Because STAT1 was phosphorylated after IFN-α stimulation of primary fibroblasts from healthy control subjects and patients, the initial steps of the signaling cascade were conserved in the setting of ...IRF9 deficiency, but no induction of ISGs, including MX1, IFIT3, or ISG15, was observed (Fig 1, E). ...PCR analysis of freshly isolated PBMCs treated or not with IFN-αβ revealed that IRF9-deficient cells were profoundly defective in induction of multiple ISGs (Fig 1, H). Because IFN-α induction of ISG expression in the mother's PBMCs was comparable with the average of 4 healthy donors, IRF9 p.Glu166LeufsTer80 does not exert any dominant negative effect on IFN-αβ stimulation. At presentation, the patient was profoundly lymphopenic, with an inverted CD4/CD8 ratio and diminished lymphocyte proliferation in response to mitogens. Because immunologic studies also revealed IgG and IgM hypogammaglobulinemia (IgG, 252 mg/dL; IgM, 24 mg/dL) with undetectable antibodies to tetanus and diphtheria toxins or pneumococci, treatment with IVIG replacement therapy was instituted. At birth, she was given a diagnosis of clubfoot (left) and congenital (left) hip dysplasia. Because of her family history, immunologic analyses were carried out when she was 3 days old, and these studies revealed normal levels of IgG and IgM and normal lymphocyte proliferation in response to PHA but a B-cell and natural killer cell lymphopenia.
Immune responses to vaccines against severe acute respiratory syndrome (SARS)-coronavirus (CoV)-2 are variable. In the absence of disease, youngsters are expected to better react to vaccines than ...adults. Nevertheless, chronic immunosuppression in transplant recipients may impair their capability to generate protection. We aim to explore immune responses after BNT162b2 SARS-CoV-2 vaccination in our cohort of young liver-transplanted patients.
A prospective study of adolescent liver-transplanted patients (n=33) in the long-term follow-up was performed. Immune responses after receiving Pfizer-BioNTech BNT162b2 vaccine were analyzed at two time-points: baseline and 30 days after the second dose. Humoral responses were measured by fluoroenzyme-immunoassay and T-cell responses by interferon-γ-release assay. Post-vaccine coronavirus disease (COVID-19) events were recorded by a survey.
Pre-vaccine SARS-CoV-2-specific antibodies were undetectable in 27/32 (84.4%), negative/indeterminate in 3/32 (9.4%) and positive in 2/32 (6.3%) patients. Cellular responses at baseline were negative in 12/18 (66.6%), positive in 3/18 (16.6%) and indeterminate in 3/18 (16.6%) recipients. None of the baseline positives recalled any symptoms. Post-vaccine antibodies were detected in all patients and 92.6% showed levels >816 BAU/mL. Twenty (71.4%) recipients had positive T-cell responses. Regarding post-vaccine SARS-Cov-2 infection, 10 (30.3%) patients reported COVID-19 without hospitalization and 21 (63.6%) did not notify any infection. Negative and positive cell-response groups after vaccination showed statistically significant differences regarding COVID-19 cases (62.5% vs 22.2%, respectively; p=0.046).
Adolescents and young adults with liver transplantation responded to SARS-Cov-2 vaccine, generating both humoral and cellular responses. Recipients developing cellular responses after vaccination had a lower incidence of COVID-19.
Predominantly antibody deficiencies (PADs) are the most prevalent primary immunodeficiencies, but their B-cell defects and underlying genetic alterations remain largely unknown.
We investigated ...patients with PADs for the distribution of 41 blood B-cell and plasma cell (PC) subsets, including subsets defined by expression of distinct immunoglobulin heavy chain subclasses.
Blood samples from 139 patients with PADs, 61 patients with common variable immunodeficiency (CVID), 68 patients with selective IgA deficiency (IgAdef), 10 patients with IgG subclass deficiency with IgA deficiency, and 223 age-matched control subjects were studied by using flow cytometry with EuroFlow immunoglobulin isotype staining. Patients were classified according to their B-cell and PC immune profile, and the obtained patient clusters were correlated with clinical manifestations of PADs.
Decreased counts of blood PCs, memory B cells (MBCs), or both expressing distinct IgA and IgG subclasses were identified in all patients with PADs. In patients with IgAdef, B-cell defects were mainly restricted to surface membrane (sm)IgA+ PCs and MBCs, with 2 clear subgroups showing strongly decreased numbers of smIgA+ PCs with mild versus severe smIgA+ MBC defects and higher frequencies of nonrespiratory tract infections, autoimmunity, and affected family members. Patients with IgG subclass deficiency with IgA deficiency and those with CVID showed defects in both smIgA+ and smIgG+ MBCs and PCs. Reduced numbers of switched PCs were systematically found in patients with CVID (absent in 98%), with 6 different defective MBC (and clinical) profiles: (1) profound decrease in MBC numbers; (2) defective CD27+ MBCs with almost normal IgG3+ MBCs; (3) absence of switched MBCs; and (4) presence of both unswitched and switched MBCs without and; (5) with IgG2+ MBCs; and (6) with IgA1+ MBCs.
Distinct PAD defective B-cell patterns were identified that are associated with unique clinical profiles.
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Epigenetic Deregulation in Human Primary Immunodeficiencies Campos-Sanchez, Elena; Martínez-Cano, Jorge; del Pino Molina, Lucía ...
Trends in immunology,
January 2019, 2019-Jan, 2019-01-00, 20190101, Letnik:
40, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Primary immunodeficiencies (PIDs) are immune disorders resulting from defects in genes involved in immune regulation, and manifesting as an increased susceptibility to infections, autoimmunity, and ...cancer. However, the molecular basis of some prevalent entities remains poorly understood. Epigenetic control is essential for immune functions, and epigenetic alterations have been identified in different PIDs, including syndromes such as immunodeficiency-centromeric-instability-facial-anomalies, Kabuki, or Wolf–Hirschhorn, among others. Although the epigenetic changes may differ among these PIDs, the reversibility of epigenetic modifications suggests that they might become potential therapeutic targets. Here, we review recent mechanistic advances in our understanding of epigenetic alterations associated with certain PIDs, propose that a fully epigenetically driven mechanism might underlie some PIDs, and discuss the possible prophylactic and therapeutic implications.
PIDs are rare disorders resulting from impaired function(s) in the immune system. Most are caused by mutations affecting proteins with key roles in the development or function of cells of the immune system.
Being mostly diseases of genetic origin, it is difficult to cure PIDs, and lifelong immunoglobulin (Ig) replacement therapy (periodical intravenous or subcutaneos administration of nonspecific plasma-derived antibodies from healthy donors) is the only treatment for many patients with PIDs.
Alterations in epigenetic regulators (mainly controlling DNA methylation, histone modifications, or chromatin remodeling) are increasingly being described for PIDs. Since epigenetic marks, unlike DNA mutations, can be pharmacologically reprogrammed, an understanding of how aberrant epigenetic patterns are initiated and maintained in PIDs might help us devise approaches to restore normal immune function.
Background
Primary antibody deficiencies (PADs) are characterized by hypogammaglobulinemia and impaired B‐cell differentiation. Patients with common variable immunodeficiency (CVID) present severe ...reductions in at least 2 serum immunoglobulins and impaired terminal differentiation of B cells. Most patients with CVID do not appear to present monogenic defects. Activated phosphoinositide 3‐kinase delta syndrome (APDS), caused by gain‐of‐function mutations in the PIK3CD gene (p110δ), can present in patients with a CVID‐like phenotype. Memory B‐cell differentiation requires the orchestrated activation of numerous intracellular signaling pathways, which promote transcriptional programs required for long‐term B‐cell survival. The aim of this study was to develop a flow cytometry assay to trace the PI3K‐Akt‐mTOR pathway, a critical component of B‐cell homeostasis, and analyze its status in PADs.
Methods
We analyzed the intracellular expression of Akt and S6 by flow cytometry and their phosphorylation status in both baseline conditions and upon B‐cell receptor activation with anti‐IgM in various primary B‐cell subsets of patients with CVID and APDS.
Results
B cells from CVID patients showed reduced phosphorylation in Akt and S6 proteins after anti‐IgM stimulation. Constitutive high baseline B‐cell levels of Akt and S6 phosphorylation in a patient with APDS were reduced once m‐TOR inhibition therapy was initiated.
Conclusions
Intracellular flow cytometry can be routinely employed to explore alterations in the PI3K‐Akt‐mTOR pathway in B cells from patients with PADs. AKT and S6 phosphorylation levels are informative biomarkers that could be employed as mTOR inhibitors for monitoring therapies targeting this pathway.
Common variable immunodeficiency (CVID), the most frequent primary immunodeficiency characterized by loss of B-cell function, depends partly on genetic defects, and epigenetic changes are thought to ...contribute to its aetiology. Here we perform a high-throughput DNA methylation analysis of this disorder using a pair of CVID-discordant MZ twins and show predominant gain of DNA methylation in CVID B cells with respect to those from the healthy sibling in critical B lymphocyte genes, such as PIK3CD, BCL2L1, RPS6KB2, TCF3 and KCNN4. Individual analysis confirms hypermethylation of these genes. Analysis in naive, unswitched and switched memory B cells in a CVID patient cohort shows impaired ability to demethylate and upregulate these genes in transitioning from naive to memory cells in CVID. Our results not only indicate a role for epigenetic alterations in CVID but also identify relevant DNA methylation changes in B cells that could explain the clinical manifestations of CVID individuals.
Currently, there is a need for reliable tests that allow identification of individuals that have been infected with SARS-CoV-2 even if the infection was asymptomatic. To date, the vast majority of ...the serological tests for SARS-CoV-2-specific Abs are based on serum detection of Abs to either the viral spike glycoprotein (the major target for neutralizing Abs) or the viral nucleocapsid protein that is known to be highly immunogenic in other coronaviruses. Conceivably, exposure of Ags released from infected cells could stimulate Ab responses that might correlate with tissue damage and, hence, they may have some value as a prognostic indicator. We addressed whether other nonstructural viral proteins, not incorporated into the infectious viral particle, specifically the viral cysteine-like protease, might also be potent immunogens. Using ELISA tests, coating several SARS-CoV-2 proteins produced in vitro, we describe that COVID-19 patients make high titer IgG, IgM, and IgA Ab responses to the Cys-like protease from SARS-CoV-2, also known as 3CLpro or Mpro, and it can be used to identify individuals with positive serology against the coronavirus. Higher Ab titers in these assays associated with more-severe disease, and no cross-reactive Abs against prior betacoronavirus were found. Remarkably, IgG Abs specific for Mpro and other SARS-CoV-2 Ags can also be detected in saliva. In conclusion, Mpro is a potent Ag in infected patients that can be used in serological tests, and its detection in saliva could be the basis for a rapid, noninvasive test for COVID-19 seropositivity.
Activated phosphoinositide 3-kinase (PI3K)δ syndrome (APDS) is an ultra-rare inborn error of immunity (IEI) combining immunodeficiency and immune dysregulation. This study determined what represents ...value in APDS in Spain from a multidisciplinary perspective applying multicriteria decision analysis (MCDA) methodology.
A multidisciplinary committee of nine experts scored the evidence matrix. A specific framework for orphan drug evaluation in Spain and the weights assigned by a panel of 98 evaluators and decision-makers was used. Re-evaluation of scores was performed.
APDS is considered a very severe disease with important unmet needs, including misdiagnosis and diagnostic delay. Current management is limited to treatment of symptoms with off-label use of therapies supported by limited evidence. Therapeutic benefit is partial, resulting in limited disease control. Haematopoietic stem cell transplantation (HSCT), the only potential curative alternative, is restricted to a reduced patient population and without evidence of long-term efficacy or safety. All options present a limited safety profile. Data on patients' quality of life are lacking. APDS is associated with high pharmacological, medical and indirect costs.
APDS is considered a severe disease, with limited understanding by key stakeholders of how treatment success is assessed in clinical practice, the serious impact that has on patients and the associated high economic burden. This study brings to light how MCDA methodology could represent a useful tool to complement current clinical and decision-making methods used by APDS experts and evaluators.
Heterotrimers composed of B cell CLL/lymphoma 10 (BCL10), mucosa-associated lymphoid tissue lymphoma translocation protein 1 (MALT1), and caspase recruitment domain-containing (CARD) family adaptors ...play a role in NF-κB activation and have been shown to be involved in both the innate and the adaptive arms of immunity in murine models. Moreover, individuals with inherited defects of MALT1, CARD9, and CARD11 present with immunological and clinical phenotypes. Here, we characterized a case of autosomal-recessive, complete BCL10 deficiency in a child with a broad immunodeficiency, including defects of both hematopoietic and nonhematopoietic immunity. The patient died at 3 years of age and was homozygous for a loss-of-expression, loss-of-function BCL10 mutation. The effect of BCL10 deficiency was dependent on the signaling pathway, and, for some pathways, the cell type affected. Despite the noted similarities to BCL10 deficiency in mice, including a deficient adaptive immune response, human BCL10 deficiency in this patient resulted in a number of specific features within cell populations. Treatment of the patient's myeloid cells with a variety of pathogen-associated molecular pattern molecules (PAMPs) elicited a normal response; however, NF-κB-mediated fibroblast functions were dramatically impaired. The results of this study indicate that inherited BCL10 deficiency should be considered in patients with combined immunodeficiency with B cell, T cell, and fibroblast defects.
Common Variable Immunodeficiency (CVID) is characterized by impaired antibody production and poor terminal differentiation of the B cell compartment, yet its pathogenesis is still poorly understood. ...We first reported the occurrence of epigenetic alterations in CVID by high-throughput methylation analysis in CVID-discordant monozygotic twins. Data from a recent whole DNA methylome analysis throughout different stages of normal B cell differentiation allowed us to design a new experimental approach. We selected CpG sites for analysis based on two criteria: one, CpGs with potential association with the transcriptional status of relevant genes for B cell activation and differentiation; and two, CpGs that undergo significant demethylation from naïve to memory B cells in healthy individuals. DNA methylation was analyzed by bisulfite pyrosequencing of specific CpG sites in sorted naïve and memory B cell subsets from CVID patients and healthy donors. We observed impaired demethylation in two thirds of the selected CpGs in CVID memory B cells, in genes that govern B cell-specific processes or participate in B cell signaling. The degree of demethylation impairment associated with the extent of the memory B cell reduction. The impaired demethylation in such functionally relevant genes as
in switched memory B cells correlated with a lower proliferative rate. Our new results reinforce the hypothesis of altered demethylation during B cell differentiation as a contributing pathogenic mechanism to the impairment of B cell function and maturation in CVID. In particular, deregulated epigenetic control of
could play a role in the defective establishment of a post-germinal center B cell compartment in CVID.
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