The Role of Interferon-γ in Autoimmune Polyendocrine Syndrome Type 1.

BACKGROUND: Autoimmune polyendocrine syndrome type 1 (APS-1) is a life-threatening, autosomal recessive syndrome caused by autoimmune regulator (AIRE) deficiency. In APS-1, self-reactive T cells escape thymic negative selection, infiltrate organs, and drive autoimmune injury. The effector mechanisms governing T-cell-mediated damage in APS-1 remain poorly understood. METHODS: We examined whether APS-1 could be classified as a disease mediated by interferon-γ. We first assessed patients with APS-1 who were participating in a prospective natural history study and evaluated mRNA and protein expression in blood and tissues. We then examined the pathogenic role of interferon-γ using Aire-/-Ifng-/- mice and Aire-/- mice treated with the Janus kinase (JAK) inhibitor ruxolitinib. On the basis of our findings, we used ruxolitinib to treat five patients with APS-1 and assessed clinical, immunologic, histologic, transcriptional, and autoantibody responses. RESULTS: Patients with APS-1 had enhanced interferon-γ responses in blood and in all examined autoimmunity-affected tissues. Aire-/- mice had selectively increased interferon-γ production by T cells and enhanced interferon-γ, phosphorylated signal transducer and activator of transcription 1 (pSTAT1), and CXCL9 signals in multiple organs. Ifng ablation or ruxolitinib-induced JAK-STAT blockade in Aire-/- mice normalized interferon-γ responses and averted T-cell infiltration and damage in organs. Ruxolitinib treatment of five patients with APS-1 led to decreased levels of T-cell-derived interferon-γ, normalized interferon-γ and CXCL9 levels, and remission of alopecia, oral candidiasis, nail dystrophy, gastritis, enteritis, arthritis, Sjögren's-like syndrome, urticaria, and thyroiditis. No serious adverse effects from ruxolitinib were identified in these patients. CONCLUSIONS: Our findings indicate that APS-1, which is caused by AIRE deficiency, is characterized by excessive, multiorgan interferon-γ-mediated responses. JAK inhibition with ruxolitinib in five patients showed promising results. (Funded by the National Institute of Allergy and Infectious Diseases and others.).

Ex vivo effect of JAK inhibition on JAK-STAT1 pathway hyperactivation in patients with dominant-negative STAT3 mutations.

PURPOSE: STAT1 gain-of-function (GOF) and dominant-negative (DN) STAT3 syndromes share clinical manifestations including infectious and inflammatory manifestations. Targeted treatment with Janus-kinase (JAK) inhibitors shows promising results in treating STAT1 GOF-associated symptoms while management of DN STAT3 patients has been largely supportive. We here assessed the impact of ruxolitinib on the JAK-STAT1/3 pathway in DN STAT3 patients' cells. METHODS: Using flow cytometry, immunoblot, qPCR, and ELISA techniques, we examined the levels of basal STAT1 and phosphorylated STAT1 (pSTAT1) of cells obtained from DN STAT3, STAT1 GOF patients, and healthy donors following stimulation with type I/II interferons (IFNs) or interleukin (IL)-6. We also describe the impact of ruxolitinib on cytokine-induced STAT1 signaling in these patients. RESULTS: DN STAT3 and STAT1 GOF resulted in a similar phenotype characterized by increased STAT1 and pSTAT1 levels in response to IFNα (CD3+ cells) and IFNγ (CD14+ monocytes). STAT1-downstream gene expression and C-X-C motif chemokine 10 secretion were higher in most DN STAT3 patients upon stimulation compared to healthy controls. Ex vivo treatment with the JAK1/2-inhibitor ruxolitinib reduced cytokine responsiveness and normalized STAT1 phosphorylation in DN STAT3 and STAT1 GOF patient' cells. In addition, ex vivo treatment was effective in modulating STAT1 downstream signaling in DN STAT3 patients. CONCLUSION: In the absence of effective targeted treatment options for AD-HIES at present, modulation of the JAK/STAT1 pathway with JAK inhibitors may be further explored particularly in those AD-HIES patients with autoimmune and/or autoinflammatory manifestations.

Biallelic TRAF3IP2 variants causing chronic mucocutaneous candidiasis in a child harboring a STAT1 variant.

BACKGROUND: Inherited chronic mucocutaneous candidiasis (CMC) is often caused by inborn errors of immunity, impairing the response to, or the production of IL-17A and IL-17F. About half of the cases carry STAT1 gain-of-function (GOF) mutations. Only few patients have been reported with mutations of TRAF3IP2, a gene encoding the adaptor ACT1 essential for IL-17 receptor(R) signaling. We investigated a 10-year-old girl with CMC, carrying a heterozygous variant of STAT1 and compound heterozygous variants of TRAF3IP2. METHODS: By flow cytometry, STAT1 levels and phosphorylation (CD14+) as well as IL-17A, IL-22, IFN-γ, and IL-4 production (memory CD4+ T cells) were determined. ACT1 expression and binding to IL-17RA were assessed by Western blot and co-immunoprecipitation in HEK-293T cells transfected with plasmids encoding wild-type or mutant HA-tagged ACT1 and Flag-IL-17RA. We evaluated IL-17A responses by measuring luciferase induction under a NF-κB-driven reporter system in HEK-293T cells and Gro-α secretion in fibroblasts. RESULTS: A STAT1 variant (c.1363G>A/p.V455I) was identified by next-generation sequencing and classified as likely non-pathogenic as functional testing revealed normal STAT1 expression and phosphorylation upon IFN-γ. We also found compound heterozygous variants (c.1325A>G/p.D451G and c.1335delA/p.K454fs11*) of TRAF3IP2. By overexpression, despite normal protein expression, and impaired (K454fs11*) or normal (D451G) interaction with IL-17RA, both mutant alleles resulted in impaired NF-κB activation. Patient's fibroblasts displayed abolished GRO-α secretion upon IL-17A stimulation. Finally, ex vivo CD4+ T cells showed increased IL-17A, IL-22, and IL-4 and normal low IFN-γ expression upon stimulation. CONCLUSION: We identify novel compound heterozygous variants of TRAFP3IP2 causing autosomal recessive ACT1 deficiency in a child with CMC and provide a review of the current literature.

Activated PI3Kδ syndrome type 2: Two patients, a novel mutation, and review of the literature.

BACKGROUND: Autosomal dominant gain-of-function mutations in PIK3R1 encoding for the regulatory subunit (p85α, p55α, and p50α) of Class IA phosphoinositide 3-kinase (PI3K) result in the activated PI3Kδ syndrome (APDS) type 2 characterized by childhood-onset combined immunodeficiency, lymphoproliferation, and immune dysregulation. To improve clinical awareness and understanding of these rare diseases, we reviewed all hitherto published cases with APDS type 1 and type 2 for their clinical and immunologic symptoms and added novel clinical, immunologic, and genetic findings of two patients with APDS type 2. METHODS: Clinical, immunologic, and genetic evaluation of two new patients with APDS2 was performed followed by the systematic collection of all available previously published data of patients with APDS1 and APDS2. RESULTS: Patients with APDS type 1 (n = 49) and type 2 (n = 15) showed an indistinguishable immunologic phenotype. Overlapping clinical features shared by APDS type 1 and type 2 were observed, but our review also revealed previously unnoticed clinical differences such as remarkably high incidence of microcephaly, poor growth/short stature in patients with APDS2. Clinical management and outcome were variable and included prophylactic antibiotics, immunosuppression, immunoglobulin substitution, and hematopoietic stem cell transplantation. CONCLUSIONS: A disease-specific registry collecting prospective and long-term follow-up data of patients with APDS, as currently set up by the European Society for Immunodeficiencies, are needed to better understand the natural history and to optimize treatment concepts and thereby improving the outcome of this heterogenous patient group.

Monitoring of kinetics and exhaustion markers of circulating CAR-T cells as early predictive factors in patients with B-cell malignancies.

Purpose: CAR-T cell therapy has proven to be a disruptive treatment in the hematology field, however, less than 50% of patients maintain long-term response and early predictors of outcome are still inconsistently defined. Here, we aimed to optimize the detection of CD19 CAR-T cells in blood and to identify phenotypic features as early biomarkers associated with toxicity and outcomes. Experimental design: In this study, monitoring by flow cytometry and digital PCR (dPCR), and immunophenotypic characterization of circulating CAR-T cells from 48 patients treated with Tisa-cel or Axi-cel was performed. Results: Validation of the flow cytometry reagent for the detection of CAR-T cells in blood revealed CD19 protein conjugated with streptavidin as the optimal detection method. Kinetics of CAR-T cell expansion in blood confirmed median day of peak expansion at seven days post-infusion by both flow cytometry and digital PCR. Circulating CAR-T cells showed an activated, proliferative, and exhausted phenotype at the time of peak expansion. Patients with increased expansion showed more severe CRS and ICANs. Immunophenotypic characterization of CAR-T cells at the peak expansion identified the increased expression of co-inhibitory molecules PD1 and LAG3 and reduced levels of the cytotoxicity marker CD107a as predictors of a better long-term disease control. Conclusions: These data show the importance of CAR-T cells in vivo monitoring and identify the expression of PD1LAG3 and CD107a as early biomarkers of long-term disease control after CAR-T cell therapy.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Executive Summary of the Consensus Document on the Diagnosis and Management of Patients with Primary Immunodeficiencies.

Primary immunodeficiencies (PIDs) are rare, undiagnosed and potentially fatal diseases. Clinical manifestations of PID can be fatal or leave sequelae that worsen the quality of life of patients. Traditionally, the treatment of PIDs has been largely supportive, with the exception of bone marrow transplantation and, more recently, gene therapy. The discovering of new affected pathways, the development of new molecules and biologics, and the increasing understanding of the molecular basis of these disorders have created opportunities in PIDs therapy. This document aims to review current knowledge and to provide recommendations about the diagnosis and clinical management of adults and children with PIDs based on the available scientific evidence taking in to account current practice and future challenges. A systematic review was conducted, and evidence levels based on the available literature are given for each recommendation where available.

Typhoid fever causing haemophagocytic lymphohistiocytosis in a non-endemic country - first case report and review of the current literature.

INTRODUCTION: Development of secondary haemophagocytic lymphohistiocytosis (sHLH) in the context of typhoid fever (TF) is a very rare but serious complication. METHODS: Description of the first pediatric case of typhoid fever acquired in a non-endemic area complicated by sHLH. A systematic literature review of sHLH in the context of TF was performed with extraction of epidemiological, clinical and laboratory data. RESULTS: The literature search revealed 17 articles (22 patients). Fifteen patients were eligible for data analysis (53.4% children). All patients had fever and pancytopenia. Transaminases and LDH were frequently elevated (46.6%). Salmonella typhi was detected mainly by blood culture (64.3%). All the patients received antibiotics whereas immunomodulation (dexamethasone) was used in two cases. CONCLUSIONS: A high suspicion index for this condition is needed even in non-endemic areas. The addition of immunmodulation to standard antimicrobial therapy should be considered in selected cases.

Secondary C1q Deficiency in Activated PI3Kδ Syndrome Type 2.

Monogenic forms of vasculitis are rare but increasingly recognized. Furthermore, genetic immunodeficiency is increasingly associated with inflammatory immune dysregulatory features, including vasculitis. This case report describes a child of non-consanguineous parents who presented with chronic digital vasculitis early in life, is of short stature, has facial dysmorphia, immunodeficiency (low serum IgA, high serum IgM), recurrent bacterial infections, lymphoproliferation, absence of detectable serum C1q, and low classical complement pathway activity. We identified a previously reported de novo heterozygous pathogenic splice mutation in PIK3R1 (c.1425 + 1G > A), resulting in the skipping of exon 11 of the p85α subunit of phosphatidylinositol 3-kinase and causing activated PI3Kδ syndrome type II (APDS2). This explained the phenotype, with the exception of digital vasculitis and C1q deficiency, which have never been described in association with APDS2. No mutations were identified in C1QA, B, or C, their promoter regions, or in any other complement component. Functional studies indicated normal monocytic C1q production and release, suggesting that the observed C1q deficiency was caused by peripheral consumption of C1q. Since C1q deficiency has never been associated with APDS2, we assessed C1q levels in two unrelated patients with genetically confirmed APDS2 and confirmed C1q deficiency in those two cases as well. This observation suggests C1q deficiency to be an inherent but previously unrecognized feature of APDS2. We speculate that the consumption of C1q is driven by increased apoptotic bodies derived from immune cellular senescence, combined with elevated IgM production (both inherent features of APDS2). Secondary C1q deficiency in APDS2 may further contribute to immunodeficiency and could also be associated with inflammatory immune dysregulatory phenotypes, such as the digital vasculitis observed in our case.

The phenolic fraction of extra virgin olive oil modulates the activation and the inflammatory response of T cells from patients with systemic lupus erythematosus and healthy donors.

SCOPE: Systemic lupus erythematosus (SLE) is a chronic multiorgan autoimmune disease characterized by immune deregulation, which involves altered T-cell response and imbalance of cytokine production. The phenolic fraction (PE) of extra virgin olive oil (EVOO) possesses anti-inflammatory and immunomodulatory properties and exerts preventive effects in murine models of immune-inflammatory diseases, such as SLE. The present study was designed to determine the in vitro effects of the PE from EVOO on peripheral blood mononuclear cells (PBMC) from inactive patients with SLE and healthy donors. METHODS AND RESULTS: T-cell phenotype was investigated by flow cytometry, cytokine levels were determined by ELISA, and protein expression was detected by Western blot. The PE of EVOO decreased the frequency of CD69+ cells and the secretion of IFN-γ, TNF-α, IL-6, IL-1ß, and IL-10. Moreover, PE increased the expression of I-kappa-B-α and decreased extracellular signal regulated kinase phosphorylation on PBMC from patients with SLE and healthy donors. CONCLUSION: PE modulates cytokine production and attenuates induced T-cell activation, probably through NF-κB signaling pathway, providing the first evidence that PE from EVOO has an anti-inflammatory and immunomodulatory role in SLE patients and it might therefore be considered as a dietary complement in SLE management.

Glucose uptake and its effect on gene expression in prochlorococcus.

The marine cyanobacteria Prochlorococcus have been considered photoautotrophic microorganisms, although the utilization of exogenous sugars has never been specifically addressed in them. We studied glucose uptake in different high irradiance- and low irradiance-adapted Prochlorococcus strains, as well as the effect of glucose addition on the expression of several glucose-related genes. Glucose uptake was measured by adding radiolabelled glucose to Prochlorococcus cultures, followed by flow cytometry coupled with cell sorting in order to separate Prochlorococcus cells from bacterial contaminants. Sorted cells were recovered by filtration and their radioactivity measured. The expression, after glucose addition, of several genes (involved in glucose metabolism, and in nitrogen assimilation and its regulation) was determined in the low irradiance-adapted Prochlorococcus SS120 strain by semi-quantitative real time RT-PCR, using the rnpB gene as internal control. Our results demonstrate for the first time that the Prochlorococcus strains studied in this work take up glucose at significant rates even at concentrations close to those found in the oceans, and also exclude the possibility of this uptake being carried out by eventual bacterial contaminants, since only Prochlorococcus cells were used for radioactivity measurements. Besides, we show that the expression of a number of genes involved in glucose utilization (namely zwf, gnd and dld, encoding glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and lactate dehydrogenase, respectively) is strongly increased upon glucose addition to cultures of the SS120 strain. This fact, taken together with the magnitude of the glucose uptake, clearly indicates the physiological importance of the phenomenon. Given the significant contribution of Prochlorococcus to the global primary production, these findings have strong implications for the understanding of the phytoplankton role in the carbon cycle in nature. Besides, the ability of assimilating carbon molecules could provide additional hints to comprehend the ecological success of Prochlorococcus.