Recent advances in understanding the pathophysiology of Wiskott-Aldrich syndrome

Blood ◽  
2009 ◽  
Vol 113 (25) ◽  
pp. 6288-6295 ◽  
Author(s):  
Marita Bosticardo ◽  
Francesco Marangoni ◽  
Alessandro Aiuti ◽  
Anna Villa ◽  
Maria Grazia Roncarolo
Keyword(s):  
Bone Marrow ◽  
Wide Spectrum ◽  
Clinical Manifestations ◽  
Cellular Mechanisms ◽  
Gene Encoding ◽  
Hematopoietic Stem ◽  
Wiskott Aldrich Syndrome ◽  
Alternative Therapeutic Approach ◽  
Unrelated Donors ◽  
Was Gene

Abstract Wiskott-Aldrich syndrome (WAS) is a severe X-linked immunodeficiency caused by mutations in the gene encoding for WASP, a key regulator of signaling and cytoskeletal reorganization in hematopoietic cells. Mutations in WASP result in a wide spectrum of clinical manifestations ranging from the relatively mild X-linked thrombocytopenia to the classic full-blown WAS phenotype characterized by thrombocytopenia, immunodeficiency, eczema, and high susceptibility to developing tumors and autoimmune manifestations. The life expectancy of patients affected by severe WAS is reduced, unless they are successfully cured by bone marrow transplantation from related identical or matched unrelated donors. Because many patients lack a compatible bone marrow donor, the administration of WAS gene–corrected autologous hematopoietic stem cells could represent an alternative therapeutic approach. In the present review, we focus on recent progress in understanding the molecular and cellular mechanisms contributing to the pathophysiology of WAS. Although molecular and cellular studies have extensively analyzed the mechanisms leading to defects in T, B, and dendritic cells, the basis of autoimmunity and thrombocytopenia still remains poorly understood. A full understanding of these mechanisms is still needed to further implement new therapeutic strategies for this peculiar immunodeficiency.

New insights into the biology of Wiskott-Aldrich syndrome (WAS)

Hematology ◽  
2009 ◽  
Vol 2009 (1) ◽  
pp. 132-138 ◽  
Author(s):  
Adrian J. Thrasher
Keyword(s):  
Actin Polymerization ◽  
Treatment Strategies ◽  
Molecular Defect ◽  
Somatic Gene Therapy ◽  
Cellular Mechanisms ◽  
Hematopoietic Stem ◽  
Wiskott Aldrich Syndrome ◽  
Somatic Gene ◽  
Immunodeficiency Disease ◽  
Was Gene

Abstract The Wiskott-Aldrich syndrome (WAS) is an X-linked immunodeficiency disease with a characteristic clinical phenotype that includes thrombocytopenia with small platelets, eczema, recurrent infections due to immunodeficiency, and an increased incidence of autoimmune manifestations and malignancies. The identification of the molecular defect in the WAS gene has broadened the clinical spectrum of disease to include chronic or intermittent X-linked thrombocytopenia (XLT), a relatively mild form of WAS, and X-linked neutropenia (XLN) due to an arrest of myelopoiesis. The pathophysiological mechanisms relate to defective actin polymerization in hematopoietic cells as a result of deficient or dysregulated activity of the WAS protein (WASp). The severity of disease is variable and somewhat predictable from genotype. Treatment strategies therefore range from conservative through to early definitive intervention by using allogeneic hematopoietic stem cell transplantation and potentially somatic gene therapy. All aspects of the condition from clinical presentation to molecular pathology and basic cellular mechanisms have been reviewed recently.

scholarly journals Conditioning with Fludarabine-Busulfan versus Busulfan-Cyclophosphamide Is Associated with Lower aGVHD and Higher Survival but More Extensive and Long Standing Bone Marrow Damage

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Xin He ◽  
YongBin Ye ◽  
XiaoJun Xu ◽  
Jing Wang ◽  
YuXian Huang ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bone Marrow Cells ◽  
Conditioning Regimen ◽  
Clinical Manifestations ◽  
Major Complication ◽  
Clinical Situation ◽  
Hematopoietic Stem ◽  
T Cell Infiltration ◽  
Bone Marrow Damage ◽  
The Impact

Acute graft-versus-host disease (aGVHD) is a major complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT) and a major cause of nonrelapse mortality after allo-HSCT. A conditioning regimen plays a pivotal role in the development of aGVHD. To provide a platform for studying aGVHD and evaluating the impact of different conditioning regimens, we established a murine aGVHD model that simulates the clinical situation and can be conditioned with Busulfan-Cyclophosphamide (Bu-Cy) and Fludarabine-Busulfan (Flu-Bu). In our study, BALB/c mice were conditioned with Bu-Cy or Flu-Bu and transplanted with 2×107 bone marrow cells and 2×107 splenocytes from either allogeneic (C57BL/6) or syngeneic (BALB/c) donors. The allogeneic recipients conditioned with Bu-Cy had shorter survivals (P<0.05), more severe clinical manifestations, and higher hepatic and intestinal pathology scores, associated with increased INF-γ expression and diminished IL-4 expression in serum, compared to allogeneic recipients conditioned with Flu-Bu. Moreover, higher donor-derived T-cell infiltration and severely impaired B-cell development were seen in the bone marrow of mice, exhibiting aGVHD and conditioned with Flu-Bu. Our study showed that the conditioning regimen with Bu-Cy resulted in more severe aGVHD while the Flu-Bu regimen was associated with more extensive and long standing bone marrow damage.

Evidence for Efficacy and Safety of Lentiviral Mediated Gene Transfer in T Cells and CD34+ Cells from Wiskott-Aldrich Syndrome Patients.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 3279-3279
Author(s):  
Samantha Scaramuzza ◽  
Sara Trifari ◽  
Francesco Marangoni ◽  
Silvana Martino ◽  
Ayse Metin ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
T Cells ◽  
Gene Transfer ◽  
Lentiviral Vector ◽  
Efficacy And Safety ◽  
Wiskott Aldrich Syndrome ◽  
Cd34 Cells ◽  
Was Gene

Abstract Wiskott-Aldrich Syndrome (WAS) is an X-linked primary immunodeficiency characterized by eczema, recurrent infections, severe hemorrhages and lymphomas. Transplantation of hematopoietic stem cells from HLA-identical sibling donors is a resolutive treatment, but it is available only for a minority of patients. Therapy based on the transplant of genetically correct autologous stem cells could represent a valid alternative approach. We investigated the efficacy and the safety of WAS gene transfer using HIV-based lentiviral vector encoding for WAS cDNA under the control of an autologous promoter (1.6 kb). T cells obtained from WAS patients showed normal level of WAS expression after lentiviral transduction. Transduced T cells showed a correction in TCR-driven proliferation and IL-2 production. Furthermore, a selective growth advantage of transduced T cells was observed in long-term in vitro cultures. Studies in T cell clones generated from transduced WAS CD4+ T cells revealed that 1–2 vector copies were necessary and sufficient to correct T cells function. CD34+ cells, isolated from mobilized peripheral blood and bone marrow of healthy donors, were transduced using WASP or GFP-encoding lentiviral vectors. Cells were cultured in the presence of different cytokines to investigate if WAS gene transfer could have any effect on short and long-term differentiation (CFU-C, LTC-IC and B/NK assays). Transduction resulted in a comparable number of CFU-C and LTC-IC colonies and normal B and NK cells differentiation with respect to untransduced cells. Furthermore, transduction of CD34+ cells isolated from the bone marrow of a WAS patient was performed under optimized culture conditions. Lentiviral gene transfer led to restoration of WASP expression in differentiated cells with copy number ranging from 1 to 5 copies per cell. In conclusion, our data demonstrate that the WAS promoter/cDNA-containing lentiviral vector can efficiently transduce and restore WASP expression in CD34+ cells and T cells from WAS patients. Experiments in the Rag2−/−/γchain- murine model are ongoing to test the efficacy and safety of the WASP transduced CD34+ cells. Together, our studies provide a preclinical basis for the implementation of a gene therapy trial for WAS patients.

Human Herpes Virus-6 and Clinical Manifestations After Allogeneic Hematopoietic Stem Cell Transplantation

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1960-1960
Author(s):  
Raffaella Greco ◽  
Francesca Lorentino ◽  
Daniela Clerici ◽  
Francesca Matteazzi ◽  
Alessandra Forcina ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Cerebrospinal Fluid ◽  
Stem Cell ◽  
Viral Load ◽  
Hematopoietic Stem Cell Transplantation ◽  
Clinical Manifestations ◽  
Median Viral Load ◽  
Hematopoietic Stem ◽  
Allogeneic Hsct ◽  
Clinical Complications

Abstract Abstract 1960 BACKGROUND: Human herpesvirus 6 (HHV-6) is increasingly recognized as an opportunistic and potentially life-threatening pathogen in recipients of allogeneic Hematopoietic Stem Cell Transplantation (HSCT). Reported clinical manifestations of HHV-6 infection in transplanted patients are skin rash, interstitial pneumonia, bone marrow suppression and encephalitis. Moreover, an increasing number of clinical reports suggest that HHV-6 can facilitate the occurrence of other severe clinical complications of allogeneic HSCT, including Graft-versus-Host Disease (GvHD), ultimately increasining transplant-related mortality. Still, the actual incidence of HHV-6 infection in recipients of HSCT and the causative link between infection and clinical complications remain elusive, mostly due to the small and heterogeneous patient cohorts analyzed to date. METHODS: From January 2009 to July 2011, we retrospectively evaluated 43 consecutive adult patients (median age 51 years) who developed positivity to HHV-6 after allogeneic HSCT for high-risk hematological malignancies. Stem cell donor was for 30 patients family haploidentical, for 5 an HLA identical sibling, and for 8 an unrelated volunteer (1 of which cord blood). The viral load was determined by quantitative PCR in cell-free body fluids such as plasma, bronchoalveolar lavage, cerebrospinal fluid, bone marrow aspirates or in gastrointestinal biopsies. At the time of positivity all patients were receiving acyclovir as viral prophylaxis except 5. Sixteen patients had clinical acute GvHD at time of HHV-6 positivity (grade III-IV in 14), and 33 were profoundly immunosuppressed with variable association of 2–4 immunosuppressive drugs (steroids included). Moreover concomitant CMV positivity was detected in 11 patients, while a severe neutropenia in 12. RESULTS: Median time from allogeneic HSCT to HHV-6 reactivation was 36 days (range: 7–625). In 19 patients HHV-6 was detected in plasma, with a median viral load of 19,454 cp/mL (34-4,524,600); 15 had concomitant fever, 5 skin rash of new onset, 4 impaired liver function, and 5 developed cytopenia subsequently to the infection. In 7 patients HHV-6 was detected in the bone marrow: the median viral load was 163'800 cp/mL (568-1'552'982). In 8 patients, all febrile, HHV-6 was observed in bronchoalveolar lavage samples with a median of 4'149 cp/mL (85–39250). In 16 patients, 10 with documented gut aGvHD, 11 with diarrhoea, HHV-6 was detected in gastrointestinal biopsies with a median of 7'510 cp/mL (120-4'524'600). HHV-6 was found in cerebrospinal fluid in 4 cases (all within 30 days after HSCT); the median viral load was 29'352 cp/mL (4'508-1'552'982); all these patients experienced encephalitis with confusion and anxiety, 2 suffered seizures and 3 showed abnormal findings on brain MRI. Amongst patients with organ localizations of HHV-6 only 28% had concomitant plasma positivity. HHV-6 positivity led to antiviral pharmacological treatment only when associated with clinical manifestations (n=21), using as first choice therapy foscarnet. Amongst the total 43 patients with documented HHV-6 positivity 11 completely solved the clinical event, whereas 19 (44%) died. CONCLUSIONS: HHV-6 infection/reactivation is associated with high morbidity and mortality in patients who undergo allogeneic HSCT. HHV-6 infection typically occurred close to the time of neutrophil engraftment. HSCT from an HLA-mismatched donor and steroid administration were associated with increased risk of active HHV-6 infection. Development of encephalitis was associated with high HHV-6 viral load. The regular monitoring of HHV-6 DNA in allogeneic HSCT recipients, using a real-time PCR assay, may be useful for identifying active HHV-6 infection and for the introduction of a pre-emptive treatment, possibly reducing the incidence of the most severe clinical complications. Disclosures: No relevant conflicts of interest to declare.

Two novel activating mutations in the Wiskott-Aldrich syndrome protein result in congenital neutropenia

Blood ◽  
2006 ◽  
Vol 108 (7) ◽  
pp. 2182-2189 ◽  
Author(s):  
Phil J. Ancliff ◽  
Michael P. Blundell ◽  
Giles O. Cory ◽  
Yolanda Calle ◽  
Austen Worth ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Bacterial Infections ◽  
Killer Cell ◽  
Significant Proportion ◽  
Congenital Neutropenia ◽  
Gene Encoding ◽  
Wiskott Aldrich Syndrome ◽  
Immunologic Function ◽  
Syndrome Protein

Abstract Severe congenital neutropenia (SCN) is characterized by neutropenia, recurrent bacterial infections, and maturation arrest in the bone marrow. Although many cases have mutations in the ELA2 gene encoding neutrophil elastase, a significant proportion remain undefined at a molecular level. A mutation (Leu270Pro) in the gene encoding the Wiskott-Aldrich syndrome protein (WASp) resulting in an X-linked SCN kindred has been reported. We therefore screened the WAS gene in 14 young SCN males with wild-type ELA2 and identified 2 with novel mutations, one who presented with myelodysplasia (Ile294Thr) and the other with classic SCN (Ser270Pro). Both patients had defects of immunologic function including a generalized reduction of lymphoid and natural killer cell numbers, reduced lymphocyte proliferation, and abrogated phagocyte activity. In vitro culture of bone marrow progenitors demonstrated a profound reduction in neutrophil production and increased levels of apoptosis, consistent with an intrinsic disturbance of normal myeloid differentiation as the cause of the neutropenia. Both mutations resulted in increased WASp activity and produced marked abnormalities of cytoskeletal structure and dynamics. Furthermore, these results also suggest a novel cause of myelodysplasia and that male children with myelodysplasia and disturbance of immunologic function should be screened for such mutations.

scholarly journals Paroxysmal Nocturnal Hemoglobinuria with a Distinct Molecular Signature Diagnosed Ten Years after Allogenic Bone Marrow Transplantation for Acute Myeloid Leukemia

2019 ◽  
Vol 2019 ◽  
pp. 1-3
Author(s):  
Alberto Santagostino ◽  
Laura Lombardi ◽  
Gerard Dine ◽  
Pierre Hirsch ◽  
Srimanta Chandra Misra
Keyword(s):  
Bone Marrow ◽  
Acute Myeloid Leukemia ◽  
Somatic Mutation ◽  
Myeloid Leukemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Clonal Selection ◽  
Bone Marrow Failure ◽  
Clinical Manifestations ◽  
Hematopoietic Stem ◽  
Acute Myeloid

Paroxysmal nocturnal hemoglobinurea (PNH) is a rare disorder of complement regulation due to somatic mutation of PIGA (phosphatidylinositol glycan anchor) gene. We herewith report a case who developed a symptomatic PNH long after an allogenic marrow transplant. Some reasonable arguments concerning the origin of PNH clone have been discussed. The molecular studies revealed presence of JAK2 and TET2 mutations without a BCOR mutation. The literature review has been performed to probe into the complex interplay of autoimmunity and clonal selection and expansion of PNH cells, which occurs early in hematopoietic differentiation. The consequent events such as hypoplastic and/or hemato-oncologic features could further be explained on the basis of next-generation sequencing (NGS) studies. Paroxysmal nocturnal hemoglobinuria (PNH) is a rare clonal disorder of hematopoietic stem cells, characterized by a somatic mutation of the phosphatidylinositol glycan-class A (PIGA). The PIGA gene products are crucial for biosynthesis of glycosylphosphatidylinositol (GPI) anchors, which attaches a number of proteins to the plasma membrane of the cell. Amongst these proteins, the CD55 and CD59 are complement regulatory proteins. The CD55 inhibits C3 convertase whereas the CD59 blocks the membrane attack complex (MAC) by inhibiting the incorporation of C9 to MAC. The loss of complement regulatory protein renders the red cell susceptible to complement-mediated lysis leading to intravascular and extravascular hemolysis. The intravascular hemolysis explains most of the morbid clinical manifestations of the disease. The clinical features of syndrome of PNH are recurrent hemolytic episodes, thrombosis, smooth muscle dystonia, and bone marrow failure; other important complications include renal failure, myelodysplastic syndrome (MDS), and acute myeloid leukemia (AML). The most used therapies were blood transfusions, immunosuppressive, and steroid. Allogeneic stem cell transplantation was also practiced. At present, the therapy of choice is eculizumab (Soliris, Alexion Pharmaceuticals), a humanized monoclonal antibody that blocks activation of the terminal complement at C5. The limiting factor for this therapy is breakthrough hemolysis and the frequent dosing schedule. Ravulizumab (ALXN1210) is the second generation terminal compliment inhibitor which seems to provide a sustained control of hemolysis without breakthrough hemolysis and with a longer dosing interval.

scholarly journals High expression of BCL6 inhibits the differentiation and development of hematopoietic stem cells and affects the growth and development of chickens

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Hongmei Li ◽  
Bowen Hu ◽  
Shang Hu ◽  
Wen Luo ◽  
Donglei Sun ◽  
...  
Keyword(s):  
Stem Cells ◽  
Bone Marrow ◽  
Hematopoietic Stem Cells ◽  
Mitochondrial Function ◽  
Growth And Development ◽  
Clinical Manifestations ◽  
High Expression ◽  
Ros Production ◽  
Hematopoietic Stem ◽  
Atp Concentration

Abstract Background B-cell CLL/lymphoma 6 (BCL6) is a transcriptional master regulator that represses more than 1200 potential target genes. Our previous study showed that a decline in blood production in runting and stunting syndrome (RSS) affected sex-linked dwarf (SLD) chickens compared to SLD chickens. However, the association between BCL6 gene and hematopoietic function remains unknown in chickens. Methods In this study, we used RSS affected SLD (RSS-SLD) chickens, SLD chickens and normal chickens as research object and overexpression of BCL6 in hematopoietic stem cells (HSCs), to investigate the effect of the BCL6 on differentiation and development of HSCs. Results The results showed that comparison of RSS-SLD chickens with SLD chickens, the BCL6 was highly expressed in RSS-SLD chickens bone marrow. The bone marrow of RSS-SLD chickens was exhausted and red bone marrow was largely replaced by yellow bone marrow, bone density was reduced, and the levels of immature erythrocytes in peripheral blood were increased. At the same time, the hematopoietic function of HSCs decreased in RSS-SLD chickens, which was manifested by a decrease in the hematopoietic growth factors (HGFs) EPO, SCF, TPO, and IL-3, as well as hemoglobin α1 and hemoglobin β expression. Moreover, mitochondrial function in the HSCs of RSS-SLD chickens was damaged, including an increase in ROS production, decrease in ATP concentration, and decrease in mitochondrial membrane potential (ΔΨm). The same results were also observed in SLD chickens compared with normal chickens; however, the symptoms were more serious in RSS-SLD chickens. Additionally, after overexpression of the BCL6 in primary HSCs, the secretion of HGFs (EPO, SCF, TPO and IL-3) was inhibited and the expression of hemoglobin α1 and hemoglobin β was decreased. However, cell proliferation was accelerated, apoptosis was inhibited, and the HSCs entered a cancerous state. The function of mitochondria was also abnormal, ROS production was decreased, and ATP concentration and ΔΨm were increased, which was related to the inhibition of apoptosis of stem cells. Conclusions Taken together, we conclude that the high expression of BCL6 inhibits the differentiation and development of HSCs by affecting mitochondrial function, resulting in impaired growth and development of chickens. Moreover, the abnormal expression of BCL6 might be a cause of the clinical manifestations of chicken comb, pale skin, stunted growth and development, and the tendency to appear RSS in SLD chickens.

scholarly journals Lentiviral Hematopoietic Stem Cell Gene Therapy in Patients with Wiskott-Aldrich Syndrome

Science ◽  
2013 ◽  
Vol 341 (6148) ◽  
pp. 1233151 ◽  
Author(s):  
Alessandro Aiuti ◽  
Luca Biasco ◽  
Samantha Scaramuzza ◽  
Francesca Ferrua ◽  
Maria Pia Cicalese ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Lentiviral Vector ◽  
Ex Vivo ◽  
Conditioning Regimen ◽  
Immune Functions ◽  
Gene Encoding ◽  
Hematopoietic Stem ◽  
Wiskott Aldrich Syndrome ◽  
Vector Integration ◽  
Lentiviral Gene Therapy

Wiskott-Aldrich syndrome (WAS) is an inherited immunodeficiency caused by mutations in the gene encoding WASP, a protein regulating the cytoskeleton. Hematopoietic stem/progenitor cell (HSPC) transplants can be curative, but, when matched donors are unavailable, infusion of autologous HSPCs modified ex vivo by gene therapy is an alternative approach. We used a lentiviral vector encoding functional WASP to genetically correct HSPCs from three WAS patients and reinfused the cells after a reduced-intensity conditioning regimen. All three patients showed stable engraftment of WASP-expressing cells and improvements in platelet counts, immune functions, and clinical scores. Vector integration analyses revealed highly polyclonal and multilineage haematopoiesis resulting from the gene-corrected HSPCs. Lentiviral gene therapy did not induce selection of integrations near oncogenes, and no aberrant clonal expansion was observed after 20 to 32 months. Although extended clinical observation is required to establish long-term safety, lentiviral gene therapy represents a promising treatment for WAS.

scholarly journals Comprehensive analysis on phenotype and genetic basis of Chinese Fanconi anemia patients: dismal outcomes call for nationwide studies

2020 ◽  
Author(s):  
Daijing Nie ◽  
Jing Zhang ◽  
Fang Wang ◽  
Wei Zhang ◽  
Lili Liu ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Fanconi Anemia ◽  
Genetic Basis ◽  
Bone Marrow Failure ◽  
Clinical Manifestations ◽  
Multicenter Studies ◽  
Hematopoietic Stem ◽  
Cytogenetic Abnormalities ◽  
Number Of Patients

Abstract Background: Fanconi anemia (FA) is the most common inherited bone marrow failure (BMF) syndrome with 22 related genes identified. The ALDH2 rs671variant has been proved related to accelerate the progression of BMF in FA patients. The phenotype and genetic basis of Chinese FA patients have not been investigated yet.Methods: We analyzed the 22 FA-related genes of 63 BMF patients suspected to be FA. Clinical manifestations, morphological and cytogenetic feathers, ALDH2 genotypes, treatment, and outcomes of the definite cases were retrospectively studied.Results: A total of 21 patients were confirmed the diagnosis of FA with the median age of BMF onset was 4-year-old. The number of patients manifested as congenital malformations and growth retardation were 20/21 and 14/21, respectively. BM dysplasia and cytogenetic abnormalities were found in 13/20 and 8/19 patients. All the patients with abnormal karyotypes also manifested as BM dysplasia or had evident blasts. Thirty-five different mutations were identified involving six genes and including twenty novel mutations. FANCA mutations contributed to 66.67% of cases. Eight patients harboring ALDH2-G/A genotype have a significantly younger age of BMF onset (p=0.025). Within the 19 patients adhering to continuous follow-up, 15 patients underwent hematopoietic stem cell transplantations (HSCTs). During the 29 months of follow-up, 8/19 patients died, seven of which were HSCT-related, and one patient who did not receive HSCT died from severe infection.Conclusions: The phenotypic and genetic spectrum of Chinese FA patients is broad. Bone marrow dysplasia and cytogenetic abnormalities are prevalent and highly consistent. The overall outcome of HSCTs is disappointing. Nationwide multicenter studies are needed for the rarity and adverse outcome of this disease.

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