Aldrich Syndrome Research Articles

Acute Myeloid Leukemia in a Patient with Wiskott Aldrich Syndrome: A Case Report

Acute Myeloid Leukemia in a Patient with Wiskott Aldrich Syndrome: A Case Report

Hematopoietic Stem Cell Transplantation for Primary Immunodeficiency Disorders: Experience from a Referral Center in India

To share experience of over 15 years in hematopoietic stem cell transplantation in children with primary immunodeficiency disorders. Medical record review. A referral center for pediatric hemato-oncological disorders. Children (<18 y) diagnosed to have primary immune deficiencies who underwent hematopoietic stem cell transplantation between 2002 and August 2017. Disease-free survival, morbidity and mortality. 85 primary immunodeficiency disorder transplants were performed with engraftment noted in 80 (94%) transplants and an overall survival of 67%. The conditioning regimen was individualized based on the underlying immune defect. Mixed chimerism was noted in 20% children with 56% (9/16) remaining disease-free. Graft versus host disease was noted in 33 (39.2%) children with most seen in children with chronic granulomatous disease. Severe combined immune deficiency transplants were mainly complicated by infections. Immune cytopenias complicated Wiskott Aldrich syndrome and Hemophagocytic lymphohistiocytosis transplants. 29.4% (25/85) children underwent haploidentical transplant in our cohort with a survival of 70% in this group. Infectious complications were the most common cause of death. Primary immunodeficiency disorders are curable in India when transplanted in centers with experienced and trained pediatric transplant physicians and intensivists.

The Wave2 scaffold Hem-1 is required for transition of fetal liver hematopoiesis to bone marrow

The transition of hematopoiesis from the fetal liver (FL) to the bone marrow (BM) is incompletely characterized. We demonstrate that the Wiskott–Aldrich syndrome verprolin-homologous protein (WAVE) complex 2 is required for this transition, as complex degradation via deletion of its scaffold Hem-1 causes the premature exhaustion of neonatal BM hematopoietic stem cells (HSCs). This exhaustion of BM HSC is due to the failure of BM engraftment of Hem-1−/− FL HSCs, causing early death. The Hem-1−/− FL HSC engraftment defect is not due to the lack of the canonical function of the WAVE2 complex, the regulation of actin polymerization, because FL HSCs from Hem-1−/− mice exhibit no defects in chemotaxis, BM homing, or adhesion. Rather, the failure of Hem-1−/− FL HSC engraftment in the marrow is due to the loss of c-Abl survival signaling from degradation of the WAVE2 complex. However, c-Abl activity is dispensable for the engraftment of adult BM HSCs into the BM. These findings reveal a novel function of the WAVE2 complex and define a mechanism for FL HSC fitness in the embryonic BM niche.

Discovering the Cause of Wiskott-Aldrich Syndrome and Laying the Foundation for Understanding Immune Cell Structuring.

The discovery of the Wiskott–Aldrich syndrome (WAS) protein gene ( WASP , now known as WAS ) by Derry et al. ([1][1]) in 1994 accelerated the field of immune cell biology and studies of the molecular basis of inborn human immune defects, otherwise known as primary immunodeficiencies (PIDs). It was

WASP-mediated regulation of anti-inflammatory macrophages is IL-10 dependent and is critical for intestinal homeostasis

Mutations in Wiskott–Aldrich syndrome protein (WASP) cause autoimmune sequelae including colitis. Yet, how WASP mediates mucosal homeostasis is not fully understood. Here we show that WASP-mediated regulation of anti-inflammatory macrophages is critical for mucosal homeostasis and immune tolerance. The generation and function of anti-inflammatory macrophages are defective in both human and mice in the absence of WASP. Expression of WASP specifically in macrophages, but not in dendritic cells, is critical for regulation of colitis development. Importantly, transfer of WT anti-inflammatory macrophages prevents the development of colitis. DOCK8-deficient macrophages phenocopy the altered macrophage properties associated with WASP deficiency. Mechanistically, we show that both WASP and DOCK8 regulates macrophage function by modulating IL-10-dependent STAT3 phosphorylation. Overall, our study indicates that anti-inflammatory macrophage function and mucosal immune tolerance require both WASP and DOCK8, and that IL-10 signalling modulates a WASP-DOCK8 complex.

Wash exhibits context-dependent phenotypes and, along with the WASH regulatory complex, regulates Drosophila oogenesis.

WASH, a Wiskott-Aldrich syndrome (WAS) family protein, has many cell and developmental roles related to its function as a branched actin nucleation factor. Similar to mammalian WASHC1, which is embryonic lethal, Drosophila Wash was found to be essential for oogenesis and larval development. Recently, however, Drosophila wash was reported to be homozygous viable. Here, we verify that the original wash null allele harbors an unrelated lethal background mutation; however, this unrelated lethal mutation does not contribute to any Wash oogenesis phenotypes. Significantly, we find that: (1) the homozygous wash null allele retains partial lethality, leading to non-Mendelian inheritance; (2) the allele's functions are subject to its specific genetic background; and (3) the homozygous stock rapidly accumulates modifications that allow it to become robust. Together, these results suggest that Wash plays an important role in oogenesis via the WASH regulatory complex. Finally, we show that another WAS family protein, SCAR/WAVE, plays a similar role in oogenesis and that it is upregulated as one of the modifications that allows the wash allele to survive in the homozygous state.

Dock8 regulates BCR signaling and activation of memory B cells via WASP and CD19

AbstractDock8 deficiency leads to immunodeficiency, and the role of Dock8 in B-cell development and function has been revealed; however, the role of DocK8 on B-cell receptor (BCR) signaling and function of memory B cells remains elusive. In this study, we generated a Dock8 knockout mouse model and collected peripheral blood mononuclear cells from Dock8 patients to study the effect of Dock8 deficiency on the BCR signaling and activation of memory B cells with confocal microscopy and total internal reflection fluorescence microscopy. The activation of key, positive upstream BCR signaling molecules, pCD19 and phosphorylated Brutons tyrosine kinase (pBtk), is reduced. Interestingly, the total protein and activated levels of Wiskott–Aldrich syndrome protein (WASP) are decreased in Dock8-deficient mouse B cells. Our previous research has shown that WASP positively regulates cd19 transcription; furthermore, we found that Dock8 regulates cd19 transcription. What we found in Dock8 patients can be a phenotype copied from Dock8 mice. The early activation of memory B cells from Dock8 patients is disrupted with reduced BCR clustering, B-cell spreading, and signalosome recruitment into the degree of naïve B cells, as well as the transition from naïve B cells to unswitched memory B cells. Overall, our study provides a novel mechanism for Dock8 regulation of BCR signaling by regulating cd19 transcription, as well as the underlying mechanism of noncompetence of memory B cells in Dock8 patients.

Mangiferin inhibits cell migration and invasion through Rac1/WAVE2 signalling in breast cancer.

Breast tumour progression results from the advancement of the disease to a metastatic phenotype. Rac1 and Cdc42 belong to the Rho family of genes that, together with their downstream effectors, Wiskott-Aldrich Syndrome protein-family verprolin-homologous protein 2 (WAVE2) and Arp2/3, assume a vital part in cytoskeletal rearrangement and the arrangement of film projections that advance malignant cell relocation and invasion. Mangiferin is a characteristic polyphenolic compound from Mangifera indica L. (Anacardiaceae), ordinarily referred to as mango, that is consumed worldwide as a natural product, including culinary and seasoning applications. Mangiferin delays breast malignancy development and progression by inhibiting different signalling pathways required in mitogenic signalling and metastatic progression. Studies were performed to analyse the impact of mangiferin on Rac1/WAVE2 flagging, relocation and invasion in highly metastatic human MDA-MB-231 mammary cells. Additional studies led to the observation that comparative treatment with mangiferin caused marked reduction in tumour cell movement and invasion. Taken together, these discoveries demonstrate that mangiferin treatment adequately hinders Rac1/WAVE2 flagging and diminishes metastatic phenotypic expression in malignant mammary cells, indicating that mangiferin may provide a benefit as a novel restorative approach in the treatment of metastatic breast cancer.

457 - Challenges of Haematopoietic Stem Cell Transplantation in Primary Immunodeficiency Disorders in a Developing Country

Hematopoietic stem cell transplant (HSCT) is required in a subset of patients with primary immunodeficiency disorders (PID). The diagnosis of PID is often delayed in a developing country, and active infections and delay in transplantation may lead to poorer outcomes in this setting. This is a retrospective analysis of allogeneic HSCTs carried out from January 1998 to August 2017 in patients with PID in a tertiary care centre in India. Thirty-two patients with a median age 36 months (Range 6 months to 18 years) underwent allogeneic HSCT. The two most common disorders were Wiskott Aldrich syndrome (n = 8) and severe combined immunodeficiency (n = 7). Six patients had active infection at the time of transplant (1 patient with tuberculosis, 2 with nocardiosis and tuberculosis, 1 patient with fungal pneumonia and 2 with skin/soft tissue infection). Haploidentical transplants were carried out in 12 (37.5%) patients, matched sibling donor (MSD) in 10 (31.2%), matched family donor (MFD) and matched unrelated donor (MUD) in 5 (15.6%) each. Stem cells were derived from peripheral blood in 19 (59.3%) patients, bone marrow in 12 (37.5%) and cord blood in one (3.1%). Median CD34+ cell dose infused was 10.4 × 106/kg. Conditioning regimes used were busulfan based in 9 (28.1%) patients and treosulfan based in 22 (68.8%). One patient did not receive conditioning. Six patients expired prior to engraftment due to infectious complications. Of the remaining patients, all except one engrafted. Grade 3-4 acute GVHD occurred in 8 (25%) patients. Bacterial, viral and fungal infections were noted in 22 (68.8%), 19 (59.3%) and 11 (34.3%) patients respectively in peri-transplant period. Seven (21.8%) patients had chronic GVHD. The 2 year OS and EFS in MSD was 88.9 ± 10.5%, with a significantly lower OS in MUD/MFD and Haplo-identical transplants, 33.3 ± 17.2% and 40.0 ± 14.6% respectively (P = .033), and EFS 33.3 ± 17.2% and 33.3 ± 13.6% respectively (P = .022) (Figure 1). Outcomes in matched sibling donor HSCT is comparable to data in the West, however there are significant challenges associated with haplo-identical transplants in the Indian setting, with a significant mortality secondary to infections.

Somatic mutations activating Wiskott-Aldrich syndrome protein concomitant with RAS pathway mutations in juvenile myelomonocytic leukemia patients.

The WAS gene product is expressed exclusively in the cytoplasm of hematopoietic cells and constitutional genetic abrogation of WASP leads to Wiskott-Aldrich syndrome (WAS). Moreover, mutational activation of WASP has been associated with X-linked neutropenia. Although studies reported that patients with constitutional WAS mutations affecting functional WASP expression may present juvenile myelomonocytic leukemia (JMML)-like features, confounding differential diagnosis above all in the copresence of mutated RAS, an activating somatic mutation of WASP has not been previously described in JMML patients. In our ongoing studies on JMML genomics, we at first detected a somatic WAS mutation in a major clone found at two consecutive relapses in one of two twins with JMML. Both twins were treated with hematopoietic stem cell transplantation after diagnosis of JMML. The somatic WAS mutation detected here displayed an activating WASP phenotype. Screening of 46 sporadic JMML patients at disease onset for mutations in the same PBD domain of WAS revealed two additional singleton patients carrying minor mutated clones. This is the first study to associate somatically acquired WASP mutations with a hematopoietic malignancy and increases insight in the complexity of the genomic landscape of JMML that shows low recurrent mutations concomitant with general hyperactivation of RAS pathway signaling.

Семейный случай легкого течения синдрома Вискотта–Олдрича

Wiskott–Aldrich syndrome (WAS) is a Х-linked combined immunodeficiency, characterized by thrombocytopenia, eczema, infections and predisposition to autoimmunity and tumors. The severity of the disease correlates with localization of the mutations in the WAS gene. In the most cases WAS is lethal during the first years of life, except of rare patients with the milder XLT. HSCT is a curative option for the majority of patients with WAS. In some cases conservative management is possible. This article presents a family case of the milder form of Wiskott–Aldrich syndrome.14 y.o. patient's condition is described in details.

Cobl-like promotes actin filament formation and dendritic branching using only a single WH2 domain.

Local actin filament formation powers the development of the signal-receiving arbor of neurons that underlies neuronal network formation. Yet, little is known about the molecules that drive these processes and may functionally connect them to the transient calcium pulses observed in restricted areas in the forming dendritic arbor. Here we demonstrate that Cordon-Bleu (Cobl)-like, an uncharacterized protein suggested to represent a very distantly related, evolutionary ancestor of the actin nucleator Cobl, despite having only a single G-actin-binding Wiskott-Aldrich syndrome protein Homology 2 (WH2) domain, massively promoted the formation of F-actin-rich membrane ruffles of COS-7 cells and of dendritic branches of neurons. Cobl-like hereby integrates WH2 domain functions with those of the F-actin-binding protein Abp1. Cobl-like-mediated dendritic branching is dependent on Abp1 as well as on Ca2+/calmodulin (CaM) signaling and CaM association. Calcium signaling leads to a promotion of complex formation with Cobl-like's cofactor Abp1. Thus, Ca2+/CaM control of actin dynamics seems to be a much more broadly used principle in cell biology than previously thought.

Diagnosis of platelet function disorders: A standardized, rational, and modular flow cytometric approach

A high proportion of patients with mucocutaneous bleeding diathesis and suspected inherited or acquired platelet disorder remain without diagnosis even after comprehensive laboratory testing. Since flow cytometry allows investigation of resting and activated platelets on the single cell level by requiring only minimal amounts of blood, this method has become an important assay within the diagnostic algorithm, especially in pediatrics. We therefore developed a standardized and modular flow cytometric approach that contributes to clarify impaired platelet function in a rational step-by-step manner.Due to simultaneous analysis of four fluorophores in a basic panel design, we are able to readily detect the most common and clinically significant platelet disorders: Glanzmann thrombasthenia or Glanzmann-like diseases (fibrinogen receptor GPIIb-IIIa), Bernard–Soulier syndrome (von Willebrand-factor receptor complex GPIb-IX-V) and less well characterized β1-integrins that serve as the collagen, laminin or fibronectin receptor (CD29-CD49b, e and f, respectively). Platelet reactivity was investigated in response to the agonists adenosine diphosphate (ADP) and thrombin receptor activator peptide 6 (TRAP6) in suboptimal and optimal concentrations by quantifying surface expression of activation markers CD62P and CD63 as well as binding of PAC-1 antibody to the high affinity conformation of the fibrinogen receptor. For advanced diagnostic questions, several further modules were implemented: (i) calcium mobilization for evaluation of early signal transduction, (ii) a kinetically resolved mepacrine assay for estimation of delta-granule content and release, and (iii) a module to determine platelet reactivity upon additional agonists like the thromboxane A2-analogue U46619 or collagen. Blood withdrawn from a healthy control cohort allowed generating preliminary standard values for all parameters. The modules were validated by analysis of patients with known or suspected platelet defects (leukocyte-adhesion deficiency type III, Wiskott–Aldrich syndrome, acute myeloid leukemia, sickle cell disease and chronic immune thrombocytopenia).

New Structural Insights into Formation of the Key Actin Regulating WIP-WASp Complex Determined by NMR and Molecular Imaging.

Wiskott-Aldrich syndrome protein (WASp) is exclusively expressed in hematopoietic cells and responsible for actin-dependent processes, including cellular activation, migration, and invasiveness. The C-terminal domain of WASp-Interacting Protein (WIP) binds to WASp and regulates its activity by shielding it from degradation in a phosphorylation dependent manner as we previously demonstrated. Mutations in the WAS-encoding gene lead to the primary immunodeficiencies Wiskott-Aldrich syndrome (WAS) and X-linked thrombocytopenia (XLT). Here, we shed a first structural light upon this function of WIP using nuclear magnetic resonance (NMR) and in vivo molecular imaging. Coexpression of fragments WASp(20-158) and WIP(442-492) allowed the purification and structural characterization of a natively folded complex, determined to form a characteristic pleckstrin homology domain with a mixed α/β-fold and central two-winged β-sheet. The WIP-derived peptide, unstructured in its free form, wraps around and interacts with WASp through short structural elements. Förster resonance energy transfer (FRET) and biochemical experiments demonstrated that, of these elements, WIP residues 454-456 are the major contributor to WASp affinity, and the previously overlooked residues 449-451 were found to have the largest effect upon WASp ubiquitylation and, presumably, degradation. Results obtained from this complementary combination of technologies link WIP-WASp affinity to protection from degradation. Our findings about the nature of WIP·WASp complex formation are relevant for ongoing efforts to understand hematopoietic cell behavior, paving the way for new therapeutic approaches to WAS and XLT.

Wiskott-Aldrich syndrome protein regulates autophagy and inflammasome activity in innate immune cells

Dysregulation of autophagy and inflammasome activity contributes to the development of auto-inflammatory diseases. Emerging evidence highlights the importance of the actin cytoskeleton in modulating inflammatory responses. Here we show that deficiency of Wiskott–Aldrich syndrome protein (WASp), which signals to the actin cytoskeleton, modulates autophagy and inflammasome function. In a model of sterile inflammation utilizing TLR4 ligation followed by ATP or nigericin treatment, inflammasome activation is enhanced in monocytes from WAS patients and in WAS-knockout mouse dendritic cells. In ex vivo models of enteropathogenic Escherichia coli and Shigella flexneri infection, WASp deficiency causes defective bacterial clearance, excessive inflammasome activation and host cell death that are associated with dysregulated septin cage-like formation, impaired autophagic p62/LC3 recruitment and defective formation of canonical autophagosomes. Taken together, we propose that dysregulation of autophagy and inflammasome activities contribute to the autoinflammatory manifestations of WAS, thereby identifying potential targets for therapeutic intervention.

Evaluation of Classic Wiskott Aldrich Syndrome with Mild Symptoms in Two Cousins: A Case Report

Introduction: Wiskott–Aldrich syndrome (WAS) is characterized by microthrombocytopenia, eczema, recurrent infections, and an increased incidence of autoimmunity. Commonly, classicWAS is presented with severe clinical symptoms. Case Presentation:We report a new phenotype of classic Wiskott–Aldrich syndrome with mild symptoms in two cousins who were 7 years old. They had not severe infections or hemorrhage, in spite of having genetic mutation in WAS gene. The symptoms and infections of the patients responded to treatment with IVIG and antibiotics. Conclusions: This report is presenting a novel clinical phenotype of classicWAS with milder symptoms.

BCR\u2013ABL1-induced downregulation of WASP in chronic myeloid leukemia involves epigenetic modification and contributes to malignancy

Chronic myeloid leukemia (CML) is a myeloproliferative disease caused by the BCR–ABL1 tyrosine kinase (TK). The development of TK inhibitors (TKIs) revolutionized the treatment of CML patients. However, TKIs are not effective to those at advanced phases when amplified BCR–ABL1 levels and increased genomic instability lead to secondary oncogenic modifications. Wiskott–Aldrich syndrome protein (WASP) is an important regulator of signaling transduction in hematopoietic cells and was shown to be an endogenous inhibitor of the c-ABL TK. Here, we show that the expression of WASP decreases with the progression of CML, inversely correlates with the expression of BCR–ABL1 and is particularly low in blast crisis. Enforced expression of BCR–ABL1 negatively regulates the expression of WASP. Decreased expression of WASP is partially due to DNA methylation of the proximal WASP promoter. Importantly, lower levels of WASP in CML advanced phase patients correlate with poorer overall survival (OS) and is associated with TKI response. Interestingly, enforced expression of WASP in BCR–ABL1-positive K562 cells increases the susceptibility to apoptosis induced by TRAIL or chemotherapeutic drugs and negatively modulates BCR–ABL1-induced tumorigenesis in vitro and in vivo. Taken together, our data reveal a novel molecular mechanism that operates in BCR–ABL1-induced tumorigenesis that can be used to develop new strategies to help TKI-resistant, CML patients in blast crisis (BC).

Wiskott-Aldrich syndrome protein: Emerging mechanisms in immunity.

The Wiskott-Aldrich syndrome protein (WASP) participates in innate and adaptive immunity through regulation of actin cytoskeleton-dependent cellular processes, including immune synapse formation, cell signaling, migration and cytokine release. There is also emerging evidence for a direct role in nuclear transcription programmes uncoupled from actin polymerization. A deeper understanding of some of the more complex features of Wiskott Aldrich syndrome (WAS) itself, such as the associated autoimmunity and inflammation, has come from identification of defects in the number and function of anti-inflammatory myeloid cells and regulatory T and B cells, as well as defects in positive and negative B-cell selection. In this review we outline the cellular defects that have been characterized in both human WAS patients and murine models of the disease. We will emphasize in particular recent discoveries that provide a mechanistic insight into disease pathology, including lymphoid and myeloid cell homeostasis, immune synapse assembly and immune cell signaling.

764P - Crucial relationship of neural wiskott aldrich syndrome protein(N-WASP) and lysyl oxidase-like 2(LOXL2) in the promotion of pancreatic cancer metastasis

764P - Crucial relationship of neural wiskott aldrich syndrome protein(N-WASP) and lysyl oxidase-like 2(LOXL2) in the promotion of pancreatic cancer metastasis

P84: COMBINED IMMUNODEFICIENCY DUE TO DEFICIENCY OF ACTINRELATED PROTEIN COMPLEX 1B (ARPC1B)

A number of cytoskeletal defects arising from perturbations in actin polymerisation and resulting in combined primary immunodeficiency (PID) have been described. Defects include Wiskott Aldrich Syndrome (WAS), WAS Interacting Protein (WIP) and Dedicator of Cytokinesis 8 (DOCK-8) deficiencies. A newly reported cytoskeletal defect is Actin-related Protein Complex 1B (ARPC1B) deficiency. Here we report the first Australian, youngest yet diagnosed, and 5th only reported case of ARPC1B deficiency. A female infant born to Nepalese parents presented with bloody diarrhoea and metabolic acidosis at 2 months of age. A diagnosis of cow’s milk enteritis was made and she was commenced on an elemental formula with resolution of the hematochezia and improvement in the diarrhoea. Subsequently she developed an eczematous rash which progressed to an erosive purpuric dermatitis with ulceration, and later took on a psoriasiform appearance. Skin biopsy showed a leucocytoclastic vasculitis. Her progress was complicated by cytomegalovirus infection, recurrent suppurative otitis media, twice by periorbital cellulitis, persistent oral candidiasis, urinary tract infection and failure to thrive. Investigations showed defective neutrophil chemotaxis and random migration, reduced Natural Killer cell cytotoxicity, decreased naïve T-cells, variable thrombocytopenia, eosinophilia, and raised IgA and IgE. Whole exome sequencing showed her to be homozygote for an exon 2 splice site mutation in ARPC1B (c.64+2T>A) which is predicted to cause loss of gene function. Western blot analysis showed low expression of the ARPC1B protein. ARPC1B is a regulatory subunit of the actin-related protein 2/3 complex critical for F-actin polymerisation in haemopoetic cells. Deficiency of ARPC1B results in defective actin polymerisation and a combined immunodeficiency similar but distinct to WAS.