: Experience of an academic center over two decades.

BACKGROUND: The treatment outcomes and prognosis of lymphoma are affected by various factors such as hospital types. This study was to describe the temporal trend in the survival of lymphoma in an academic center in China. METHODS: A total of 3840 consecutive patients with lymphoma diagnosed between 1996 and 2015 were reviewed. Eighty patients were excluded, and finally, 3760 patients were analyzed in this study. The cohort was divided into four groups according to calendar periods at diagnosis: 1996-2000, 2001-2005, 2006-2010, and 2010-2015. The overall survival (OS) rates among the four groups were compared. RESULTS: The 5- and 10-year OS for the whole cohort were 62% and 52%, respectively. The 5-year OS of patient with classic Hodgkin lymphoma (cHL), mature B-cell lymphoma (BCL), and peripheral T-cell lymphoma (PTCL) were 79%, 63%, and 50%, respectively. Among mature BCL, the 5-year OS was highest in follicular lymphoma (77.8%), followed by Burkitt lymphoma (76.5%), marginal zone lymphoma (74.1%), diffuse large B-cell lymphoma (61.5%), small lymphocytic lymphoma/chronic lymphocytic leukemia (55.1%), and mantle cell lymphoma (44.3%). Among PTCL, the 5-year OS was highest in ALK+anaplastic large cell lymphoma (79.0%), followed by ALK-anaplastic large cell lymphoma (63.1%), natural killer/T-cell lymphoma (57.7%), angioimmunoblastic T-cell lymphoma (34.9%, and peripheral T-cell lymphoma not otherwise specified (27.6%). Significant improvement in the survival of lymphoma was observed, with the 5-year OS increasing from 48% in 1996-2000 to 65% in 2011-2015 (P < .001). The 5-year OS of patients with cHL, mature BCL, and PTCL changed from 55%, 49%, and 41% in 1996-2000 to 79%, 65%, and 51% in 2011-2015, respectively (P values were .014, .002, and .592, respectively). CONCLUSION: The survival of most types of lymphoma such as cHL and mature BCL, rather than PTCL, was improved significantly during the past two decades.

Dysregulated megakaryocyte distribution associated with nestin+ mesenchymal stem cells in immune thrombocytopenia.

Impaired megakaryocyte (MK) maturation and reduced platelet production are important causes of immune thrombocytopenia (ITP). However, MK distribution and bone marrow (BM) niche alteration in ITP are unclear. To investigate the maturation and distribution of MKs in the BM niche and examine the components of BM niche regulation of MK migration, BM and peripheral blood were obtained from 30 ITP patients and 28 healthy donors. Nestin+ mesenchymal stem cells (MSCs) and CD41+ MKs were sorted by fluorescence-activated cell sorting. The components of the BM niche and related signaling were analyzed via immunofluorescence, flow cytometry, enzyme-linked immunosorbent assay, reverse transcription polymerase chain reaction, and western blot analysis. The number of MKs in the BM vascular niche was reduced in ITP. Moreover, the concentrations of CXCL12 and CXCR4+ MKs in the BM were decreased in ITP. Further investigation demonstrated that nestin+ MSCs and CXCL12 messenger RNA (mRNA) in nestin+ MSCs were both reduced whereas the apoptosis of nestin+ MSCs was significantly increased in ITP. Sympathetic nerves, Schwann cells, the proportion of ß3-adrenoreceptor (ß3-AR)+ nestin+ MSCs, and ß3-AR mRNA in nestin+ MSCs were all markedly reduced in ITP. Moreover, matrix metalloproteinase 9, vascular endothelial growth factor (VEGF), and VEGF receptor 1 were significantly reduced in ITP. Our data show that impaired MK distribution mediated by an abnormal CXCL12/CXCR4 axis is partially involved in reduced platelet production in ITP. Moreover, sympathetic neuropathy and nestin+ MSC apoptosis may have an effect on the alterations of BM CXCL12 in ITP.

Oral all-trans retinoic acid plus danazol versus danazol as second-line treatment in adults with primary immune thrombocytopenia: a multicentre, randomised, open-label, phase 2 trial.

BACKGROUND: Primary immune thrombocytopenia is a severe bleeding disorder. About 50-85% of patients achieve initial remission from first-line therapies, but optimal second-line treatment remains a challenge. All-trans retinoic acid (ATRA) has an immunomodulatory effect on haemopoiesis, making it a possible treatment option. We aimed to evaluate the efficacy and safety of ATRA plus danazol versus danazol in non-splenectomised patients with corticosteroid-resistant or relapsed primary immune thrombocytopenia. METHODS: We did a multicentre, randomised, open-label, phase 2 study of adult patients (≥18 years) with primary immune thrombocytopenia from five different tertiary medical centres in China. Those eligible were non-splenectomised, resistant to corticosteroid treatment or relapsed, and had a platelet count less than 30 × 109 per L. Masked statisticians used simple randomisation to assign patients (1:1) to receive oral ATRA (10 mg twice daily) plus oral danazol (200 mg twice daily) or oral danazol monotherapy (200 mg twice daily) for 16 weeks. Neither clinicians nor patients were masked to group assignments. All patients were assessed every week during the first 8 weeks of treatment, and at 2-week intervals thereafter. The primary endpoint was 12-month sustained response defined as platelet count of 30 × 109 per L or more and at least a doubling of baseline platelet count (partial response), or a platelet count of 100 × 109 per L or more (complete response) and the absence of bleeding without rescue medication at the 12-month follow-up. All randomly allocated patients, except for those who withdrew consent, were included in the modified intention-to-treat population and efficacy assessment, and all patients who received at least one dose of the study agents were included in the safety analysis. Study enrolment was stopped early because the trial results crossed the interim analysis efficacy boundary for sustained response. This trial is registered with ClinicalTrials.gov, number NCT01667263. FINDINGS: From June 1, 2012, to July 1, 2016, we screened 130 patients for eligibility; 34 were excluded and 96 were randomly assigned. 93 patients were included in the modified intention-to-treat analysis: 45 in the ATRA plus danazol group and 48 in the danazol group. At the 12-month follow-up, sustained response was achieved more frequently in patients receiving ATRA plus danazol than in those receiving danazol monotherapy (28 [62%] of 45 vs 12 [25%] of 48; odds ratio 4·94, 95% CI 2·03-12·02, p=0·00037). Only two grade 3 adverse events were reported: one (2%) patient receiving ATRA plus danazol with dry skin, and one (2%) patient receiving danazol monotherapy with liver injury. There was no grade 4 or worse adverse event or treatment-related death in either group. INTERPRETATION: Patients with primary immune thrombocytopenia given ATRA plus danazol had a rapid and sustained response compared with danazol monotherapy. This finding suggests that ATRA represents a promising candidate for patients with corticosteroid-resistant or relapsed primary immune thrombocytopenia. FUNDING: National Natural Science Foundation of China, Beijing Natural Science Foundation, Beijing Municipal Science and Technology Commission, and the National Key Research and Development Program of China.

Impaired Function of Bone Marrow Mesenchymal Stem Cells from Immune Thrombocytopenia Patients in Inducing Regulatory Dendritic Cell Differentiation Through the Notch-1/Jagged-1 Signaling Pathway.

Immune thrombocytopenia (ITP) is an autoimmune disease in which dendritic cells (DCs) play a crucial role in the breakdown of self-tolerance. Studies have identified the function of mesenchymal stem cells (MSCs) in promoting the development of regulatory DCs (regDCs). Our previous work revealed that MSCs in ITP exerted senescence, apoptosis, and impaired immunosuppressive effects on T and B cells. However, it is unclear whether the effects of MSCs on regDC induction are altered in ITP. Our data demonstrated that MSCs in ITP were impaired in inhibiting CD1a+ DC and CD14+ DC differentiation from CD34+ hematopoietic progenitor cells (CD34+ HPCs). DCs differentiated with MSCs in ITP exhibited an increased expression of costimulatory molecules CD80/CD86 and secretion of proinflammatory interleukin-12 (IL-12). Accordingly, the tolerogenic characteristics were deficient in DCs induced by MSCs in ITP. DCs differentiated with MSCs in ITP exhibited an impaired ability to inhibit CD3+ T cell proliferation, to suppress T helper (Th)1 cell differentiation, and to induce anergic and regulatory T cells (Tregs). The expression of Notch signaling components was measured in MSCs in ITP. Reduced expression of the ligand Jagged-1, the receptor Notch-1 intracellular domain (NICD-1), and the target gene Hes-1 was identified in MSCs in ITP. The addition of biologically active Jagged-1 to CD34+ HPCs was observed to promote regDC differentiation. When cultured on Jagged-1-coated plates, MSCs in ITP showed an enhancement of the Notch-1 pathway activation, Jagged-1 expression, and the function in inducing regDCs. Pretreatment with all-trans retinoic acid (ATRA) was found to partially restore the capacity of MSCs in both ITP patients and healthy controls in inducing CD34+-derived regDCs. Our data elucidated that MSCs in ITP were impaired in inducing CD34+-regDCs, associated with the Notch-1/Jagged-1 signaling pathway. ATRA could partially correct the impairment of MSCs, suggesting that ATRA could serve as a potential therapeutic alternative for ITP.

Adipose-Derived Mesenchymal Stem Cells (ADSCs) With the Potential to Ameliorate Platelet Recovery, Enhance Megakaryopoiesis, and Inhibit Apoptosis of Bone Marrow Cells in a Mouse Model of Radiation-Induced Thrombocytopenia.

Substantial damage to the bone marrow can be caused by exposure to radiation, which can then develop into severe thrombocytopenia. In this study, we investigated the in vivo impact of adipose-derived mesenchymal stem cells (ADSCs) on megakaryopoiesis and platelet recovery in irradiated mice. Radiation markedly reduced peripheral blood counts. Recovery of both platelets and WBCs was better in the ADSC-treated group compared with the saline group and the fibroblast group 21 days after irradiation. A significant increase in the total CFU and MK-CFU after irradiation was observed in the ADSC group compared with the saline group and the fibroblast group. Further, the proportion of CD41(+) cells in the ADSC group was significantly higher than that in the saline group and the fibroblast group. ADSC treatment significantly improved the cellularity and decreased the apoptotic cells in the bone marrow while normal fibroblasts did not. Administration of ADSCs upregulated protein expression of phosphorylated Akt and Bcl-xL, whereas the expression of Bax, a protein related to apoptosis, was significantly lower in the ADSC group. In conclusion, this study suggests that ADSCs were capable of promoting platelet recovery, improving megakaryopoiesis, and inhibiting apoptosis of bone marrow cells in irradiated mice. The antiapoptotic effect of ADSCs is likely to be mediated via the PI3K/Akt pathway. These findings may provide a scientific basis for using ADSCs as a new therapy after irradiation.

Platelet-Derived Growth Factor-BB Protects Mesenchymal Stem Cells (MSCs) Derived From Immune Thrombocytopenia Patients Against Apoptosis and Senescence and Maintains MSC-Mediated Immunosuppression.

: Immune thrombocytopenia (ITP) is characterized by platelet destruction and megakaryocyte dysfunction. Mesenchymal stem cells (MSCs) from ITP patients (MSC-ITP) do not exhibit conventional proliferative abilities and thus exhibit defects in immunoregulation, suggesting that MSC impairment might be a mechanism involved in ITP. Platelet-derived growth factor (PDGF) improves growth and survival in various cell types. Moreover, PDGF promotes MSC proliferation. The aim of the present study was to analyze the effects of PDGF-BB on MSC-ITP. We showed that MSC-ITP expanded more slowly and appeared flattened and larger. MSC-ITP exhibited increased apoptosis and senescence compared with controls. Both the intrinsic and extrinsic pathways account for the enhanced apoptosis. P53 and p21 expression were upregulated in MSC-ITP, but inhibition of p53 with pifithrin-α markedly inhibited apoptosis and senescence. Furthermore, MSCs from ITP patients showed a lower capacity for inhibiting the proliferation of activated T cells inducing regulatory T cells (Tregs) and suppressing the synthesis of anti-glycoprotein (GP)IIb-IIIa antibodies. PDGF-BB treatment significantly decreased the expression of p53 and p21 and increased survivin expression in MSC-ITP. In addition, the apoptotic rate and number of senescent cells in ITP MSCs were reduced. Their impaired ability for inhibiting activated T cells, inducing Tregs, and suppressing the synthesis of anti-GPIIb-IIIa antibodies was restored after PDGF-BB treatment. In conclusion, we have demonstrated that PDGF-BB protects MSCs derived from ITP patients against apoptosis, senescence, and immunomodulatory defects. This protective effect of PDGF-BB is likely mediated via the p53/p21 pathway, thus potentially providing a new therapeutic approach for ITP. SIGNIFICANCE: Immune thrombocytopenia (ITP) is characterized by platelet destruction and megakaryocyte dysfunction. Platelet-derived growth factor (PDGF) improves growth and survival in various cell types and promotes mesenchymal stem cell (MSC) proliferation. PDGF-BB protects MSCs derived from ITP patients against apoptosis, senescence, and immunomodulatory defects. This protective effect of PDGF-BB is likely mediated via the p53/p21 pathway, thus potentially providing a new therapeutic approach for ITP.

High-dose corticosteroid associated with catheter-related thrombosis after allogeneic hematopoietic stem cell transplantation.

BACKGROUND: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients are at an increased risk of thrombotic complications, most of which are catheter-related and present a substantial challenge. The incidence of CRT varies considerably depending on clinical factors. However, the underlying pathogenesis and risk factors remain unclear. METHODS: We performed a retrospective nested case-control study in patients following allo-HSCT. Thrombotic episodes were diagnosed based on the clinical suspicion of the physician (pain, swelling, etc.) with subsequent CVC or PICC thrombosis confirmed via duplex ultrasound. Cases with CRT and controls were matched for time of HSCT, age at HSCT, donor source and type of insertion (CVCs or PICC). RESULTS: During the 8-year period, catheters were placed in 2896 patients, with a total of 40 patients (1.38%) developed CRT, among which 11 were associated with CVCs and 29 were associated with PICCs. The median duration from catheter insertion to thrombosis was 97days. Despite reports of an association between thrombosis and infection, central line-associated bloodstream infection was comparable between groups. No significant differences were noted in terms of primary disease, donor type, conditioning regimen or catheter type between the cases and controls. A multivariate regression analysis identified high-dose corticosteroids as independent risk factors for the development of CRT. CRT seems to negatively affect prognosis in allo-HSCT patients. CONCLUSION: In conclusion, we demonstrate that the use of high-dose corticosteroids is correlated with the onset of CRT. However, the efficacy and safety of thromboprophylaxis in this population require further investigation.

Increased prostacyclin levels inhibit the aggregation and activation of platelets via the PI3K-AKT pathway in prolonged isolated thrombocytopenia after allogeneic hematopoietic stem cell transplantation.

OBJECTIVES: The aim of this study was to investigate the role of prostacyclin (PGI2) in prolonged isolated thrombocytopenia (PT) following allogeneic hematopoietic stem cell transplantation (allo-HSCT) and the effect of PGI2 on the activation and aggregation of platelets in PT. METHODS: We enrolled 37 patients with PT and 36 controls following allo-HSCT in this study. Platelet aggregation and activation and PGI2 levels were measured. Endothelial progenitor cells (EPCs) from either PT or control patients were cultured ex vivo with serum from either PT or control patients. PGI2 secretions were then measured. PGI2 was added to the platelets ex vivo, and platelet aggregation and activation and PI3K/Akt phosphorylation were analyzed. RESULTS: A higher PGI2 level was observed in the PT patients. The activation and aggregation of platelets were significantly lower in the PT patients. EPCs from PT patients cultured in PT serum secreted higher levels of PGI2, and PGI2 inhibited platelet activation and aggregation in a concentration-dependent manner ex vivo. PI3K/Akt phosphorylation of platelets was regulated by PGI2 after allo-HSCT. Disease status, serum PGI2 level and platelet aggregation were independent risk factors in patients with PT after allo-HSCT. CONCLUSIONS: Higher PGI2 levels and lower platelet activation and aggregation occurred simultaneously in PT patients. PGI2 inhibited platelet activation and aggregation, probably by regulating the phosphorylation of PI3K/Akt.

[Pathogenesis and Prevention of Transfusion-Associated Graft-versus-Host Disease].

Transfusion-associated graft-versus-host disease (TA-GVHD) is a rare complication of blood transfusion. The disease is fulminant and fatal in most patients. TA-GVHD is caused by transfused alloreactive donor T lymphocytes that attack host tissue, including skin, liver, gastrointestinal tract and bone marrow. Most patients are immunocompromised, but immunocompetent patients can also be involved. Irradiation of blood components is generally recommended to prevent the onset of TA-GVHD for susceptible recipients. This review focus on pathogenesis and prevention of TA-GVHD.