Activating germline mutations in STAT3 cause early-onset multi-organ autoimmune disease.

NOVEL HETEROZYGOUS SINGLE NUCLEOTIDE POLYMORPHISM IN STAT-3 GENE IN PATIENT WITH SUSPECTED HYPER IGE SYNDROME

Defects along the T H17 differentiation pathway underlie genetically distinct forms of the hyper IgE syndrome

Rationale:Hyper-IgE syndrome (HIES) is a rare primary immunodeficiency presenting as two forms including autosomal dominant HIES (AD-HIES) and autosomal recessive HIES (AR-HIES), which are mainly caused by mutations in STAT3 and DOCK8, respectively. To date, only about 500 cases have been reported worldwide including 37 cases in China. The spectrum and prevalence of mutations and molecular pathogenesis in HIES remain poorly understood.Patient concerns:Here we reported two Chinese children presenting clinical manifestations of HIES.Diagnosis:Based on medical history, clinical manifestations, and laboratory findings, a diagnosis of HIES was made for both children. Targeted next-generation sequencing (NGS) identified a novel heterozygous deletion of 15 bp (c.1960_1974del, p.G654_D658del or alternatively c.1966_1980del, and p.G656_D660del), and a recurrent missense mutation (c.1144C>T, p.R382W) in STAT3 in the two patients, respectively.Interventions:The two patients have been given the successful treatment of skin infections with cefaclor.Outcomes:Both patients have been under follow-up for more than 6 months, with no signs of recurrent infections.Lessons:Our results extend the spectrum of STAT3 mutations associated with ADHIES and highlight the value of targeted NGS in confirming diagnosis of genetic disorders.

Background: Hyper IgE syndrome (HIES) is a primary immunodeficiency with sporadic, autosomal dominant (STAT3 mutation) and autosomal recessive (DOCK8 and TYK2 mutations) inheritance patterns. HIES is characterized by recurrent Staphylococcus infections including lung infections, skin and visceral abcesses, pulmonary pneumatoceles, mucocutaneous candidiasis, and eczematous rash with associated elevated IgE. Patients with STAT3 mutations have additional features including connective tissue, skeletal, dental, and vascular abnormalities. Methods: This case series highlights the clinical presentation, radiographic findings, and immunologic investigations of 4 siblings with HIES caused by STAT3 mutation. Results: Our patients presented with infections including Staphylococcus aureus visceral abscesses, skin lesions, pneumonia with associated pneumatocele, and minimal signs of inflammation such as fever. Additional characteristic features included eczematous rash, scoliosis, fractures, and delayed shedding of primary teeth. Immune investigations were essentially unremarkable apart from elevated IgE and eosinophil counts. Detailed imaging identified infectious processes and associated noninfectious features of STAT3 mutations. Conclusion: Patients presenting with recurrent Staphylococcal cutaneous and visceral infections, pneumatoceles, candidiasis, and eczematous rash with associated elevated IgE should be investigated for STAT3 mutations. This case series highlights the important role of radiographic imaging to identify infectious processes as well as noninfectious associated features in patients with STAT3 mutations. Statement of novelty: Detailed images of morbidity associated with a STAT3 deficiency.

In Allergology International ( AI ) Vol. 61 No. 2, we have 6 Review Articles, 11 Original Articles, and 1 Letter-to-the-Editor report. AI is publishing theme issues that include reviews in important fields of current research activity written by eminent experts. The theme of this issue is “ Primary Immunodeficiency and Related Diseases”. Cutaneous manifestations are displayed as both concomitant or more rarely main symptoms in immunological disorders such as immunedeficiency disease, autoimmune disease, or autoinflammatory disease. Patients with immunedeficiency often have cutaneous abnormalities ( eczema, telangiectasia, molluscum contagiosum, warts, etc.) and chronic eczema is a common problem, including atopic dermatitis-like skin lesion. On the other hand, autoinflammatory disease, which is categorized as a group of inflammatory disorders that are non-infectious, non-allergic, nonautoimmune and non-immuno-deficient, also displays distinctive cutaneous manifestations. 1 Tadashi Ariga discusses about Wiskott-Aldrich syndrome (WAS), including the renewed clinical and basic researches for WAS. WAS is characterized clinically with the triad; immunodeficiency, bleeding tendency with microthrombocytopenia and severe eczema. Topical tacrolimus would be effective in some WAS patients with severe eczema. The pathogenesis of eczema in WAS remains unknown; however, the similar basis for atopic dermatitis could be considered, because high level of IgE and inbalanced cytokine production patterns (Th1 < Th2) are generally observed. 2 Minegishi and Saito discusses comprehensively reviewed hyper-IgE syndrome (HIES). HIES is a complex primary immunodeficiency, characterized by atopic dermatitis-like skin lesion associated with extremely high serum IgE levels and susceptibility to infections with extracellular bacteria and fungi. Yoshiyuki Minegishi is an excellent pioneer for clinical and basic researches of HIES and identified that most of the patients with HIES have dominant negative mutations in STAT3. 3

Reduced expression of chemoattractant receptors by polymorphonuclear leukocytes in Hyper IgE Syndrome patients

Gain-of-function STAT1 mutations are associated with PD-L1 overexpression and a defect in B-cell survival

A CASE OF AUTOSOMAL-DOMINANT HYPER-IGE SYNDROME MASQUERADING AS CYSTIC FIBROSIS

Hyper-IgE syndrome (HIES) is a primary immunodeficiency characterized by recurrent staphylococcal infections and atopic dermatitis associated with elevated serum IgE levels. Although defective differentiation of IL-17-producing CD4(+) T cells (Th17) partly accounts for the susceptibility to staphylococcal skin abscesses and pneumonia, the pathogenesis of atopic manifestations in HIES still remains an enigma. In this study, we examined the differentiation and function of Th1, Th2, regulatory T cells (T(reg) cells), and dendritic cells (DCs) in HIES patients carrying either STAT3 or TYK2 mutations. Although the in vitro differentiation of Th1 and Th2 cells and the number and function of T(reg) cells in the peripheral blood were normal in HIES patients with STAT3 mutations, primary and monocyte-derived DCs showed defective responses to IL-10 and thus failed to become tolerogenic. When treated with IL-10, patient DCs showed impaired up-regulation of inhibitory molecules on their surface, including PD-L1 and ILT-4, compared with control DCs. Moreover, IL-10-treated DCs from patients displayed impaired ability to induce the differentiation of naive CD4(+) T cells to FOXP3(+) induced T(reg) cells (iT(reg) cells). These results suggest that the defective generation of IL-10-induced tolerogenic DCs and iT(reg) cells may contribute to inflammatory changes in HIES.

Large granular lymphocyte (LGL) leukemia is a rare, chronic leukemia associated with clinical manifestations of anemia (RBC < 4.5 million/mcL in males, < 4 million/mcL in females), neutropenia (ANC < 1500/mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> ), and autoimmune disease. Progress has been made in identifying a significant and frequent mutation in the STAT3 gene among LGL patients; however, STAT signaling is still largely unexplained in about 60% of those LGL leukemia patients lacking STAT3 mutations. This paper sought to confirm previous studies regarding the association of a STAT3 mutation with clinical manifestations, as well as search for other significant mutations across the rest of the genome in order to determine whether the specific clinical features of autoimmune disease, anemia, and neutropenia present in LGL leukemia patients are associated with additional genomic mutations in LGL cells. As LGL leukemia is rare, presents heterogeneous conditions, and does not have a high mutation burden, our approach is distinct from standard approaches in cancer research where mutation rates are much higher. Methods of dimension reduction are employed in tandem with association analysis and decision trees to search for signals between significant genetic mutations and clinical manifestations of anemia, neutropenia, and autoimmune disease within the LGL patient sample. Results indicate an association exists between anemia and concurrent mutations in STAT3 and TTN (p = 0.03) in T-LGLL patients. Additionally, an association was identified between neutropenia and a mutation in either TTN (p = 0.049) or STAT3 (p = 0.03) in T-LGLL patients as well. These findings imply that TTN may be responsible for STAT activation in combination with a STAT3 mutation or independently in T-LGLL patients. Through XGBoost, 66% accuracy was achieved in predicting neutropenia and 55% accuracy in predicting anemia using gene mutations as the predictor variables. However, the relatively small sample size (N=116 patients), presents concerns of limited statistical power, and the expectation on the number of times these findings might be repeated in independent samples. The ideal sample size needed for an association test to have adequate statistical power was examined. Additionally, a review of past LGL leukemia publications was undertaken to compare the statistical power of their reported analyses. To obtain satisfactory statistical power in analyzing the association between a STAT3 gene mutation and neutropenia in the T-LGLL population (e.g. p ≤ 0.01, power = 0.9), the T-LGLL sample size must be at least 312 patients. This sample size exceeds not only that of the present study but also that in the majority of sample sizes in the LGLL literature. The pooling of extant LGLL datasets as well as the undertaking of new, major multi-site trials is, therefore, warranted.

Advances in basic and clinical immunology in 2012

STAT1 mutations cause chronic mucocutaneous candidiasis (CMC), while STAT3 mutations cause hyper-IgE syndrome (HIES). CMC and HIES patients have T helper (Th) 17 defects suffering from mucosal Candida infections, but only patients with HIES show an allergic phenotype with eczema, eosinophilia and high IgE levels. We investigated whether differential Th2 and Th9 responses may explain the clinical differences. Peripheral blood mononuclear cells of patients with CMC (n = 4), patients with HIES (n = 4), patients with atopic dermatitis (n = 4) and healthy volunteers (n = 13) were stimulated with Candida and Staphylococcus aureus, with and without IL-4. The cytokines IL-5, IL-13, IL-9, IL-17 and TGFβ and regulatory T cells were measured in cell culture supernatants by ELISA or flow cytometry, respectively. Peripheral blood mononuclear cells of patients with CMC showed a significantly impaired production of the Th2 cytokines IL-5 and IL-13, especially in the presence of IL-4. Moreover, IL-9 production was significantly lower in patients with CMC compared to healthy controls. In contrast, patients with HIES and patients with AD showed normal IL-5 and IL-13 production, while IL-9 production was significantly lower in patients with HIES compared to healthy controls. Although TGFβ was involved in the IL-4-induced IL-9 production, TGFβ levels and the frequency of regulatory T cells did not differ between patients with HIES and controls. Flow cytometry analysis demonstrated an IL-9+ IL-17+ CD4+ subset in healthy controls after stimulation with Candida which was less present in patients with HIES. Patients with CMC have a general Th defect including Th2 and Th9, while patients with HIES have normal Th2 cytokines. These differences are in line with their clinical presentation. Surprisingly, the allergic cytokine IL-9 was deficient in both HIES and CMC, suggesting a Th-17-derived origin.

Inborn errors of immunity, or primary immunodeficiency disorders (PID), are monogenic diseases of the immune system. These affections give rise to complex diseases with a wide range of susceptibility to infections. At one end of the spectrum, severe combined immunodeficiency (SCID) patients, with broad deficiencies in the adaptive immune system, present with a high risk of multiple opportunistic microorganisms, invariably fatal without transplantation. At the other end of the spectrum, PID can be present with very narrow cellular defects and pathogen-specific susceptibility, as seen with predisposition to develop herpes encephalitis in TLR3-deficient patients.1 In addition to the intrinsic value of studying (and curing) such severe diseases, PID patients are proving to be the key to unlocking our knowledge of human immunology. Just as knockout mice have been the tool of choice to understand the basic components of the murine immune system, PID patients provide the chance to study the essential nonredundant functions of each immune gene. From the innate to adaptive immune system, from cellular differentiation pathways to effector molecules, every aspect of the immune response can be affected in PID. In the early 1990s, fewer than five genes were identified as causing PID. The advent of next-generation sequencing, has, however, ushered in the Golden Age of PID research. The number of genes identified as responsible for PID has been rapidly rising, with a new PID gene identified on average every week for the past 10 years.2, 3 Despite the recent explosion of knowledge, a wealth of untapped cases remain to be studied: 90% of the estimated 3000 PID genes have yet to be studied.4 Importantly, each of these unique mutations can advance our understanding of the complexity of the immune system. In this Special Feature, four selected reviews will highlight recent advances in understanding the mechanisms that underlie PID genetics. The in-depth investigations reviewed here explain the susceptibility of different PID patients to specific pathogens, describe the role of precise cellular subsets in human immunity and identify novel regulatory mechanisms of immunological pathways. Fortunately, this understanding of the mechanistic basis of PID often unlocks treatment: unlike common immune diseases, where multiple pathways contribute to pathology, PID often require correction of only a single pathway to reverse disease. We start with the Mendelian susceptibility of mycobacterial disease (MSMD). MSMD has allowed the comprehensive exploration of the IFNγ signaling pathway in humans. While IFNGR1 was the first gene to be identified as responsible for MSMD in the mid-1990s,5, 6 there are now up to 11 different genes involved as a direct cause of MSMD. Importantly, the molecules implicated in this pathway reveal the importance of the cross-talk between innate and adaptive cells for complete elimination of mycobacteria infections. In their article, Rosain et al. review the clinical characteristics of the disease, with a special focus on the new genes recently described to play a mechanistic role.7 The article by Ochs et al. in the Special Feature8 highlights the constant evolution of PID diagnoses, using hyper IgE syndrome (HIES) as a prime example. What was once thought to be a characteristic well-defined clinical syndrome now needs to be revisited and broadened with the addition of new mutations included in the same disease spectrum. Initially defined by mutation in STAT3, this syndrome now encompasses many more mutations, covering multiple distinct molecular pathways. At the same time, mutations initially linked to HIES, such as mutations in TYK2, are now attributed to alternative PID (MSMD, in the TYK2 example). Multiple different PIDs share part of HIES clinical presentation, despite different molecular origins, challenging patient diagnosis. The study of PID is constantly providing unique insights into the healthy immune system. Worley and colleagues review how analysis of patients with STAT mutations can identify mechanisms of action of each gene, and indeed the role of particular domains and residues within each gene.9 The exploration of patients affected with STAT3 loss-of-function and STAT1 gain-of-function allele, and their impact on Th9 differentiation, demonstrate the value in understanding the phenotypic impact of point mutations. Finally, this Special Feature with a focus on PID concludes with a review by Tangye and colleagues on PID with cytoskeleton dysfunction.10 For a long time, Wiskott–Aldrich syndrome was the only cytoskeleton associated disorder, discovered in the mid-1950s. However, as attested in this featured review, there are now more than 10 molecules associated with this specific disorder, described within the last 10 years. The extensive and rapid growth of knowledge in the field of cytoskeleton dysfunction is a microcosm of the advancements within the broader PID field.

STAT3 mutation-associated airway epithelial defects in Job syndrome

Phenotyping and long-term follow up of patients with hyper IgE syndrome