An autosomal-dominant form of hyper-IgE syndrome caused by mutations in signal transducer and activator of transcription 3 is characterized by elevated IgE, eosinophilia, eczema, recurrent skin and ...pulmonary infections, and skeletal abnormalities.1 Recently, an autosomal recessive form of hyper-IgE syndrome caused by mutations in the dedicator of cytokinesis 8 (DOCK8) gene has been identified and is characterized by elevated IgE levels, eosinophilia, atopic dermatitis, asthma, food allergies, recurrent upper and lower respiratory tract infections, and unusual susceptibility to infections with herpesvirus family members (herpes simplex virus, human papilloma virus) and molluscum contagiosum.2,3 Cutaneous infections with human papilloma virus have progressed to squamous cell carcinomas in some cases. Furthermore, early diagnosis of this newly discovered immune deficiency before repeated infectious injury will likely optimize clinical outcomes after HCT. Because DOCK8 is expressed in both hematopoietic and nonhematopoietic tissues, further experience and long-term follow-up will be needed to determine whether correction of the hematopoietic compartment is sufficient to protect DOCK8-deficient patients from infection and cancer.
Background Primary immunodeficiency diseases (PIDDs) are inherited disorders of the immune system. The most severe form, severe combined immunodeficiency (SCID), presents with profound deficiencies ...of T cells, B cells, or both at birth. If not treated promptly, affected patients usually do not live beyond infancy because of infections. Genetic heterogeneity of SCID frequently delays the diagnosis; a specific diagnosis is crucial for life-saving treatment and optimal management. Objective We developed a next-generation sequencing (NGS)–based multigene-targeted panel for SCID and other severe PIDDs requiring rapid therapeutic actions in a clinical laboratory setting. Methods The target gene capture/NGS assay provides an average read depth of approximately 1000×. The deep coverage facilitates simultaneous detection of single nucleotide variants and exonic copy number variants in one comprehensive assessment. Exons with insufficient coverage (<20× read depth) or high sequence homology (pseudogenes) are complemented by amplicon-based sequencing with specific primers to ensure 100% coverage of all targeted regions. Results Analysis of 20 patient samples with low T-cell receptor excision circle numbers on newborn screening or a positive family history or clinical suspicion of SCID or other severe PIDD identified deleterious mutations in 14 of them. Identified pathogenic variants included both single nucleotide variants and exonic copy number variants, such as hemizygous nonsense, frameshift, and missense changes in IL2RG ; compound heterozygous changes in ATM , RAG1 , and CIITA ; homozygous changes in DCLRE1C and IL7R ; and a heterozygous nonsense mutation in CHD7. Conclusion High-throughput deep sequencing analysis with complete clinical validation greatly increases the diagnostic yield of severe primary immunodeficiency. Establishing a molecular diagnosis enables early immune reconstitution through prompt therapeutic intervention and guides management for improved long-term quality of life.
...CD45+lin-CD3-CD90.2+IL7R+ innate lymphoid cells and CD45+CD3-NKp46+ natural killer cells could be detected in the skin of all 4 strains (see Fig E1, C and D).
Background B cells receive activating signals from T cells through CD40, from microbial DNA through Toll-like receptor (TLR) 9, and from dendritic cells through transmembrane activator and ...calcium-modulating cyclophilin ligand interactor (TACI). TLR9 and CD40 ligation augment TACI-driven B-cell activation, but only the mechanism of synergy between CD40 and TACI has been explored. Synergy between CD40 and TLR9 in B-cell activation is controversial. Objective We sought to examine the mechanisms by which TLR9 modulates CD40- and TACI-mediated activation of B cells and to determine whether all 3 receptors synergize to activate B cells. Methods Naive murine B cells and human PBMCs were stimulated with combinations of anti-CD40, CpG, and a proliferation inducing ligand in the presence of IL-4. Proliferation was measured by means of tritiated thymidine incorporation. Immunoglobulin production was measured by means of ELISA. Class-switch recombination (CSR) was examined by measuring mRNA for germline transcripts, activation-induced cytidine deaminase (AICDA) , and mature immunoglobulin transcripts. Plasma cell differentiation was examined by using syndecan-1/CD138 staining and mRNA expression of B lymphocyte–induced maturation protein 1 (Blimp-1). Results TLR9 synergized with CD40 and TACI in driving CSR and inducing IgG1 and IgE secretion by naive murine B cells and synergized with TACI in driving B-cell proliferation and plasma cell differentiation. All 3 receptors synergized together in driving murine B-cell proliferation, CSR, plasma cell differentiation, and IgG1 and IgE secretion. TLR9 synergized with CD40 and TACI in driving IgG secretion in IL-4–stimulated human B cells. Conclusion Signals from TLR9, TACI, and CD40 are integrated to promote B-cell activation and differentiation.
Background Nuclear factor κB (NF-κB) is a master transcriptional regulator critical for ectodermal development and normal innate and adaptive immune function. Mutations in the IκB kinase γ/NF-κB ...essential modifier have been described in male subjects with the syndrome of X-linked ectodermal dysplasia with immune deficiency that results from impaired activation of NF-κB. Objectives We sought to determine the genetic cause of ectodermal dysplasia with immune deficiency in a female patient. Methods Toll-like receptor–induced production of the NF-κB–dependent cytokines TNF-α and IFN-α was examined by means of ELISA, the patient's IκBα gene was sequenced, and NF-κB activation was evaluated by means of electrophoretic mobility shift assay and NF-κB–luciferase assays in transfectants. Results Toll-like receptor function was impaired in the patient. Sequencing of the patient's IκBα gene revealed a novel heterozygous mutation at amino acid 11 (W11X). The mutant IκBαW11X protein did not undergo ligand-induced phosphorylation or degradation and retained NF-κB in the cytoplasm. This led to roughly a 50% decrease in NF-κB DNA-binding activity, leading to functional haploinsufficiency of NF-κB activation. Unlike the only other reported IκBα mutant associated with ectodermal dysplasia associated with immune deficiency (ED-ID), S32I, IκBαW11X exerted no dominant-negative effect. Conclusions Functional NF-κB haploinsufficiency was associated with ED-ID, and this strongly suggests that normal ectodermal development and immune function are stringently dependent on NF-κB in that they might require more than half of normal NF-κB activity. Clinical implications Although ED-ID is well described in male subjects, female subjects can present with a similar syndrome of ectodermal dysplasia with immune deficiency resulting from mutations in autosomal genes within the NF-κB pathway.
Abstract Whole exome sequencing is increasingly used in the diagnosis of primary immunodeficiencies due to the overlapping and atypical presentations of these disorders. We report two patients who ...presented with recurrent infections and early onset colitis. They were investigated by whole exome sequencing due to suspicion of primary immunodeficiency and found to have mutations in pyrin known to cause familial Mediterranean fever.
Background Transmembrane activator and calcium modulator and cyclophilin ligand interactor (TACI) is a receptor used by B cell–activating factor of the TNF family and a proliferation-inducing ligand ...(APRIL) to induce isotype switching independently of CD40 and is mutated in patients with common variable immunodeficiency. Objective We sought to determine whether TACI and CD40 cooperate in inducing class switch recombination and immunoglobulin production. Methods Naive mouse B cells were stimulated with suboptimal concentrations of anti-CD40 plus IL-4 in the presence or absence of APRIL or anti-TACI. IgG1 and IgE production was measured by means of ELISA. mRNA for Cγ1 and Cε germ-line transcripts, activation-induced cytidine deaminase, and mature γ1 and ε transcripts were measured by means of RT-PCR. Plasmablasts were enumerated by using syndecan-1/CD138 staining. Interferon regulatory factor 4, B lymphocyte–induced maturation protein 1, and IL6 mRNA expression was measured by using quantitative PCR. Results TACI ligation enhanced IgG1 and IgE secretion by naive murine B cells stimulated by anti-CD40 plus IL-4, with little effect on B-cell proliferation or class switch recombination. In contrast, TACI ligation of anti-CD40 plus IL-4–stimulated B cells induced a significant increase in syndecans-1/CD138–positive cells. TACI ligation caused a modest but significant increase in the expression of interferon regulatory factor 4, with no detectable change in B lymphocyte–induced maturation protein 1 expression. Conclusion TACI and CD40 signaling converge to promote B-cell differentiation into plasmablasts. Clinical implications Our data suggest that TACI dysfunction could contribute to the impaired antibody response to T-dependent antigens in common variable immunodeficiency.
Signaling by the intracellular domain mutants (K188M and V246F) was intact. Because TACI assembles as a trimer or higher-order oligomer,6 TACI mutants with disrupted function might potentially exert ...a dominant-negative (DN) effect on signaling by WT TACI in heterozygotes. 293T cells were cotransfected with equal amounts of WT TACI and either empty vector or TACI mutant cDNA, and ligand-driven NF-κB activity was measured.
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