RESUMO
Mutations in proteasome ß-subunits or their chaperone and regulatory proteins are associated with proteasome-associated autoinflammatory disorders (PRAAS). We studied six unrelated infants with three de novo heterozygous missense variants in PSMB10, encoding the proteasome ß2i-subunit. Individuals presented with T-B-NK± severe combined immunodeficiency (SCID) and clinical features suggestive of Omenn syndrome, including diarrhea, alopecia, and desquamating erythematous rash. Remaining T cells had limited T cell receptor repertoires, a skewed memory phenotype, and an elevated CD4/CD8 ratio. Bone marrow examination indicated severely impaired B cell maturation with limited V(D)J recombination. All infants received an allogeneic stem cell transplant and exhibited a variety of severe inflammatory complications thereafter, with 2 peri-transplant and 2 delayed deaths. The single long-term transplant survivor showed evidence for genetic rescue through revertant mosaicism overlapping the affected PSMB10 locus. The identified variants (c.166G>C [p.Asp56His] and c.601G>A/c.601G>C [p.Gly201Arg]) were predicted in silico to profoundly disrupt 20S immunoproteasome structure through impaired ß-ring/ß-ring interaction. Our identification of PSMB10 mutations as a cause of SCID-Omenn syndrome reinforces the connection between PRAAS-related diseases and SCID.
Assuntos
Imunodeficiência Combinada Severa , Lactente , Humanos , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/metabolismo , Complexo de Endopeptidases do Proteassoma/genética , Complexo de Endopeptidases do Proteassoma/metabolismo , Mutação/genética , Linfócitos T/metabolismo , Mutação de Sentido Incorreto/genéticaRESUMO
OBJECTIVES: Diagnosis of light chain amyloidosis (AL) requires demonstration of amyloid deposits in a tissue biopsy followed by appropriate typing. Previous studies demonstrated increased dimerization of monoclonal serum free light chains (FLCs) as a pathological feature of AL. To further examine the pathogenicity of FLC, we aimed at testing amino acid sequence homology between circulating and deposited light chains (LCs). METHODS: Matched tissue biopsy and serum of 10 AL patients were subjected to tissue proteomic amyloid typing and nephelometric FLC assay, respectively. Serum FLC monomers (M) and dimers (D) were analyzed by Western blotting (WB) and mass spectrometry (MS). RESULTS: WB of serum FLCs showed predominance of either κ or λ type, in agreement with the nephelometric assay data. Abnormal FLC M-D patterns typical of AL amyloidosis were demonstrated in 8 AL-λ patients and in one of two AL-κ patients: increased levels of monoclonal FLC dimers, high D/M ratio values of involved FLCs, and high ratios of involved to uninvolved dimeric FLCs. MS of serum FLC dimers showed predominant constant domain sequences, in concordance with the tissue proteomic amyloid typing. Most importantly, variable domain sequence homology between circulating and deposited LC species was demonstrated, mainly in AL-λ cases. CONCLUSIONS: This is the first study to demonstrate homology between circulating FLCs and tissue-deposited LCs in AL-λ amyloidosis. The applied methodology can facilitate studying the pathogenicity of circulating FLC dimers in AL amyloidosis. The study also highlights the potential of FLC monomer and dimer analysis as a non-invasive screening tool for this disease.
Assuntos
Amiloidose , Amiloidose de Cadeia Leve de Imunoglobulina , Humanos , Projetos Piloto , Homologia de Sequência de Aminoácidos , Proteômica , Amiloidose de Cadeia Leve de Imunoglobulina/diagnóstico , Cadeias Leves de Imunoglobulina , Amiloidose/diagnóstico , Proteínas Amiloidogênicas , Cadeias lambda de ImunoglobulinaRESUMO
BACKGROUND: Cardiac amyloidosis (CA) is characterized by the extracellular deposition of misfolded protein in the heart. Precise identification of the amyloid type is often challenging, but critical, since the treatment and prognosis depend on the disease form and the type of deposited amyloid. Coexistence of clinical conditions such as old age, monoclonal gammopathy, chronic inflammation, or peripheral neuropathy in a patient with cardiomyopathy creates a differential diagnosis between the major types of CA: amyloidosis light chains (AL), amyloidosis transthyretin (ATTR) and amyloidosis A (AA). OBJECTIVES: To demonstrate the utility of the Western blotting (WB)-based amyloid typing method in patients diagnosed with cardiac amyloidosis where the type of amyloid was not obvious based on the clinical context. METHODS: Congo red positive endomyocardial biopsy specimens were studied in patients where the type of amyloid was uncertain. Amyloid proteins were extracted and identified by WB. Mass spectrometry (MS) of the electrophoretically resolved protein-in-gel bands was used for confirmation of WB data. RESULTS: WB analysis allowed differentiation between AL, AA, and ATTR in cardiac biopsies based on specific immunoreactivity of the electrophoretically separated proteins and their characteristic molecular weight. The obtained results were confirmed by MS. CONCLUSIONS: WB-based amyloid typing method is cheaper and more readily available than the complex and expensive gold standard techniques such as MS analysis or immunoelectron microscopy. Notably, it is more sensitive and specific than the commonly used immunohistochemical techniques and may provide an accessible diagnostic service to patients with amyloidosis in Israel.
Assuntos
Neuropatias Amiloides Familiares , Amiloidose , Cardiomiopatias , Humanos , Amiloidose/diagnóstico , Amiloide/análise , Amiloide/metabolismo , Proteínas Amiloidogênicas , Cardiomiopatias/diagnóstico , Western Blotting , Neuropatias Amiloides Familiares/patologia , Pré-AlbuminaRESUMO
Increased susceptibility to develop severe forms of Epstein-Barr virus (EBV) infection in early age is a significant hallmark of an underlying primary immunodeficiency (PID). Here, we present immunologic and genetic evaluations of a 3-year-old child who was born to first-cousins parents and presented with recurrent infections, failure to thrive, and severe EBV-related infection and proliferation. A diagnosis of diffuse large B cell lymphoma was made and the immunological workup was suggestive of T cell immunodeficiency. Unfortunately, the patient succumbed to EBV-related lymphoma. Whole-exome sequencing revealed a novel homozygous mutation, c.991del.C; p. Q331Sfs*6 in the SLP76 gene. The SLP76 protein, a TCR signaling molecule, was recently linked to a human disease of the immune system. In order to examine the effect of this new SLP76 mutation on T cell signaling, a SLP76-deficient Jurkat-derived T cell line was transduced either with wild-type (WT), or with the specific SLP76 mutant, or with a mock vector. Downstream TCR signaling events, including ERK1/2 phosphorylation, CD69 expression, and Ca2 + mobilization, were reduced in cells harboring the reported mutation, linking this novel mutation to the expected immunological outcome. SLP76 deficiency should be added to the growing list of monogenetic diseases that predispose affected individuals to acquire severe and uncontrolled EBV infections and to develop substantial complications. This case further links mutations in the SLP76 gene to a significant human immunodeficiency and extends its clinical phenotype.
Assuntos
Infecções por Vírus Epstein-Barr , Síndromes de Imunodeficiência , Linfoma , Doenças da Imunodeficiência Primária , Pré-Escolar , Humanos , Herpesvirus Humano 4 , Síndromes de Imunodeficiência/diagnóstico , Linfoma/complicações , Mutação , Doenças da Imunodeficiência Primária/complicações , Receptores de Antígenos de Linfócitos T/genéticaRESUMO
Mutations affecting T-cell receptor (TCR) signaling typically cause combined immunodeficiency (CID) due to varying degrees of disturbed T-cell homeostasis and differentiation. Here, we describe two cousins with CID due to a novel nonsense mutation in LCK and investigate the effect of this novel nonsense mutation on TCR signaling, T-cell function, and differentiation. Patients underwent clinical, genetic, and immunological investigations. The effect was addressed in primary cells and LCK-deficient T-cell lines after expression of mutated LCK. RESULTS: Both patients primarily presented with infections in early infancy. The LCK mutation led to reduced expression of a truncated LCK protein lacking a substantial part of the kinase domain and two critical regulatory tyrosine residues. T cells were oligoclonal, and especially naïve CD4 and CD8 T-cell counts were reduced, but regulatory and memory including circulating follicular helper T cells were less severely affected. A diagnostic hallmark of this immunodeficiency is the reduced surface expression of CD4. Despite severely impaired TCR signaling mTOR activation was partially preserved in patients' T cells. LCK-deficient T-cell lines reconstituted with mutant LCK corroborated partially preserved signaling. Despite detectable differentiation of memory and effector T cells, their function was severely disturbed. NK cell cytotoxicity was unaffected. Residual TCR signaling in LCK deficiency allows for reduced, but detectable T-cell differentiation, while T-cell function is severely disturbed. Our findings expand the previous report on one single patient on the central role of LCK in human T-cell development and function.
Assuntos
Síndromes de Imunodeficiência , Doenças da Imunodeficiência Primária , Humanos , Códon sem Sentido , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/genética , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/genética , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/química , Proteína Tirosina Quinase p56(lck) Linfócito-Específica/metabolismo , Fosforilação , Doenças da Imunodeficiência Primária/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Transdução de SinaisRESUMO
INTRODUCTION: Renal ischemia and reperfusion (IR) injury introduces cellular stress and is the main cause of acute kidney damage. Renal cells exposed to noxious stress induce the expression of the pleiotropic hormone leptin. As we have previously revealed a deleterious stress-related role for leptin expression, these results suggested that leptin is also involved in pathological renal remodeling. The systemic functions of leptin preclude the study of its local effects using conventional approaches. We have therefore designed a method to locally perturb leptin activity in specific tissues without affecting its systemic levels. This study explores whether local anti-leptin strategy is renoprotective in a post-IR porcine kidney model. METHODS: We induced renal IR injury in pigs by exposing kidneys to ischemia and revascularization. Upon reperfusion, kidneys instantly received an intra-arterial bolus of either a leptin antagonist (LepA) or saline solution. Peripheral blood was sampled to assess systemic leptin, IL-6, creatinine, and BUN levels, and postoperative tissue samples were analyzed by hematoxylin and eosin histochemistry and immunohistochemistry. RESULTS: Histology of IR/saline kidneys exhibited extensive necrosis of proximal tubular epithelial cells, as well as elevated levels of apoptosis markers and inflammation. In contrast, IR/LepA kidneys showed no signs of necrosis or inflammation with normal IL-6 and tall-like receptor 4 levels. LepA treatment led to upregulation in mRNA levels of leptin, leptin receptor, ERK1/2, STAT3, and transport molecule Na/H exchanger-3. CONCLUSIONS: Local, intrarenal postischemic LepA treatment at reperfusion prevented apoptosis and inflammation and was renoprotective. Selective intrarenal administration of LepA at reperfusion may provide a viable option for clinical implementation.
Assuntos
Injúria Renal Aguda , Traumatismo por Reperfusão , Animais , Suínos , Leptina , Interleucina-6 , Rim/patologia , Traumatismo por Reperfusão/tratamento farmacológico , Traumatismo por Reperfusão/prevenção & controle , Inflamação/complicações , Isquemia/tratamento farmacológico , Isquemia/complicações , Necrose , Injúria Renal Aguda/tratamento farmacológico , Injúria Renal Aguda/etiologia , Injúria Renal Aguda/prevenção & controleRESUMO
Diagnosis of primary complement deficiencies requires a high index of suspicion. Thus, susceptible patients are often underdiagnosed and untreated. Here, we present a multicenter experience with two novel inborn errors of the classical complement system. This is a retrospective multicenter analysis of computerized medical records of children (<18 years) admitted in the period between 2012 and 2018 at Shaare Zedek Medical Center in Jerusalem and Edmond and Lily Safra Children's Hospital, Tel-Hashomer Medical Center, in Ramat Gan, Israel. Patients were genetically diagnosed by a complementary immune workup. We identified 5 patients (3 males) from four different families harboring two novel mutations in the complement components C6-C8. Genetic mutations were identified by whole-exome sequencing or by sequencing of the coding exons of a single gene based on the findings in the immune workup. Clinical manifestations consisted of meningitis with or without meningococcemia. The immune workup demonstrated nearly absent levels of CH50, compatible with a complement pathway defect. Diagnosis delay ranged between 0 and 30 years. CONCLUSION: Awareness of risk factors for primary complement deficiencies, even at the first infectious episode, should facilitate prompt immune and genetic workup, commencing diagnosis and proper treatment for the patient and family. WHAT IS KNOWN: ⢠Deficiencies in the classical terminal complement components increase susceptibility to invasive meningococcal infections. ⢠Recurrent meningococcal infections mandate a diagnostic workup of the complement system. WHAT IS NEW: ⢠Genetic workup can be utilized for prompt diagnosis of complement deficiencies. ⢠High rates of consanguinity, even in the presence of a single meningococcal infection, should promote immune and genetic workups.
Assuntos
Meningite Meningocócica , Infecções Meningocócicas , Neisseria meningitidis , Criança , Complemento C6 , Complemento C8/genética , Proteínas do Sistema Complemento/genética , Feminino , Doenças da Deficiência Hereditária de Complemento , Humanos , Masculino , Estudos RetrospectivosRESUMO
Signal transducer and activator of transcription (STAT)1 heterozygous gain-of-function (GOF) mutations are known to induce immune dysregulation and chronic mucocutaneous candidiasis (CMCC). Previous reports suggest an association between demodicosis and STAT1 GOF. However, immune characterization of these patients is lacking. Here, we present a retrospective analysis of patients with immune dysregulation and STAT1 GOF who presented with facial and ocular demodicosis. In-depth immune phenotyping and functional studies were used to characterize the patients. We identified five patients (three males) from two non-consanguineous Jewish families. The mean age at presentation was 11.11 (range = 0.58-24) years. Clinical presentation included CMCC, chronic demodicosis and immune dysregulation in all patients. Whole-exome and Sanger sequencing revealed a novel heterozygous c.1386C>A; p.S462R STAT1 GOF mutation in four of the five patients. Immunophenotyping demonstrated increased phosphorylated signal transducer and activator of transcription in response to interferon-α stimuli in all patients. The patients also exhibited decreased T cell proliferation capacity and low counts of interleukin-17-producing T cells, as well as low forkhead box protein 3+ regulatory T cells. Specific antibody deficiency was noted in one patient. Treatment for demodicosis included topical ivermectin and metronidazole. Demodicosis may indicate an underlying primary immune deficiency and can be found in patients with STAT1 GOF. Thus, the management of patients with chronic demodicosis should include an immunogenetic evaluation.
Assuntos
Mutação com Ganho de Função , Doenças Genéticas Inatas , Doenças do Sistema Imunitário , Infestações por Ácaros , Ácaros/imunologia , Fator de Transcrição STAT1 , Dermatopatias Parasitárias , Adolescente , Adulto , Animais , Criança , Doença Crônica , Feminino , Doenças Genéticas Inatas/genética , Doenças Genéticas Inatas/imunologia , Doenças Genéticas Inatas/parasitologia , Humanos , Doenças do Sistema Imunitário/genética , Doenças do Sistema Imunitário/imunologia , Doenças do Sistema Imunitário/parasitologia , Lactente , Masculino , Pessoa de Meia-Idade , Infestações por Ácaros/genética , Infestações por Ácaros/imunologia , Estudos Retrospectivos , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/imunologia , Dermatopatias Parasitárias/genética , Dermatopatias Parasitárias/imunologiaRESUMO
Dysregulated immune responses are essential underlying causes of a plethora of pathologies including cancer, autoimmunity, and immunodeficiency. We here investigated 4 patients from unrelated families presenting with immunodeficiency, autoimmunity, and malignancy. We identified 4 distinct homozygous mutations in TNFRSF9 encoding the tumor necrosis factor receptor superfamily member CD137/4-1BB, leading to reduced, or loss of, protein expression. Lymphocytic responses crucial for immune surveillance, including activation, proliferation, and differentiation, were impaired. Genetic reconstitution of CD137 reversed these defects. CD137 deficiency is a novel inborn error of human immunity characterized by lymphocytic defects with early-onset Epstein-Barr virus (EBV)-associated lymphoma. Our findings elucidate a functional role and relevance of CD137 in human immune homeostasis and antitumor responses.
Assuntos
Doenças Autoimunes/genética , Síndromes de Imunodeficiência/genética , Linfoma/genética , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/genética , Doenças Autoimunes/imunologia , Feminino , Predisposição Genética para Doença , Humanos , Síndromes de Imunodeficiência/imunologia , Linfoma/imunologia , Masculino , Linhagem , Membro 9 da Superfamília de Receptores de Fatores de Necrose Tumoral/deficiênciaRESUMO
Mutations in the common gamma chain of the interleukin 2 receptor (IL2RG) or the associated downstream signaling enzyme Janus kinase 3 (JAK3) genes are typically characterized by a T cell-negative, B cell-positive, natural killer (NK) cell-negative (T-B+NK-) severe combined immunodeficiency (SCID) immune phenotype. We report clinical course, immunological, genetic and proteomic work-up of two patients with different novel mutations in the IL-2-JAK3 pathway with a rare atypical presentation of T-B+NK- SCID. Lymphocyte subpopulation revealed significant T cells lymphopenia, normal B cells, and NK cells counts (T-B+NK+SCID). Despite the presence of B cells, IgG levels were low and IgA and IgM levels were undetectable. T-cell proliferation in response to mitogens in patient 1 was very low and T-cell receptor V-beta chain repertoire in patient 2 was polyclonal. Whole-exome sequencing revealed novel mutations in both patients (patient 1-c.923delC frame-shift mutation in the IL2RG gene, patient 2-c.G172A a homozygous missense mutation in the JAK3 gene). Bioinformatic analysis of the JAK3 mutation indicated deleterious effect and 3D protein modeling located the mutation to a surface exposed alpha-helix structure. Our findings help to link between genotype and phenotype, which is a key factor for the diagnosis and treatment of SCID patients.
Assuntos
Subunidade gama Comum de Receptores de Interleucina/genética , Janus Quinase 3/genética , Fenótipo , Imunodeficiência Combinada Severa/genética , Feminino , Humanos , Lactente , Janus Quinase 3/química , Masculino , Mutação , Linhagem , Conformação Proteica em alfa-Hélice , Imunodeficiência Combinada Severa/patologiaRESUMO
Primary immunodeficiencies (PIDs) are a heterogeneous group of monogenic inborn errors of immunity. The genetic causes of these diseases can be identified using whole exome sequencing (WES). Here, DNA samples from 106 patients with a clinical suspicion of PID were subjected to WES in order to test the diagnostic yield of this test in a highly consanguineous community. A likely genetic diagnosis was achieved in 70% of patients. Several factors were considered to possibly influence the diagnostic rate of WES among our cohort including early age, presence of consanguinity, family history suggestive of PID, the number of family members who underwent WES and the clinical phenotype of the patient. The highest diagnostic rate was in patients with combined immunodeficiency or with a syndrome. Notably, WES findings altered the clinical management in 39% (41/106) of patients in our cohort. Our findings support the use of WES as an important diagnostic tool in patients with suspected PID, especially in highly consanguineous communities.
Assuntos
Sequenciamento do Exoma , Mutação , Doenças da Imunodeficiência Primária/diagnóstico , Adolescente , Adulto , Doenças Autoimunes/epidemiologia , Doenças Autoimunes/genética , Criança , Pré-Escolar , Tomada de Decisão Clínica , Consanguinidade , Gerenciamento Clínico , Feminino , Genótipo , Transplante de Células-Tronco Hematopoéticas , Humanos , Lactente , Recém-Nascido , Doenças Inflamatórias Intestinais/epidemiologia , Doenças Inflamatórias Intestinais/genética , Israel/epidemiologia , Masculino , Doenças da Imunodeficiência Primária/epidemiologia , Doenças da Imunodeficiência Primária/genética , Doenças da Imunodeficiência Primária/terapia , Adulto JovemRESUMO
INTRODUCTION: Severe combined immunodeficiency (SCID) is a fatal disorder resulting from various genetic defects. In the Middle East, where consanguineous marriage is prevalent, autosomal recessive mutations in recombination-activating genes (RAG) are a leading cause of SCID. We present a large cohort of SCID patients due to RAG1 or RAG2 mutations. METHODS: Twenty-six patients with RAG1 or RAG2 deficiency, diagnosed at Sheba Medical Center, were retrospectively investigated. Clinical presentation, immunologic phenotype, genetic analysis, treatment, and outcome were analyzed. RESULTS: Majority of patients were referred from the Palestinian Authority. Most patients were males of Muslim Arab descent, 77% were born to consanguineous parents, and 65% had family history of immunodeficiency. Nearly all patients suffered from various infections before turning 2 months old, eight patients (31%) presented with Omenn and Omenn-like syndrome, and three patients (11%) had maternal engraftment. Notably, seven patients (27%) suffered from vaccine-derived infections, including a rare case of measles encephalitis. Nineteen patients underwent hematopoietic stem cell transplantation (HSCT) at a median age of 6 months, with a successful outcome for 72% of them. Genetic analysis revealed 11 different mutations (7 RAG2, 4 RAG1), two of them novel. CONCLUSIONS: Consanguineous marriages account for a genetic "founder effect." SCID is a pediatric emergency that dictates immediate precautions and curative treatment with HSCT. Due to lack of newborn screening for SCID within the Palestinian population, most patients in this cohort were diagnosed upon clinical symptoms, which led to a delayed diagnosis, harmful administration of contra-indicated live vaccines, delay in HSCT, and poor outcome.
Assuntos
Proteínas de Ligação a DNA/genética , Proteínas de Homeodomínio/genética , Proteínas Nucleares/genética , Imunodeficiência Combinada Severa/genética , Consanguinidade , Feminino , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Lactente , Recém-Nascido , Masculino , Mutação/genética , Fenótipo , Prognóstico , Estudos RetrospectivosRESUMO
BACKGROUND: The SRP54 (signal recognition protein 54) is a conserved component of the ribonucleoprotein complex that mediates cotranslational targeting and translocation of proteins to the endoplasmic reticulum. In 2017, mutations in the gene have been described as a cause of congenital neutropenia with or without pancreatic insufficiency, and since then, only limited cases were added to the literature. METHODS: Two patients with neutropenia underwent hematological, immunological, and genetic work-up, including lymphocyte phenotyping, immunoglobulins, and complement levels, antineutrophil and antinuclear antibodies, bone marrow FISH panel for myelodysplastic syndrome, whole-exome sequencing, and in silico proteomic analysis. RESULTS: Clinical findings in the two families revealed a wide spectrum of immunological and clinical manifestations, ranging from mild asymptomatic neutropenia during febrile illnesses to severe neutropenia and life-threatening infection requiring leg amputation. Immunological and hematological work-up showed isolated neutropenia with normal lymphocyte subpopulations, immunoglobulin and complement levels, and negative autoimmune tests. Bone marrow aspirations showed variability ranging from normal myelopoiesis to myeloid maturation arrest at the promyelocytic stage, with normal FISH panel for myelodysplastic syndrome. Genetic analysis identified a novel, de novo, in-frame deletion in the SRP54 gene, c.342-344delAAC, p.T115del. In silico proteomic analysis suggested impaired SRP54 protein function due to reduced GTP activity and stability. CONCLUSIONS: We describe congenital neutropenia with variable clinical presentation in novel mutation of the SRP54 gene.
Assuntos
Mutação , Neutropenia/congênito , Neutropenia/patologia , Partícula de Reconhecimento de Sinal/genética , Pré-Escolar , Feminino , Humanos , Lactente , Masculino , Neutropenia/genética , Neutropenia/metabolismo , Linhagem , Prognóstico , Proteômica , Sequenciamento do ExomaRESUMO
Benign neutropenia, observed in different ethnic groups, is the most common form of neutropenia worldwide. A specific single nucleotide polymorphism, rs2814778, located at the promoter of the ACKR1 (previously termed DARC) gene, which disrupts a binding site for the GATA1 erythroid transcription factor, resulting in a ACKR1-null phenotype, was found to serve as a predictor of low white blood cell and neutrophil counts in African-Americans and Yemenite Jews. Individuals with benign neutropenia due to the ACKR1-null allele have been found to have an increased susceptibility to human immunodeficiency virus infection and, on the other hand, a protective effect against malaria. The associated protective effect may explain the spread of the ACKR1-null allele by natural selection. The reviewed relationships between ACKR1 polymorphism and various pathological states may have important clinical implications to individuals with and without benign neutropenia. Potential mechanisms for ACKR1 (previously termed DARC) modulation during neutrophil recruitment to inflammation, and chemokine bioavailability in the circulation and in local tissue are reviewed and discussed.
Assuntos
Sistema do Grupo Sanguíneo Duffy , Fator de Transcrição GATA1 , Neutropenia , Polimorfismo de Nucleotídeo Único , Receptores de Superfície Celular , Elementos de Resposta/imunologia , Sistema do Grupo Sanguíneo Duffy/genética , Sistema do Grupo Sanguíneo Duffy/imunologia , Fator de Transcrição GATA1/genética , Fator de Transcrição GATA1/imunologia , Predisposição Genética para Doença , Infecções por HIV/genética , Infecções por HIV/imunologia , Infecções por HIV/patologia , HIV-1/imunologia , Humanos , Malária/genética , Malária/imunologia , Malária/patologia , Neutropenia/genética , Neutropenia/imunologia , Neutropenia/patologia , Neutrófilos/imunologia , Neutrófilos/patologia , Receptores de Superfície Celular/genética , Receptores de Superfície Celular/imunologiaRESUMO
MALT1 (mucosa-associated lymphoid tissue lymphoma-translocation gene 1) is an intracellular signaling protein that activates NFκB and is crucial for both the adaptive and innate immune responses. Only 6 patients with immune deficiencies secondary to inherited mutations in the MALT1 gene have been described. PURPOSE: To provide clinical and immunological insights from 2 patients diagnosed with MALT1 immunodeficiency syndrome due to a novel MALT1 mutation. METHODS: Two cousins with suspected combined immunodeficiency underwent immunological and genetic work-up, including lymphocyte phenotyping, lymphocyte activation by mitogen stimulation, and next-generation sequencing (NGS) of T cell receptor gamma chain (TRG) repertoire. Whole exome sequencing was performed to identify the underlying genetic defect. RESULTS: Clinical findings included recurrent infections, failure to thrive, lymphadenopathy, dermatitis, and autoimmunity. Immune work-up revealed lymphocytosis, low to normal levels of immunoglobulins, absence of regulatory T cells, and low Th17 cells. A normal proliferative response was induced by phytohemagglutinin and IL-2 but was diminished with anti-CD3. TRG repertoire was diverse with a clonal expansion pattern. Genetic analysis identified a novel autosomal recessive homozygous c.1799T>A; p. I600N missense mutation in MALT1. MALT1 protein expression was markedly reduced, and in vitro IL-2 production and NFκB signaling pathway were significantly impaired. CONCLUSIONS: Two patients harboring a novel MALT1 mutation presented with signs of immune deficiency and dysregulation and were found to have an abnormal T cell receptor repertoire. These findings reinforce the link between MALT1 deficiency and combined immunodeficiency. Early diagnosis is crucial, and curative treatment by hematopoietic stem cell transplantation may be warranted.
Assuntos
Predisposição Genética para Doença , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Proteína de Translocação 1 do Linfoma de Tecido Linfoide Associado à Mucosa/genética , Mutação , Receptores de Antígenos de Linfócitos T/genética , Receptores de Antígenos de Linfócitos T/metabolismo , Sequência de Aminoácidos , Biomarcadores , Consanguinidade , Citocinas/metabolismo , Feminino , Estudos de Associação Genética , Sequenciamento de Nucleotídeos em Larga Escala , Humanos , Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/metabolismo , Imunofenotipagem , Masculino , NF-kappa B/metabolismo , Linhagem , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismoRESUMO
BACKGROUND: Infantile cortical hyperostosis (ICH)/Caffey disease is an inflammatory collagenopathy of infancy, manifested by subperiosteal bone hyperplasia. Genetically, ICH was linked with heterozygosity for an R836C mutation in the COL1A1 gene. Although an autosomal-recessive trait is also suspected, it has not been proven thus far. METHODS: A case of an infant male born to consanguineous parents is reported, presenting with classical findings, course, and clinical outcome of ICH. Whole-exome sequencing (WES) was performed in order to identify a possible underlying genetic defect. RESULTS: WES analysis revealed a novel homozygous nonsense mutation in lysine 2 of fetuin-A, encoded by the ALPHA-2-HS-GLYCOPROTEIN (AHSG) gene (c.A4T; p.K2X). Fetuin-A is an important regulator of bone remodeling and an inhibitor of ectopic mineralization. By enzyme-linked immunosorbent assay (ELISA), we show a complete deficiency of this protein in the patient's serum, compared to controls. CONCLUSION: A novel homozygous nonsense mutation in AHSG gene has been found in ICH patient with a typical phenotype, resulting in fetuin-A deficiency. This finding postulates an autosomal-recessive mode of inheritance in ICH, which, unlike the autosomal-dominant inheritance associated with COL1A1, is associated with AHSG and fetuin-A deficiency.
Assuntos
Deficiências Nutricionais/complicações , Hiperostose Cortical Congênita/complicações , alfa-2-Glicoproteína-HS/deficiência , Humanos , Hiperostose Cortical Congênita/genética , Lactente , Masculino , Sequenciamento do Exoma , alfa-2-Glicoproteína-HS/genéticaRESUMO
Neutrophil chemotactic defects have been reported previously in patients with hyper-IgE syndrome. Bi-allelic mutations in dedicator of cytokinesis 8 (DOCK8) gene usually cause an autosomal recessive hyper-IgE syndrome phenotype. Data are lacking about expression of DOCK8 protein in neutrophils or the possible role of DOCK8 in neutrophil function. We sought to determine if DOCK8 protein is expressed in neutrophils and if DOCK8 plays a role in neutrophil function. The expression of DOCK8 protein was assessed in neutrophils from healthy volunteers with and without activators. Neutrophil chemotaxis, phagocytosis and superoxide generation were studied in neutrophils from DOCK8-deficient patients compared to neutrophils from healthy controls before and after stimulation with activators: phorbol 12-myristate 13-acetate (PMA) or N-Formylmethionyl-leucyl-phenylalanine (fMLP). DOCK8 protein is expressed in resting neutrophils from healthy controls, with a significant increase in DOCK8 expression after stimulation. Neutrophil functions were assessed in 6 DOCK8-deficient patients. All patients had the same non-sense mutation (c.C5134A, p.S1711X). Normal chemotaxis was recorded in 4/6 patients while a mild to moderate chemotaxis defect was recorded in 2/6. Superoxide generation was mainly normal in neutrophils from all six patients and phagocytosis was normal in five patients tested. We conclude that DOCK8 protein is expressed in resting human neutrophils and DOCK8 expression is increased after stimulation with either PMA or fMLP. Most patients with a disease-causing mutation in DOCK8 have normal neutrophil functions, while a minority showed a mild to moderate chemotactic defect.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/fisiologia , Síndromes de Imunodeficiência/imunologia , Neutrófilos/fisiologia , Adolescente , Células Cultivadas , Quimiotaxia , Criança , Pré-Escolar , Códon sem Sentido , Humanos , Síndromes de Imunodeficiência/genética , N-Formilmetionina Leucil-Fenilalanina/farmacologia , Neutrófilos/efeitos dos fármacos , Fagocitose , Superóxidos/metabolismo , Acetato de Tetradecanoilforbol/farmacologiaRESUMO
Regulation of the actin cytoskeleton is crucial for normal development and function of the immune system, as evidenced by the severe immune abnormalities exhibited by patients bearing inactivating mutations in the Wiskott-Aldrich syndrome protein (WASP), a key regulator of actin dynamics. WASP exerts its effects on actin dynamics through a multisubunit complex termed Arp2/3. Despite the critical role played by Arp2/3 as an effector of WASP-mediated control over actin polymerization, mutations in protein components of the Arp2/3 complex had not previously been identified as a cause of immunodeficiency. Here, we describe two brothers with hematopoietic and immunologic symptoms reminiscent of Wiskott-Aldrich syndrome (WAS). However, these patients lacked mutations in any of the genes previously associated with WAS. Whole-exome sequencing revealed a homozygous 2 bp deletion, n.c.G623DEL-TC (p.V208VfsX20), in Arp2/3 complex component ARPC1B that causes a frame shift resulting in premature termination. Modeling of the disease in zebrafish revealed that ARPC1B plays a critical role in supporting T cell and thrombocyte development. Moreover, the defects in development caused by ARPC1B loss could be rescued by the intact human ARPC1B ortholog, but not by the p.V208VfsX20 variant identified in the patients. Moreover, we found that the expression of ARPC1B is restricted to hematopoietic cells, potentially explaining why a mutation in ARPC1B has now been observed as a cause of WAS, whereas mutations in other, more widely expressed, components of the Arp2/3 complex have not been observed.
Assuntos
Complexo 2-3 de Proteínas Relacionadas à Actina/genética , Plaquetas/patologia , Mutação da Fase de Leitura , Síndromes de Imunodeficiência/genética , Linfopoese/genética , Linfócitos T/patologia , Trombopoese/genética , Citoesqueleto de Actina/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/deficiência , Complexo 2-3 de Proteínas Relacionadas à Actina/metabolismo , Complexo 2-3 de Proteínas Relacionadas à Actina/fisiologia , Pré-Escolar , Códon sem Sentido , Consanguinidade , Evolução Fatal , Humanos , Lactente , Masculino , Complexos Multiproteicos , Linhagem , Polimerização , Recombinação V(D)J , Síndrome de Wiskott-Aldrich/genética , Proteínas de Peixe-Zebra/deficiência , Proteínas de Peixe-Zebra/genéticaRESUMO
The original version of this article unfortunately contained mistakes in Author's name, in Table 1 and in result section.
RESUMO
PURPOSE: RAS guanyl-releasing protein 1 (RASGRP1) deficiency has recently been shown to cause a primary immunodeficiency (PID) characterized by CD4+ T cell lymphopenia and Epstein-Barr virus (EBV)-associated B cell lymphoma. Our report of three novel patients widens the scope of RASGRP1 deficiency by providing new clinical and immunological insights on autoimmunity, immune cell development, and predisposition to lymphoproliferative disease. METHODS: One patient of Turkish origin (P1) and two Palestinian patients (P2, P3) were evaluated for immunodeficiency. To decipher the molecular cause of disease, whole exome sequencing was conducted. Identified mutations were validated by immunological and biochemical assays. RESULTS: We report three patients presenting with similar clinical characteristics of immunodeficiency and EBV-associated lymphoproliferative disease. In addition, P2 and P3 exhibited overt autoimmune manifestations. Genetic screening identified two novel loss-of-function mutations in RASGRP1. Immunoblotting and active Ras pull-down assays confirmed perturbed ERK1/2 signaling and reduced Ras-GTPase activity in heterologous Jurkat cells with ectopic expression of RASGRP1 mutants. All three patients had CD4+ T cell lymphopenia. P2 and P3 showed decreased mitogen-induced lymphocyte proliferation, reduced T cell receptor excision circles, abnormal T cell receptor (TCR) Vß repertoires, and increased frequencies of TCRγδ cells. TCR gamma repertoire diversity was significantly reduced with a remarkable clonal expansion. CONCLUSIONS: RASGRP1 deficiency is associated with life-threatening immune dysregulation, severe autoimmune manifestations, and susceptibility to EBV-induced B cell malignancies. Early diagnosis is critical and hematopoietic stem cell transplantation might be considered as curative treatment.