Novel aspects of regulatory T cell dysfunction as a therapeutic target in giant cell arteritis.

OBJECTIVES: Giant cell arteritis (GCA) is the most common primary vasculitis, preferentially affecting the aorta and its large-calibre branches. An imbalance between proinflammatory CD4+ T helper cell subsets and regulatory T cells (Tregs) is thought to be involved in the pathogenesis of GCA and Treg dysfunction has been associated with active disease. Our work aims to explore the aetiology of Treg dysfunction and the way it is affected by remission-inducing immunomodulatory regimens. METHODS: A total of 41 GCA patients were classified into active disease (n=14) and disease in remission (n=27). GCA patients' and healthy blood donors' (HD) Tregs were sorted and subjected to transcriptome and phenotypic analysis. RESULTS: Transcriptome analysis revealed 27 genes, which were differentially regulated between GCA-derived and HD-derived Tregs. Among those, we identified transcription factors, glycolytic enzymes and IL-2 signalling mediators. We confirmed the downregulation of forkhead box P3 (FOXP3) and interferon regulatory factor 4 (IRF4) at protein level and identified the ineffective induction of glycoprotein A repetitions predominant (GARP) and CD25 as well as the reduced T cell receptor (TCR)-induced calcium influx as correlates of Treg dysfunction in GCA. Inhibition of glycolysis in HD-derived Tregs recapitulated most identified dysfunctions of GCA Tregs, suggesting the central pathogenic role of the downregulation of the glycolytic enzymes. Separate analysis of the subgroup of tocilizumab-treated patients identified the recovery of the TCR-induced calcium influx and the Treg suppressive function to associate with disease remission. CONCLUSIONS: Our findings suggest that low glycolysis and calcium signalling account for Treg dysfunction and inflammation in GCA.

TLR9 Deficiency Leads to Accelerated Renal Disease and Myeloid Lineage Abnormalities in Pristane-Induced Murine Lupus.

Systemic lupus erythematosus (SLE) is a chronic, life-threatening autoimmune disorder, leading to multiple organ pathologies and kidney destruction. Analyses of numerous murine models of spontaneous SLE have revealed a critical role for endosomal TLRs in the production of autoantibodies and development of other clinical disease manifestations. Nevertheless, the corresponding TLR9-deficient autoimmune-prone strains consistently develop more severe disease pathology. Injection of BALB/c mice with 2,6,10,14-tetramethylpentadecane (TMPD), commonly known as pristane, also results in the development of SLE-like disease. We now show that Tlr9(-/-) BALB/c mice injected i.p. with TMPD develop more severe autoimmunity than do their TLR-sufficient cohorts. Early indications include an increased accumulation of TLR7-expressing Ly6C(hi) inflammatory monocytes at the site of injection, upregulation of IFN-regulated gene expression in the peritoneal cavity, and an increased production of myeloid lineage precursors (common myeloid progenitors and granulocyte myeloid precursors) in the bone marrow. TMPD-injected Tlr9(-/-) BALB/c mice develop higher autoantibody titers against RNA, neutrophil cytoplasmic Ags, and myeloperoxidase than do TMPD-injected wild-type BALB/c mice. The TMP-injected Tlr9(-/-) mice, and not the wild-type mice, also develop a marked increase in glomerular IgG deposition and infiltrating granulocytes, much more severe glomerulonephritis, and a reduced lifespan. Collectively, the data point to a major role for TLR7 in the response to self-antigens in this model of experimental autoimmunity. Therefore, the BALB/c pristane model recapitulates other TLR7-driven spontaneous models of SLE and is negatively regulated by TLR9.

Gain-of-function STAT1 mutations are associated with intracranial aneurysms.

Chronic mucocutaneous candidiasis, characterized by persistent or recurrent fungal infections, represents the clinical hallmark in gain-of-function (GOF) signal transducer and activator of transcription 1 (STAT1) mutation carriers. Several cases of intracranial aneurysms have been reported in patients with GOF STAT1 mutation but the paucity of reported cases likely suggested this association still as serendipity. In order to endorse this association, we link the development of intracranial aneurysms with STAT1 GOF mutation by presenting the two different cases of a patient and her mother, and demonstrate upregulated phosphorylated STAT4 and IL-12 receptor ß1 upon stimulation in patient's blood cells. We also detected increased transforming growth factor (TGF)-ß type 2 receptor expression, particularly in CD14+ cells, and a slightly higher phosphorylation rate of SMAD3. In addition, the mother of the patient developed disseminated bacille Calmette-Guérin disease after vaccination, speculating that GOF STAT1 mutations may confer a predisposition to weakly virulent mycobacteria.

Tetanus and diphtheria immunity in refugees in Europe in 2015.

BACKGROUND: Current political crises in the Middle East and economic discrepancies led millions of people to leave their home countries and to flee to Western Europe. This development raises unexpected challenges for receiving health care systems. Although pan-European initiatives strive for updated and optimized vaccination strategies, little data on immunity against vaccine-preventable diseases in the current refugee population exist. METHODS: We quantified serum IgG against tetanus and diphtheria (TD) in n = 678 refugees currently seeking shelter in six German refugee centers. FINDINGS: Reflecting current migration statistics in Europe, the median age within the cohort was 26 years, with only 23.9 % of female subjects. Insufficient IgG levels without long-term protection against tetanus were found in 56.3 % of all refugees. 76.1 % of refugees had no long-term protection against diphtheria. 47.7 % of subjects needed immediate vaccination against tetanus, and 47.7 % against diphtheria. For both diseases, an age-dependent decline in protective immunity occurred. INTERPRETATION: We observed a considerably low rate of tetanus-protected refugees, and the frequency of diphtheria-immune refugees was far from sufficient to provide herd immunity. These findings strongly support recent intentions to implement and enforce stringent guidelines for refugee vaccination in the current crisis.

Norovirus outbreaks in german refugee camps in 2015.

Purpose Refugees often live in confined housing conditions with shared kitchen and sanitary facilities, rendering susceptible to communicable diseases. We here describe the outbreak, spread and self-limiting nature of a norovirus outbreak in a German refugee camp in the winter of 2015. Methods During a norovirus outbreak, data on clinical symptoms, nationality and living conditions was obtained in a refugee camp in northern Germany in the winter of 2015. Furthermore secondary data on norovirus outbreaks in 2015 was assessed. Results Amongst n = 982 refugees, n = 36 patients (3.7 %) presented with acute norovirus gastroenteritis. The vast majority of cases were children, only the first patient was admitted to the hospital. Intensified hygiene measures were implemented on day 2 of the outbreak, but new cases peaked on day 21 and occurred until one month after the first case. Different cultural backgrounds, eating habits and hygiene standards amongst the refugees made it particularly challenging to implement stringent isolation and hygiene measures. Despite these predisposing factors, only minor norovirus outbreaks were reported in refugee camps in 2015. Conclusion Adults refugees had a low attack rate of symptomatic norovirus infection, while small children are at high risk. Infection spreads despite hygiene measures and camp sites and staff should be prepared for the particular challenges of such situations with a particular focus on cultural-background specific implementation of hygiene measures.

Measles, mumps, rubella, and varicella seroprevalence in refugees in Germany in 2015.

PURPOSE: The current extent of migration poses emerging socio-economic and humanitarian challenges. Little is known on vaccination rates in migrants entering Europe, and the implementation of guidelines for serological testing and vaccination of refugees are pending. METHODS: We conducted seroprevalence analyses for measles, mumps, rubella and varicella (MMRV) in 678 refugees coming to Germany during the current crisis. RESULTS: The mean age of refugees was 28.8±11.4 years, and 76.1 % of subjects were male. Overall, IgG seronegativity was 7.4 % (95 % CI 5.5-9.6) for measles, 10.2 % (95 % CI 8.0-12.5) for mumps, 2.2 % (95 % CI 1.2-3.4) for rubella, and 3.3 % (95 % CI 1.9-4.9) for varicella. Seropositivity rates were age-dependent with considerably low values in children. For example, overall MMR immunity was 90.9 % (95 % CI 88.8-93.1), but only 73.1 % of minor aged refugees displayed complete seroprevalence against all three diseases, and only 68.9 % of children and adolescents were completely MMRV immune. CONCLUSION: Our initial data set suggests overall satisfactory MMRV immunity in adult migrants coming to Europe, but the observed low MMRV seroprevalences in refugee children support thorough and prompt vaccination of young migrants entering Europe. Taken together, our data set underlines the urgent need to implement and validate vaccination guidelines for refugee care in the current crisis.

Role of gamma-secretase in human umbilical-cord derived mesenchymal stem cell mediated suppression of NK cell cytotoxicity.

BACKGROUND: Mesenchymal stem cells (MSCs) are increasingly considered to be used as biological immunosuppressants in hematopoietic stem cell transplantation (HSCT). In the early reconstitution phase following HSCT, natural killer (NK) cells represent the major lymphocyte population in peripheral blood and display graft-vs-leukemia (GvL) effects. The functional interactions between NK cells and MSCs have the potential to influence the leukemia relapse rate after HSCT. Until date, MSC-NK cell interaction studies are largely focussed on bone marrow derived (BM)-MSCs. Umbilical cord derived (UC)-MSCs might be an alternative source of therapeutic MSCs. Thus, we studied the interaction of UC-MSCs with unstimulated allogeneic NK cells. RESULTS: UC-MSCs could potently suppress NK cell cytotoxicity in overnight cultures via soluble factors. The main soluble immunosuppressant was identified as prostaglandin (PG)-E2. Maximal PGE2 release involved IL-1ß priming of MSCs after close contact between the NK cells and UC-MSCs. Interestingly, blocking gamma-secretase activation alleviated the immunosuppression by controlling PGE2 production. IL-1 receptor activation and subsequent downstream signalling events were found to require gamma-secretase activity. CONCLUSION: Although the role of PGE2 in NK cell-MSC has been reported, the requirement of cell-cell contact for PGE2 induced immunosuppression remained unexplained. Our findings shed light on this puzzling observation and identify new players in the NK cell-MSC crosstalk.

Corrigendum: Vulnerability to meningococcal disease in immunodeficiency due to a novel pathogenic missense variant in NFKB1.

[This corrects the article DOI: 10.3389/fimmu.2021.767188.].

Common Variable Immunodeficiency-Associated Cancers: The Role of Clinical Phenotypes, Immunological and Genetic Factors.

OBJECTIVE: The aim of this study was to investigate the prevalence of cancer and associating clinical, immunological, and genetic factors in a German cohort of patients with common variable immunodeficiency (CVID). METHODS: In this retrospective monocenter cohort study, we estimated the standardized incidence ratio (SIR) for different forms of cancer diagnosed in CVID patients. Furthermore, we evaluated the likely association of infectious and non-infectious CVID-related phenotypes with the diagnosis of cancer by calculation of the odds ratio. The genetic background of CVID in patients with cancer was evaluated with sequential targeted next-generation sequencing (tNGS) and whole-exome sequencing (WES). Patients' family history and WES data were evaluated for genetic predisposition to cancer. RESULTS: A total of 27/219 patients (12.3%) were diagnosed with at least one type of cancer. Most common types of cancer were gastric cancer (SIR: 16.5), non-melanoma skin cancer (NMSC) (SIR: 12.7), and non-Hodgkin lymphoma (NHL) (SIR: 12.2). Immune dysregulation manifesting as arthritis, atrophic gastritis, or interstitial lung disease (ILD) was associated with the diagnosis of cancer. Furthermore, diagnosis of NMSC associated with the diagnosis of an alternative type of cancer. Studied immunological parameters did not display any significant difference between patients with cancer and those without. tNGS and/or WES yielded a definite or likely genetic diagnosis in 11.1% of CVID patients with cancer. Based on identified variants in cancer-associated genes, the types of diagnosed cancers, and family history data, 14.3% of studied patients may have a likely genetic susceptibility to cancer, falling under a known hereditary cancer syndrome. CONCLUSIONS: Gastric cancer, NMSC, and NHL are the most frequent CVID-associated types of cancer. Manifestations of immune dysregulation, such as arthritis and ILD, were identified as risk factors of malignancy in CVID, whereas studied immunological parameters or the identification of a monogenic form of CVID appears to have a limited role in the evaluation of cancer risk in CVID.

Cellular and molecular mechanisms breaking immune tolerance in inborn errors of immunity.

In addition to susceptibility to infections, conventional primary immunodeficiency disorders (PIDs) and inborn errors of immunity (IEI) can cause immune dysregulation, manifesting as lymphoproliferative and/or autoimmune disease. Autoimmunity can be the prominent phenotype of PIDs and commonly includes cytopenias and rheumatological diseases, such as arthritis, systemic lupus erythematosus (SLE), and Sjogren's syndrome (SjS). Recent advances in understanding the genetic basis of systemic autoimmune diseases and PIDs suggest an at least partially shared genetic background and therefore common pathogenic mechanisms. Here, we explore the interconnected pathogenic pathways of autoimmunity and primary immunodeficiency, highlighting the mechanisms breaking the different layers of immune tolerance to self-antigens in selected IEI.

Vulnerability to Meningococcal Disease in Immunodeficiency Due to a Novel Pathogenic Missense Variant in NFKB1.

NF-κB1 deficiency is suggested to be the most common cause of common variable immunodeficiency (CVID). NFKB1 encodes for the p105 precursor protein of NF-κB1, which is converted into the active transcriptional subunit p50 through proteasomal processing of its C-terminal half upon stimulation and is implicated in the canonical NF-kB pathway. Rare monoallelic NFKB1 variants have been shown to cause (haplo) insufficiency. Our report describes a novel NFKB1 missense variant (c.691C>T, p.R230C; allele frequency 0.00004953) in a family vulnerable to meningitis, sepsis, and late-onset hypogammaglobulinemia. We investigated the pathogenic relevance of this variant by lymphocyte stimulation, immunophenotyping, overexpression study and immunoblotting. The ectopic expression of p50 for c.691 C>T restricted transcriptionally active p50 in the cytoplasm, and immunoblotting revealed reduced p105/50 expression. This study shows that the deleterious missense variant in NFKB1 adversely affects the transcriptional and translational activity of NFκB1, impairing its function. Patients immunological parameters show a progressive course of hypogammaglobulinemia, which may partially account for the incomplete disease penetrance and suggest the need for closer immunological monitoring of those mutation carriers.

Homeostatic and pathogenic roles of PI3Kδ in the human immune system.

Phosphoinositide 3-kinase delta (PI3Kδ) mediates signaling transduction downstream of diverse immune receptors, including the T cell receptor (TCR), the B cell receptor (BCR), costimulatory molecules and cytokine receptors. Our understanding of the role of PI3Kδ in the immune system comes primarily from mice, and especially from the consequences of pharmacological inhibition of PI3Kδ in mouse models of human disease as well as the consequences of genetic manipulation, resulting in hyperactivation or loss of PI3Kδ function. In case of humans, in vitro studies with PI3Kδ-specific inhibitors, the consequences of treatment of hematologic malignancies with the PI3Kδ-specific inhibitor idelalisib and primary immunodeficiency disorders due to germline variants hyper- or underactivating PI3Kδ provide most of our knowledge on the role of PI3Kδ in immunity and immune regulation. In this review, we summarize the physiological and pathophysiological roles of PI3Kδ in the human immune system, focusing on immunodeficiency due to defects in PI3Kδ signaling and especially on the recently reported cases with mutations resulting in loss of PI3Kδ activity.

Lung Involvement in Primary Sjögren's Syndrome-An Under-Diagnosed Entity.

Interstitial lung disease (ILD) represents a frequent extra-glandular manifestation of primary Sjögren's Syndrome (pSS). Limited published data regarding phenotyping and treatment exists. Advances in managing specific ILD phenotypes have not been comprehensively explored in patients with coexisting pSS. This retrospective study aimed to phenotype lung diseases occurring in a well-described pSS-ILD cohort and describe treatment course and outcomes. Between April 2018 and February 2020, all pSS patients attending our Outpatient clinic were screened for possible lung involvement. Clinical, laboratory and high-resolution computed tomography (HRCT) findings were analyzed. Patients were classified according to HRCT findings into five groups: usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), combined pulmonary fibrosis and emphysema (CPFE), and non-specific-ILD. Lung involvement was confirmed in 31/268 pSS patients (13%). One-third (10/31) of pSS-ILD patients were Ro/SSA antibody negative. ILD at pSS diagnosis was present in 19/31 (61%) patients. The commonest phenotype was UIP n = 13 (43%), followed by NSIP n = 9 (29%), DIP n = 2 (6 %), CPFE n = 2 (6 %), and non-specific-ILD n = 5 (16%). Forced vital capacity (FVC) and carbon monoxide diffusion capacity (DLCO) appeared lower in UIP and DIP, without reaching a significant difference. Treatment focused universally on intensified immunosuppression, with 13/31 patients (42%) receiving cyclophosphamide. No anti-fibrotic treatments were used. Median follow-up was 38.2 [12.4-119.6] months. Lung involvement in pSS is heterogeneous. Better phenotyping and tailored treatment may improve outcomes and requires further evaluation in larger prospective studies.

Peripheral Blood Lymphocyte Phenotype Differentiates Secondary Antibody Deficiency in Rheumatic Disease from Primary Antibody Deficiency.

The phenotype of primary immunodeficiency disorders (PID), and especially common variable immunodeficiency (CVID), may be dominated by symptoms of autoimmune disorders. Furthermore, autoimmunity may be the first manifestation of PID, frequently preceding infections and the diagnosis of hypogammaglobulinemia, which occurs later on. In this case, distinguishing PID from hypogammaglobulinemia secondary to anti-inflammatory treatment of autoimmunity may become challenging. The aim of this study was to evaluate the diagnostic accuracy of peripheral blood lymphocyte phenotyping in resolving the diagnostic dilemma between primary and secondary hypogammaglobulinemia. Comparison of B and T cell subsets from patients with PID and patients with rheumatic disease, who developed hypogammaglobulinemia as a consequence of anti-inflammatory regimes, revealed significant differences in proportion of naïve B cells, class-switched memory B cells and CD21low B cells among B cells as well as in CD4+ memory T cells and CD4+ T follicular cells among CD4+ T cells. Identified differences in B cell and T cell subsets, and especially in the proportion of class-switched memory B cells and CD4+ T follicular cells, display a considerable diagnostic efficacy in distinguishing PID from secondary hypogammaglobulinemia due to anti-inflammatory regimens for rheumatic disease.

Lowered anti-beta1 adrenergic receptor antibody concentrations may have prognostic significance in acute coronary syndrome.

Although several risk factors exist for acute coronary syndrome (ACS) no biomarkers for survival or risk of re-infarction have been validated. Previously, reduced serum concentrations of anti-ß1AR Ab have been implicated in poorer ACS outcomes. This study further evaluates the prognostic implications of anti-ß1AR-Ab levels at the time of ACS onset. Serum anti-ß1AR Ab concentrations were measured in randomly selected patients from within the PLATO cohort. Stratification was performed according to ACS event: ST-elevation myocardial infarct (STEMI) vs. non-ST elevation myocardial infarct (NSTEMI). Antibody concentrations at ACS presentation were compared to 12-month all-cause and cardiovascular mortality, as well as 12-month re-infarction. Sub-analysis, stratifying for age and the correlation between antibody concentration and conventional cardiac risk-factors was subsequently performed. Serum anti-ß1AR Ab concentrations were measured in 400/799 (50%) STEMI patients and 399 NSTEMI patients. Increasing anti-ß1AR Ab concentrations were associated with STEMI (p = 0.001). Across all ACS patients, no associations between anti-ß1AR Ab concentration and either all-cause cardiovascular death or myocardial re-infarction (p = 0.14) were evident. However among STEMI patients ≤60 years with anti-ß1AR Ab concentration median (14/198 (7.1%) vs. 2/190 (1.1%)); p = 0.01). Similarly, the same sub-group demonstrated greater risk of cardiovascular death in year 1, including re-infarction and stroke (22/198 (11.1%) vs. 10/190 (5.3%); p = 0.017). ACS Patients ≤60 years, exhibiting lower concentrations of ß1AR Ab carry a greater risk for early re-infarction and cardiovascular death. Large, prospective studies quantitatively assessing the prognostic relevance of Anti-ß1AR Ab levels should be considered.

Tuberculous coxitis with trochanteric bursitis manifesting a year after immigration to Germany: a case report.

BACKGROUND: Osteoarticular tuberculosis is rare in Germany. In particular, trochanteric bursitis is an extremely rare manifestation of osteoarticular tuberculosis. We describe a case of tuberculous coxitis with trochanteric bursitis, successfully treated with a fourfold tuberculostatic therapy. CASE PRESENTATION: We report the case of a 43-year-old human immunodeficiency virus-negative Sudanese man with osteoarticular tuberculosis, who was originally admitted with the suspected diagnosis of ankylosing spondylitis. Low grade fever together with the positive result of an interferon-gamma release assay test as well as findings from magnetic resonance imaging provided clues to the diagnosis. A definitive diagnosis could be set after a computed tomography-guided biopsy. CONCLUSIONS: Apart from a rare involvement pattern of osteoarticular tuberculosis, including trochanteric bursitis, this case highlights the increasing importance of osteoarticular tuberculosis as a differential diagnosis of rheumatic disorders. With the growing migration flows from tuberculosis-endemic African countries, clinicians in central and northern Europe may be more frequently confronted with atypical involvement patterns of osteoarticular tuberculosis.

Prevalence and Types of Anemia in a Large Refugee Cohort in Western Europe in 2015.

Currently, vast numbers of migrants with largely unknown health statuses have been entering Europe. To improve care taking strategies, prevalence, severity and types of anemia in a large refugee cohort were assessed. Blood counts were performed in n = 787 inhabitants from six German refugee centers. Most included migrants were young, male adults. Anemia was present in 22.5% of subjects with an age-dependent prevalence increase (7.9% > 18 years vs. 30.8% > 50 years). More females than males were anemic (27.1% vs. 20.4%). The majority of affected migrants had mild anemia (86.2%) of either normocytic/normochromic (55.9%) or microcytic/hypochromic (20.9%) type. Observed anemia frequencies are in accordance with global anemia prevalence recently estimated by the WHO. However, the observed high rates of anemia particularly in female and older refugees emphasize the need for adapted care taking strategies in refugee medicine. Further evaluation of causes of anemia in the migrating population is needed.

Tuberculosis Specific Interferon-Gamma Production in a Current Refugee Cohort in Western Europe.

BACKGROUND: In 2015, a high number of refugees with largely unknown health statuses immigrated to Western Europe. To improve caretaking strategies, we assessed the prevalence of latent tuberculosis infection (LTBI) in a refugee cohort. METHODS: Interferon-Gamma release assays (IGRA, Quantiferon) were performed in n = 232 inhabitants of four German refugee centers in the summer of 2015. RESULTS: Most refugees were young, male adults. Overall, IGRA testing was positive in 17.9% (95% CI = 13.2⁻23.5%) of subjects. Positivity rates increased with age (0% <18 years versus 46.2% >50 years). Age was the only factor significantly associated with a positive IGRA in multiple regression analysis including gender, C reactive protein, hemoglobin, leukocyte, and thrombocyte count and lymphocyte, monocyte, neutrophil, basophil, and eosinophil fraction. For one year change in age, the odds are expected to be 1.06 times larger, holding all other variables constant (p = 0.015). CONCLUSION: Observed LTBI frequencies are lower than previously reported in similar refugee cohorts. However, as elderly people are at higher risk for developing active tuberculosis, the observed high rate of LTBI in senior refugees emphasizes the need for new policies on the detection and treatment regimens in this group.