X-Linked syndrome of polyendocrinopathy, immune dysfunction, and diarrhea maps to Xp11.23-Xq13.3

Increased miR-6132 promotes deep vein thrombosis formation by downregulating FOXP3 expression

Background

Deep vein thrombosis (DVT) is associated with aberrant gene expression that is a common peripheral vascular disease. Here, we aimed to elucidate that the epigenetic modification of forkhead box protein 3 (FOXP3) at the post-transcriptional level, which might be the key trigger leading to the down-regulation of FOXP3 expression in DVT.

Methods

In order to explore the relationship between microRNAs (miRNAs) and FOXP3, mRNA and microRNA microarray analysis were performed. Dual luciferase reporter assay was used to verify the upstream miRNAs of FOXP3. Quantitative real-time polymerase chain reaction, flow cytometry and Western blot were used to detect the relative expression of miR-6132 and FOXP3. Additionally, DVT models were established to investigate the role of miR-6132 by Murine Doppler Ultrasound and Hematoxylin-Eosin staining.

Results

Microarray and flow cytometry results showed that the FOXP3 expression was decreased while miR-6132 level was increased substantially in DVT, and there was significant negative correlation between miR-6132 and FOXP3. Moreover, we discovered that overexpressed miR-6132 reduced FOXP3 expression and aggravated DVT formation, while miR-6132 knockdown increased FOXP3 expression and alleviated DVT formation. Dual luciferase reporter assay validated the direct binding of miR-6132 to FOXP3.

Conclusion

Collectively, our data elucidate a new avenue through which up-regulated miR-6132 contributes to the formation and progression of DVT by inhibiting FOXP3 expression.

Genes and Microbiota Interaction in Monogenic Autoimmune Disorders

Monogenic autoimmune disorders represent an important tool to understand the mechanisms behind central and peripheral immune tolerance. Multiple factors, both genetic and environmental, are known to be involved in the alteration of the immune activation/immune tolerance homeostasis typical of these disorders, making it difficult to control the disease. The latest advances in genetic analysis have contributed to a better and more rapid diagnosis, although the management remains confined to the treatment of clinical manifestations, as there are limited studies on rare diseases. Recently, the correlation between microbiota composition and the onset of autoimmune disorders has been investigated, thus opening up new perspectives on the cure of monogenic autoimmune diseases. In this review, we will summarize the main genetic features of both organ-specific and systemic monogenic autoimmune diseases, reporting on the available literature data on microbiota alterations in these patients.

Immune checkpoint blockade enhances chemophototherapy in a syngeneic pancreatic tumor model

Pancreatic cancer (PaCa) suffers from poor treatment options for locally advanced cases. Chemophototherapy (CPT) is an emerging anti-tumor modality, and porphyrin–phospholipid liposomes have been shown to be versatile drug carriers for CPT in preclinical rodent models. Here we show that in the syngeneic subcutaneous KPC PaCa tumor model, exhausted CD8⁺ T cells are localized in the tumor, and that CPT is enhanced in combination with immune checkpoint blockade (ICB). Addition of ICB using anti-programmed cell death 1 (PD-1) and cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) antibodies resulted in ablation of medium-sized, established KPC tumors (∼200 mm³) without recurrence for over 100 days. Mice rejected subsequent tumor re-challenge. Flow cytometry and tumor slice analysis following injection of a fluorescently labeled anti-PD-1 antibody showed that CPT improved antibody delivery to the tumor microenvironment. Treatment of large established tumors (∼400 mm³) using with CPT and ICB induced appreciable tumor regression and delay in regrowth. Taken together, these data demonstrate the utility of combining CPT with immunotherapies.

Differences in potential key genes and pathways between primary and radiation-associated angiosarcoma of the breast

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Angiosarcoma of the breast is a high-grade malignant soft tissue tumor, it can be divided into primary and secondary.

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The differences between primary and secondary angiosarcomas in terms of pathogenesis, clinical behavior, early diagnosis biomarkers, genetic abnormalities, and therapeutic targets remain to be fully elucidated.

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Due to its rarity, most of the current information relating to angiosarcoma is provided by case reports and single-institution retrospective cohort studies and the research with large-scale genomic studies published to date are very limited.

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We identified the differentially expressed genes (DEGs) between primary and second breast angiosarcomas and identified the hub genes as well as predicted novel biomarkers, pathways, and potential therapeutic targets for primary and secondary breast angiosarcomas.

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We aimed to identify novel biomarkers, pathways, and potential therapeutic targets for primary and secondary breast angiosarcomas to facilitate future research.

Background

Angiosarcoma of the breast is a high-grade malignant soft tissue tumor, it can be divided into primary and radiation-associated angiosarcoma(secondary). However, the differences between primary and secondary angiosarcomas in terms of pathogenesis, clinical behavior, early diagnosis biomarkers, genetic abnormalities, and therapeutic targets remain to be fully elucidated. At the same time, due to its rarity, most of current information relating to angiosarcoma is provided by case reports. Therefore, exploring the mechanisms of primary and secondary breast angiosarcoma have important value for the discovery of new biomarkers and research into potential therapeutic targets.

Methods

The differentially expressed genes (DEGs) between 36 cases of primary angiosarcoma and 54 cases of secondary angiosarcoma were screened. Then, the DEGs were used to gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Then, a protein-protein interaction (PPI) network was constructed using the STRING database.

Results

A total of 18 DEGs were identified, of which 13 were upregulated and 5 were downregulated in secondary breast angiosarcoma. The GO enrichment analysis showed that the DEGs were most enriched in metabolism, energy pathways, and protein metabolism in biological processes. The enriched signaling pathways of DEGs were the transforming growth factor-β (TGF-β), Wnt, Hippo and PI3K-Akt signaling pathways. Then, the PPI network was conducted and hub genes were identified and they were involved in thyroid hormone, Hippo and other signaling pathways.

Conclusion

This study lay the foundation for the discovery of effective and reliable molecular biomarkers and essential therapeutic targets for these malignancies.

The Importance of the Transcription Factor Foxp3 in the Development of Primary Immunodeficiencies

Transcription factors are an extremely important group of proteins that are responsible for the process of selective activation or deactivation of other cellular proteins, usually at the last stage of signal transmission in the cell. An important family of transcription factors that regulate the body’s response is the FOX family which plays an important role in regulating the expression of genes involved in cell growth, proliferation, and differentiation. The members of this family include the intracellular protein Foxp3, which regulates the process of differentiation of the T lymphocyte subpopulation, and more precisely, is responsible for the development of regulatory T lymphocytes. This protein influences several cellular processes both directly and indirectly. In the process of cytokine production regulation, the Foxp3 protein interacts with numerous proteins and transcription factors such as NFAT, nuclear factor kappa B, and Runx1/AML1 and is involved in the process of histone acetylation in condensed chromatin. Malfunctioning of transcription factor Foxp3 caused by the mutagenesis process affects the development of disorders of the immune response and autoimmune diseases. This applies to the impairment or inability of the immune system to fight infections due to a disruption of the mechanisms supporting immune homeostasis which in turn leads to the development of a special group of disorders called primary immunodeficiencies (PID). The aim of this review is to provide information on the role of the Foxp3 protein in the human body and its involvement in the development of two types of primary immunodeficiency diseases: IPEX (Immunodysregulation Polyendocrinopathy Enteropathy X-linked syndrome) and CVID (Common Variable Immunodeficiency).

Immunohistochemical expression of FOXP3 in gastric carcinoma; its relation to Ki-67 proliferation marker, HER2/neu expression, and other clinicopathological parameters

Gastric cancer is common cancer in the world. Contradictory results regarding FOXP3 expression in gastric carcinoma were detected and the role of Ki-67 in prognosis is not completely understood. Furthermore, due to increasing use of anti-HER2 drug trastuzumab for gastric cancer, assessment of HER2 expression becomes important. This study tried to assess the FOXP3 expression in gastric carcinoma and to study the relation between its expression and Ki-67 and HER2/neu expression and relation between their expression and other clinicopathological variables. This retrospective study was carried out on 60 gastric adenocarcinoma cases. Tissue microarrays and immunohistochemical staining for FOXP3, Ki-67 and HER2/neu were done and then assessed and scored. HER2/neu expression showed significant relation to Lauren histological type and lymph node status. High Ki-67 index was related significantly to patients' age, lympho-vascular tumor emboli, peri-neural invasion, tumor grade, lymph node status, and cancer stage. There was significant relation between high FOXP3 expression and patients' age, lympho-vascular tumor emboli, peri-neural invasion, tumor grade, lymph node status, and cancer stage. Direct positive significant relationships between HER2/neu, Ki-67, and FOXP3 expression were noticed. Finally, high FOXP3 expression, positive HER2/neu, and high Ki-67 nuclear proliferation index may be an indication of the aggressiveness of gastric carcinoma.

Intestinal immunoregulation: lessons from human mendelian diseases

The mechanisms that maintain intestinal homeostasis despite constant exposure of the gut surface to multiple environmental antigens and to billions of microbes have been scrutinized over the past 20 years with the goals to gain basic knowledge, but also to elucidate the pathogenesis of inflammatory bowel diseases (IBD) and to identify therapeutic targets for these severe diseases. Considerable insight has been obtained from studies based on gene inactivation in mice as well as from genome wide screens for genetic variants predisposing to human IBD. These studies are, however, not sufficient to delineate which pathways play key nonredundant role in the human intestinal barrier and to hierarchize their respective contribution. Here, we intend to illustrate how such insight can be derived from the study of human Mendelian diseases, in which severe intestinal pathology results from single gene defects that impair epithelial and or hematopoietic immune cell functions. We suggest that these diseases offer the unique opportunity to study in depth the pathogenic mechanisms leading to perturbation of intestinal homeostasis in humans. Furthermore, molecular dissection of monogenic intestinal diseases highlights key pathways that might be druggable and therapeutically targeted in common forms of IBD.

Post-Translational Modifications in Transcription Factors that Determine T Helper Cell Differentiation

CD4+ T helper (Th) cells play a crucial role in the modulation of innate and adaptive immune responses through the differentiation of Th precursor cells into several subsets, including Th1, Th2, Th17, and regulatory T (Treg) cells. Effector Th and Treg cells are distinguished by the production of signature cytokines and are important for eliminating intracellular and extracellular pathogens and maintaining immune homeostasis. Stimulation of naïve Th cells by T cell receptor and specific cytokines activates master transcription factors and induces lineage specification during the differentiation of Th cells. The master transcription factors directly activate the transcription of signature cytokine genes and also undergo post-translational modifications to fine-tune cytokine production and maintain immune balance through cross-regulation with each other. This review highlights the post-translational modifications of master transcription factors that control the differentiation of effector Th and Treg cells and provides additional insights on the immune regulation mediated by protein arginine-modifying enzymes in effector Th cells.

IPEX Syndrome: Genetics and Treatment Options

(1) Background: IPEX (immune dysregulation, polyendocrinopathy, enteropathy, X-linked) syndrome characterizes a complex autoimmune reaction beginning in the perinatal period, caused by a dysfunction of the transcription factor forkhead box P3 (FOXP3). (2) Objectives: Studies have shown the clinical, immunological, and molecular heterogeneity of patients with IPEX syndrome. The symptoms, treatment, and survival were closely connected to the genotype of the IPEX syndrome. Recognition of the kind of mutation is important for the diagnostics of IPEX syndrome in newborns and young infants, as well as in prenatal screening. The method of choice for treatment is hematopoietic stem cell transplantation and immunosuppressive therapy. In children, supportive therapy for refractory diarrhea is very important, as well as replacement therapy of diabetes mellitus type 1 (DMT1) and other endocrinopathies. In the future, genetic engineering methods may be of use in the successful treatment of IPEX syndrome. (3) Conclusions: The genetic defects determine a diagnostic approach and prognosis, making the knowledge of the genetics of IPEX syndrome fundamental to introducing novel treatment methods.

Genetics of Pediatric Immune-Mediated Diseases and Human Immunity

Primary immunodeficiency diseases (PIDs) are a rapidly growing, heterogeneous group of genetically determined diseases characterized by defects in the immune system. While individually rare, collectively PIDs affect between 1/1,000 and 1/5,000 people worldwide. The clinical manifestations of PIDs vary from susceptibility to infections to autoimmunity and bone marrow failure. Our understanding of the human immune response has advanced by investigation and discovery of genetic mechanisms of PIDs. Studying patients with isolated genetic variants in proteins that participate in complex signaling pathways has led to an enhanced understanding of host response to infection, and mechanisms of autoimmunity and autoinflammation. Identifying genetic mechanisms of PIDs not only furthers immunological knowledge but also benefits patients by dictating targeted therapies or hematopoietic stem cell transplantation. Here, we highlight several of these areas in the field of primary immunodeficiency, with a focus on the most recent advances.

IPEX Syndrome with Normal FOXP3 Protein Expression in Treg Cells in an Infant Presenting with Intractable Diarrhea as a Single Symptom

IPEX (immune dysregulation-polyendocrinopathy-enteropathy-X-linked) syndrome is a rare, potentially fatal multisystem disorder caused by mutations in the FOXP3 gene. This can lead to quantitative or functional deficiency of regulatory T cells (Treg), thereby affecting their immune-suppressive actions which can in turn cause autoimmune and inflammatory disorders. We describe an infant with IPEX syndrome with unremarkable maternal family history whose only presentations were severe diarrhea and malnutrition. The patient had a normal percentage of Treg cells and FOXP3 protein expression, but further testing revealed a hemizygous missense mutation in the FOXP3 gene. IPEX syndrome should be considered in young children even if severe intractable diarrhea is the only symptom with no other autoimmune manifestations. Sequencing of the FOXP3 gene should always be considered for accurate diagnosis to look for mutations even in the face of normal FOXP3 protein expression in the Treg cell.

Autoimmunity and immunological tolerance in autoimmune bullous diseases

Autoimmune diseases are devastating conditions in which the immune system is directed against the host, leading to life-threatening destruction of organs. Although autoantigens are ill-defined in most autoimmune diseases, this is not the case in the skin. Autoimmune bullous diseases have been extensively studied with detailed characterization of autoantigens, the epitopes that are targeted, and the mechanisms of action that mediate autoimmune tissue destruction. Pemphigus is an autoimmune bullous disease caused by circulating IgG that targets two desmosomal proteins, desmoglein 1 and 3, which are crucial for cell-cell adhesion of keratinocytes. Binding of auto-antibodies to desmogleins impairs keratinocyte adhesion, leading to severe blistering disease. Mouse models that recapitulate the human disease have been instrumental in elucidating the detailed pathophysiology. Taking advantage of the fact that desmogleins are specifically targeted in pemphigus, studying humoral and cellular autoimmunity against these autoantigens provides us with an opportunity to understand not only the effector mechanisms of B and T cells in mediating pathology but also how autoreactive lymphocytes are regulated during development in the thymus and post-development in the periphery. This review introduces pemphigus and its subtypes as prototypic autoimmune diseases from which recent basic and translational developments should provide insight into how autoimmunity develops.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome: A systematic review

BACKGROUND

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a monogenic disorder characterized by early onset fatal multi-system autoimmunity due to loss-of-function mutations in the gene encoding the forkhead box P3 (FOXP3) transcription factor which is crucial for the development, maturation, and maintenance of CD4⁺ regulatory T (T-reg) cells. Various autoimmune phenomena such as enteropathy, endocrinopathies, cytopenias, renal disease, and skin manifestations are characteristic findings in patients affected by IPEX syndrome.

OBJECTIVES

In this systematic review, we focus on both clinical and demographic characteristics of IPEX patients, highlighting possible genotype-phenotype correlations and address prognostic factors for disease outcome.

METHODS

We performed a literature search to systematically investigate the case reports of IPEX which were published before August 7^th, 2017.

RESULTS

A total of 75 articles (195 patients) were identified. All IPEX patients included had FOXP3 mutations which were most frequently located in the forkhead domain (n = 68, 34.9%) followed by the leucine-zipper domain (n = 30, 15.4%) and repressor domain (n = 36, 18.4%). Clinical manifestations were as follows: enteropathy (n = 191, 97.9%), skin manifestations (n = 121, 62.1%), endocrinopathy (n = 104, 53.3%), hematologic abnormalities (n = 75, 38.5%), infections (n = 78, 40.0%), other immune-related complications (n = 43, 22.1%), and renal involvement (n = 32, 16.4%). Enteropathic presentations (P = 0.017), eczema (P = 0.030), autoimmune hemolytic anemia (P = 0.022) and food allergy (P = 0.009) were associated with better survival, while thrombocytopenia (P = 0.034), septic shock (P = 0.045) and mutations affecting the repressor domain (P = 0.021), intron 7 (P = 0.033) or poly A sequence (P = 0.025) were associated with increased risk of death. Immunosuppressive therapy alone was significantly associated with increased cumulative survival compared to patients who received no treatment (P = 0.041).

CONCLUSIONS

We report the most comprehensive summary of demographic and clinical profiles derived from a total of 195 IPEX patients with deleterious mutations in FOXP3. Analysis of our findings provides new insights into genotype/phenotype correlations, and clinical and genetic factors associated with increased risk of death and response to treatment strategies.

The Role of PD-1 in Acute and Chronic Infection

PD-1 as an immune checkpoint molecule down-regulates T cell activity during immune responses in order to prevent autoimmune tissue damage. In chronic infections or tumors, lasting antigen-exposure leads to permanent PD-1 expression that can limit immune-mediated clearance of pathogens or degenerated cells. Blocking PD-1 can enhance T cell function; in cancer treatment PD-1 blockade is already used as a successful therapy. However, the role of PD-1 expression and blocking in the context of acute and chronic infections is less defined. Building on its success in cancer therapy leads to the hypothesis that blocking PD-1 in infectious diseases is also beneficial in acute or chronic infections. This review will focus on the role of PD-1 expression in acute and chronic infections with virus, bacteria, and parasites, with a particular focus on recent studies regarding PD-1 blockade in infectious diseases.

Molecular feature and therapeutic perspectives of immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome

Regulatory T (Treg) cells, a subtype of immunosuppressive CD4⁺ T cells, are vital for maintaining immune homeostasis in healthy people. Forkhead box protein P3 (FOXP3), a member of the forkhead-winged-helix family, is the pivotal transcriptional factor of Treg cells. The expression, post-translational modifications, and protein complex of FOXP3 present a great impact on the functional stability and immune plasticity of Treg cells in vivo. In particular, the mutation of FOXP3 can result in immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome, which is a rare genetic disease mostly diagnosed in early childhood and can soon be fatal. IPEX syndrome is related to several manifestations, including dermatitis, enteropathy, type 1 diabetes, thyroiditis, and so on. Here, we summarize some recent findings on FOXP3 regulation and Treg cell function. We also review the current knowledge about the underlying mechanism of FOXP3 mutant-induced IPEX syndrome and some latest clinical prospects. At last, this review offers a novel insight into the role played by the FOXP3 complex in potential therapeutic applications in IPEX syndrome.

Intrauterine IPEX

IPEX is one of the few Inborn Errors of Immunity that may manifest in the fetal period, and its intrauterine forms certainly represent the earliest human autoimmune diseases. Here, we review the clinical, histopathologic, and genetic findings from 21 individuals in 11 unrelated families, with nine different mutations, described as cases of intrauterine IPEX. Recurrent male fetal death (multigenerational in five families) due to hydrops in the midsemester of pregnancy was the commonest presentation (13/21). Noteworthy, in the affected families, there were only fetal- or perinatal-onset cases, with no affected individuals presenting milder forms with later-life manifestation. Most alive births were preterm (5/6). Skin desquamation and intrauterine growth restriction were observed in part of the cases. Fetal ultrasonography showed hyperechoic bowel or dilated bowel loops in the five cases with available imaging data. Histopathology showed multi-visceral infiltrates with T lymphocytes and other cells, including eosinophils, the pancreas being affected in most of the cases (11/21) and as early as at 18 weeks of gestational age. Regarding the nine FOXP3 mutations found in these cases, six determine protein truncation and three predictably impair protein function. Having found distinct presentations for the same FOXP3 mutation in different families, we resorted to the mouse system and showed that the scurfy mutation also shows divergent severity of phenotype and age of death in C57BL/6 and BALB/c backgrounds. We also reviewed age-of-onset data from other monogenic Tregopathies leading to IPEX-like phenotypes. In monogenic IPEX-like syndromes, the intrauterine onset was only observed in two kindreds with IL2RB mutations, with two stillbirths and two premature neonates who did not survive. In conclusion, intrauterine IPEX cases seem to constitute a particular IPEX subgroup, certainly with the most severe clinical presentation, although no strict mutation-phenotype correlations could be drawn for these cases.

Foxp3 Post-translational Modifications and Treg Suppressive Activity

Regulatory T cells (Tregs) are engaged in maintaining immune homeostasis and preventing autoimmunity. Treg cells include thymic Treg cells and peripheral Treg cells, both of which can suppress the immune response via multiple distinct mechanisms. The differentiation, proliferation, suppressive function and survival of Treg cells are affected by distinct energy metabolic programs. Tissue-resident Treg cells hold unique features in comparison with the lymphoid organ Treg cells. Foxp3 transcription factor is a lineage master regulator for Treg cell development and suppressive activity. Accumulating evidence indicates that the activity of Foxp3 protein is modulated by various post-translational modifications (PTMs), including phosphorylation, O-GlcNAcylation, acetylation, ubiquitylation and methylation. These modifications affect multiple aspects of Foxp3 function. In this review, we define features of Treg cells and roles of Foxp3 in Treg biology, and summarize current research in PTMs of Foxp3 protein involved in modulating Treg function. This review also attempts to define Foxp3 dimer modifications relevant to mediating Foxp3 activity and Treg suppression. Understanding Foxp3 protein features and modulation mechanisms may help in the design of rational therapies for immune diseases and cancer.

Clinical, Immunological, and Molecular Heterogeneity of 173 Patients With the Phenotype of Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-Linked (IPEX) Syndrome

Background: Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX) Syndrome is a rare recessive disorder caused by mutations in the FOXP3 gene. In addition, there has been an increasing number of patients with wild-type FOXP3 gene and, in some cases, mutations in other immune regulatory genes. Objective: To molecularly asses a cohort of 173 patients with the IPEX phenotype and to delineate the relationship between the clinical/immunologic phenotypes and the genotypes. Methods: We reviewed the clinical presentation and laboratory characteristics of each patient and compared clinical and laboratory data of FOXP3 mutation-positive (IPEX patients) with those from FOXP3 mutation-negative patients (IPEX-like). A total of 173 affected patients underwent direct sequence analysis of the FOXP3 gene while 85 IPEX-like patients with normal FOXP3 were investigated by a multiplex panel of "Primary Immune Deficiency (PID-related) genes." Results: Forty-four distinct FOXP3 variants were identified in 88 IPEX patients, 9 of which were not previously reported. Among the 85 IPEX-like patients, 19 different disease-associated variants affecting 9 distinct genes were identified. Conclusions: We provide a comprehensive analysis of the clinical features and molecular bases of IPEX and IPEX-like patients. Although we were not able to identify major distinctive clinical features to differentiate IPEX from IPEX-like syndromes, we propose a simple flow-chart to effectively evaluate such patients and to focus on the most likely molecular diagnosis. Given the large number of potential candidate genes and overlapping phenotypes, selecting a panel of PID-related genes will facilitate a molecular diagnosis.

Quantitative proteomic Analysis Reveals up-regulation of caveolin-1 in FOXP3-overexpressed human gastric cancer cells

Forkhead box protein 3 (FOXP3) is implicated in tumor progression and prognosis in various types of tumor cells. We have recently reported that FOXP3 inhibited proliferation of gastric cancer (GC) cells through activating the apoptotic signaling pathway. In this study, we found that over-expression of FOXP3 inhibited GC cell migration, invasion and proliferation. Then, the label-free quantitative proteomic approach was employed to further investigating the down-stream proteins regulated by FOXP3, resulting in a total of 3,978 proteins quantified, including 186 significantly changed proteins. Caveolin-1 (CAV1), as a main constituent protein of caveolae, was one of those changed proteins up-regulated in FOXP3-overexpressed GC cells, moreover, it was assigned as one of the node proteins in the protein-protein interaction network and the key protein involved in focal adhesion pathway by bioinformatics analysis. Further biological experiments confirmed that FOXP3 directly bound to the promoter regions of CAV1 to positively regulate CAV1 transcription in GC cells. In summary, our study suggested that FOXP3 can be considered as a tumor suppressor in GC via positively regulating CAV1 through transcriptional activation, and this FOXP3-CAV1 transcriptional regulation axis may play an important role in inhibiting invasion and metastasis of GC cells. Data are available via ProteomeXchange under identifier PXD007725.

Nonclassic Inflammatory Bowel Disease in Young Infants: Immune Dysregulation, Polyendocrinopathy, Enteropathy, X-Linked Syndrome, and Other Disorders

This article discusses non-classical forms of inflammatory bowel disease (IBD) mainly occurs in infants and very young children. Defects in every aspect of the immune system, such as neutrophils, T-cell and B-cell lymphocytes, and macrophages are associated with IBD in infants. Also, non lympho-hematopoietic defects with primary defects in enterocytes can also lead to IBD-like manifestations. Clinical vignettes are presented and the genetic origins and possible management strategies are outlined. Early evaluation of these patients is important because identification of underlying immune defects would facilitate the use of better-targeted therapy for the specific genetic defect.

Humoral Immunodeficiency with Hypotonia, Feeding Difficulties, Enteropathy, and Mild Eczema Caused by a Classical FOXP3 Mutation

We describe here the case of a boy who presented with pulmonary infections, feeding difficulties due to velopharyngeal insufficiency and gastroesophageal reflux, myopathy, and hypotonia soon after birth. Later, he was also found to have an elevated immunoglobulin (Ig) E and mild eczema and was diagnosed with inflammatory bowel disease. Further immunological screening at the age of 7 years showed low B and NK cell numbers but normal CD4⁺ and CD8⁺ T cells and notably, normal numbers of CD4⁺ regulatory T (Treg) cells. Serum IgG, IgA, and IgM were low to normal, but he had a deficient response to a pneumococcal polysaccharide vaccine and thus a humoral immunodeficiency. To our surprise, whole exome sequencing revealed a mutation in forkhead box protein 3 (FOXP3), encoding an essential transcription factor for the development and function of Treg cells. This classical mutation is associated with immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome. Further in vitro studies indeed showed defective function of Treg cells despite normal FOXP3 protein expression and nuclear localization. The boy underwent hematopoietic stem cell transplantation at 11 years of age and despite the temporary development of diabetes while on prednisone is now doing much better, IgE levels have declined, and his fatigue has improved. This case illustrates that a classical pathogenic mutation in FOXP3 can lead to a clinical phenotype where the diagnosis of IPEX syndrome was never considered because of the lack of diabetes and the presence of only mild eczema, in addition to the normal Treg cell numbers and FOXP3 expression.

Expression of tumoral FOXP3 in gastric adenocarcinoma is associated with favorable clinicopathological variables and related with Hippo pathway

FOXP3 is a transcription factor and well-known hallmark of immune suppressive T regulatory cells (Tregs). Recent studies indicate that, in addition to its association with Treg function in the immune system, FOXP3 plays an important role in tumor development. And important tumor suppressor relay between the FOXP3 and Hippo pathways was found in human cancer. Thus, we investigated tumoral FOXP3, infiltrated Tregs count, Lats2, and YAP expression in gastric adenocarcinoma, and the relationships between expression of these three proteins and p53, Ki67, and other clinicopathological variables. We used 118 gastric adenocarcinoma tissues via immunohistochemical analysis, using a tissue microarray, in relation to survival and other clinicopathological factors. We report the several novel observations about the relationship between tumoral FOXP3 and Hippo pathway components in gastric adenocarcinoma. Positive tumoral FOXP3 expression was significantly related with smaller tumor size, tubular tumor type, lower histological grade, lower T stage, lower recurrence rate, less lymphatic invasion, and less neural invasion. Furthermore, patients with positive tumoral FOXP3 experienced significantly better disease-free and overall survival compared to patients with negative tumoral FOXP3. These findings show that tumoral FOXP3 expression is associated with favorable clinicopathological variables in gastric adenocarcinoma. And we report the novel observation of a relationship between tumoral FOXP3 and Hippo pathway components in gastric adenocarcinoma. Tumoral FOXP3 expression, infiltrated Tregs count, and Lats2 expression were all positively correlated with YAP expression. These findings suggest that the Hippo pathway in gastric adenocarcinoma might be influenced by both tumoral FOXP3 and infiltrated Tregs. In conclusion, the loss of FOXP3 expression in cancer cells is thought to contribute to tumorigenesis and progression of gastric adenocarcinoma. The expression of FOXP3 in gastric adenocarcinoma is related with Lats2 and YAP expression of the Hippo pathway.

Identifying genetic determinants of autoimmunity and immune dysregulation

Common autoimmune diseases are relatively heterogeneous with both genetic and environmental factors influencing disease susceptibility and progression. As the populations in developed countries age, these chronic diseases will become an increasing burden in human suffering and health care costs. By contrast, rare immune diseases that are severe and develop early in childhood are frequently monogenic and fully penetrant, often with a Mendelian inheritance pattern. Although these may be incompatible with survival or cured by hematopoietic stem cell transplantation, we will argue that they constitute a rich source of genetic insights into immunological diseases. Here, we discuss five examples of well-studied Mendelian disease-causing genes and their known or predicted roles in conferring susceptibility to common, polygenic diseases of autoimmunity. Mendelian disease mutations, as experiments of nature, reveal human loci that are indispensable for immune regulation and, therefore, most promising as therapeutic targets.

Clinical Case of Immune Dysregulation, Polyendocrinopaty, Enteropathy, X-Linked (IPEX) Syndrome with Severe Immune Deficiency and Late Onset of Endocrinopathy and Enteropathy

Objective. To describe the clinical characteristics of IPEX syndrome in a child with FOXP3 mutation. Clinical Case. A boy aged 2.3 years was born from first normal pregnancy with a weight of 3420 gr. Family History. Two brothers of the mother died before the age of 3 years with severe infections, diarrhea, erythroderma, and elevated immunoglobulins class E (IgEs). Since first month of life, our patient suffered from septicemia, pneumonias, pyelonephritis, and meningitis, accompanied with eczematous dermatitis and IgEs up to 4000 IU/L (normal <10). At the age of 1.6 years, he developed type 1 diabetes mellitus (T1DM). He was underweighted (-3.42 SDS) and had some phenotypic features like coarse face, muscle hypotonia, joint hyperextensibility, eczematous dermatitis, and subcutaneous cold abscesses. Autoimmune thyroiditis and celiac disease were excluded. After diabetes, intermittent watery diarrhea appeared with progression to severe intractable form. Finally, aggravating symptoms of nephritis, cachexia, and respiratory insufficiency were the cause for his death at the age of 2 years and 3 months. The DNA analysis at the University of Exeter Medical School established mutation at exon 10 of FOXP3 gene c.1010G >A, p. (Arg337Gln), which confirmed IPEX syndrome. The same mutation in heterozygotic state was found in the mother. A prenatal diagnosis of her second pregnancy ensured a daughter carrier of the mutation.

The role of FOXP3 in the development and metastatic spread of breast cancer

The transcription factor FOXP3 is widely known for its role in the development and function of immunoregulatory T cells. However, it has been discovered recently that FOXP3 is also expressed in epithelial cells of the normal human breast, ovary and prostate. Aggressive cancer of these epithelial tissues often correlates with abnormal expression of FOXP3, which can be either absent or underexpressed at transcript or protein levels. It is becoming clear that this failure of normal FOXP3 expression can result in dysregulation of the expression of a range of oncogenes which have been implicated in the development and metastasis of cancer. Recent evidence suggests that FOXP3 might also regulate chemokine receptor expression, providing a possible explanation for the chemokine-driven, tissue-specific spread that is characteristic of many cancers. This review first summarises the general structure, function and properties of FOXP3. This is followed by an analysis of the tumour-suppressive properties of this transcription factor, with particular reference to the development and chemokine-mediated spread of human breast cancer. A final section focuses on potential applications of this new knowledge for therapeutic intervention.

APECED: is this a model for failure of T cell and B cell tolerance?

In APECED, the key abnormality is in the T cell defect that may lead to tissue destruction chiefly in endocrine organs. Besides, APECED is characterized by high-titer antibodies against a wide variety of cytokines that could partly be responsible for the clinical symptoms during APECED, mainly chronic mucocutaneous candidiasis, and linked to antibodies against Th17 cells effector molecules, IL-17 and IL-22. On the other hand, the same antibodies, together with antibodies against type I interferons may prevent the patients from other immunological diseases, such as psoriasis and systemic lupus erythematous. The same effector Th17 cells, present in the lymphocytic infiltrate of target organs of APECED, could be responsible for the tissue destruction. Here again, the antibodies against the corresponding effector molecules, anti-IL-17 and anti-IL-22 could be protective. The occurrence of several effector mechanisms (CD4(+) Th17 cell and CD8(+) CTL and the effector cytokines IL-17 and IL-22), and simultaneous existence of regulatory mechanisms (CD4(+) Treg and antibodies neutralizing the effect of the effector cytokines) may explain the polymorphism of APECED. Almost all the patients develop the characteristic manifestations of the complex, but temporal course and severity of the symptoms vary considerably, even among siblings. The autoantibody profile does not correlate with the clinical picture. One could speculate that a secondary homeostatic balance between the harmful effector mechanisms, and the favorable regulatory mechanisms, finally define both the extent and severity of the clinical condition in the AIRE defective individuals. The proposed hypothesis that in APECED, in addition to strong tissue destructive mechanisms, a controlling regulatory mechanism does exist, allow us to conclude that APECED could be treated, and even cured, with immunological manipulation.

Immune dysregulation, polyendocrinopathy, enteropathy, x-linked syndrome: a paradigm of immunodeficiency with autoimmunity

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is a rare monogenic primary immunodeficiency (PID) due to mutations of FOXP3, a key transcription factor for naturally occurring (n) regulatory T (Treg) cells. The dysfunction of Treg cells is the main pathogenic event leading to the multi-organ autoimmunity that characterizes IPEX syndrome, a paradigm of genetically determined PID with autoimmunity. IPEX has a severe early onset and can become rapidly fatal within the first year of life regardless of the type and site of the mutation. The initial presenting symptoms are severe enteritis and/or type-1 diabetes mellitus, alone or in combination with eczema and elevated serum IgE. Other autoimmune symptoms, such as hypothyroidism, cytopenia, hepatitis, nephropathy, arthritis, and alopecia can develop in patients who survive the initial acute phase. The current therapeutic options for IPEX patients are limited. Supportive and replacement therapies combined with pharmacological immunosuppression are required to control symptoms at onset. However, these procedures can allow only a reduction of the clinical manifestations without a permanent control of the disease. The only known effective cure for IPEX syndrome is hematopoietic stem cell transplantation, but it is always limited by the availability of a suitable donor and the lack of specific guidelines for bone marrow transplant in the context of this disease. This review aims to summarize the clinical histories and genomic mutations of the IPEX patients described in the literature to date. We will focus on the clinical and immunological features that allow differential diagnosis of IPEX syndrome and distinguish it from other PID with autoimmunity. The efficacy of the current therapies will be reviewed, and possible innovative approaches, based on the latest highlights of the pathogenesis to treat this severe primary autoimmune disease of childhood, will be discussed.

Monogenic autoimmunity

Monogenic autoimmune syndromes provide a rare yet powerful glimpse into the fundamental mechanisms of immunologic tolerance. Such syndromes reveal not only the contribution of an individual breakpoint in tolerance but also patterns in the pathogenesis of autoimmunity. Disturbances in innate immunity, a system built for ubiquitous sensing of danger signals, tend to generate systemic autoimmunity. For example, defects in the clearance of self-antigens and chronic stimulation of type 1 interferons lead to the systemic autoimmunity seen in C1q deficiency, SPENCDI, and AGS. In contrast, disturbances of adaptive immunity, which is built for antigen specificity, tend to produce organ-specific autoimmunity. Thus, the loss of lymphocyte homeostasis, whether through defects in apoptosis, suppression, or negative selection, leads to organ-specific autoimmunity in ALPS, IPEX, and APS1. We discuss the unique mechanisms of disease in these prominent syndromes as well as how they contribute to the spectrum of organ-specific or systemic autoimmunity. The continued study of rare variants in autoimmune disease will inform future investigations and treatments directed at rare and common autoimmune diseases alike.

Inflammatory bowel disease: is it a primary immunodeficiency?

Inflammatory bowel diseases (IBD) such as ulcerative colitis and Crohn's disease are chronic and relapsing conditions, characterized by abdominal pain, diarrhea, bleeding and malabsorption. IBD has been considered a hyperinflammatory state due to disturbed interactions between the immune system and the commensal bacterial flora of the gut. However, there is evidence that Crohn's disease might be the consequence of a reduced release of pro-inflammatory cytokines and an impaired acute inflammatory response, thereby suggesting that IBD might be an immunodeficiency rather than an excessive inflammatory reaction. This theory has been supported by observations in patients with primary immunodeficiencies such as the Wiskott-Aldrich syndrome and IPEX (immunodysregulation, polyendocrinopathy, enteropathy, X-linked syndrome). In contrary, defects in the anti-inflammatory down-regulation of the immune response as they are seen in patients with Mendelian defects in the IL10 signaling pathway support the hyper-inflammatory theory. In this review, we describe and discuss primary immunodeficiencies associated with IBD and show that the bowel is a highly sensitive indicator of dysregulations, making IBD a model disease to study and identify key regulators required to balance the human mucosal immune system.

IL-10 and IL-10 receptor defects in humans

Inflammatory bowel disease (IBD), which includes Crohn's disease (CD) and ulcerative colitis (UC), is chronic in nature and is characterized by abdominal pain, diarrhea, bleeding, and malabsorption. It is considered a complex multigenic and multifactorial disorder that results from disturbed interactions between the immune system and commensal bacteria of the gut. Recent work has demonstrated that IBD with an early-onset within the first months of life can be monogenic: mutations in IL-10 or its receptor lead to a loss of IL-10 function and cause severe intractable enterocolitis in infants and small children. Both IL-10 and IL-10 receptor deficiency can be successfully treated by hematopoietic stem cell transplantation.

Stable hematopoietic cell engraftment after low-intensity nonmyeloablative conditioning in patients with immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome

BACKGROUND

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked (IPEX) syndrome is characterized by severe systemic autoimmunity caused by mutations in the forkhead box protein 3 (FOXP3) gene. Hematopoietic cell transplantation is currently the only viable option for long-term survival, but patients are frequently very ill and may not tolerate traditional myeloablative conditioning regimens.

OBJECTIVE

Here we present the outcome of hematopoietic cell transplantation using a low-intensity, nonmyeloablative conditioning regimen in 2 patients with IPEX syndrome and significant pretransplant risk factors.

METHODS

Two high-risk patients with IPEX syndrome received HLA-matched related bone marrow or unrelated peripheral blood stem cell grafts following conditioning with 90 mg/m(2) fludarabine and 4 Gy total body irradiation. Postgrafting immunosuppression consisted of mycophenolate mofetil and cyclosporine. Immune reconstitution and immune function was evaluated by measurement of donor chimerism, regulatory T-cell numbers, absolute lymphocyte subsets, and T-cell proliferation assays.

RESULTS

Both patients experienced minimal conditioning toxicity and successfully engrafted after hematopoietic cell transplantation. With a follow-up of 4 and 1 years, respectively, patients 1 and 2 have full immune function and normal FOXP3 protein expression.

CONCLUSION

A low-intensity, nonmyeloablative conditioning regimen can establish stable engraftment and correct the life-threatening immune deficiency and enteropathy of IPEX syndrome despite the presence of comorbidities that preclude conventional hematopoietic cell transplantation.

FOXP3 and its role in the immune system

FOXP3 is a member of the forkhead transcription factor family. Unlike other members, it is mainly expressed in a subset of CD4+ T-cells that play a suppressive role in the immune system. A function of FOXP3 is to suppress the function of NFAT and NFkappaB and this leads to suppression ofexpression of many genes including IL-2 and effector T-cell cytokines. FOXP3 acts also as a transcription activator for many genes induding CD2S, Cytotoxic T-Lymphocyte Antigen 4 (CTLA4), glucocorticoid-induced TNF receptorfamily gene (GITR) andfolate receptor 4. FOXP3+ T-cells are made in the thymus and periphery. The FOXP3+ T-cells made in the thymus migrate to secondary lymphoid tissues and suppress antigen priming of lymphocytes. Antigen priming of naive FOXP3 T-cdlls and naive FOXP3 T-cells leads to generation of memory FOXP3+ T-cells which are efficient in migration to nonlymphoid tissues. Memory FOXP3+ T-cells are, therefore, effective in suppression of effector T-cell function, while naive FOXP3 T-cells are adept at suppressing the early immune responses in lymphoid tissues. Both naive and memory FOXP3 T-cells are required for effective maintenance of tolerance and prevention of autoimmune diseases throughout the body. Many factors such as cytokines and noncytokine factors regulate the generation of FOXP3 T-cells. For example, retinoic acid, produced by the dendritic cells and epithelial cells in the intestine, works together with TGF-beta1 and promotes generation of small intestine-homing FOXP3 T-cells by upregulating the expression ofFOXP3 and gut homing receptors. FOXP3+ T-cells can be produced in vitro from autologous naive T-cells and, therefore, have great therapeutic potentials in treating a number of inflammatory diseases and grafi rejection.

Immune deficiency disorders with autoimmunity and abnormalities in immune regulation-monogenic autoimmune diseases

Autoimmunity is frequently observed in patients with primary immune deficiency disorders. Monogenic autoimmune diseases include a group of disorders with characteristic autoimmunity and immune deficiency for which single gene defects have been identified. Currently recognized monogenic autoimmune diseases include autoimmune polyendocrinopathy candidiasis and ectodermal dystrophy, immunodysregulation polyendocrinopathy enteropathy and X-linked inheritance syndrome, autoimmune lymphoproliferative syndrome, and interleukin-2 receptor alpha-chain deficiency. These diseases offer important insights into the mechanisms of central and peripheral immune tolerance and the pathogenesis of defects in these mechanisms.

Primary immune deficiency disorders presenting as autoimmune diseases: IPEX and APECED

BACKGROUND

Several primary immune deficiency disorders are associated with autoimmunity and malignancy, suggesting a state of immune dysregulation. The concept of immune dysregulation as a direct cause of autoimmunity in primary immune deficiency disorders (PIDDs) has been strengthened by the recent discovery of distinct clinical entities linked to single-gene defects resulting in multiple autoimmune phenomena including immune dysregulation, polyendocrinopathy, enteropathy and X-linked (IPEX) syndrome, and autoimmune polyendocrinopathy, candidiasis and ectodermal dystrophy (APECED) syndrome.

CONCLUSION

Reviewing recent advances in our understanding of the small subgroup of PIDD patients with defined causes for autoimmunity may lead to the development of more effective treatment strategies for idiopathic human autoimmune diseases.

Neonatal diabetes mellitus

An explosion of work over the last decade has produced insight into the multiple hereditary causes of a nonimmunological form of diabetes diagnosed most frequently within the first 6 months of life. These studies are providing increased understanding of genes involved in the entire chain of steps that control glucose homeostasis. Neonatal diabetes is now understood to arise from mutations in genes that play critical roles in the development of the pancreas, of beta-cell apoptosis and insulin processing, as well as the regulation of insulin release. For the basic researcher, this work is providing novel tools to explore fundamental molecular and cellular processes. For the clinician, these studies underscore the need to identify the genetic cause underlying each case. It is increasingly clear that the prognosis, therapeutic approach, and genetic counseling a physician provides must be tailored to a specific gene in order to provide the best medical care.

IPEX syndrome: Case report

INTRODUCTION IPEX syndrome, namely, a hereditary (X-linked) immunodysregulation with autoimmune polyendocrinopathy and enteropathy, as the basic manifestations, presents a rare and exceptionally severe disease. It develops due to gene mutation responsible for the synthesis of a specific protein (FOXP3), which, by differentiation and activation of regular T-lymphocytic CD4+CD25+, has the key role in the induction and maintenance of the peripheral tolerance of one's own tissue. CASE OUTLINE We present a male infant with classic clinical features of IPEX syndrome, which manifested by the end of the first month after birth, first with type 1 diabetes mellitus and chronic diarrhoea followed by dehydration and disordered development, and then with facial eczema and laboratory signs of thyroiditis without thyroid dysfunction (antithyreoglobulin antibodies 1:5500, antimicrosomal antibodies 1:40). In addition, plasma IgE level was high (517 IU/l), while antibodies to tissue transglutaminase were mildly increased (IgA 7.5 U/ml), and anti-smooth muscle and anti-DNA antibodies were absent. Based on the typical clinical features, as well as the laboratory findings, IPEX syndrome was diagnosed, which was further confirmed by proved IVS7+5G>A mutations in the FOXP3 gene. Therapy with insulin and Pronison, combined with parenteral and semielementary nutrition resulted in the patient's clinical improvement. At the age of 9 months, despite Pronison and hypoallergenic nutrition, the child had a relapse of severe and persistent diarrhoeal disorder followed by dehydration, weight loss and deterioration of general condition. Beside the complete parenteral nutrition, as well as other measures, azathioprine was introduced into the treatment, but without the desired effect. At the age of 12.5 months, due to bacteraemia and disseminated intravascular coagulation as complications, the patient ended lethally. CONCLUSION IPEX syndrome should be kept in mind in all the cases of associated type 1 diabetes mellitus and chronic diarrhoea in male neonates or infants. Although treatment results have still been modest, it is quite certain they will be far better in the near future.

A potential screening tool for IPEX syndrome

IPEX syndrome is a rare, inherited condition characterized by immune dysfunction, polyendocrinopathy, enteropathy, and X-linked recessive inheritance. Patients typically present in infancy with severe diarrhea and failure to thrive. Most children die by 1 year of age without therapy. The diagnosis is established by genetic analysis, which often takes several weeks to complete and can sometimes delay crucial immunosuppressive treatment. We attempted to develop a screening tool that allows rapid identification of patients with IPEX syndrome using immunocytochemical staining of FOXP3+ cells in bowel biopsies. We found that 2 patients with classic IPEX syndrome due to protein-truncating mutations in FOXP3 had markedly decreased staining of FOXP3+ T cells in the lamina propria and lymphoid aggregates. One patient with a mild, late-onset presentation and a missense mutation in FOXP3 had intact staining of FOXP3+ cells. This screening test provides a valuable tool for diagnosing IPEX syndrome in extremely ill patients who may not tolerate a delay in therapeutic intervention.

Immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) associated with pemphigoid nodularis: a case report and review of the literature

The immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX) is a rare disorder caused by mutations of the FOXP3 gene. The FOXP3 gene encodes a DNA-binding protein of the forkhead/winged-helix family and is the central controller of the development of CD4+CD25+ regulatory T cells. CD4+CD25+ regulatory T cells help prevent autoimmune disease; a deficiency of these cells causes increased immunologic reactivity and autoimmunity. We describe a 14-year-old boy with IPEX syndrome confirmed by mutation analysis of the FOXP3 gene. The patient had chronic dermatitis and later developed bullous pemphigoid. He subsequently formed diffuse prurigo nodularis-like lesions resistant to multiple topical and systemic immunosuppressive medications. These lesions were confirmed by biopsy, direct immunofluorescence, and enzyme-linked immunosorbent assay of the 180 kd bullous pemphigoid antigen to be pemphigoid nodularis. He recently responded to rituximab, allowing discontinuation of his oral prednisone.

Immunodeficiencies with Autoimmune Consequences

Far from being mutually exclusive, immunodeficiency and autoimmunity may occur simultaneously. During the last years, analysis of Autoimmune Polyendocrinopathy--Candidiasis--Ectodermal Dystrophy (APECED) and Immunodysregulation--Polyendocrinopathy--Enteropathy--X-linked (IPEX), two rare monogenic forms of immunodeficiency associated with autoimmunity, has led to the identification of Auto Immune Regulator (AIRE) and Forkhead Box P3 (FOXP3), essential transcriptional regulators, involved in central tolerance and peripheral immune homeostasis, respectively. Characterization of the molecular and cellular mechanisms involved in APECED, and recognition that AIRE expression is sustained by effective thymopoiesis, has recently allowed to define that the autoimmunity of Omenn syndrome, a combined immunodeficiency due to defects of V(D)J recombination, also results from defective expression of AIRE. The implications of identification of the basis of autoimmunity in these rare forms of immunodeficiency have important implications for a better understanding of more common autoimmune disorders, and for development of novel therapeutic approaches.

IPEX and FOXP3: clinical and research perspectives

Immunodysregulation, Polyendocrinopathy, Enteropathy, X-linked (IPEX) syndrome is a rare inborn error of immune regulation characterized by the early onset of one or more autoimmune diseases in boys. IPEX is caused by mutations in FOXP3, and is thus the homologue of the scurfy mutant mouse. The gene product, Scurfin, is required for the development of CD4+CD25+ T regulatory cells. In the absence of T regulatory cells, activated CD4+ T cells instigate multi-organ damage resulting in type 1 diabetes, enteropathy, eczema, hypothyroidism, and other autoimmune disorders. While effective therapies are currently limited, studies in the scurfy mouse are revealing aspects of pathophysiology and genetics that will lead to novel approaches for treating IPEX and other autoimmune disorders. Females carrying Foxp3 mutations are unaffected. In new experiments we show that female scurfy mice that are also heterozygous in trans for the X-linked recessive common gamma chain knockout contract autoimmune disease, proving that murine Foxp3 is subject to X-inactivation and providing an example of gene-gene interaction causing autoimmune disease in females. One explanation for the lesser disease severity in these females is proposed.

Prospective immunological profiling in a case of immune dysregulation, polyendocrinopathy, enteropathy, X-linked syndrome (IPEX)

IPEX syndrome is a genetic autoimmune disease characterized by immune-mediated polyendocrinopathy, enteropathy, and X-linked inheritance. We describe a case of IPEX in which lymphocyte phenotypes were assessed at birth, before initiation of Cyclosporin A therapy, and at frequent intervals to 18 months of age. We performed flow cytometry for lymphocyte subtypes and for activation markers (HLA-DR, CD25, and CD69 or CD71). The ratios of both T to B cells and CD4+ to CD8+ cells were elevated at birth, but CD4+ cells were not activated. HLA-DR+ and CD25+ activated T-cells increased in association with two episodes of clinical deterioration: colitis and the onset of type I diabetes mellitus. These results indicate that measures of activation, particularly HLA-DR+ and CD25+ frequency, correlate well with the development of early active disease and may presage clinical episodes. Continuous maintenance of immunosuppression, once started, appears critical for prevention of permanent tissue damage.