A patient-based murine model recapitulates human STAT3 gain-of-function syndrome.

STAT3 gain-of-function (GOF) variants results in a heterogeneous clinical syndrome characterized by early onset immunodeficiency, multi-organ autoimmunity, and lymphoproliferation. While 191 documented cases with STAT3 GOF variants have been reported, the impact of individual variants on immune regulation and the broad clinical spectrum remains unclear. We developed a Stat3p.L387R mouse model, mirroring a variant identified in a family exhibiting common STAT3 GOF symptoms, and rare phenotypes including pulmonary hypertension and retinal vasculitis. In vitro experiments revealed increased STAT3 phosphorylation, nuclear migration, and DNA binding of the variant. Our Stat3p.L387R model displayed similar traits from previous Stat3GOF strains, such as splenomegaly and lymphadenopathy. Notably, Stat3p.L387R/+ mice exhibited heightened embryonic lethality compared to prior Stat3GOF/+ models and ocular abnormalities were observed. This research underscores the variant-specific pathology in Stat3p.L387R/+ mice, highlighting the ability to recapitulate human STAT3 GOF syndrome in patient-specific transgenic murine models. Additionally, such models could facilitate tailored treatment development.

High Prevalence of Long COVID in Common Variable Immunodeficiency: An Italian Multicentric Study.

The long-term effects of SARS-CoV-2 infection represent a relevant global health problem. Long COVID (LC) is defined as a complex of signs and symptoms developed during or after SARS-CoV-2 infection and lasting > 12 weeks. In common variable immunodeficiency (CVID) patients, we previously reported higher risk of hospitalization and death during SARS-CoV-2 infection, as well as prolonged swab positivity and frequent reinfections. The aim of the present study was to assess the risk of LC in an Italian cohort of CVID patients. We used a translated version of the survey proposed by Centers for Disease Control and Prevention (CDC) to collect data on LC. In the enrolled cohort of 175 CVID patients, we found a high prevalence of LC (65.7%). The most frequent LC symptoms were fatigue (75.7%), arthralgia/myalgia (48.7%), and dyspnea (41.7%). The majority of patients (60%) experienced prolonged symptoms, for at least 6 months after infection. In a multivariate analysis, the presence of complicated phenotype (OR 2.44, 95% CI 1.88-5.03; p = 0.015), obesity (OR 11.17, 95% CI 1.37-90.95; p = 0.024), and female sex (OR 2.06, 95% CI 1.09-3.89; p = 0.024) significantly correlated with the development of LC. In conclusion, in this multicenter observational cohort study, we demonstrated that CVID patients present an increased prevalence of LC when compared to the general population. Improved awareness on the risk of LC in CVID patients could optimize management of this new and alarming complication of SARS-CoV-2 infection.

"Deficiency in ELF4, X-Linked": a Monogenic Disease Entity Resembling Behçet's Syndrome and Inflammatory Bowel Disease.

Defining monogenic drivers of autoinflammatory syndromes elucidates mechanisms of disease in patients with these inborn errors of immunity and can facilitate targeted therapeutic interventions. Here, we describe a cohort of patients with a Behçet's- and inflammatory bowel disease (IBD)-like disorder termed "deficiency in ELF4, X-linked" (DEX) affecting males with loss-of-function variants in the ELF4 transcription factor gene located on the X chromosome. An international cohort of fourteen DEX patients was assessed to identify unifying clinical manifestations and diagnostic criteria as well as collate findings informing therapeutic responses. DEX patients exhibit a heterogeneous clinical phenotype including weight loss, oral and gastrointestinal aphthous ulcers, fevers, skin inflammation, gastrointestinal symptoms, arthritis, arthralgia, and myalgia, with findings of increased inflammatory markers, anemia, neutrophilic leukocytosis, thrombocytosis, intermittently low natural killer and class-switched memory B cells, and increased inflammatory cytokines in the serum. Patients have been predominantly treated with anti-inflammatory agents, with the majority of DEX patients treated with biologics targeting TNFα.

Unraveling the Immunogenetics of STAT Proteins: Clinical Perspectives on Gain-of-Function and Loss-of-Function Variants.

Signal Transducer and Activator of Transcription (STAT) proteins play pivotal roles in immune regulation. The dysregulation of these proteins, attributed to both gain-of-function (GOF) and loss-of-function (LOF) variants, has emerged as a substantial and intricate area of research. This comprehensive review delves into the intricate details of the diverse clinical spectrum associated with STAT variants and the immunological findings linked to these genetic alterations. Although this review does not encompass the treatment of each individual disease, we discuss investigative approaches ranging from immunophenotyping assessment to evaluation of STAT protein activity. These investigations play a crucial role in identifying affected patients and understanding the complexities of STAT.

Long-term treatment with selective PI3Kδ inhibitor leniolisib in adults with activated PI3Kδ syndrome.

ABSTRACT: Activated phosphoinositide 3-kinase delta (PI3Kδ) syndrome (APDS) is an inborn error of immunity that manifests as immune deficiency and dysregulation; symptoms include frequent infections and lymphoproliferation. In our dose-finding and phase 3 placebo-controlled trials, treatment with the selective PI3Kδ inhibitor leniolisib reduced lymphoproliferation and normalized lymphocyte subsets. Here, we present 6 years of follow-up from the 6 adult patients in the original dose-finding trial receiving leniolisib. We used data from the ongoing open-label extension study, which was supplemented at later time points by investigators, including health-related quality of life (HRQoL) assessed through a clinician-reported questionnaire. We observed improvements in HRQoL: 5 of 6 patients experienced an increase in physical capabilities and socialization, and a decrease in prescribed medications. Immune subsets improved in all patients: mean transitional B-cell levels decreased from 38.17% to 2.47% and the CD4:CD8 T-cell ratio normalized to 1.11. Manifestations seen before and within the first year of leniolisib exposure, such as infections and gastrointestinal conditions, attenuated after year 2, with few new conditions emerging out to year 6. Thrombocytopenia or lymphopenia remained present in half of patients at year 6. Of 83 adverse events through year 5, 90.36% were grade 1; none were grade 4/5 nor deemed leniolisib related. Collectively, we saw an enhancement in HRQoL as well as durable changes in lymphocyte subsets and clinical manifestations, further supporting the use of leniolisib as a long-term therapeutic option for the treatment of APDS. This trial was registered at www.ClinicalTrials.gov as #NCT02859727.

Bioinformatic meta-analysis reveals novel differentially expressed genes and pathways in sarcoidosis.

Introduction: Sarcoidosis is a multi-system inflammatory disease of unknown origin with heterogeneous clinical manifestations varying from a single organ non-caseating granuloma site to chronic systemic inflammation and fibrosis. Gene expression studies have suggested several genes and pathways implicated in the pathogenesis of sarcoidosis, however, due to differences in study design and variable statistical approaches, results were frequently not reproducible or concordant. Therefore, meta-analysis of sarcoidosis gene-expression datasets is of great importance to robustly establish differentially expressed genes and signalling pathways. Methods: We performed meta-analysis on 22 published gene-expression studies on sarcoidosis. Datasets were analysed systematically using same statistical cut-offs. Differentially expressed genes were identified by pooling of p-values using Edgington's method and analysed for pathways using Ingenuity Pathway Analysis software. Results: A consistent and significant signature of novel and well-known genes was identified, those collectively implicated both type I and type II interferon mediated signalling pathways in sarcoidosis. In silico functional analysis showed consistent downregulation of eukaryotic initiation factor 2 signalling, whereas cytokines like interferons and transcription factor STAT1 were upregulated. Furthermore, we analysed affected tissues to detect differentially expressed genes likely to be involved in granuloma biology. This revealed that matrix metallopeptidase 12 was exclusively upregulated in affected tissues, suggesting a crucial role in disease pathogenesis. Discussion: Our analysis provides a concise gene signature in sarcoidosis and expands our knowledge about the pathogenesis. Our results are of importance to improve current diagnostic approaches and monitoring strategies as well as in the development of targeted therapeutics.

The association of inflammatory markers with frailty and in-hospital mortality in older COVID-19 patients.

INTRODUCTION: During the COVID19 pandemic, older patients hospitalized for COVID-19 exhibited an increased mortality risk compared to younger patients. While ageing is associated with compromised immune responses and frailty, their contributions and interplay remain understudied. This study investigated the association between inflammatory markers and mortality and potential modification by frailty among older patients hospitalized for COVID-19. METHODS: Data were from three multicenter Dutch cohorts (COVID-OLD, CliniCo, Covid-Predict). Patients were 70 years or older, hospitalized for COVID-19and categorized into three frailty groups: fit (Clinical frailty score (CFS) 1-3), pre-frail (CFS 4-5), and frail (CFS 6-9). Immunological markers (lymphocyte count, neutrophil count, C-reactive protein, neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR) and systemic inflammation index (SII)) were measured at baseline. Associations with in hospital mortality were examined using logistic regression. RESULTS: A total of 1697 patients were included from COVID-OLD, 656 from Covid-Predict, and 574 from CliniCo. The median age was 79, 77, and 78 years for each cohort. Hospital mortality rates were 33 %, 27 % and 39 % in the three cohorts, respectively. A lower CRP was associated with a higher frailty score in all three cohorts (all p < 0.01). Lymphocyte count, neutrophil count, NLR, PLR, or SII, were similar across frailty groups. Higher CRP levels were associated with increased in-hospital mortality risk across all frailty groups, across all cohorts (OR (95 % CI), 2.88 (2.20-3.78), 3.15 (1.95-5.16), and 3.28 (1.87-5.92)), and frailty did not modify the association between inflammatory markers and in-hospital mortality (all p-interaction>0.05). CONCLUSION: While frailty is a significant factor in determining overall outcomes in older patients, our study suggests that the elevated risk of mortality in older patients with frailty compared to fit patients is likely not explained by difference in inflammatory responses.

Immunogenicity of COVID-19 booster vaccination in IEI patients and their one year clinical follow-up after start of the COVID-19 vaccination program.

Purpose: Previous studies have demonstrated that the majority of patients with an inborn error of immunity (IEI) develop a spike (S)-specific IgG antibody and T-cell response after two doses of the mRNA-1273 COVID-19 vaccine, but little is known about the response to a booster vaccination. We studied the immune responses 8 weeks after booster vaccination with mRNA-based COVID-19 vaccines in 171 IEI patients. Moreover, we evaluated the clinical outcomes in these patients one year after the start of the Dutch COVID-19 vaccination campaign. Methods: This study was embedded in a large prospective multicenter study investigating the immunogenicity of COVID-19 mRNA-based vaccines in IEI (VACOPID study). Blood samples were taken from 244 participants 8 weeks after booster vaccination. These participants included 171 IEI patients (X-linked agammaglobulinemia (XLA;N=11), combined immunodeficiency (CID;N=4), common variable immunodeficiency (CVID;N=45), isolated or undefined antibody deficiencies (N=108) and phagocyte defects (N=3)) and 73 controls. SARS-CoV-2-specific IgG titers, neutralizing antibodies, and T-cell responses were evaluated. One year after the start of the COVID-19 vaccination program, 334 study participants (239 IEI patients and 95 controls) completed a questionnaire to supplement their clinical data focusing on SARS-CoV-2 infections. Results: After booster vaccination, S-specific IgG titers increased in all COVID-19 naive IEI cohorts and controls, when compared to titers at 6 months after the priming regimen. The fold-increases did not differ between controls and IEI cohorts. SARS-CoV-2-specific T-cell responses also increased equally in all cohorts after booster vaccination compared to 6 months after the priming regimen. Most SARS-CoV-2 infections during the study period occurred in the period when the Omicron variant had become dominant. The clinical course of these infections was mild, although IEI patients experienced more frequent fever and dyspnea compared to controls and their symptoms persisted longer. Conclusion: Our study demonstrates that mRNA-based booster vaccination induces robust recall of memory B-cell and T-cell responses in most IEI patients. One-year clinical follow-up demonstrated that SARS-CoV-2 infections in IEI patients were mild. Given our results, we support booster campaigns with newer variant-specific COVID-19 booster vaccines to IEI patients with milder phenotypes.

Original COVID-19 priming regimen impacts the immunogenicity of bivalent BA.1 and BA.5 boosters.

Waning antibody responses after COVID-19 vaccination combined with the emergence of the SARS-CoV-2 Omicron lineage led to reduced vaccine effectiveness. As a countermeasure, bivalent mRNA-based booster vaccines encoding the ancestral spike protein in combination with that of Omicron BA.1 or BA.5 were introduced. Since then, different BA.2-descendent lineages have become dominant, such as XBB.1.5, JN.1, or EG.5.1. Here, we report post-hoc analyses of data from the SWITCH-ON study, assessing how different COVID-19 priming regimens affect the immunogenicity of bivalent booster vaccinations and breakthrough infections (NCT05471440). BA.1 and BA.5 bivalent vaccines boosted neutralizing antibodies and T-cells up to 3 months after boost; however, cross-neutralization of XBB.1.5 was poor. Interestingly, different combinations of prime-boost regimens induced divergent responses: participants primed with Ad26.COV2.S developed lower binding antibody levels after bivalent boost while neutralization and T-cell responses were similar to mRNA-based primed participants. In contrast, the breadth of neutralization was higher in mRNA-primed and bivalent BA.5 boosted participants. Combined, our data further support the current use of monovalent vaccines based on circulating strains when vaccinating risk groups, as recently recommended by the WHO. We emphasize the importance of the continuous assessment of immune responses targeting circulating variants to guide future COVID-19 vaccination policies.