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Background/Aims Haemophagocytic lymphohistiocytosis (HLH) is a devastating condition caused by uncontrolled activation of the immune system. If left untreated, the condition leads to multi-organ failure and death. Even with treatment, recent UK data has shown a mortality rate of 50%. In 2019, a group of clinicians from University College London Hospital (UCLH) came together with the aim of improving outcomes for patients with HLH. The UCLH HLH multi-disciplinary meeting (MDM) has been running since that time and includes representation from rheumatology, haematology, infectious diseases, tropical medicine, virology, neurology, and critical care. Clinicians from any UK trust are invited to join and present patients. As part of a service evaluation project, we aimed to assess the scope of this meeting with regards to the number, demographics and primary diagnoses of patients discussed and the geographical location of the referring clinical team. Methods This is a retrospective descriptive analysis of all patients discussed at the UCLH HLH MDT from 2nd September 2020 to 20th July 2022. Data were obtained from electronic health records and analysed in Prism version 9.4.1. This work has been registered as a service evaluation project within the Division of Medical Specialities at UCLH. Results 93 patients were discussed. 38 were female. 55 were male. The median age was 38 years. Triggers for HLH were haematological malignancy (38.0%), infection (29.3%) rheumatological (14.1%) primary HLH (6.5%) and unknown (7.6%). In 4 patients, HLH was not felt to be the underlying diagnosis. 40 patients were managed as inpatients at UCLH, 37 of whom were transferred from other trusts. Geographical data were obtained on 81 patients. Patients were referred from all 9 regions of England: London (34), North East (1), North West (2), Yorkshire (2), East Midlands (1), West Midlands (3) South East (11), East of England (11), South West (11) as well as Wales (2), Scotland (2) and Ireland (1). Haemophagocytosis was confirmed on bone marrow biopsy in 66.7% of patients. Mortality data showed that 32 (34%) patients died following their diagnosis. Conclusion A multi-disciplinary approach is essential in the management of HLH. Our data show that patients with HLH are young, have a high mortality and broad range of pathology. The UCLH HLH MDT currently serves a wide geographical area across the UK and UCLH acts as a tertiary referral centre for patients with the condition. Disclosure N.S. Shah: None. M. Hutchinson: None. S. Clark: None. E. Sanchez: None. M. Brown: None. N. Stone: None. A.S. Carr: None. B. Carpenter: None. A. Laurence: None. S.H. Gohil: None. R.S. Tattersall: None. J.J. Manson: None. A. Jones: None.

Background/Aims Haemophagocytic lymphohistiocytosis (HLH) is a rare systemic inflammatory condition that is characterised by excessive macrophage activation in response to a wide range of triggers, including infections, rheumatological and haematological conditions. HLH is associated with high morbidity and mortality, and treatment requires significant immunosuppression. University College London Hospitals (UCLH) operates an HLH service; we were keen to understand the burden of infective complications in our cohort of patients and establish specific guidelines. Methods A retrospective descriptive analysis was performed of all adults with secondary HLH over a two-year time-frame (1stApril 2019 to 1st April 2021) at UCLH. UCLH has a designated HLH multi-disciplinary team (MDT) supported by rheumatology, infectious diseases, tropical medicine, virology, haematology and critical care. This work was registered as a service evaluation project by the Medical Specialities Division. Data was collated from electronic health records into REDCap, and processed in R version 1.4.1103 and Microsoft Excel by two independent authors. Results 40 patients were identified, with a median age of 37. 14 patients had an identified haematological trigger (35%), 12 an infectious one (30%) and 5 a rheumatological (12.5%). 24 patients (60%) were admitted to intensive care and 13 died during admission (32.5%). 35 patients (87.5%) received steroids at some time during their admission, with 24 (60%) receiving a long course. Four patients (10%) had prolonged neutropaenia during admission. Twenty-four patients (60%) developed an infection during their admission; with 33 bacterial, 7 viral and 12 fungal infections (5 proven, 2 probable and 5 possible) identified. Sixteen patients had >1 infection. Those who did not have a diagnosed infection during their admission were more likely to survive than those who did (93% vs 44%, p = 0.047). The mortality rate of those with fungal infections was 89%, compared to 43% for bacterial and viral infections. Of the 24 patients who received a long course of steroids, 14 (58%) did not receive anti-fungal prophylaxis during their admission and three of these patients were diagnosed with fungal infections during their admission. Of the 4 patients with prolonged neutropenia, 1 (25%) did not receive antifungal prophylaxis and did suffer from a confirmed fungal infection. One patient with confirmed PCP had not previously been taking PCP prophylaxis. Of the seven patients with viral infections, 2 had HSV-1 infections and neither had received anti-viral prophylaxis before their infection start date. Conclusion We demonstrate that a high proportion of patients with HLH develop infective complications, which is associated with increased mortality. Prior to this analysis, the use of antimicrobial prophylaxis was variable. We have since written a specific guideline for the routine use of antimicrobial prophylaxis for patients with HLH, with a view to auditing future care against this guideline. Disclosure P. Saha: None. N. McCann: None. M. Brown: None. N. Stone: None. E. Sanchez: None. B. Carpenter: None. A. Laurence: None. M. Hutchinson: None. A. Jones: None. S.H. Gohil: None. J. Manson: None.

No effect of TFEB on RCC tumor growth in nude mice

Purpose:Despite the FDA approval of mTOR inhibitors (mTORi) for the treatment of renal cell carcinoma (RCC), the benefits are relatively modest and the few responders usually develop resistance. We investigated whether the resistance to mTORi is due to upregulation of PD-L1 and the underlying molecular mechanism.Experimental Design:The effects of transcription factor EB (TFEB) on RCC proliferation, apoptosis, and migration were evaluated. Correlation of TFEB with PD-L1 expression, as well as effects of mTOR inhibition on TFEB and PD-L1 expression, was assessed in human primary clear cell RCCs. The regulation of TFEB on PD-L1 was assessed by chromatin immunoprecipitation and luciferase reporter assay. The therapeutic efficacies of mTORi plus PD-L1 blockade were evaluated in a mouse model. The function of tumor-infiltrating CD8+ T cells was analyzed by flow cytometry.Results:TFEB did not affect tumor cell proliferation, apoptosis, and migration. We found a positive correlation between TFEB and PD-L1 expression in RCC tumor tissues, primary tumor cells, and RCC cells. TFEB bound to PD-L1 promoter in RCCs and inhibition of mTOR led to enhanced TFEB nuclear translocation and PD-L1 expression. Simultaneous inhibition of mTOR and blockade of PD-L1 enhanced CD8+ cytolytic function and tumor suppression in a xenografted mouse model of RCC.Conclusions:These data revealed that TFEB mediates resistance to mTOR inhibition via induction of PD-L1 in human primary RCC tumors, RCC cells, and murine xenograft model. Our data provide a strong rationale to target mTOR and PD-L1 jointly as a novel immunotherapeutic approach for RCC treatment.

Patient characteristics

Overexpression of the immunosuppressive cytokine transforming growth factor β (TGF-β) is one strategy that tumors have developed to evade effective immunesurveillance. Using transplantable models of breast and colon cancer, we made the unexpected finding that CD8+ cells in tumor-bearing animals can directly promote tumorigenesis, by a mechanism that is dependent on TGF-β. We showed that CD8+ splenocytes from tumor-bearing mice expressed elevated interleukin (IL)-17 when compared with naive mice, and that CD8+ T cells could be induced to make IL-17 on addition of TGF-β and IL-6 in vitro. Treatment of mice with anti–TGF-β antibodies in vivo reduced IL-17 expression both in the tumor and the locoregional lymph nodes. Although IL-17 has not previously been shown to act as a survival factor for epithelial cells, we found that IL-17 suppressed apoptosis of several tumor cell lines in vitro, suggesting that this altered T-cell polarization has the potential to promote tumorigenesis directly, rather than indirectly through inflammatory sequelae. Consistent with this hypothesis, knockdown of the IL-17 receptor in 4T1 mouse mammary cancer cells enhanced apoptosis and decreased tumor growth in vivo. Thus, in addition to suppressing immune surveillance, tumor-induced TGF-β may actively subvert the CD8+ arm of the immune system into directly promoting tumor growth by an IL-17–dependent mechanism. [Cancer Res 2008;68(10):3915–23]

Supplementary Figures 1-5, Table 1 from Transforming Growth Factor β Subverts the Immune System into Directly Promoting Tumor Growth through Interleukin-17

Genomic medicine enables the identification of patients with rare or ultra-rare monogenic forms of inflammatory bowel disease (IBD) and supports clinical decision making. Patients with monogenic IBD frequently experience extremely early onset of treatment-refractory disease, with complex extraintestinal disease typical of immunodeficiency. Since more than 100 monogenic disorders can present with IBD, new genetic disorders and variants are being discovered every year, and as phenotypic expression of the gene defects is variable, adaptive genomic technologies are required. Monogenic IBD has become a key area to establish the concept of precision medicine. Clear guidance and standardised, affordable applications of genomic technologies are needed to implement exome or genome sequencing in clinical practice. This joint British Society of Gastroenterology and British Society of Paediatric Gastroenterology, Hepatology and Nutrition guideline aims to ensure that testing resources are appropriately applied to maximise the benefit to patients on a national scale, minimise health-care disparities in accessing genomic technologies, and optimise resource use. We set out the structural requirements for genomic medicine as part of a multidisciplinary team approach. Initiation of genomic diagnostics should be guided by diagnostic criteria for the individual patient, in particular the age of IBD onset and the patient's history, and potential implications for future therapies. We outline the diagnostic care pathway for paediatric and adult patients. This guideline considers how to handle clinically actionable findings in research studies and the impact of consumer-based genomics for monogenic IBD. This document was developed by multiple stakeholders, including UK paediatric and adult gastroenterology physicians, immunologists, transplant specialists, clinical geneticists, scientists, and research leads of UK genetic programmes, in partnership with patient representatives of several IBD and rare disease charities.

T regulatory (Treg) cells are essential for self-tolerance whereas they are detrimental for dampening the host anti-tumor immunity. How Treg cells adapt to environmental signals to orchestrate their homeostasis and functions remains poorly understood. Here, we identified that transcription factor EB (TFEB) is induced by host nutrition deprivation or interleukin (IL)-2 in CD4 + T cells. The loss of TFEB in Treg cells leads to reduced Treg accumulation and impaired Treg function in mouse models of cancer and autoimmune disease. TFEB intrinsically regulates genes involved in Treg cell differentiation and mitochondria function while it suppresses expression of proinflammatory cytokines independently of its established roles in autophagy. This coordinated action is required for mitochondria integrity and appropriate lipid metabolism in Treg cells. These findings identify TFEB as a critical regulator for orchestrating Treg generation and function, which may contribute to the adaptive responses of T cells to local environmental cues.

The molecular mechanisms governing orderly shutdown and retraction of CD4+ type 1 helper T (TH1) cell responses remain poorly understood. Here we show that complement triggers contraction of TH1 responses by inducing intrinsic expression of the vitamin D (VitD) receptor and the VitD-activating enzyme CYP27B1, permitting T cells to both activate and respond to VitD. VitD then initiated the transition from pro-inflammatory interferon-γ+ TH1 cells to suppressive interleukin-10+ cells. This process was primed by dynamic changes in the epigenetic landscape of CD4+ T cells, generating super-enhancers and recruiting several transcription factors, notably c-JUN, STAT3 and BACH2, which together with VitD receptor shaped the transcriptional response to VitD. Accordingly, VitD did not induce interleukin-10 expression in cells with dysfunctional BACH2 or STAT3. Bronchoalveolar lavage fluid CD4+ T cells of patients with COVID-19 were TH1-skewed and showed de-repression of genes downregulated by VitD, from either lack of substrate (VitD deficiency) and/or abnormal regulation of this system. During homeostasis TH1 cells activate a cell-intrinsic inflammatory shutdown program and shift to IL-10 production. Chauss et al. find that this TH1 homeostatic program is dependent on vitamin D signaling and is disrupted in severe COVID-19.

Allogeneic hematopoietic stem cell transplantation (alloSCT) is curative for severe inborn errors of immunity (IEIs), with recent data suggesting alloSCT in adulthood is safe and effective in selected patients. However, questions remain regarding the indications for and optimal timing of transplant. We retrospectively compared outcomes of transplanted vs matched nontransplanted adults with severe IEIs. Seventy-nine patients (aged ≥ 15 years) underwent alloSCT between 2008 and 2018 for IEIs such as chronic granulomatous disease (n = 20) and various combined immune deficiencies (n = 59). A cohort of nontransplanted patients from the French Centre de Référence Déficits Immunitaires Héréditaires registry was identified blindly for case-control analysis, with ≤3 matched controls per index patient, without replacement. The nontransplanted patients were matched for birth decade, age at last review greater than index patient age at alloSCT, chronic granulomatous disease or combined immune deficiencies, and autoimmune/lymphoproliferative complications. A total of 281 patients were included (79 transplanted, 202 nontransplanted). Median age at transplant was 21 years. Transplant indications were mainly lymphoproliferative disease (n = 23) or colitis (n = 15). Median follow-up was 4.8 years (interquartile range, 2.5-7.2). One-year transplant-related mortality rate was 13%. Estimated disease-free survival at 5 years was higher in transplanted patients (58% vs 33%; P = .007). Nontransplanted patients had an ongoing risk of severe events, with an increased mean cumulative number of recurrent events compared with transplanted patients. Sensitivity analyses removing patients with common variable immune deficiency and their matched transplanted patients confirm these results. AlloSCT prevents progressive morbidity associated with IEIs in adults, which may outweigh the negative impact of transplant-related mortality.

Abstract Purpose Allogeneic hematopoietic stem cell transplant (HSCT) remains the treatment of choice for patients with inborn errors of immunity (IEI). There is little published medical outcome data assessing late medical complications following transition to adult care. We sought to document event-free survival (EFS) in transplanted IEI patients reaching adulthood and describe common late-onset medical complications and factors influencing EFS. Methods In this landmark analysis, 83 adults surviving 5 years or more following prior HSCT in childhood for IEI were recruited. The primary endpoint was event-free survival, defined as time post-first HSCT to graft failure, graft rejection, chronic infection, life-threatening or recurrent infections, malignancy, significant autoimmune disease, moderate to severe GVHD or major organ dysfunction. All events occurring less than 5 years post-HSCT were excluded. Results EFS was 51% for the whole cohort at a median of 20 years post HSCT. Multivariable analysis identified age at transplant and whole blood chimerism as independent predictors of long-term EFS. Year of HSCT, donor, conditioning intensity and underlying diagnosis had no significant impact on EFS. 59 events occurring beyond 5 years post-HSCT were documented in 37 patients (45% cohort). A total of 25 patients (30% cohort) experienced ongoing significant complications requiring active medical intervention at last follow-up. Conclusion Although most patients achieved excellent, durable immune reconstitution with infrequent transplant-related complications, very late complications are common and associated with mixed chimerism post-HSCT. Early intervention to correct mixed chimerism may improve long-term outcomes and adult health following HSCT for IEI in childhood.

Purpose: Despite the FDA approval of mTOR inhibitors (mTORi) for the treatment of renal cell carcinoma (RCC), the benefits are relatively modest and the few responders usually develop resistance. We investigated whether the resistance to mTORi is due to upregulation of PD-L1 and the underlying molecular mechanism. Experimental Design: The effects of transcription factor EB (TFEB) on RCC proliferation, apoptosis, and migration were evaluated. Correlation of TFEB with PD-L1 expression, as well as effects of mTOR inhibition on TFEB and PD-L1 expression, was assessed in human primary clear cell RCCs. The regulation of TFEB on PD-L1 was assessed by chromatin immunoprecipitation and luciferase reporter assay. The therapeutic efficacies of mTORi plus PD-L1 blockade were evaluated in a mouse model. The function of tumor-infiltrating CD8+ T cells was analyzed by flow cytometry. Results: TFEB did not affect tumor cell proliferation, apoptosis, and migration. We found a positive correlation between TFEB and PD-L1 expression in RCC tumor tissues, primary tumor cells, and RCC cells. TFEB bound to PD-L1 promoter in RCCs and inhibition of mTOR led to enhanced TFEB nuclear translocation and PD-L1 expression. Simultaneous inhibition of mTOR and blockade of PD-L1 enhanced CD8+ cytolytic function and tumor suppression in a xenografted mouse model of RCC. Conclusions: These data revealed that TFEB mediates resistance to mTOR inhibition via induction of PD-L1 in human primary RCC tumors, RCC cells, and murine xenograft model. Our data provide a strong rationale to target mTOR and PD-L1 jointly as a novel immunotherapeutic approach for RCC treatment.

Patients with coronavirus disease 2019 (COVID-19) present a wide range of acute clinical manifestations affecting the lungs, liver, kidneys and gut. Angiotensin converting enzyme (ACE) 2, the best-characterized entry receptor for the disease-causing virus SARS-CoV-2, is highly expressed in the aforementioned tissues. However, the pathways that underlie the disease are still poorly understood. Here, we unexpectedly found that the complement system was one of the intracellular pathways most highly induced by SARS-CoV-2 infection in lung epithelial cells. Infection of respiratory epithelial cells with SARS-CoV-2 generated activated complement component C3a and could be blocked by a cell-permeable inhibitor of complement factor B (CFBi), indicating the presence of an inducible cell-intrinsic C3 convertase in respiratory epithelial cells. Within cells of the bronchoalveolar lavage of patients, distinct signatures of complement activation in myeloid, lymphoid and epithelial cells tracked with disease severity. Genes induced by SARS-CoV-2 and the drugs that could normalize these genes both implicated the interferon-JAK1/2-STAT1 signaling system and NF-κB as the main drivers of their expression. Ruxolitinib, a JAK1/2 inhibitor, normalized interferon signature genes and all complement gene transcripts induced by SARS-CoV-2 in lung epithelial cell lines, but did not affect NF-κB-regulated genes. Ruxolitinib, alone or in combination with the antiviral remdesivir, inhibited C3a protein produced by infected cells. Together, we postulate that combination therapy with JAK inhibitors and drugs that normalize NF-κB-signaling could potentially have clinical application for severe COVID-19.

The IL-6 family of cytokines mediates functions in host protective immunity, development of multiple organs, tissue regeneration and metabolism. Inborn errors in cytokines or cytokine receptor units highlight specific roles for IL-6, IL-11, LIF, OSM, and CLC signaling whereas incomplete loss-of-function variants in the common receptor chain GP130 encoded by IL6ST or the transcription factor STAT3, as well as genes that affect either GP130 glycosylation (PGM3) or STAT3 transcriptional control (ZNF341) lead to complex phenotypes including features of hyper-IgE syndrome. Gain-of-function variants in the GP130-STAT3 signaling pathway cause immune dysregulation disorders. Insights into IL-6 family cytokine signaling inform on therapeutic application in immune-mediated disorders and potential side effects such as infection susceptibility.

Appropriate migration of cytotoxic T effector cells into the tumors is crucial for their antitumor function. Despite the controversial role of PI3K-Akt in CD8+ T cell mTORC1 activation, a link between Akt-mTORC1 signaling and CD8+ trafficking has been demonstrated. We have recently discovered that TCR-induced calcineurin activates DAPK1, which interacts with TSC2 via its death domain and phosphorylates TSC2 via its kinase domain to mediate mTORC1 activation in CD8+ T cells. However, whether DAPK1 regulates CD8+ trafficking into tumors remains unclear. Here, using pharmacological inhibitor and genetic approaches, we found that like rapamycin, inhibition of DAPK1 activity led to enhanced expression of the homing receptors CD62L and CCR7. Deletion of either kinase domain or death domain in the T cell compartment reduced the T cell activation and maintained the expression of CD62L and CCR7. DAPK1-DD-deficient mice were more susceptible to tumor growth and deficiency of DAPK1 activity significantly reduced the migratory ability of CD8+ into the tumors. These data revealed a crucial role of DAPK1-mTORC1 in mediating CD8+ trafficking and antitumor function.

Pro-inflammatory immune responses are necessary for effective pathogen clearance, but cause severe tissue damage if not shut down in a timely manner1,2. Excessive complement and IFN-γ-associated responses are known drivers of immunopathogenesis3 and are among the most highly induced immune programs in hyper-inflammatory SARS-CoV2 lung infection4. The molecular mechanisms that govern orderly shutdown and retraction of these responses remain poorly understood. Here, we show that complement triggers contraction of IFN-γ producing CD4+ T helper (Th) 1 cell responses by inducing expression of the vitamin D (VitD) receptor (VDR) and CYP27B1, the enzyme that activates VitD, permitting T cells to both activate and respond to VitD. VitD then initiates the transition from pro-inflammatory IFN-γ+ Th1 cells to suppressive IL-10+ Th1 cells. This process is primed by dynamic changes in the epigenetic landscape of CD4+ T cells, generating superenhancers and recruiting c-JUN and BACH2, a key immunoregulatory transcription factor5–7. Accordingly, cells in psoriatic skin treated with VitD increased BACH2 expression, and BACH2 haplo-insufficient CD4+ T cells were defective in IL-10 production. As proof-of-concept, we show that CD4+ T cells in the bronchoalveolar lavage fluid (BALF) of patients with COVID-19 are Th1-skewed and that VDR is among the top regulators of genes induced by SARS-CoV2. Importantly, genes normally down-regulated by VitD were de-repressed in CD4+ BALF T cells of COVID-19, indicating that the VitD-driven shutdown program is impaired in this setting. The active metabolite of VitD, alfacalcidol, and cortico-steroids were among the top predicted pharmaceuticals that could normalize SARS-CoV2 induced genes. These data indicate that adjunct therapy with VitD in the context of other immunomodulatory drugs may be a beneficial strategy to dampen hyperinflammation in severe COVID-19.

Background Biallelic variants in IL6ST, encoding GP130, cause a recessive form of hyper-IgE syndrome (HIES) characterized by high IgE level, eosinophilia, defective acute phase response, susceptibility to bacterial infections, and skeletal abnormalities due to cytokine-selective loss of function in GP130, with defective IL-6 and IL-11 and variable oncostatin M (OSM) and IL-27 levels but sparing leukemia inhibitory factor (LIF) signaling. Objective Our aim was to understand the functional and structural impact of recessive HIES-associated IL6ST variants. Methods We investigated a patient with HIES by using exome, genome, and RNA sequencing. Functional assays assessed IL-6, IL-11, IL-27, OSM, LIF, CT-1, CLC, and CNTF signaling. Molecular dynamics simulations and structural modeling of GP130 cytokine receptor complexes were performed. Results We identified a patient with compound heterozygous novel missense variants in IL6ST (p.Ala517Pro and the exon-skipping null variant p.Gly484_Pro518delinsArg). The p.Ala517Pro variant resulted in a more profound IL-6– and IL-11–dominated signaling defect than did the previously identified recessive HIES IL6ST variants p.Asn404Tyr and p.Pro498Leu. Molecular dynamics simulations suggested that the p.Ala517Pro and p.Asn404Tyr variants result in increased flexibility of the extracellular membrane–proximal domains of GP130. We propose a structural model that explains the cytokine selectivity of pathogenic IL6ST variants that result in recessive HIES. The variants destabilized the conformation of the hexameric cytokine receptor complexes, whereas the trimeric LIF-GP130-LIFR complex remained stable through an additional membrane-proximal interaction. Deletion of this membrane-proximal interaction site in GP130 consequently caused additional defective LIF signaling and Stuve-Wiedemann syndrome. Conclusion Our data provide a structural basis to understand clinical phenotypes in patients with IL6ST variants.

The GP130 cytokine receptor subunit encoded by IL6ST is the shared receptor for ten cytokines of the IL-6 family. We describe a homozygous non-synonymous variant in IL6ST (p.R281Q) in a patient with craniosynostosis and retained deciduous teeth. We characterize the impact of the variant on cytokine signaling in vitro using transfected cell lines as well as primary patient-derived cells and support these findings using a mouse model with the corresponding genome-edited variant Il6st p.R279Q. We show that human GP130 p.R281Q is associated with selective loss of IL-11 signaling without affecting IL-6, IL-27, OSM, LIF, CT1, CLC, and CNTF signaling. In mice Il6st p.R279Q lowers litter size and causes facial synostosis and teeth abnormalities. The effect on IL-11 signaling caused by the GP130 variant shows incomplete penetrance but phenocopies aspects of IL11RA deficiency in humans and mice. Our data show that a genetic variant in a pleiotropic cytokine receptor can have remarkably selective defects.

Patients with coronavirus disease 2019 (COVID-19) present with a range of devastating acute clinical manifestations affecting the lungs, liver, kidneys and gut. The best-characterized entry receptor for the disease-causing virus SARS-CoV2, angiotensin converting enzyme (ACE) 2, is highly expressed in these tissues. However, the pathways that underlie the disease are still poorly understood. Here we show that the complement system is unexpectedly one of the intracellular pathways most highly induced by SARS-CoV2 infection in lung epithelial and liver cells. Within cells of the bronchoalveolar lavage of patients, distinct signatures of complement activation in myeloid, lymphoid and epithelial cells tracked with disease severity. Modelling the regulome of host genes induced by COVID-19 and the drugs that could normalize these genes both implicated the JAK1/2-STAT1 signaling system downstream of type I interferon receptors, and NF-kB. Ruxolitinib, a JAK1/2 inhibitor and the top predicted pharmaceutical candidate, normalized interferon signature genes, IL-6 (the best characterized severity marker in COVID-19) and all complement genes induced by SARS-CoV2, but did not affect NF-kB-regulated genes. We predict that combination therapy with JAK inhibitors and other agents with the potential to normalize NF-kB-signaling, such as anti-viral agents, may serve as an effective clinical strategy.

International audience; Autosomal dominant hyper-IgE syndrome (AD-HIES) is typically caused by dominant-negative (DN) STAT3 mutations. Patients suffer from cold staphylococcal lesions and mucocutaneous candidiasis, severe allergy, and skeletal abnormalities. We report 12 patients from 8 unrelated kindreds with AD-HIES due to DN IL6ST mutations. We identified seven different truncating mutations, one of which was recurrent. The mutant alleles encode GP130 receptors bearing the transmembrane domain but lacking both the recycling motif and all four STAT3-recruiting tyrosine residues. Upon overexpression, the mutant proteins accumulate at the cell surface and are loss of function and DN for cellular responses to IL-6, IL-11, LIF, and OSM. Moreover, the patients’ heterozygous leukocytes and fibroblasts respond poorly to IL-6 and IL-11. Consistently, patients with STAT3 and IL6ST mutations display infectious and allergic manifestations of IL-6R deficiency, and some of the skeletal abnormalities of IL-11R deficiency. DN STAT3 and IL6ST mutations thus appear to underlie clinical phenocopies through impairment of the IL-6 and IL-11 response pathways.

Purpose Macrophages are important regulators of environmental allergen-induced airway inflammation and asthma. ATP6V0d2 is a subunit of vacuolar ATPase highly expressed in macrophages. However, the functions of ATP6V0d2 in the regulation of pathogenesis of allergic asthma remain unclear. The aim of this study is to determine the function and related molecular mechanisms of macrophage protein ATP6V0d2 in allergic asthma. Methods We compared the disease severity between female C57BL/6 wild-type and ATP6V0d2-/- mice in an ovalbumin (OVA)-induced asthma model. We also investigated the association of expression of ATP6V0d2, PU.1 and CCL17 with disease severity among asthmatic patients. Results The expression of ATP6V0d2 in sputum cells of asthmatic patients and in the lungs of OVA-challenged mice was enhanced compared to healthy subjects and their counterparts, respectively. However, ATP6V0d2-deficient mice exaggerated inflammatory cell infiltration as well as enhanced alternative activated macrophage (AAM) polarization and mucus production in an OVA-induced asthma model. Furthermore, we found that Atp6v0d2 promoted lysosomal degradation of Pu.1, which induced AAM polarization and Ccl17 production. Among asthma patients, ATP6V0d2 expression was inversely associated with disease severity, whereas PU.1 and CCL17 expression was positively associated with disease severity. Conclusions Our results identify macrophage Atp6v0d2, as an induced feedback inhibitor of asthma disease severity by promoting Pu.1 lysosomal degradation, which may in turn leads to reduced AAM polarization and Ccl17 production.

Background Pro-inflammatory CD4+ T helper (Th)1 cells clear pathogens effectively but cause excessive tissue injury if not shut down appropriately. The complement (C’) system both induces Th1 differentiation and their shutdown, but the mechanisms regulating orderly shutdown remain unknown. Hypothesis C’ receptor engagement recruits transcriptional regulators essential to Th1 shutdown. Methods Multi-modal profiling of activated, or patient-derived Th cells, psoriatic skin, and SARS-CoV2-infected tissues was carried out by epigenome profiling, RNAseq, network modeling, phospho-arrays, confocal, and regulator knockdown. Results C’ receptor signaling induced the vitamin D (VitD) receptor (VDR) and CYP27B1, the enzyme that activates VitD, allowing T cells to both fully activate and respond to VitD. Active VitD shut down IFN-γ production by Th1 cells and induced IL-10. This was mediated by activation of IL-6 production by T cells and signaling through STAT3. Mechanistically, VitD reprogrammed the Th1 transcriptomes by forming super-enhancers and recruiting a transcription factor (TF) network consisting of VDR, c-JUN, STAT3, and BACH2. We mapped genome-wide targets of these TFs by CUT&RUN/Tag. As proof of principal, psoriatic skin treated with VitD induced BACH2 in Th cells, and genetic deficiency of either BACH2 or STAT3 inhibited IL-10 produced in response to VitD. Bronchoalveolar lavage fluid of COVID-19 patients, a C’-rich environment, showed excessive Th1 skewing and perturbation of the VitD-regulated program of genes. Conclusion We identified a C’-recruited autocrine VitD system as key to Th1 shutdown and indicate the potential for adjunct therapy with VitD in hyper-inflammatory syndromes, e.g. COVID-19. This work was supported by the Wellcome Trust (grant 097261/Z/11/Z to B.A.), the Crohn’s and Colitis Foundation of America (grant CCFA no. 3765 — CCFA genetics initiative to A.L.), British Heart Foundation (grant RG/13/12/30395 to G.L.), the National Institute of General Medical Sciences (R35GM138283 to M.K.), the Showalter Trust (research award to M.K.), German Research Foundation (DFG scholarship to T.F.; FR 3851/2-1), the NIDDK (DK12262401A1 to D.P.) and the National Agency of Research and Development of Chile (grant PAI79170073 to E.N.L.). Research was also supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guy’s and St Thomas’ NHS Foundation Trust and King’s College London and/or the NIHR Clinical Research Facility. The views expressed are those of the authors and not necessarily those of the NHS, the NIHR or the Department of Health. This research was supported (in part) by the Intramural Research Programs of the NIDDK (project no. ZIA/DK075149 to B.A), the National Heart, Lung and Blood Institute (project nos. ZIA/Hl006223 to C.K. and ZIA/HL006193 to N.M.), the NIAID (project no. ZIA/AI001175 to M.S.L.) of the NIH. D.C. is supported by an NIH Office of Dietary Supplements research scholar award.

Autosomal dominant hyper IgE syndrome (AD-HIES), or Job's syndrome, is a primary immune deficiency caused by dominant-negative mutations in STAT3. Recurrent Staphylococcus aureus skin abscesses are a defining feature of this syndrome. A widely held hypothesis that defects in peripheral Th17 differentiation confer this susceptibility has never been directly evaluated. To assess the cutaneous immune response in AD-HIES, we induced suction blisters in healthy volunteers (HVs) and patients with AD-HIES and then challenged the wound with lethally irradiated bacteria. We show that cutaneous production of IL-17A and IL-17F was normal in patients with AD-HIES. Overproduction of TNF-α differentiated the responses in AD-HIES from HVs. This was associated with reduced IL-10 family signaling in blister-infiltrating cells and defective epithelial cell function. Mouse models of AD-HIES recapitulated these aberrant epithelial responses to S. aureus and involved defective epithelial-to-mesenchymal transition (EMT) rather than a failure of bacterial killing. Defective responses in mouse models of AD-HIES and primary keratinocyte cultures from patients with AD-HIES could be reversed by TNF-α blockade and by drugs with reported modulatory effects on EMT. Our results identify these as potential therapeutic approaches in patients with AD-HIES suffering S. aureus infections.

ObjectiveThere is little evidence that adjuvant therapy after radical surgical resection of hepatocellular carcinoma (HCC) improves recurrence-free survival (RFS) or overall survival (OS). We conducted a multicentre, randomised, controlled, phase IV trial evaluating the benefit of an aqueous extract of Trametes robinophila Murr (Huaier granule) to address this unmet need.Design and resultsA total of 1044 patients were randomised in 2:1 ratio to receive either Huaier or no further treatment (controls) for a maximum of 96 weeks. The primary endpoint was RFS. Secondary endpoints included OS and tumour extrahepatic recurrence rate (ERR). The Huaier (n=686) and control groups (n=316) had a mean RFS of 75.5 weeks and 68.5 weeks, respectively (HR 0.67; 95% CI 0.55 to 0.81). The difference in the RFS rate between Huaier and control groups was 62.39% and 49.05% (95% CI 6.74 to 19.94; p=0.0001); this led to an OS rate in the Huaier and control groups of 95.19% and 91.46%, respectively (95% CI 0.26 to 7.21; p=0.0207). The tumour ERR between Huaier and control groups was 8.60% and 13.61% (95% CI −12.59 to −2.50; p=0.0018), respectively.ConclusionsThis is the first nationwide multicentre study, involving 39 centres and 1044 patients, to prove the effectiveness of Huaier granule as adjuvant therapy for HCC after curative liver resection. It demonstrated a significant prolongation of RFS and reduced extrahepatic recurrence in Huaier group.Trial registrationNCT01770431; Post-results.

St. Leger et al. identify and examine innate-like αβ T cells that circumvent canonical STAT-3 phosphorylation to produce protective IL-17. These cells can exist in the ocular mucosa and protect the ocular surface from pathogenic Staphylococcus aureus infection., Appropriate regulation of IL-17 production in the host can mean the difference between effective control of pathogens and uncontrolled inflammation that causes tissue damage. Investigation of conventional CD4+ T cells (Th17 cells) has yielded invaluable insights into IL-17 function and its regulation. More recently, we and others reported production of IL-17 from innate αβ+ T cell populations, which was shown to occur primarily via IL-23R signaling through the transcription factor STAT-3. In our current study, we identify promyelocytic leukemia zinc finger (PLZF)–expressing iNKT, CD4−/CD8+, and CD4−/CD8− (DN) αβ+T cells, which produce IL-17 in response to TCR and IL-1 receptor ligation independently of STAT-3 signaling. Notably, this noncanonical pathway of IL-17 production may be important in mucosal defense and is by itself sufficient to control pathogenic Staphylococcus aureus infection at the ocular surface., Graphical Abstract

For most inflammatory skin diseases topical glucocorticosteroids and traditional oral immunosuppressive drugs remain the principle treatment choices, but this has started to change. A deeper understanding in individual disease pathogenesis, basic immune mechanisms and molecular signalling pathways, together with advances in pharmaceutical drug development, allow us to interfere more precisely with disease-related factors. Some examples of inflammation-controlling interventions include antibodies neutralizing disease-associated cytokines, and small molecules targeting intracellular pathways relevant to cytokine production or cytokine signalling. So far, this is best established for psoriasis, an inflammatory skin disease dominated by Th17 cytokines. In this review, we focus on chronic inflammatory skin diseases where cytokines using type I/II cytokine receptors play a dominant role in disease pathogenesis and where novel treatments with inhibitors of the JAK/STAT pathway are already under clinical investigation. To better understand the rationale of using JAK/STAT inhibitors in the discussed skin diseases, we give an overview of important genetic and immunological associations with the JAK/STAT pathway and summarize the stage of clinical development of small molecular inhibitors. JAK/STAT inhibitors will presumably find wide application in dermatology, since they can be applied not only systematically but also topically for the treatment of inflammatory skin diseases.

Autoimmune disease results from an inability of the immune system to differentiate self-antigens from those of a foreign and harmful organism. Since the immune system is forced to deal with an unforeseeable variety of pathogens, it is impossible to design an effective immune system that is incapable of reacting against self-antigens. Instead, a complex system of checks and balances has evolved to keep the immune system from reacting harmfully against “self.” Accordingly, while autoimmune T cells and B cells may well be part of the healthy immune system, as often are autoantibodies, a failure to repress these cells results in the activation of the immune system’s effector mechanisms. This will almost always lead to inflammation and damage, i.e., autoimmune disease. In the absence of a reliable way of specifically removing autoimmune cells, most successful clinical strategies target the effector mechanisms in the treatment of autoimmunity. It is therefore important to understand these effector mechanisms and to both recognize their role in autoimmune diseases and minimize their harmful effects.

Appropriate migration of cytotoxic T effector cells into the tumors is crucial for their antitumor function. Despite the controversial role of PI3K-Akt in CD8

Cytokine-induced signaling pathways are tightly regulated and self-limiting, as their dysregulation causes immune disorders and cancer. The precise mechanisms that fine-tune these responses are incompletely understood. We show that the E3 ubiquitin ligaseRNF144Ais an IL-2/STAT5-induced gene in T cells and critically orchestrates the hierarchy of IL-2R signaling to promote STAT5 activation and limit RAF-ERK-MAPK output from the IL-2R. Mechanistically, RNF144A increased the interaction between IL-2Rβ and STAT5 and polyubiquitinated RAF1, enhancing its proteasomal degradation and preventing the formation of the potent RAF1/BRAF kinase complex. CD8+T cells fromRnf144a–/–mice had impaired IL-2-induction of effector genes, includingTnfand granzymes, and these mice demonstrated increased susceptibility to influenza. Reduced RNF144A expression was associated with more severe influenza in humans and its expression in patients was a biomarker distinguishing moderate from severe disease. These studies reveal a vital physiological role for RNF144A in maintaining the fidelity of IL-2R signaling in CTLs to prevent severe inflammation in response to infection.One Sentence SummaryRNF144A promotes anti-viral immunity by regulating the hierarchy of cytokine signal output

Mechanistic target of rapamycin complex 1 (mTORC1) regulates CD8(+) T-cell differentiation and function. Despite the links between PI3K-AKT and mTORC1 activation in CD8(+) T cells, the molecular mechanism underlying mTORC1 activation remains unclear. Here, we show that both the kinase activity and the death domain of DAPK1 are required for maximal mTOR activation and CD8(+) T-cell function. We found that TCR-induced activation of calcineurin activates DAPK1, which subsequently interacts with TSC2 via its death domain and phosphorylates TSC2 to mediate mTORC1 activation. Furthermore, both the kinase domain and death domain of DAPK1 are required for CD8(+) T-cell antiviral responses in an LCMV infection model. Together, our data reveal a novel mechanism of mTORC1 activation that mediates optimal CD8(+) T-cell function and antiviral activity.

The lipid and protein phosphatase and tensin homolog (PTEN) controls the differentiation and activation of multiple immune cells. PTEN acts downstream from T- and B-cell receptors, costimulatory molecules, cytokine receptors, integrins, and also growth factor receptors. Loss of PTEN activity in human and mice is associated with cellular and humoral immune dysfunction, lymphoid hyperplasia, and autoimmunity. Although most patients with PTEN hamartoma tumor syndrome (PHTS) have no immunological symptoms, a subclinical immune dysfunction is present in many, and clinical immunodeficiency in few. Comparison of the immune phenotype caused by PTEN haploinsufficiency in PHTS, phosphoinositide 3-kinase (PI3K) gain-of-function in activated PI3K syndrome, and mice with conditional biallelic Pten deletion suggests a threshold model in which coordinated activity of several phosphatases control the PI3K signaling in a cell-type-specific manner. Emerging evidence highlights the role of PTEN in polygenic autoimmune disorders, infection, and the immunological response to cancer. Targeting the PI3K axis is an emerging therapeutic avenue.

Reversible protein phosphorylation is a critical regulator of homeostasis in all eukaryotic cells. It is a major means for transmitting information from outside the cell and between the subcellular components within the cell. The importance of protein phosphorylation is illustrated both in cancer, in which mutant protein kinases function as oncogenes, and in disorders of the immune system, where inherited deficiencies of protein kinase signaling are responsible for the majority of cases of severe combined immunodeficiency. On the basis of these findings, targeting protein kinases has been proposed to be a useful strategy in the development of novel immunosuppressant drugs and is one of the most active areas of pharmaceutical drug development, with much of the impetus coming from oncology. This chapter will describe many of the key signaling pathways in immune cells and highlight attempts to design specific inhibitors of key kinases within each pathway to design drugs that limit discrete components of the immune system responsible for particular autoimmune diseases while preserving defense against infections.

Macroautophagy/autophagy is a conserved ubiquitous pathway that performs diverse roles in health and disease. Although many key, widely expressed proteins that regulate autophagosome formation followed by lysosomal fusion have been identified, the possibilities of cell-specific elements that contribute to the autophagy fusion machinery have not been explored. Here we show that a macrophage-specific isoform of the vacuolar ATPase protein ATP6V0D2/subunit d2 is dispensable for lysosome acidification, but promotes the completion of autophagy via promotion of autophagosome-lysosome fusion through its interaction with STX17 and VAMP8. Atp6v0d2-deficient macrophages have augmented mitochondrial damage, enhanced inflammasome activation and reduced clearance of Salmonella typhimurium. The susceptibility of atp6v0d2 knockout mice to DSS-induced colitis and Salmonella typhimurium-induced death, highlights the in vivo significance of ATP6V0D2-mediated autophagosome-lysosome fusion. Together, our data identify ATP6V0D2 as a key component of macrophage-specific autophagosome-lysosome fusion machinery maintaining macrophage organelle homeostasis and, in turn, limiting both inflammation and bacterial infection. Abbreviations: ACTB/β-actin: actin, beta; ATG14: autophagy related 14; ATG16L1: autophagy related 16-like 1 (S. cerevisiae); ATP6V0D1/2: ATPase, H+ transporting, lysosomal V0 subunit D1/2; AIM2: absent in melanoma 2; BMDM: bone marrow-derived macrophage; CASP1: caspase 1; CGD: chronic granulomatous disease; CSF1/M-CSF: colony stimulating factor 1 (macrophage); CTSB: cathepsin B; DSS: dextran sodium sulfate; IL1B: interleukin 1 beta; IL6: interleukin 6; IRGM: immunity-related GTPase family M member; KO: knockout; LAMP1: lysosomal-associated membrane protein 1; LC3: microtubule-associated protein 1 light chain 3; LPS: lipo-polysaccaride; NLRP3: NLR family, pyrin domain containing 3; PYCARD/ASC: PYD and CARD domain containing; SNARE: soluble N-ethylmaleimide-sensitive factor attachment protein receptor; SNAP29: synaptosomal-associated protein 29; SQSTM1/p62: sequestosome 1; STX17: syntaxin 17; TLR: toll-like receptor; TNF: tumor necrosis factor ; TOMM20: translocase of outer mitochondrial membrane 20; ULK1: unc-51 like kinase 1; VAMP8: vesicle-associated membrane protein 8; WT: wild type; 3-MA: 3-methyladenine

Repair of tissue damaged during inflammatory processes is key to the return of local homeostasis and restoration of epithelial integrity. Here we describe CD161+ regulatory T (Treg) cells as a distinct, highly suppressive population of Treg cells that mediate wound healing. These Treg cells were enriched in intestinal lamina propria, particularly in Crohn's disease. CD161+ Treg cells had an all-trans retinoic acid (ATRA)-regulated gene signature, and CD161 expression on Treg cells was induced by ATRA, which directly regulated the CD161 gene. CD161 was co-stimulatory, and ligation with the T cell antigen receptor induced cytokines that accelerated the wound healing of intestinal epithelial cells. We identified a transcription-factor network, including BACH2, RORγt, FOSL2, AP-1 and RUNX1, that controlled expression of the wound-healing program, and found a CD161+ Treg cell signature in Crohn's disease mucosa associated with reduced inflammation. These findings identify CD161+ Treg cells as a population involved in controlling the balance between inflammation and epithelial barrier healing in the gut.