Reduced bone density in patients with autosomal dominant hyper-IgE syndrome.

BACKGROUND AND PURPOSE: Autosomal dominant hyper-IgE syndrome (AD-HIES) is a rare primary immunodeficiency disorder . It has been recognized as a multisystem disorder and is characterized by both immunologic and non-immunologic manifestations. Possible bone involvement in autosomal dominant HIES include fractures, scoliosis, cystic bone changes, and osteopenia. We sought to evaluate the changes in bone density in adolescents and young adults with AD-HIES, mostly with proven STAT3 mutation, followed in our institute. METHODS: We studied eight patients with AD-HIES who attended our immunology clinic. All patients underwent at least one bone mass dual-energy x-ray absorptiometry assessment (dual-energy x-ray absorptiometry scan).These findings were evaluated. RESULTS: The age of the patients at the time of their first bone density scan ranged between 10 and 24 years (mean 16.1 ± 4.0 years); the duration of follow-up was 4-11 years (mean 5.8 ± 3.5 years). Four patients had a history of fractures. Mean Z score in these patients was -1.8 ± 0.7. For three patients, Z score was below -1. The other four patients had no history of fractures. Mean Z score in these patients was -0.9 ± 0.5. Only one patient in this group had a Z score below -1. Bone density was below average in all patients; mean spinal Z score was -1.6 ± 0.4. Four patients were followed through the second decade, and all showed progressive deterioration in bone density. Three were treated with alendronate sodium, with improvement in the bone scan results. CONCLUSIONS: Bone density decreases considerably over time in adolescents and young adults suffering from AD- HIES. Treatment with alendronate sodium may be effective in alleviating osteopenia.

A homozygous CARD9 mutation in a family with susceptibility to fungal infections.

BACKGROUND: Chronic mucocutaneous candidiasis may be manifested as a primary immunodeficiency characterized by persistent or recurrent infections of the mucosa or the skin with candida species. Most cases are sporadic, but both autosomal dominant inheritance and autosomal recessive inheritance have been described. METHODS: We performed genetic studies in 36 members of a large, consanguineous five-generation family, in which 4 members had recurrent fungal infections and an additional 3 members died during adolescence, 2 after invasive infection of the brain with candida species. All 36 family members were enrolled in the study, and 22 had blood samples taken for DNA analysis. Homozygosity mapping was used to locate the mutated gene. In the 4 affected family members (patients) and the 18 unaffected members we sequenced CARD9, the gene encoding the caspase recruitment domain-containing protein 9, carried out T-cell phenotyping, and performed functional studies, with the use of either leukocytes from the patients or a reconstituted murine model of the genetic defect. RESULTS: We found linkage (lod score, 3.6) to a genomic interval on chromosome 9q, including CARD9. All four patients had a homozygous point mutation in CARD9, resulting in a premature termination codon (Q295X). Healthy family members had wild-type expression of the CARD9 protein; the four patients lacked wild-type expression, which was associated with low numbers of Th17 cells (helper T cells producing interleukin-17). Functional studies based on genetic reconstitution of myeloid cells from Card9(-/-) mice showed that the Q295X mutation impairs innate signaling from the antifungal pattern-recognition receptor dectin-1. CONCLUSIONS: An autosomal recessive form of susceptibility to chronic mucocutaneous candidiasis is associated with homozygous mutations in CARD9.

Inflammatory bowel disease and mutations affecting the interleukin-10 receptor.

BACKGROUND: The molecular cause of inflammatory bowel disease is largely unknown. METHODS: We performed genetic-linkage analysis and candidate-gene sequencing on samples from two unrelated consanguineous families with children who were affected by early-onset inflammatory bowel disease. We screened six additional patients with early-onset colitis for mutations in two candidate genes and carried out functional assays in patients' peripheral-blood mononuclear cells. We performed an allogeneic hematopoietic stem-cell transplantation in one patient. RESULTS: In four of nine patients with early-onset colitis, we identified three distinct homozygous mutations in genes IL10RA and IL10RB, encoding the IL10R1 and IL10R2 proteins, respectively, which form a heterotetramer to make up the interleukin-10 receptor. The mutations abrogate interleukin-10-induced signaling, as shown by deficient STAT3 (signal transducer and activator of transcription 3) phosphorylation on stimulation with interleukin-10. Consistent with this observation was the increased secretion of tumor necrosis factor alpha and other proinflammatory cytokines from peripheral-blood mononuclear cells from patients who were deficient in IL10R subunit proteins, suggesting that interleukin-10-dependent "negative feedback" regulation is disrupted in these cells. The allogeneic stem-cell transplantation performed in one patient was successful. CONCLUSIONS: Mutations in genes encoding the IL10R subunit proteins were found in patients with early-onset enterocolitis, involving hyperinflammatory immune responses in the intestine. Allogeneic stem-cell transplantation resulted in disease remission in one patient.

Mutations in STAT3 and diagnostic guidelines for hyper-IgE syndrome.

BACKGROUND: The hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by infections of the lung and skin, elevated serum IgE, and involvement of the soft and bony tissues. Recently, HIES has been associated with heterozygous dominant-negative mutations in the signal transducer and activator of transcription 3 (STAT3) and severe reductions of T(H)17 cells. OBJECTIVE: To determine whether there is a correlation between the genotype and the phenotype of patients with HIES and to establish diagnostic criteria to distinguish between STAT3 mutated and STAT3 wild-type patients. METHODS: We collected clinical data, determined T(H)17 cell numbers, and sequenced STAT3 in 100 patients with a strong clinical suspicion of HIES and serum IgE >1000 IU/mL. We explored diagnostic criteria by using a machine-learning approach to identify which features best predict a STAT3 mutation. RESULTS: In 64 patients, we identified 31 different STAT3 mutations, 18 of which were novel. These included mutations at splice sites and outside the previously implicated DNA-binding and Src homology 2 domains. A combination of 5 clinical features predicted STAT3 mutations with 85% accuracy. T(H)17 cells were profoundly reduced in patients harboring STAT3 mutations, whereas 10 of 13 patients without mutations had low (<1%) T(H)17 cells but were distinct by markedly reduced IFN-gamma-producing CD4(+)T cells. CONCLUSION: We propose the following diagnostic guidelines for STAT3-deficient HIES. Possible: IgE >1000IU/mL plus a weighted score of clinical features >30 based on recurrent pneumonia, newborn rash, pathologic bone fractures, characteristic face, and high palate. Probable: These characteristics plus lack of T(H)17 cells or a family history for definitive HIES. Definitive: These characteristics plus a dominant-negative heterozygous mutation in STAT3.

STAT3 mutations in the hyper-IgE syndrome.

BACKGROUND: The hyper-IgE syndrome (or Job's syndrome) is a rare disorder of immunity and connective tissue characterized by dermatitis, boils, cyst-forming pneumonias, elevated serum IgE levels, retained primary dentition, and bone abnormalities. Inheritance is autosomal dominant; sporadic cases are also found. METHODS: We collected longitudinal clinical data on patients with the hyper-IgE syndrome and their families and assayed the levels of cytokines secreted by stimulated leukocytes and the gene expression in resting and stimulated cells. These data implicated the signal transducer and activator of transcription 3 gene (STAT3) as a candidate gene, which we then sequenced. RESULTS: We found increased levels of proinflammatory gene transcripts in unstimulated peripheral-blood neutrophils and mononuclear cells from patients with the hyper-IgE syndrome, as compared with levels in control cells. In vitro cultures of mononuclear cells from patients that were stimulated with lipopolysaccharide, with or without interferon-gamma, had higher tumor necrosis factor alpha levels than did identically treated cells from unaffected persons (P=0.003). In contrast, the cells from patients with the hyper-IgE syndrome generated lower levels of monocyte chemoattractant protein 1 in response to the presence of interleukin-6 (P=0.03), suggesting a defect in interleukin-6 signaling through its downstream mediators, one of which is STAT3. We identified missense mutations and single-codon in-frame deletions in STAT3 in 50 familial and sporadic cases of the hyper-IgE syndrome. Eighteen discrete mutations, five of which were hot spots, were predicted to directly affect the DNA-binding and SRC homology 2 (SH2) domains. CONCLUSIONS: Mutations in STAT3 underlie sporadic and dominant forms of the hyper-IgE syndrome, an immunodeficiency syndrome involving increased innate immune response, recurrent infections, and complex somatic features.

Pneumocystis jirovecii pneumonia in a baby with hyper-IgE syndrome.

A 4-month-old baby with a family history of hyper-IgE syndrome acquired Pneumocystis jirovecii pneumonia. The patient's hyper-IgE syndrome score was low, but a genetic study yielded a STAT3 mutation. P. jirovecii pneumonia can be added to the infections associated with hyper-IgE syndrome. In some cases, it may be the presenting manifestation of this immunodeficiency.

Large deletions and point mutations involving the dedicator of cytokinesis 8 (DOCK8) in the autosomal-recessive form of hyper-IgE syndrome.

BACKGROUND: The genetic etiologies of the hyper-IgE syndromes are diverse. Approximately 60% to 70% of patients with hyper-IgE syndrome have dominant mutations in STAT3, and a single patient was reported to have a homozygous TYK2 mutation. In the remaining patients with hyper-IgE syndrome, the genetic etiology has not yet been identified. OBJECTIVES: We aimed to identify a gene that is mutated or deleted in autosomal recessive hyper-IgE syndrome. METHODS: We performed genome-wide single nucleotide polymorphism analysis for 9 patients with autosomal-recessive hyper-IgE syndrome to locate copy number variations and homozygous haplotypes. Homozygosity mapping was performed with 12 patients from 7 additional families. The candidate gene was analyzed by genomic and cDNA sequencing to identify causative alleles in a total of 27 patients with autosomal-recessive hyper-IgE syndrome. RESULTS: Subtelomeric biallelic microdeletions were identified in 5 patients at the terminus of chromosome 9p. In all 5 patients, the deleted interval involved dedicator of cytokinesis 8 (DOCK8), encoding a protein implicated in the regulation of the actin cytoskeleton. Sequencing of patients without large deletions revealed 16 patients from 9 unrelated families with distinct homozygous mutations in DOCK8 causing premature termination, frameshift, splice site disruption, and single exon deletions and microdeletions. DOCK8 deficiency was associated with impaired activation of CD4+ and CD8+T cells. CONCLUSION: Autosomal-recessive mutations in DOCK8 are responsible for many, although not all, cases of autosomal-recessive hyper-IgE syndrome. DOCK8 disruption is associated with a phenotype of severe cellular immunodeficiency characterized by susceptibility to viral infections, atopic eczema, defective T-cell activation and T(h)17 cell differentiation, and impaired eosinophil homeostasis and dysregulation of IgE.

An antibody-deficiency syndrome due to mutations in the CD19 gene.

BACKGROUND: The CD19 protein forms a complex with CD21, CD81, and CD225 in the membrane of mature B cells. Together with the B-cell antigen receptor, this complex signals the B cell to decrease its threshold for activation by the antigen. METHODS: We evaluated four patients from two unrelated families who had increased susceptibility to infection, hypogammaglobulinemia, and normal numbers of mature B cells in blood. We found a mutation in the CD19 gene in all four patients. The CD19 gene in the patients and their first-degree relatives was sequenced, and flow-cytometric immunophenotyping of B cells, immunohistochemical staining of lymphoid tissues, and DNA and messenger RNA analysis were performed. B-cell responses on the triggering of the B-cell receptor were investigated by in vitro stimulation; the antibody response after vaccination with rabies vaccine was also studied. RESULTS: All four patients had homozygous mutations in the CD19 gene. Levels of CD19 were undetectable in one patient and substantially decreased in the other three. Levels of CD21 were decreased, whereas levels of CD81 and CD225 were normal, in all four patients. The composition of the precursor B-cell compartment in bone marrow and the total numbers of B cells in blood were normal. However, the numbers of CD27+ memory B cells and CD5+ B cells were decreased. Secondary follicles in lymphoid tissues were small to normal in size and had a normal cellular composition. The few B cells that showed molecular signs of switching from one immunoglobulin class to another contained V(H)-C(alpha) and V(H)-C(gamma) transcripts with somatic mutations. The response of the patients' B cells to in vitro stimulation through the B-cell receptor was impaired, and in all four patients, the antibody response to rabies vaccination was poor. CONCLUSIONS: Mutation of the CD19 gene causes a type of hypogammaglobulinemia in which the response of mature B cells to antigenic stimulation is defective.

Screening of functional and positional candidate genes in families with common variable immunodeficiency.

BACKGROUND: Common variable immunodeficiency (CVID) comprises a heterogeneous group of primary antibody deficiencies with complex clinical and immunological phenotypes. The recent discovery that some CVID patients show monogenic defects in the genes encoding ICOS, TACI or CD19 prompted us to investigate several functional candidate genes in individuals with CVID. RESULTS: The exonic, protein coding regions of the genes encoding: APRIL, BCMA, IL10, IL10Ralpha, IL10Rbeta, IL21, IL21R, and CCL18, were analyzed primarily in familial CVID cases, who showed evidence of genetic linkage to the respective candidate gene loci and CVID families with a recessive pattern of inheritance. Two novel SNPs were identified in exon 5 and exon 8 of the IL21R gene, which segregated with the disease phenotype in one CVID family. Eleven additional SNPs in the genes encoding BCMA, APRIL, IL10, IL10Ralpha, IL21 and IL21R were observed at similar frequencies as in healthy donors. CONCLUSION: We were unable to identify obvious disease causing mutations in the protein coding regions of the analyzed genes in the studied cohort.

Toll-like receptor stimulation induces higher TNF-alpha secretion in peripheral blood mononuclear cells from patients with hyper IgE syndrome.

Hyper IgE syndromes (HIES) are primary immunodeficiency disorders of unknown pathogenesis. Patients are typically affected with 'cold' abscesses of the skin, recurrent cyst-forming pneumonia, chronic mucocutaneous candidiasis and other less frequent features such as progressive skeletal abnormalities. Defective signaling in the Toll-like receptor (TLR) pathways has been suggested as a responsible pathologic mechanism, however, in previous reports, 10 patients revealed no defect in inflammatory cytokine responses to different TLR ligands. Here, we report the increase in pro-inflammatory cytokines TNF-alpha and IL-8, following TLR2 and TLR4 stimulation in a larger cohort of 25 additional patients with HIES, and provide a meta-analysis of the TLR data in HIES.

Community acquired Staphylococcus aureus meningitis and cerebral abscesses in a patient with a hyper-IgE and a Dubowitz-like syndrome.

The Hyper-IgE syndrome (HIES) is a rare primary immunodeficiency which recently has been associated with heterozygous dominant-negative mutations in the signal transducer and activator of transcription 3 (STAT3). Although HIES is characterized by recurrent staphylococcal infections, the microbial invasion of the central nervous system (CNS) is definitively uncommon. We here report on Staphylococcus aureus meningitis and cerebral abscesses acquired in the community in a 31-year-old female patient with a de novo heterozygous mutation of STAT3 and a Dubowitz-like syndrome characterized by growth retardation, microcephaly and eczema. The patient presented with a relative paucity of clinical symptoms despite severe cerebrospinal fluid pathology and multiple cerebral abscesses. Antimicrobial as well as treatment with intravenous immunoglobulin was well tolerated and led to a slow recovery over a 6 months period. Our observation adds community acquired S. aureus meningitis to the list of life-threatening infections in STAT3-deficient HIES and should also raise awareness for the unusual clinical presentation of severe neuroinfection in this syndrome. Whether the association of HIES with Dubowitz-like syndrome was purely coincidental, possibly supportive of the CNS infection, or suggests a genetic overlap of these syndromes, awaits clarification.

The hyper-IgE syndrome is not caused by a microdeletion syndrome.

The hyper-immunoglobulin E syndrome (HIES) is a rare primary immunodeficiency characterized by recurrent infections, elevated serum IgE-levels, and involvement of the soft- and bony tissues. We speculated that this complex disease may be caused by a microdeletion syndrome. We therefore analyzed 30 sporadic HIES patients for the presence of chromosomal imbalances using Affymetrix 50k XbaI and 23 of the 30 patients with the higher-resolution 250k StyI SNP mapping arrays. We detected only eight different copy number alterations in six patients with the 50k approach, and seven of these presented known polymorphic regions not associated with disease. However, one patient showed a unique gain on chromosome 20p. 250k array analysis identified this gain as a rare polymorphism segregating in the patient's family, but not associated with the HIES phenotype. In addition, 265 known and novel copy number variants (CNVs) were identified with the 250k arrays, but no recurrent imbalances reminescent of a microdeletion syndrome were found. We aligned the identified CNVs with loci that have been associated with HIES or phenotypically overlapping syndromes. Doing so, a 2-Mb deletion spanning the PEPD gene on 19q13.11 was identified on one allele of one patient. Homozygous mutations in PEPD are responsible for the autosomal-recessive prolidase deficiency which resembles HIES in some aspects. Sequencing of the healthy allele, however, revealed a wild-type sequence. In summary, our results suggest that HIES is not likely to be a microdeletion syndrome.