RESUMO
Hypogammaglobulinemia is a rare complication of STAT1 gain-of-function (GOF) mutations. We report an adult patient diagnosed with hypogammaglobulinemia caused by B-cell depletion during the treatment of disseminated cryptococcosis. The patient carried the STAT1 GOF mutation (c.820C>T, p.R274W). The flow cytometric analysis of his bone marrow revealed that B-cell differentiation was blocked in the stages between pre-B1b and pre-B2 cells. On the other hand, his brother who carried the same mutation displayed normal B-cell counts, thereby indicating that the unrecognized variants in same or other gene might be associated with abnormal B-cell differentiation in the patients. In conclusion, impaired B-cell differentiation in the bone marrow can cause hypogammaglobulinemia in patients with STAT1 GOF mutations.
Assuntos
Linfócitos B/citologia , Linfócitos B/metabolismo , Diferenciação Celular , Mutação com Ganho de Função , Fator de Transcrição STAT1/genética , Fator de Transcrição STAT1/metabolismo , Adulto , Agamaglobulinemia/diagnóstico , Agamaglobulinemia/etiologia , Agamaglobulinemia/metabolismo , Linfócitos B/imunologia , Biomarcadores , Medula Óssea/metabolismo , Medula Óssea/patologia , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Citocinas/metabolismo , Humanos , Imunofenotipagem , Masculino , Subpopulações de Linfócitos T/imunologia , Subpopulações de Linfócitos T/metabolismo , Tomografia Computadorizada por Raios XRESUMO
Background: Patients with predominantly antibody deficiency (PAD) suffer from severe and recurrent infections that require lifelong immunoglobulin replacement and prophylactic antibiotic treatment. Disease incidence is estimated to be 1:25,000 worldwide, and up to 68% of patients develop non-infectious complications (NIC) including autoimmunity, which are difficult to treat, causing high morbidity, and early mortality. Currently, the etiology of NIC is unknown, and there are no diagnostic and prognostic markers to identify patients at risk. Objectives: To identify immune cell markers that associate with NIC in PAD patients. Methods: We developed a standardized 11-color flow cytometry panel that was utilized for in-depth analysis of B and T cells in 62 adult PAD patients and 59 age-matched controls. Results: Nine males had mutations in Bruton's tyrosine kinase (BTK) and were defined as having X-linked agammaglobulinemia. The remaining 53 patients were not genetically defined and were clinically diagnosed with agammaglobulinemia (n = 1), common variable immunodeficiency (CVID) (n = 32), hypogammaglobulinemia (n = 13), IgG subclass deficiency (n = 1), and specific polysaccharide antibody deficiency (n = 6). Of the 53, 30 (57%) had one or more NICs, 24 patients had reduced B-cell numbers, and 17 had reduced T-cell numbers. Both PAD-NIC and PAD+NIC groups had significantly reduced Ig class-switched memory B cells and naive CD4 and CD8 T-cell numbers. Naive and IgM memory B cells, Treg, Th17, and Tfh17 cells were specifically reduced in the PAD+NIC group. CD21lo B cells and Tfh cells were increased in frequencies, but not in absolute numbers in PAD+NIC. Conclusion: The previously reported increased frequencies of CD21lo B cells and Tfh cells are the indirect result of reduced naive B-cell and T-cell numbers. Hence, correct interpretation of immunophenotyping of immunodeficiencies is critically dependent on absolute cell counts. Finally, the defects in naive B- and T-cell numbers suggest a mild combined immunodeficiency in PAD patients with NIC. Together with the reductions in Th17, Treg, and Tfh17 numbers, these key differences could be utilized as biomarkers to support definitive diagnosis and to predict for disease progression.
Assuntos
Agamaglobulinemia/diagnóstico , Agamaglobulinemia/etiologia , Subpopulações de Linfócitos B/imunologia , Contagem de Linfócitos , Subpopulações de Linfócitos T/imunologia , Adolescente , Adulto , Agamaglobulinemia/metabolismo , Idoso , Idoso de 80 Anos ou mais , Subpopulações de Linfócitos B/metabolismo , Biomarcadores , Feminino , Humanos , Imunoglobulina M/sangue , Imunoglobulina M/imunologia , Memória Imunológica , Imunofenotipagem , Masculino , Pessoa de Meia-Idade , Subpopulações de Linfócitos T/metabolismo , Linfócitos T Reguladores/imunologia , Linfócitos T Reguladores/metabolismo , Células Th17/imunologia , Células Th17/metabolismo , Adulto JovemRESUMO
Toll-like receptors (TLRs) are inevitable elements for immunity development and antibody production. TLRs are in close interaction with Bruton's tyrosine kinase which has been found mutated and malfunctioned in the prototype antibody deficiency disease named X-linked agammaglobulinemia (XLA). TLRs' ability was evaluated to induce transcription of TLR-negative regulators, including suppressor of cytokine signaling 1 (SOCS1), interleukin-1 receptor-associated kinase 3 (IRAK-M), tumor necrosis factor alpha-induced protein 3 (TNFAIP3, A20), and Ring finger protein 216 (RNF216), and Tumor necrosis factor-α (TNF-α) and Interferon-α (IFN-α) production via Lipopolysaccharides (LPS) and CpG-A oligodeoxynucleotides (CpG-A ODN). Measured by TaqMan real-time polymerase chain reaction (PCR), meaningfully increased transcripts of SOCS1 and RNF216 were found in XLA peripheral blood mononuclear cells (PBMCs). Also, TLR inductions of XLA have led to similar downregulations in the regulator's transcription which was different from that in healthy donors. Cytokine measurement by enzyme-linked immunosorbent assay (ELISA) revealed a significant lower TNF-α production both before and after LPS. By selected molecules in this study, TLRs' potential defectiveness range expands TLRs expression, downstream signaling, and cytokine production. The results show new potential elements that could play a part in TLRs defect and pathogenesis of agammaglobulinemia as well.
Assuntos
Agamaglobulinemia/metabolismo , Citocinas/metabolismo , Leucócitos Mononucleares/metabolismo , Receptor 4 Toll-Like/metabolismo , Receptor Toll-Like 9/metabolismo , Receptores Toll-Like/metabolismo , Adolescente , Agamaglobulinemia/sangue , Agamaglobulinemia/genética , Células Cultivadas , Criança , Humanos , Quinases Associadas a Receptores de Interleucina-1/genética , Quinases Associadas a Receptores de Interleucina-1/metabolismo , Leucócitos Mononucleares/efeitos dos fármacos , Lipopolissacarídeos/farmacologia , Masculino , Oligodesoxirribonucleotídeos/farmacologia , Proteína 1 Supressora da Sinalização de Citocina/genética , Proteína 1 Supressora da Sinalização de Citocina/metabolismo , Receptor 4 Toll-Like/genética , Receptor Toll-Like 9/genética , Receptores Toll-Like/genética , Transcrição Gênica/efeitos dos fármacos , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/genética , Proteína 3 Induzida por Fator de Necrose Tumoral alfa/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo , Adulto JovemRESUMO
Reduction of adenosine deaminase 2 (ADA2) activity due to autosomal-recessive loss-of-function mutations in the ADA2 gene (previously known as CECR1) results in a systemic vasculitis known as deficiency of ADA2 (DADA2). Neutrophils and a subset of neutrophils known as low-density granulocytes (LDGs) have been implicated in the pathogenesis of vasculitis, at least in part, through the formation of neutrophil extracellular traps (NETs). The study objective was to determine whether neutrophils and NETs play a pathogenic role in DADA2. In vivo evidence demonstrated NETs and macrophages in affected gastrointestinal tissue from patients with DADA2. An abundance of circulating LDGs prone to spontaneous NET formation was observed during active disease in DADA2 and were significantly reduced after remission induction by anti-tumor necrosis factor (TNF) therapy. Increased circulating LDGs were identified in unaffected family members with monoallelic ADA2 mutations. Adenosine triggered NET formation, particularly in neutrophils from female patients, by engaging A1 and A3 adenosine receptors (ARs) and through reactive oxygen species- and peptidylarginine deiminase-dependent pathways. Adenosine-induced NET formation was inhibited by recombinant ADA2, A1/A3 AR antagonists, or by an A2A agonist. M1 macrophages incubated with NETs derived from patients with DADA2 released significantly greater amounts of TNF-α. Treatment with an A2AAR agonist decreased nuclear translocation of NF-κB and subsequent production of inflammatory cytokines in DADA2 monocyte-derived macrophages. These results suggest that neutrophils may play a pathogenic role in DADA2. Modulation of adenosine-mediated NET formation may contribute a novel and directed therapeutic approach in the treatment of DADA2 and potentially other inflammatory diseases.
Assuntos
Adenosina Desaminase/deficiência , Adenosina/metabolismo , Agamaglobulinemia/etiologia , Agamaglobulinemia/metabolismo , Armadilhas Extracelulares/imunologia , Armadilhas Extracelulares/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/deficiência , Imunodeficiência Combinada Severa/etiologia , Imunodeficiência Combinada Severa/metabolismo , Fator de Necrose Tumoral alfa/biossíntese , Adenosina Desaminase/metabolismo , Biomarcadores/metabolismo , Citocinas/metabolismo , Ativação Enzimática , Feminino , Humanos , Mediadores da Inflamação/metabolismo , Macrófagos/imunologia , Macrófagos/metabolismo , Masculino , NF-kappa B/metabolismo , Neutrófilos/imunologia , Neutrófilos/metabolismo , Receptores Purinérgicos P1/metabolismo , Fatores SexuaisRESUMO
Despite the known importance of zinc for human immunity, molecular insights into its roles have remained limited. Here we report a novel autosomal recessive disease characterized by absent B cells, agammaglobulinemia and early onset infections in five unrelated families. The immunodeficiency results from hypomorphic mutations of SLC39A7, which encodes the endoplasmic reticulum-to-cytoplasm zinc transporter ZIP7. Using CRISPR-Cas9 mutagenesis we have precisely modeled ZIP7 deficiency in mice. Homozygosity for a null allele caused embryonic death, but hypomorphic alleles reproduced the block in B cell development seen in patients. B cells from mutant mice exhibited a diminished concentration of cytoplasmic free zinc, increased phosphatase activity and decreased phosphorylation of signaling molecules downstream of the pre-B cell and B cell receptors. Our findings highlight a specific role for cytosolic Zn2+ in modulating B cell receptor signal strength and positive selection.
Assuntos
Agamaglobulinemia/imunologia , Linfócitos B/imunologia , Proteínas de Transporte de Cátions/imunologia , Zinco/imunologia , Agamaglobulinemia/genética , Agamaglobulinemia/metabolismo , Animais , Linfócitos B/metabolismo , Proteínas de Transporte de Cátions/deficiência , Proteínas de Transporte de Cátions/genética , Pré-Escolar , Citosol/imunologia , Citosol/metabolismo , Modelos Animais de Doenças , Retículo Endoplasmático/imunologia , Retículo Endoplasmático/metabolismo , Feminino , Perfilação da Expressão Gênica , Humanos , Lactente , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Linhagem , Zinco/metabolismoRESUMO
Background: Primary immunodeficiency disorders (PIDD) comprise a group of life-threatening congenital diseases characterized by absent or impaired immune responses. Despite the fact that effective, curative treatments are available with optimal clinical outcomes when diagnosed early, newborn screening does not exist for the majority of these diseases due to the lack of detectable, specific biomarkers or validated methods for population-based screening. Peptide immunoaffinity enrichment coupled with selected reaction monitoring mass spectrometry (immuno-SRM) is a sensitive proteomic assay, involving antibody-mediated peptide capture, that allows for concurrent quantification of multiple analytes. This assay has promise for use in potential newborn screening of PIDDs that lead to diminished or absent target proteins in the majority of cases. Objective: To determine and evaluate if a multiplex assay based on immuno-SRM is able to reliably and precisely distinguish affected patients with X-linked agammaglobulinemia (XLA), Wiskott-Aldrich Syndrome (WAS), and CD3ϵ-associated severe combined immunodeficiency (SCID) from one another and from unaffected normal control dried blood spot (DBS) samples. Methods: We performed a blinded, multiplexed analysis of proteolytically-generated peptides from WASp, BTK, and CD3ϵ (for WAS, XLA, and SCID, respectively) in DBS samples from 42 PIDD patients, 40 normal adult controls, and 62 normal newborns. The peptide ATPase copper transporting protein (ATP7B) 1056 was simultaneously monitored for quality assurance purposes. Results: The immuno-SRM assays reliably quantified the target peptides in DBS and accurately distinguished affected patients from normal controls. Analysis of signature peptides found statistically significant reduction or absence of peptide levels in affected patients compared to control groups in each case (WASp and BTK: p = 0.0001, SCID: p = 0.05). Intra and inter-assay precision ranged from 11 to 22% and 11 to 43% respectively; linearity (1.39-2000 fmol peptide), and stability (≤ 0.09% difference in 72 h) showed high precision for the multiplexed assay. Inter-laboratory assay comparison showed high concordance for measured peptide concentrations, with R2 linearity ≥ 0.97 for the WASp 274, CD3ϵ 197, BTK 407, and ATP7B 1056 peptides. Conclusion: Immuno-SRM-based quantification of proteotypic peptides from WASp, BTK, and CD3ϵ in DBS distinguishes relevant PIDD cases from one another and from controls, raising the possibility of employing this approach for large-scale multiplexed newborn screening of selective PIDDs.
Assuntos
Síndromes de Imunodeficiência/diagnóstico , Síndromes de Imunodeficiência/metabolismo , Agamaglobulinemia/diagnóstico , Agamaglobulinemia/metabolismo , Anticorpos/metabolismo , Bioensaio/métodos , Biomarcadores/metabolismo , Cromatografia Líquida/métodos , Estudos de Coortes , ATPases Transportadoras de Cobre/metabolismo , Teste em Amostras de Sangue Seco/métodos , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Humanos , Recém-Nascido , Espectrometria de Massas/métodos , Triagem Neonatal/métodos , Peptídeos/metabolismo , Proteômica/métodosRESUMO
Heart-specific antibodies have been widely associated with myocardial infarction (MI). However, it remains unclear whether autoantibodies mediate disease progression or are a byproduct of cardiac injury. To disambiguate the role of immunoglobulins in MI, we characterized the development of ischemic heart failure in agammaglobulinemic mice (AID-/-µS-/-). Although these animals can produce functional B cells, they cannot synthesize secretory IgM (µS-/-) or perform Ig class switching (AID-/-), leading to complete antibody deficiency. Agammaglobulinemia did not affect overall post-MI survival but resulted in a significant reduction in infarct size. Echocardiographic analyses showed that, compared with wild-type infarcted control mice, AID-/-µS-/- mice exhibited improved cardiac function and reduced remodeling on day 56 post-MI. These differences remained significant even after animals with matched infarct sizes were compared. Infarcted AID-/-µS-/- mice also showed reduced myocardial expression levels of transcripts known to promote adverse remodeling, such as matrix metalloproteinase-9, collagen type I a1, collagen type III a1, and IL-6. An unbiased screening of the heart reactivity potential in the plasma of wild-type MI animals revealed the presence of antibodies that target the myocardial scar and collagenase-sensitive epitopes. Moreover, we found that IgG accumulated within the scar tissues of infarcted mice and remained in close proximity with cells expressing Fcγ receptors (CD16/32), suggesting the existence of an in situ IgG-Fcγ receptor axis. Collectively, our study results confirm that antibodies contribute to ischemic heart failure progression and provide novel insights into the mechanisms underlying this phenomenon. NEW & NOTEWORTHY Our study sheds some light on the long-standing debate over the relevance of autoantibodies in heart failure and might stimulate future research in the field. The observation of extracellular matrix-specific antibodies and the detection of Fcγ receptor-expressing cells within the scar provide novel insights into the mechanisms by which antibodies may contribute to adverse remodeling.
Assuntos
Agamaglobulinemia/imunologia , Autoanticorpos/imunologia , Insuficiência Cardíaca/prevenção & controle , Switching de Imunoglobulina , Imunoglobulina M/imunologia , Infarto do Miocárdio/imunologia , Miocardite/prevenção & controle , Miocárdio/imunologia , Agamaglobulinemia/complicações , Agamaglobulinemia/genética , Agamaglobulinemia/metabolismo , Animais , Autoanticorpos/metabolismo , Modelos Animais de Doenças , Matriz Extracelular/imunologia , Matriz Extracelular/metabolismo , Matriz Extracelular/patologia , Fibrose , Insuficiência Cardíaca/imunologia , Insuficiência Cardíaca/metabolismo , Insuficiência Cardíaca/patologia , Switching de Imunoglobulina/genética , Imunoglobulina M/genética , Imunoglobulina M/metabolismo , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Infarto do Miocárdio/complicações , Infarto do Miocárdio/metabolismo , Infarto do Miocárdio/patologia , Miocardite/imunologia , Miocardite/metabolismo , Miocardite/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Receptores de IgG/imunologia , Receptores de IgG/metabolismo , Função Ventricular Esquerda , Remodelação VentricularRESUMO
Ion channels and transporters move ions across membrane barriers and are essential for a host of cell functions in many organs. They conduct K+, Na+ and Cl-, which are essential for regulating the membrane potential, H+ to control intracellular and extracellular pH and divalent cations such as Ca2+, Mg2+ and Zn2+, which function as second messengers and cofactors for many proteins. Inherited channelopathies due to mutations in ion channels or their accessory proteins cause a variety of diseases in the nervous, cardiovascular and other tissues, but channelopathies that affect immune function are not as well studied. Mutations in ORAI1 and STIM1 genes that encode the Ca2+ release-activated Ca2+ (CRAC) channel in immune cells, the Mg2+ transporter MAGT1 and the Cl- channel LRRC8A all cause immunodeficiency with increased susceptibility to infection. Mutations in the Zn2+ transporters SLC39A4 (ZIP4) and SLC30A2 (ZnT2) result in nutritional Zn2+ deficiency and immune dysfunction. These channels, however, only represent a fraction of ion channels that regulate immunity as demonstrated by immune dysregulation in channel knockout mice. The immune system itself can cause acquired channelopathies that are associated with a variety of diseases of nervous, cardiovascular and endocrine systems resulting from autoantibodies binding to ion channels. These autoantibodies highlight the therapeutic potential of functional anti-ion channel antibodies that are being developed for the treatment of autoimmune, inflammatory and other diseases.
Assuntos
Canalopatias/imunologia , Canalopatias/metabolismo , Suscetibilidade a Doenças , Sistema Imunitário/imunologia , Sistema Imunitário/metabolismo , Canais Iônicos/metabolismo , Agamaglobulinemia/etiologia , Agamaglobulinemia/metabolismo , Animais , Autoanticorpos/imunologia , Canais de Cálcio Ativados pela Liberação de Cálcio/genética , Canais de Cálcio Ativados pela Liberação de Cálcio/metabolismo , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Proteínas de Transporte de Cátions/genética , Proteínas de Transporte de Cátions/metabolismo , Canalopatias/etiologia , Humanos , Infecções/complicações , Infecções/imunologia , Infecções/metabolismo , Canais Iônicos/genética , Proteína ORAI1/genética , Proteína ORAI1/metabolismo , Molécula 1 de Interação Estromal/genética , Molécula 1 de Interação Estromal/metabolismo , Zinco/deficiênciaRESUMO
Intravenous immunoglobulin (IVIG) therapy is commonly used to treat patients with primary antibody deficiency. This prospective, open-label, non-randomised, multicentre, phase III trial investigated the pharmacokinetics of a new 10% liquid IVIG product (panzyga®; Octapharma) in 51 patients aged 2-75â¯years with common variable immunodeficiency (nâ¯=â¯43) or X-linked agammaglobulinaemia (nâ¯=â¯8). Patients were treated with IVIG 10% every 3 (nâ¯=â¯21) or 4â¯weeks (nâ¯=â¯30) at a dose of 200-800â¯mg/kg for 12â¯months. Total immunoglobulin G (IgG) and subclass concentrations approximately doubled from pre- to 15â¯min post-infusion. The maximum concentration of total IgG (mean⯱â¯SD) was 21.82⯱â¯5.83â¯g/L in patients treated 3-weekly and 17.42⯱â¯3.34â¯g/L in patients treated 4-weekly. Median trough IgG concentrations were nearly constant over the course of the study, remaining between 11.0 and 12.2â¯g/L for patients on the 3-week schedule and between 8.10 and 8.65â¯g/L for patients on the 4-week schedule. The median terminal half-life of total IgG was 36.1 (range 18.5-65.9) days, with generally similar values for the IgG subclasses (26.7-38.0â¯days). Median half-lives for specific antibodies ranged between 21.3 and 51.2â¯days for anti-cytomegalovirus, anti-Haemophilus influenzae, anti-measles, anti-tetanus toxoid, anti-varicella zoster virus antibodies, and anti-Streptococcus pneumoniae subtype antibodies. Overall, IVIG 10% demonstrated pharmacokinetic properties similar to those of other commercial IVIG 10% preparations and 3- or 4-weekly administration achieved sufficient concentrations of IgG, IgG subclasses, and specific antibodies, exceeding the recommended level needed to effectively prevent serious bacterial infections.
Assuntos
Agamaglobulinemia/metabolismo , Imunodeficiência de Variável Comum/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Imunoglobulinas Intravenosas/farmacocinética , Adolescente , Adulto , Agamaglobulinemia/sangue , Idoso , Criança , Pré-Escolar , Imunodeficiência de Variável Comum/sangue , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/sangue , Humanos , Imunoglobulina G/sangue , Masculino , Pessoa de Meia-Idade , Adulto JovemRESUMO
Loss of adenosine deaminase activity leads to severe combined immunodeficiency (ADA-SCID); production and function of T, B, and natural killer (NK) cells are impaired. Gene therapy (GT) with an autologous CD34+-enriched cell fraction that contains CD34+ cells transduced with a retroviral vector encoding the human ADA cDNA sequence leads to immune reconstitution in most patients. Here, we report short- and medium-term safety analyses from 18 patients enrolled as part of single-arm, open-label studies or compassionate use programs. Survival was 100% with a median of 6.9 years follow-up (range, 2.3 to 13.4 years). Adverse events were mostly grade 1 or grade 2 and were reported by all 18 patients following GT. Thirty-nine serious adverse events (SAEs) were reported by 15 of 18 patients; no SAEs were considered related to GT. The most common adverse events reported post-GT include upper respiratory tract infection, gastroenteritis, rhinitis, bronchitis, oral candidiasis, cough, neutropenia, diarrhea, and pyrexia. Incidence rates for all of these events were highest during pre-treatment, treatment, and/or 3-month follow-up and then declined over medium-term follow-up. GT did not impact the incidence of neurologic/hearing impairments. No event indicative of leukemic transformation was reported.
Assuntos
Adenosina Desaminase/deficiência , Adenosina Desaminase/genética , Agamaglobulinemia/genética , Agamaglobulinemia/terapia , Terapia Genética , Imunodeficiência Combinada Severa/genética , Imunodeficiência Combinada Severa/terapia , Adenosina Desaminase/administração & dosagem , Adenosina Desaminase/imunologia , Adenosina Desaminase/metabolismo , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Autoimunidade , Criança , Pré-Escolar , Terapia Combinada , Terapia de Reposição de Enzimas , Seguimentos , Expressão Gênica , Terapia Genética/efeitos adversos , Terapia Genética/métodos , Vetores Genéticos/administração & dosagem , Vetores Genéticos/genética , Transplante de Células-Tronco Hematopoéticas/métodos , Humanos , Lactente , Masculino , Fenótipo , Imunodeficiência Combinada Severa/imunologia , Imunodeficiência Combinada Severa/metabolismo , Transgenes , Resultado do TratamentoRESUMO
BACKGROUND: Primary antibody deficiencies (PADs) are the most frequent primary immunodeficiencies in human subjects. The genetic causes of PADs are largely unknown. Sec61 translocon alpha 1 subunit (SEC61A1) is the major subunit of the Sec61 complex, which is the main polypeptide-conducting channel in the endoplasmic reticulum membrane. SEC61A1 is a target gene of spliced X-box binding protein 1 and strongly induced during plasma cell (PC) differentiation. OBJECTIVE: We identified a novel genetic defect and studied its pathologic mechanism in 11 patients from 2 unrelated families with PADs. METHODS: Whole-exome and targeted sequencing were conducted to identify novel genetic mutations. Functional studies were carried out ex vivo in primary cells of patients and in vitro in different cell lines to assess the effect of SEC61A1 mutations on B-cell differentiation and survival. RESULTS: We investigated 2 families with patients with hypogammaglobulinemia, severe recurrent respiratory tract infections, and normal peripheral B- and T-cell subpopulations. On in vitro stimulation, B cells showed an intrinsic deficiency to develop into PCs. Genetic analysis and targeted sequencing identified novel heterozygous missense (c.254T>A, p.V85D) and nonsense (c.1325G>T, p.E381*) mutations in SEC61A1, segregating with the disease phenotype. SEC61A1-V85D was deficient in cotranslational protein translocation, and it disturbed the cellular calcium homeostasis in HeLa cells. Moreover, SEC61A1-V85D triggered the terminal unfolded protein response in multiple myeloma cell lines. CONCLUSION: We describe a monogenic defect leading to a specific PC deficiency in human subjects, expanding our knowledge about the pathogenesis of antibody deficiencies.
Assuntos
Síndromes de Imunodeficiência/genética , Mutação/genética , Plasmócitos/patologia , Canais de Translocação SEC/genética , Agamaglobulinemia/genética , Agamaglobulinemia/metabolismo , Agamaglobulinemia/patologia , Linfócitos B/metabolismo , Linfócitos B/patologia , Cálcio/metabolismo , Diferenciação Celular/genética , Linhagem Celular , Linhagem Celular Tumoral , Exoma/genética , Células HEK293 , Células HeLa , Heterozigoto , Humanos , Síndromes de Imunodeficiência/metabolismo , Plasmócitos/metabolismo , Transporte Proteico/genética , Infecções Respiratórias/genética , Infecções Respiratórias/metabolismo , Infecções Respiratórias/patologia , Linfócitos T/metabolismo , Linfócitos T/patologia , Resposta a Proteínas não Dobradas/genéticaRESUMO
Common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA) are two major humoral immunodeficiencies, causing a high rate of early age mortality in children. In order to identifiy the possible factors involved in the pathogenesis of CVID and XLA, recent studies have focused on Toll-like receptors (TLRs) and demonstrate the defects in different TLR pathways in immune cells of CVID and XLA patients. Herein, we measured TLR-4 and TLR-9 RNA levels and consequently TNF-α and IFN-α production in peripheral blood mononuclear cells (PBMCs) of patients with CVID and XLA. Contrary to healthy individuals, TLR-9 expression was not significantly increased after ligand stimulation, whereas ligand-induced TLR-4 expression was not significantly different from that in healthy control PBMCs. Lipopolysaccharide (LPS)-stimulated TNF-α production was significantly reduced in patients compared to controls, whereas IFN-α production was increased in all groups after CpG stimulation without any significant inter-group difference. Our data suggest that defects in TLR-9 activated pathways may be a result of the decreased TLR-9 expression, although TLR-9 is not the only modulator of IFN-α production in these patients. On the other hand, impaired signaling in TLR-4 activated pathways which results in significant reduction in TNF-α production are not related to a defect in TLR-4 expression.
Assuntos
Agamaglobulinemia/metabolismo , Imunodeficiência de Variável Comum/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Receptores Toll-Like/metabolismo , Adolescente , Adulto , Criança , Humanos , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Ligantes , Lipopolissacarídeos/farmacologia , Masculino , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Fator de Necrose Tumoral alfa/metabolismo , Adulto JovemRESUMO
BACKGROUND: Primary antibody deficiency (PAD) is the most common group of primary immunodeficiency disorders, resulting from different defects in the development and function of B cell lineage. Common variable immunodeficiency (CVID) and X-linked agammaglobulinemia (XLA) are two of the major types of PADs. Optimal growth and subsequently bone health could potentially compromise due to the interference of several factors in PAD with childhood onset. In the present study, our aim was to evaluate bone mineral density (BMD) of patients with CVID and XLA. METHODS: BMD of 37 CVID and 19 XLA patients was examined. Total BMD was determined by dual-energy X-ray absorptiometry and the calculated scores were compared internally and externally with age-sex matched and ethnic-specific reference. Related factors associated with bone density including immune-related complications, serum calcium, phosphate, total alkaline phosphatase, 25(OH) vitamin D and parathyroid hormone levels were recorded. RESULTS: The median age at the time of study was 20 years among all patients and was not statistically different between CVID and XLA groups and the mean of body mass index (BMI) was 19.4±4.6 kg/cm². Thirty-eight (67.9%) of total patients had normal BMD and 18 (32.1%) patients had a low BMD. BMI was positively correlated with BMD at lumbar spine and femoral neck. The number of low BMD patients in CVID (40.5%) group was more than the XLA (15.8%). CONCLUSION: Beside nutritional, gastrointestinal and infectious complications which are shared in both groups of patients, CVID patients are more prone to alteration of BMD due to association with lymphoproliferative and endocrine diseases. Therefore routine evaluation of bone density and treatment adjustment should be considered in all PAD patients particularly in CVID patients.
Assuntos
Agamaglobulinemia/diagnóstico por imagem , Agamaglobulinemia/metabolismo , Densidade Óssea/fisiologia , Imunodeficiência de Variável Comum/diagnóstico por imagem , Imunodeficiência de Variável Comum/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/diagnóstico por imagem , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Absorciometria de Fóton/métodos , Adolescente , Adulto , Agamaglobulinemia/epidemiologia , Criança , Imunodeficiência de Variável Comum/epidemiologia , Feminino , Doenças Genéticas Ligadas ao Cromossomo X/epidemiologia , Humanos , Masculino , Inquéritos e Questionários , Adulto JovemRESUMO
Primary antibody deficiencies (PADs), the most prevalent inherited primary immunodeficiencies (PIDs), are associated with a wide range of genetic alterations (both monogenic or polygenic) in B cell-specific genes. However, correlations between the genotype and clinical manifestations are not evident in all cases indicating that genetic interactions, environmental and epigenetic factors may have a role in PAD pathogenesis. The recent identification of key defects in DNA methylation in common variable immunodeficiency as well as the multiple evidences on the role of epigenetic control during B cell differentiation, activation and during antibody formation highlight the importance of investing research efforts in dissecting the participation of epigenetic defects in this group of diseases. This review focuses on the role of epigenetic control in B cell biology which can provide clues for the study of potential novel pathogenic defects involved in PADs.
Assuntos
Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Epigênese Genética , Regulação da Expressão Gênica , Estudos de Associação Genética , Predisposição Genética para Doença , Agamaglobulinemia/metabolismo , Animais , Afinidade de Anticorpos/genética , Afinidade de Anticorpos/imunologia , Formação de Anticorpos/genética , Formação de Anticorpos/imunologia , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Diferenciação Celular/genética , Diferenciação Celular/imunologia , Metilação de DNA , Histonas/metabolismo , Humanos , Síndromes de Imunodeficiência/genética , Síndromes de Imunodeficiência/imunologia , Síndromes de Imunodeficiência/metabolismo , Ativação Linfocitária/genética , Ativação Linfocitária/imunologia , Mutação , Plasmócitos/citologia , Plasmócitos/imunologia , Plasmócitos/metabolismoRESUMO
Good Syndrome is an adult-onset combined immunodeficiency defined by hypogammaglobulinemia, low or absent number of B cells, T cell deficiency and thymic tumor. We have characterized CD8+ T cells from a patient with Good syndrome that presented with CD8+T-cell large granular lymphocytic leukemia (LGL). Characterization of peripheral blood CD8+ T cells revealed that majority of CD8+ T cells were terminally differentiated effector memory phenotype (TEMRA; CD8+CCR7-CD45RA+), and were PD-1high (CD279), ICOSlow (CD278), and granzymehigh. Almost all CD8+ T cells were IFN-γ+. CD8 Treg (CD8+CD183+CCR7+CD45RA-) were decreased. TEMRA phenotype along with CD279high, demonstrates that these are exhausted CD8+ T cells. This phenotype along with CD278low may also explain severe T cell functional deficiency in our patient. In the present patient, T-LGL appears to be a clonal expansion of CD279+granzyme+IFN-γ+CD8+TEMRA cells. To best of our knowledge this is the first case of CD8+T-cell LGL leukemia associated with Good syndrome.
Assuntos
Agamaglobulinemia/patologia , Linfócitos T CD8-Positivos/patologia , Leucemia Linfocítica Granular Grande/patologia , Imunodeficiência Combinada Severa/patologia , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Diferenciação Celular/imunologia , Feminino , Humanos , Imunofenotipagem , Leucemia Linfocítica Granular Grande/diagnóstico , Leucemia Linfocítica Granular Grande/imunologia , Masculino , Pessoa de Meia-Idade , Imunodeficiência Combinada Severa/diagnóstico , Imunodeficiência Combinada Severa/imunologiaAssuntos
Agamaglobulinemia/diagnóstico , Biomarcadores Tumorais/genética , Mieloma Múltiplo/diagnóstico , Plasmócitos/patologia , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Agamaglobulinemia/patologia , Idoso , Biomarcadores Tumorais/imunologia , Células da Medula Óssea/imunologia , Células da Medula Óssea/metabolismo , Células da Medula Óssea/patologia , Antígenos CD13/genética , Antígenos CD13/imunologia , Evolução Fatal , Expressão Gênica , Humanos , Imunofenotipagem , Masculino , Mieloma Múltiplo/imunologia , Mieloma Múltiplo/metabolismo , Mieloma Múltiplo/patologia , Células Mieloides/imunologia , Células Mieloides/metabolismo , Células Mieloides/patologia , Plasmócitos/imunologia , Plasmócitos/metabolismo , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/genética , Lectina 3 Semelhante a Ig de Ligação ao Ácido Siálico/imunologiaRESUMO
BACKGROUND: Granulomatous cutaneous T-cell lymphoma (G-CTCL) is a rarely encountered entity. Most G-CTCL is CD4(+), with granulomatous mycosis fungoides representing the vast majority of cases. Because of the rarity of CD8(+) G-CTCL, there is a paucity of data regarding the clinicopathologic features and expected course. OBJECTIVE: To describe the clinical and histopathologic features of G-CTCL. METHODS: This is a retrospective review of collected cases. RESULTS: We present 4 cases of CD8(+) G-CTCL. Patients presented with papules and nodules on the trunk and extremities without antecedent patch or plaque disease. In all cases, biopsy specimens were obtained, and these revealed a dense granulomatous infiltrate accompanied by an atypical lymphoid infiltrate of CD8(+) T cells. T-cell clonality studies were positive in 3 of 4 cases. Staging was negative for nodal involvement, but lung granulomas were seen in all cases. In all 4 cases, the patient's medical history was significant for immunodeficiency, either primary or iatrogenic. All 4 patients had slowly progressive disease. LIMITATIONS: This is a small retrospective case series. CONCLUSIONS: CD8(+) G-CTCL appears to be associated with immunodeficiency. The finding of a CD8(+) G-CTCL should prompt an evaluation for underlying immunodeficiency. Additional studies are required to validate these conclusions.
Assuntos
Linfócitos T CD8-Positivos/patologia , Hospedeiro Imunocomprometido , Linfoma Cutâneo de Células T/patologia , Neoplasias Cutâneas/patologia , Adulto , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Agamaglobulinemia/patologia , Idoso , Linfócitos T CD8-Positivos/imunologia , Linfócitos T CD8-Positivos/metabolismo , Imunodeficiência de Variável Comum/imunologia , Imunodeficiência de Variável Comum/metabolismo , Imunodeficiência de Variável Comum/patologia , Progressão da Doença , Doenças Genéticas Ligadas ao Cromossomo X/imunologia , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Doenças Genéticas Ligadas ao Cromossomo X/patologia , Granuloma/imunologia , Granuloma/patologia , Humanos , Linfoma Cutâneo de Células T/imunologia , Linfoma Cutâneo de Células T/metabolismo , Masculino , Pessoa de Meia-Idade , Micose Fungoide/imunologia , Micose Fungoide/metabolismo , Micose Fungoide/patologia , Estudos Retrospectivos , Neoplasias Cutâneas/imunologia , Neoplasias Cutâneas/metabolismoRESUMO
BACKGROUND: Bruton tyrosine kinase (BTK) plays an essential role in various biologic functions of different cell types. Mutations in BTK lead to X-linked agammaglobulinemia (XLA) in humans. BTK was recently linked to the innate immune system, in particular, the Toll-like receptor (TLR) pathway; however, the TLR9 pathway has never been studied in dendritic cells (DCs) of patients with XLA. OBJECTIVE: The aim of this study was to investigate the role of BTK in human DC activation upon TLR9 stimulation. METHODS: DCs of patients with XLA and healthy donors were stimulated via TLR4/9 and evaluated for cell activation and cytokine production. RESULTS: We showed that BTK plays an essential role in DC responses to unmethylated CpG oligodeoxynucleotide: although responses to lipopolysaccaride/TLR4 induce normal DC activation in terms of upregulation of specific markers (CD86, CD83, CD80, HLA-DR), the CpG/TLR9 pathway is completely impaired in patients with XLA. Furthermore, cytokine production upon TLR9 activation in patients with XLA is radically impaired in terms of IL-6, IL-12, TNF-α, and IL-10 production. Interestingly, BTK mediated STAT1/3 upregulation in a TLR9-dependent manner. The important role of BTK in human DC activation was confirmed after incubation of healthy DCs with ibrutinib, the specific BTK inhibitor, which resulted in impairment of TLR9 responses as seen in patients with XLA. CONCLUSION: Analysis of these data suggests that BTK regulates human DC responses upon TLR9 engagement in terms of activation, cytokine production, and STAT1/3 upregulation. These findings may be of important significance for better understanding and managing different clinical conditions, such as agammaglobulinemia and lymphoid malignancies.
Assuntos
Células Dendríticas/imunologia , Células Dendríticas/metabolismo , Proteínas Tirosina Quinases/metabolismo , Receptor Toll-Like 9/metabolismo , Tirosina Quinase da Agamaglobulinemia , Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Agamaglobulinemia/metabolismo , Citocinas/biossíntese , Células Dendríticas/efeitos dos fármacos , Doenças Genéticas Ligadas ao Cromossomo X/genética , Doenças Genéticas Ligadas ao Cromossomo X/imunologia , Doenças Genéticas Ligadas ao Cromossomo X/metabolismo , Humanos , Imunofenotipagem , Lipopolissacarídeos/imunologia , Lipopolissacarídeos/farmacologia , Oligodesoxirribonucleotídeos/farmacologia , Fenótipo , Fator de Transcrição STAT1/metabolismo , Fator de Transcrição STAT3/metabolismoRESUMO
Approximately 90% of patients with isolated agammaglobulinemia and failure of B cell development have mutations in genes required for signaling through the preB cell and B cell receptors. The nature of the gene defect in the majority of remaining patients is unknown. We recently identified 4 patients with agammaglobulinemia and markedly decreased numbers of peripheral B cells. The B cells that could be detected had an unusual phenotype characterized by the increased expression of CD19 but the absence of a B cell receptor. Genetic studies demonstrated that all 4 patients had the exact same de novo mutation in the broadly expressed transcription factor E47. The mutant protein (E555K) was stable in patient-derived EBV-transformed cell lines and cell lines transfected with expression vectors. E555K in the transfected cells localized normally to the nucleus and resulted in a dominant negative effect when bound to DNA as a homodimer with wild-type E47. Mutant E47 did permit DNA binding by a tissue-specific heterodimeric DNA-binding partner, myogenic differentiation 1 (MYOD). These findings document a mutational hot-spot in E47 and represent an autosomal dominant form of agammaglobulinemia. Further, they indicate that E47 plays a critical role in enforcing the block in development of B cell precursors that lack functional antigen receptors.
Assuntos
Agamaglobulinemia/genética , Agamaglobulinemia/imunologia , Linfócitos B/imunologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Mutação de Sentido Incorreto , Receptores de Antígenos de Linfócitos B/deficiência , Agamaglobulinemia/metabolismo , Sequência de Aminoácidos , Substituição de Aminoácidos , Linfócitos B/metabolismo , Sequência de Bases , Fatores de Transcrição Hélice-Alça-Hélice Básicos/imunologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Linhagem Celular Transformada , DNA/genética , DNA/metabolismo , Feminino , Genes Dominantes , Humanos , Masculino , Dados de Sequência Molecular , Linhagem , Estabilidade Proteica , Homologia de Sequência de AminoácidosRESUMO
Amyloid A amyloidosis is a protein misfolding disease characterized by deposition of extracellular aggregates derived from the acute-phase reactant serum amyloid A protein. If untreated, amyloid A amyloidosis leads to irreversible damage of various organs, including the kidneys, liver, and heart. Amyloid A deposits regress upon reduction of serum amyloid A concentration, indicating that the amyloid can be efficiently cleared by natural mechanisms. Clearance was proposed to be mediated by humoral immune responses to amyloid. Here, we report that amyloid clearance in mice lacking complement factors 3 and 4 (C3C4(-/-)) was equally efficient as in wild-type mice (C57BL/6), and was only slightly delayed in agammaglobulinemic mice (J(H-/-)). Hence, antibodies or complement factors are not necessary for natural amyloid clearance, implying the existence of alternative physiological pathways for amyloid removal.