Jinbo Huang

Intrinsic impairment of CD4+CD25+ regulatory T cells in acquired aplastic anemia

Acquired aplastic anemia (AA) is an immune-mediated bone marrow (BM) failure attacked by autoreactive effector T cells and BM is the main target organ. CD4(+)CD25(+) regulatory T cells (Tregs) were believed to control development and progression of autoimmunity by suppressing autoreactive effector T cells, but little was known regarding the function of Tregs in AA. Our study demonstrated that both peripheral blood (PB) and BM had decreased frequencies of Tregs, accompanied with a reversed lower ratio of Treg frequencies between BM and PB in AA. PB Tregs in AA had impaired migratory ability because of lower CXCR4 (but not for CXCR7) expression. Interestingly, we first showed that impairment of Treg-mediated immunosuppression was intrinsic to Tregs, rather than resistance of effector T cells to suppression in AA by coculture assays and criss-cross experiments in vitro. Furthermore, Tregs in AA were less able to inhibit interferon-γ production by effector T cells. Defective immunosuppression by Tregs could contribute to impaired hematopoiesis conducted by effector T cells in vitro. Our study provided powerful evidence that impairment of Tregs played a critical role in the pathophysiology of AA. Thus, patients with AA might greatly benefit from a Treg-oriented immunosuppressive strategy.

Outcomes of optimized over standard protocol of rabbit antithymocyte globulin for severe aplastic anemia: a single-center experience.

Background Previous reports showed that outcome of rabbit antithymocyte globulin (rATG) was not satisfactory as the first-line therapy for severe aplastic anemia (SAA). We explored a modifying schedule of administration of rATG. Design and Methods Outcomes of a cohort of 175 SAA patients, including 51 patients administered with standard protocol (3.55 mg/kg/d for 5 days) and 124 cases with optimized protocol (1.97 mg/kg/d for 9 days) of rATG plus cyclosporine (CSA), were analyzed retrospectively. Results Of all 175 patients, response rates at 3 and 6 months were 36.6% and 56.0%, respectively. 51 cases received standard protocol had poor responses at 3 (25.5%) and 6 months (41.2%). However, 124 patients received optimized protocol had better responses at 3 (41.1%, P = 0.14) and 6 (62.1%, P = 0.01). Higher incidences of infection (57.1% versus 37.9%, P = 0.02) and early mortality (17.9% versus 0.8%, P<0.001) occurred in patients received standard protocol compared with optimized protocol. The 5-year overall survival in favor of the optimized over standard rATG protocol (76.0% versus. 50.3%, P<0.001) was observed. By multivariate analysis, optimized protocol (RR = 2.21, P = 0.04), response at 3 months (RR = 10.31, P = 0.03) and shorter interval (<23 days) between diagnosis and initial dose of rATG (RR = 5.35, P = 0.002) were independent favorable predictors of overall survival. Conclusions Optimized instead of standard rATG protocol in combination with CSA remained efficacious as a first-line immunosuppressive regimen for SAA.

Mutations of ASXL1 and TET2 in aplastic anemia

Acquired aplastic anemia (AA), characterized by pancytopenia in peripheral blood (PB) and bone marrow (BM) hypoplasia, is a bone marrow failure syndrome. The late evolution to myelodysplastic syndromes (MDS)/acute myeloid leukemia (AML) is the most common clonal complication in refractory patients

The polymorphisms of human leukocyte antigen loci may contribute to the susceptibility and severity of severe aplastic anemia in Chinese patients.

The human leukocyte antigen (HLA) system has been reported to be involved in the development of aplastic anemia (AA). We compared and analyzed HLA-A, B, C, DRB1 and DQB1 alleles in 96 Chinese severe AA (SAA) patients to those in 600 healthy people chosen randomly from the China Marrow Donor Program to investigate the association of HLA class I and II allele polymorphisms with disposition of SAA and its severity degree in Chinese population. The DNA of patients was extracted and HLA high-resolution genotyping was conducted using polymerase chain reaction-sequence based typing technique. The gene frequencies of A(∗)02:01, A(∗)02:06, B(∗)13:01, DRB1(∗)07:01, DRB1(∗)09:01, DRB1(∗)15:01 and DQB1(∗)06:02 in SAA patients were significantly higher than in controls (all P<0.05), while the allelic frequencies of A(∗)02:07, A(∗)11:01 and B(∗)40:01 were notably lower in SAA patients than those in the controls (P = 0.001, 0.002, 0.005, respectively). Comparison among different severity of SAA groups exhibited significant increases of DRB1(∗)15:01 (P = 0.027) and DQB1(∗)06:02 (P = 0.013), but obviously lower frequencies of B(∗)46:01 (P = 0.023) and DRB1(∗)09:01 (P = 0.020) in non-VSAA patients than in VSAA patients. Thus, our results identified several risk and protective HLA alleles for Chinese SAA patients. Moreover, DRB1(∗)15:01, DQB1(∗)06:02, B(∗)46:01 and DRB1(∗)09:01 may be associated with severity of SAA.

Decreased expression of vitamin D receptor may contribute to the hyperimmune status of patients with acquired aplastic anemia

Acquired aplastic anemia (AA) is an immune‐mediated bone marrow failure syndrome. 1α,25‐Dihydroxyvitamin D3 [1,25(OH)2D3], the biologically active metabolite of vitamin D, is a critical modulator of immune response via binding with vitamin D receptor (VDR). Previous studies have established that 1,25(OH)2D3 and VDR were involved in the pathogenesis of some autoimmune diseases. In this study, we evaluated the involvement of 1,25(OH)2D3 and VDR on T‐cell responses in AA. Plasma 25(OH)D3 levels were comparable between patients with AA and healthy controls. Surprisingly, VDR mRNA was significantly lower in untreated patients with AA than in healthy controls. Subsequent in vitro experiments revealed that 1,25(OH)2D3 treatment suppressed the proliferation of lymphocytes and inhibited the secretion of interferon‐γ, tumor necrosis factor‐α, and interleukin‐17A, meanwhile promoting the production of transforming growth factor‐β1 in patients with AA. Moreover, 1,25(OH)2D3 inhibited the differentiation of type 1 and Th17 cells but induced the differentiation of type 2 and regulatory T cells. Interestingly, VDR mRNA was elevated in healthy controls after 1,25(OH)2D3 treatment, but not in patients with AA. In conclusion, decreased expression of VDR might contribute to the hyperimmune status of AA and appropriate vitamin D supplementation could partly correct the immune dysfunction by strengthening signal transduction through VDR in patients with AA.

CD106 is a novel mediator of bone marrow mesenchymal stem cells via NF-κB in the bone marrow failure of acquired aplastic anemia

BackgroundAcquired aplastic anemia (AA) is characterized by deficiency or dysfunction of the bone marrow (BM) microenvironment. However, little is known about the impairment of BM-derived mesenchymal stem cells (MSCs) in AA patients.MethodsWe used Illumina HiSeqTM 2000 sequencing, quantitative real-time polymerase chain reaction (qRT-PCR), flow cytometry (FCM), and Western blotting to test the expression of CD106 gene (vascular cell adhesion molecule 1 (VCAM1)) and CD106 protein of BM-MSCs. Furthermore, we used hematoxylin and eosin (H&E) and histochemical staining analysis, immunofluorescence, and the formation of capillary-like structures to analyze capillary tube-like formation in vitro; we also used the Matrigel plug assay to test in vivo vasculogenesis, and an assay of colony forming units (CFUs) and colony-forming unit-megakaryocyte (CFU-MK) to detect the support function of MSCs in vitro. The in vivo engraftment of CD34+ cells and MSCs in NOD/SCID mice was tested by FACS and survival assay; the expression of NF-κB was tested by NanoPro analysis and immunofluorescence. NF-κB-regulated CD106 gene (VCAM1) was confirmed by tumor necrosis factor alpha (TNF-α)-stimulated and lipopolysaccharide (LPS)-stimulated MSCs, blockade assay, and immunofluorescence.ResultsHere, we report that BM-MSCs from AA patients exhibited downregulation of the CD06 gene (VCAM1) and low expression of CD106 in vitro. Further analysis revealed that CD106+ MSCs from both AA patients and healthy controls had increased potential for in vitro capillary tube-like formation and in vivo vasculogenesis compared with CD106– MSCs, and the results were similar when healthy MSCs were compared with AA MSCs. CD106+ MSCs from both AA patients and healthy controls more strongly supported in vitro growth and in vivo engraftment of CD34+ cells in NOD/SCID mice than CD106– MSCs, and similar results were obtained when healthy MSCs and AA MSCs were compared. The expression of NF-κB was decreased in AA MSCs, and NF-κB regulated the CD106 gene (VCAM1) which supported hematopoiesis.ConclusionsThese results revealed the effect of CD106 and NF-κB in BM failure of AA.

A novel tri-allelic mutation of TMPRSS6 in iron-refractory iron deficiency anaemia with response to glucocorticoid.

Benjamin Chaigne Caroline Dartigeas Lotfi Benboubker Franc ois Chaumier Marjan Ertault S everine Lissandre Marion Stacoffe Franc ois Maillot H el ene Blasco Patrick Vourc’h Philippe Colombat Emmanuel Gyan Service d’h ematologie et th erapie cellulaire, Centre hospitalier universitaire de Tours, Service de m edecine interne, Centre hospitalier universitaire de Tours, UMR CNRS 7292, Universit e Franc ois Rabelais, and Service de biochimie et de biologie mol eculaire, Centre hospitalier universitaire de Tours, Tours, France E-mail: emmanuel.gyan@univ-tours.fr

Anti-inflammatory effects of interleukin-35 in acquired aplastic anemia

Interleukin (IL)-35 is a novel regulatory cytokine primarily produced by regulatory T cells. Accumulating evidence has established that IL-35 plays an important role in the regulation of immune homeostasis, but little is known regarding the function of IL-35 in acquired aplastic anemia (AA). The aim of the present study was to investigate the expression of IL-35 and its effects on T cell response in AA. Our study demonstrated that significantly decreased plasma levels of IL-35 in AA were closely correlated with disease severity. In vitro stimulation experiment further confirmed the anti-inflammatory effects of IL-35, including suppressing the proliferation of CD4(+) and CD8(+) effector T cells, inhibiting the secretion of interferon-γ, tumor necrosis factor-α and IL-17 and promoting the production of transforming growth factor-β by peripheral blood mononuclear cells from patients with AA. Furthermore, we established that IL-35 inhibited the differentiation of type 1 T cells and T helper 17 cells but promoted the differentiation of type 2 T cells. Accordingly, the expression of T-bet and RORγt was inhibited while the expression of GATA3 was induced after IL-35 treatment. In summary, our findings suggested that decreased IL-35 might contribute to the loss of immune-tolerance and be critically involved in the pathogenesis of AA.

Cyclosporine Combined with Levamisole for Lower-Risk Myelodysplastic Syndromes

Clinical and experimental evidence suggests an immune-mediated pathophysiology in subjects with lower-risk myelodysplastic syndromes (MDS) in whom immunosuppressive therapy may be effective. The novel immunosuppressive strategy of cyclosporine A (CsA) alternately combined with levamisole (LMS; CsA + LMS regimen) can dramatically improve the response rate and survival in aplastic anemia from those of our previous study. Herein, we retrospectively analyzed the data of 89 lower-risk MDS patients who received the CsA + LMS regimen. A total of 63 patients (70.8%) achieved either complete remission or hematological improvement at 4 months. Overall, 51, 41 and 19 patients had erythroid, platelet and neutrophil responses, respectively. Following the CsA + LMS regimen, 6 patients progressed to more advanced MDS at a median interval of 5 months (range, 3-42 months). The estimated 24-month progression-free survival was 82.2% (95% CI, 72.84-91.56) for all patients. Within the median follow-up of 18.5 months (range, 7.0-61.0), 6 patients died. In conclusion, the CsA + LMS regimen alleviated cytopenias and improved survival and freedom from evolution, suggesting that it could be reserved as an alternative choice for lower-risk MDS.

Cyclosporin combined with levamisole for refractory or relapsed severe aplastic anaemia

Institute, Nashville, TN, Division of Hematology and Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, MI, ARIAD Pharmaceuticals, Inc. Cambridge, MA, and Division of Cancer Medicine, Department of Leukemia, MD Anderson Cancer Center, Houston, TX, USA *Presentaddress: Division of Hematology and Hematologic Malignancies, University of Utah Huntsman Cancer Institute, Salt Lake City, UT, USA E-mail: nshah@medicine.ucsf.edu