Genome-wide association study identifies multiple HLA loci for sarcoidosis susceptibility.

Sarcoidosis is a complex systemic disease. Our study aimed to (1) identify novel alleles associated with sarcoidosis susceptibility; (2) provide an in-depth evaluation of HLA alleles and sarcoidosis susceptibility and (3) integrate genetic and transcription data to identify risk loci that may more directly impact disease pathogenesis. We report a genome-wide association study of 1335 sarcoidosis cases and 1264 controls of European descent (EA) and investigate associated alleles in a study of African Americans (AA: 1487 cases and 1504 controls). The EA and AA cohort was recruited from multiple United States sites. HLA alleles were imputed and tested for association with sarcoidosis susceptibility. Expression quantitative locus and colocalization analysis were performed using a subset of subjects with transcriptome data. Forty-nine SNPs in the HLA region in HLA-DRA, -DRB9, -DRB5, -DQA1 and BRD2 genes were significantly associated with sarcoidosis susceptibility in EA, rs3129888 was also a risk variant for sarcoidosis in AA. Classical HLA alleles DRB1*0101, DQA1*0101 and DQB1*0501, which are highly correlated, were also associated with sarcoidosis. rs3135287 near HLA-DRA was associated with HLA-DRA expression in peripheral blood mononuclear cells and bronchoalveolar lavage from subjects and lung tissue and whole blood from GTEx. We identified six novel SNPs (out of the seven SNPs representing the 49 significant SNPs) and nine HLA alleles associated with sarcoidosis susceptibility in the largest EA population. We also replicated our findings in an AA population. Our study reiterates the potential role of antigen recognition and/or presentation HLA class II genes in sarcoidosis pathogenesis.

Blood glucose and lipids are associated with sarcoidosis: findings from observational and mendelian randomization studies.

BACKGROUND: Several researches have demonstrated that patients with sarcoidosis accompanied with the abnormality in blood glucose and/or lipids, however, the causal relationship between them remains uncertain. To elucidate the potential association and causality of blood glucose and lipids with sarcoidosis, we conducted a propensity score matching (PSM)-based observational study combined with mendelian randomization (MR) analysis. METHODS: All subjects in this study were retrospectively collected from Tongji Hospital during 2010 and 2023. 1:1 PSM was employed to control the potential confounders as appropriate. Univariable and multivariable logistic regression analyses were performed to estimate the associations of sarcoidosis with fasting glucose, high density lipoprotein cholesterol (HDLC), low density lipoprotein cholesterol (LDLC), total cholesterol (TC), and total triglyceride (TG). The further subtype analysis was also conducted. Afterwards, a bidirectional MR analysis based on public data deeply explored the causality among the 5 candidate traits and sarcoidosis, for which the inverse-variance weighted (IVW) method was utilized as the main inferring approach. RESULTS: In the observational study, a total number of 756 subjects were enrolled, with 162 sarcoidosis patients and 594 non-sarcoidosis participants, while 160 pairs of subjects were matched after PSM. Multivariable logistic regression analysis indicated that HDLC (OR: 0.151; 95% CI: 0.056-0.408; P < 0.001) and TC (OR: 3.942; 95% CI: 2.644-5.877; P < 0.001) were strongly associated with sarcoidosis. Subtype analysis showed that low HDLC was independently correlated to risk of lesions in bronchus and lungs, and mediastinal lymph nodes, while high TC was to cervical lymph nodes. In MR analysis, high fasting glucose, low HDLC, and high TC were identified as the causal factors of sarcoidosis. CONCLUSION: HDLC and TC had the potential to influence the risk of sarcoidosis, which could be regarded as predictors and may provide new diagnostic and therapeutic targets for sarcoidosis.

Transcriptional and Immune Landscape of Cardiac Sarcoidosis.

BACKGROUND: Cardiac involvement is an important determinant of mortality among sarcoidosis patients. Although granulomatous inflammation is a hallmark finding in cardiac sarcoidosis, the precise immune cell populations that comprise the granuloma remain unresolved. Furthermore, it is unclear how the cellular and transcriptomic landscape of cardiac sarcoidosis differs from other inflammatory heart diseases. METHODS: We leveraged spatial transcriptomics (GeoMx digital spatial profiler) and single-nucleus RNA sequencing to elucidate the cellular and transcriptional landscape of cardiac sarcoidosis. Using GeoMX digital spatial profiler technology, we compared the transcriptomal profile of CD68+ rich immune cell infiltrates in human cardiac sarcoidosis, giant cell myocarditis, and lymphocytic myocarditis. We performed single-nucleus RNA sequencing of human cardiac sarcoidosis to identify immune cell types and examined their transcriptomic landscape and regulation. Using multichannel immunofluorescence staining, we validated immune cell populations identified by single-nucleus RNA sequencing, determined their spatial relationship, and devised an immunostaining approach to distinguish cardiac sarcoidosis from other inflammatory heart diseases. RESULTS: Despite overlapping histological features, spatial transcriptomics identified transcriptional signatures and associated pathways that robustly differentiated cardiac sarcoidosis from giant cell myocarditis and lymphocytic myocarditis. Single-nucleus RNA sequencing revealed the presence of diverse populations of myeloid cells in cardiac sarcoidosis with distinct molecular features. We identified GPNMB (transmembrane glycoprotein NMB) as a novel marker of multinucleated giant cells and predicted that the MITF (microphthalmia-associated transcription factor) family of transcription factors regulated this cell type. We also detected additional macrophage populations in cardiac sarcoidosis including HLA-DR (human leukocyte antigen-DR)+ macrophages, SYTL3 (synaptotagmin-like protein 3)+ macrophages and CD163+ resident macrophages. HLA-DR+ macrophages were found immediately adjacent to GPMMB+ giant cells, a distinct feature compared with other inflammatory cardiac diseases. SYTL3+ macrophages were located scattered throughout the granuloma and CD163+ macrophages, CD1c+ dendritic cells, nonclassical monocytes, and T cells were located at the periphery and outside of the granuloma. Finally, we demonstrate mTOR (mammalian target of rapamycin) pathway activation is associated with proliferation and is selectively found in HLA-DR+ and SYLT3+ macrophages. CONCLUSIONS: In this study, we identified diverse populations of immune cells with distinct molecular signatures that comprise the sarcoid granuloma. These findings provide new insights into the pathology of cardiac sarcoidosis and highlight opportunities to improve diagnostic testing.

The co-occurrence of sarcoidosis and anti-PLA2R-associated membranous nephropathy in a patient with underlying genetic susceptibility.

BACKGROUND: Sarcoidosis is a multisystemic inflammatory disease, characterized by the presence of non-caseating, epithelioid granulomas. Glomerular disease in patients with sarcoidosis is rare and membranous nephropathy (MN) is cited as the most common. The association between the two diseases remained unclear. This article reported a case of co-occurrence of sarcoidosis and anti-PLA2R-associated MN, to provide a possible relationship between these two entities. CASE PRESENTATION: A 61-year-old Chinese Han woman with a history of sarcoidosis was admitted to our hospital for nephrotic syndrome. Her sarcoidosis was diagnosed according to the adenopathy observed on the computed tomography scan and the biopsy of lymph nodes. The MN presented with nephrotic syndrome with a PLA2R antibody titer of 357RU/ml, and the final diagnosis was based on a renal biopsy. The patient's sarcoidosis was remitted after treatment with prednisone. One year later MN was diagnosed, and she was treated with prednisone combined with calcineurin inhibitors, based on a full dose of renin-angiotensin system (RAS) inhibitor. The patient's sarcoidosis had been in remission while the MN was recurrent, and her renal function deteriorated to end-stage renal disease 6 years later due to discontinuation of immunosuppression. A genetic test led to the identification of the HLA-DRB1*0301 and HLA-DRB1*150 genes associated with both sarcoidosis and MN, which provides a new possible explanation of the co-occurrence of these two diseases. CONCLUSION: This case suggested for the first time a potential genetic connection between idiopathic MN and sarcoidosis which needs further studies in the future.

Blau Syndrome With Delayed Cutaneous Manifestations: A Case Report.

ABSTRACT: Blau syndrome is a rare familial autoinflammatory disorder characterized by the triad of granulomatous dermatitis, polyarthritis, and uveitis. Blau syndrome exhibits an autosomal dominant inheritance pattern and can be caused by a gain-of-function mutation in nucleotide-binding oligomerization domain 2 (NOD2), a member of the NOD-like receptor family of pattern recognition receptors. Mutations in NOD2 cause upregulation of inflammatory cytokines and resultant autoinflammation. Because of the rarity of this condition and early onset of symptoms, Blau syndrome may be misdiagnosed as juvenile idiopathic arthritis. We present a case of a 37-year-old male patient with a long-documented history of juvenile idiopathic arthritis and uveitis, who developed an asymptomatic eruption of pink papules on the trunk and upper extremities. A biopsy demonstrated noncaseating, well-formed dermal granulomas with relatively sparse lymphocytic inflammation and Langerhans-type giant cells. Genetic testing confirmed a mutation in NOD2. Based on the patient's clinical history, histologic findings, genetic testing, the diagnosis of Blau syndrome was made.

Is a Vitamin K Epoxide Reductase Complex Subunit 1 (VKORC1) Polymorphism a Risk Factor for Nephrolithiasis in Sarcoidosis?

Sarcoidosis is a systemic inflammatory disorder characterized by granuloma formation in various organs. It has been associated with nephrolithiasis. The vitamin K epoxide reductase complex subunit 1 (VKORC1) gene, which plays a crucial role in vitamin K metabolism, has been implicated in the activation of proteins associated with calcification, including in the forming of nephrolithiasis. This study aimed to investigate the VKORC1 C1173T polymorphism (rs9934438) in a Dutch sarcoidosis cohort, comparing individuals with and without a history of nephrolithiasis. Retrospectively, 424 patients with sarcoidosis were divided into three groups: those with a history of nephrolithiasis (Group I: n = 23), those with hypercalcemia without nephrolithiasis (Group II: n = 38), and those without nephrolithiasis or hypercalcemia (Group III: n = 363). Of the 424 sarcoidosis patients studied, 5.4% had a history of nephrolithiasis (Group I), only two of whom possessed no VKORC1 polymorphisms (OR = 7.73; 95% CI 1.79-33.4; p = 0.001). The presence of a VKORC1 C1173T variant allele was found to be a substantial risk factor for the development of nephrolithiasis in sarcoidosis patients. This study provides novel insights into the genetic basis of nephrolithiasis in sarcoidosis patients, identifying VKORC1 C1173T as a potential contributor. Further research is warranted to elucidate the precise mechanisms and explore potential therapeutic interventions based on these genetic findings.

Proteomic Profiling of Tears in Blau Syndrome Patients in Identification of Potential Disease Biomarkers.

Blau syndrome (BS) is a rare autoinflammatory granulomatosis characterized by granulomatous arthritis, uveitis, and dermatitis. Ocular complications are particularly severe in BS, significantly contributing to morbidity. This study aims to identify potential biomarkers for BS ocular degeneration through proteomic profiling of tear samples from affected patients. Seven subjects from the same family, including four carriers of the BS-associated NOD2 mutation (p.E383K), were recruited alongside healthy controls. Tear samples were collected using Schirmer strips and analyzed via mass spectrometry. A total of 387 proteins were identified, with significant differences in protein expression between BS patients, healthy familial subjects, and healthy controls. Key findings include the overexpression of alpha-2-macroglobulin (A2M) and immunoglobulin heavy constant gamma 4 (IGHG4) in BS patients. Bioinformatic analysis revealed that differentially expressed proteins are involved in acute-phase response, extracellular exosome formation, and protein binding. Notably, neutrophils' azurophilic granule components, as azurocidin (AZU1), myeloperoxidases (MPO), and defensins (DEFA3), were highly expressed in the most severely affected subject, suggesting a potential role of neutrophils in BS ocular severity. These proteins might be promising biomarkers for ocular involvement in BS, facilitating early detection and tailored treatment strategies.

Novel HLA associations with outcomes of Mycobacterium tuberculosis exposure and sarcoidosis in individuals of African ancestry using nearest-neighbor feature selection.

Tuberculosis and sarcoidosis are inflammatory diseases characterized by granulomas that may occur in any organ but are often found in the lung. The panoply of classical human leukocyte antigen (HLA) alleles associated with occurrence and/or severity of both diseases varies considerably across studies. This heterogeneity of results, due to variation in factors like ancestry and disease subphenotype, as well as the use of simple modeling strategies to elucidate likely complex relationships, has made conclusions about underlying commonalities difficult. Here we perform HLA association analyses in individuals of African ancestry, using a greater resolution to include subphenotypes of disease and employing more comprehensive analytical techniques. Using a novel application of nearest-neighbor feature selection to score allelic importance, we investigated HLA allele association with Mycobacterium tuberculosis exposure outcomes in the first analysis of both latent Mycobacterium tuberculosis infection and active disease compared with those who, despite long-term exposure to active index cases, have neither positive diagnostic tests nor display clinical symptoms. We also compared persistent to resolved sarcoidosis. This led to the identification of novel HLA associations and evidence of main effects and interaction effects. We found strikingly similar main effects and interaction effects at HLA-DRB1, -DQB1, and -DPB1 in those resistant to tuberculosis (either latent or active) and persistent sarcoidosis.

Distinct NOD2 mutations reported in three families with Blau syndrome (BS) from a single center in India - Case series and review of literature.

OBJECTIVE: Blau syndrome (BS), considered a rare pediatric autoinflammatory disease, is characterised by a triad of granulomatous arthritis, dermatitis and uveitis. Here we present a tale of three families visited in our outpatient department in the last two years (2020-2022) where more than one member was affected with either skin, ophthalmological and joint involvement with either biopsy-proven granuloma or genetic mutation at NOD2 gene suggesting the diagnosis of BS. CASE SERIES: The first family had three affected members where the mother and her two children had skin changes, polyarthritis and a pathogenic mutation in NOD2 gene (exon 4, c.1000C > T, p.Arg334Trp) suggesting BS. The second family had two affected members where both mother and her son had uveitis, skin changes with NOD2 mutation at exon 4 with c.1147G > A (p Glu 383 Lys) variant. The son also had polyarthritis and his skin biopsy was suggestive of granulomatous inflammation. In the third family with two affected members, we found a mutation in NOD2 on exon 4 (c 1324C > T, p.Lys 442 Phe) which was described as pathogenic with only one report published till date. CONCLUSION: These three cases presented to us within the last two years and led to a diagnosis of BS in three other family members with discrete mutations (commonest to rarest) on the NOD2 gene in the three families.

Sarcoidosis and the mTOR, Rac1, and Autophagy Triad.

Sarcoidosis is an enigmatic multisystem disease characterized by the development and accumulation of granulomas: a compact collection of macrophages that have differentiated into epithelioid cells and which are associated with T helper (Th)1 and Th17 cells. Although no single causative factor has been shown to underlie sarcoidosis in humans, its etiology has been related to microbial, environmental, and genetic factors. We examine how these factors play a role in sarcoidosis pathogenesis. Specifically, we propose that dysfunction of mTOR, Rac1, and autophagy-related pathways not only hampers pathogen or nonorganic particle clearance but also participates in T cell and macrophage dysfunction, driving granuloma formation. This concept opens new avenues for potentially treating sarcoidosis and may serve as a blueprint for other granulomatous disorders.

Modeling Potential Autophagy Pathways in COVID-19 and Sarcoidosis.

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and mainly affects the lungs. Sarcoidosis is an autoinflammatory disease characterized by the diffusion of granulomas in the lungs and other organs. Here, we discuss how the two diseases might involve some common mechanistic cellular pathways around the regulation of autophagy.

Superimposed mosaicism in cutaneous sarcoidosis: A hypothesis.

Sarcoidosis is a chronic granulomatous disorder affecting the lungs, skin, and many other organs. Twin studies suggest that genetic factors account, to a large degree, for the etiology of the disorder. Hence, theoretically, we could postulate that the phenomenon of superimposed mosaicism in the form of a pronounced segmental involvement, overlaying the disseminated non-segmental lesions, should also occur in sarcoidosis. Indeed, one case suggesting superimposed mosaicism in cutaneous sarcoidosis was found in the literature and is reassessed here.

Personalized medicine in sarcoidosis: unravelling biomarkers for targeted care.

PURPOSE OF REVIEW: This review provides an assessment of biomarkers in sarcoidosis, aiming to address the need for improved diagnostic, prognostic and management tools. Sarcoidosis presents diagnostic challenges, necessitating the search for reliable biomarkers to guide clinical decisions. RECENT FINDINGS: Established biomarkers such as serum angiotensin-converting enzyme (ACE) and serum interleukin-2 receptor (sIL-2R) have limitations in sensitivity and specificity. FDG-PET/CT imaging shows promising results in assessing disease activity and guiding immunosuppression. Gene expression profiling studies reveal potential biomarkers, particularly involving TH1 immune response and IFN-γ-driven signalling pathways. The field of omics sciences offers opportunities for novel biomarker discovery. SUMMARY: These findings have implications for clinical practice and research. The limitations of established biomarkers underscore the need for improved diagnostic tools in sarcoidosis. The potential of FDG-PET/CT imaging requires further exploration. Gene expression profiling and omics sciences offer avenues for discovering novel biomarkers to enhance diagnosis and predict disease progression. Such advancements can facilitate personalized treatment strategies and improve patient outcomes. Continued research is vital to validate the efficacy and clinical applicability of these biomarkers. Overall, this review emphasizes ongoing efforts to advance sarcoidosis biomarkers research and improve disease management.

Multiple Correspondence Analysis and HLA-Associations of Organ Involvement in a Large Cohort of African-American and European-American Patients with Sarcoidosis.

Sarcoidosis is a systemic granulomatous disease with predominant pulmonary involvement and vast heterogeneity of clinical manifestations and disease outcomes. African American (AA) patients suffer greater morbidity and mortality. Using Multiple Correspondence Analysis, we identified seven clusters of organ involvement in European American (EA; n = 385) patients which were similar to those previously described in a Pan-European (GenPhenReSa) and a Spanish cohort (SARCOGEAS). In contrast, AA (n = 987) had six, less well-defined and overlapping clusters with little similarity to the cluster identified in the EA cohort evaluated at the same U.S. institutions. Association of cluster membership with two-digit HLA-DRB1 alleles demonstrated ancestry-specific patterns of association and replicated known HLA effects.These results further support the notion that genetically influenced immune risk profiles, which differ based on ancestry, play a role in phenotypic heterogeneity. Dissecting such risk profiles will move us closer to personalized medicine for this complex disease.

Anti-TNF treatment corrects IFN-γ-dependent proinflammatory signatures in Blau syndrome patient-derived macrophages.

BACKGROUND: Blau syndrome (BS) is an autoinflammatory disease associated with mutations in nucleotide-binding oligomerization domain 2. Although treatments with anti-TNF agents have been reported to be effective, the underlying molecular mechanisms remain unclear. OBJECTIVE: We aimed to elucidate the mechanisms of autoinflammation in patients with BS and to clarify how anti-TNF treatment controls the disease phenotype at the cellular level in clinical samples. METHODS: Macrophages were differentiated from monocytes of 7 BS patients, and global transcriptional profiles of 5 patients were analyzed with or without IFN-γ stimulation. Macrophages were also generated from BS-specific induced pluripotent stem cells (iPSCs), and their transcriptome was examined for comparison. RESULTS: Aberrant inflammatory responses were observed upon IFN-γ stimulation in macrophages from untreated BS patients, but not in those from patients treated with anti-TNF. iPSC-derived macrophages carrying a disease-associated mutation also showed IFN-γ-dependent accelerated inflammatory responses. Comparisons of peripheral blood- and iPSC-derived macrophages revealed the upregulation of nuclear factor kappa-light-chain enhancer of activated B cells (NF-κB) targets in unstimulated macrophages as a common feature. CONCLUSIONS: IFN-γ stimulation is one of the key signals driving aberrant inflammatory responses in BS-associated macrophages. However, long-term treatment with anti-TNF agents ameliorates such abnormalities even in the presence of IFN-γ stimulation. Our data thus suggest that preexposure to TNF or functionally similar cytokines inducing NF-κB-driven proinflammatory signaling during macrophage development is a prerequisite for accelerated inflammatory responses upon IFN-γ stimulation in BS.

Common Clinical and Molecular Pathways between Migraine and Sarcoidosis.

Migraine and sarcoidosis are two distinct medical conditions that may have some common biological and clinical pathways. Sarcoidosis is a chronic granulomatous disease characterized by the formation of granulomas in various organs, including the lungs, skin, cardiovascular system, lymph nodes, and brain. Migraine is a common comorbidity in sarcoidosis patients and a common neurological disorder characterized by recurrent headaches that can be accompanied by other symptoms, such as nausea, vomiting, and sensitivity to light and sound. There have been several reports of individuals with neurosarcoidosis experiencing migraines, though the exact relationship between the two disorders is not well understood. Both conditions have been associated with inflammation and the activation of the immune system. In sarcoidosis, the formation of granulomas is thought to be an immune response to the presence of an unknown antigen. Similarly, the pain and other symptoms associated with migraines are thought to be caused by inflammation in the brain and the surrounding blood vessels. There is also evidence to suggest an interplay of environmental and genetic factors playing a role in both conditions, but evidence is inconsistent with the hypothesis of shared genetic susceptibility. This review aims to illustrate common clinical and biological pathways between migraine and sarcoidosis, including inflammation and dysregulation of the immune system, with a focus on the cumulative burden of concurrent disorders and therapeutic implications.

Progress in the genetics of uveitis.

Uveitis is the most common form of intraocular inflammatory disease and is a significant cause of visual impairment worldwide. Aetiologically, uveitis can also be classified into infectious uveitis and non-infectious uveitis. The common non-infectious forms of uveitis include acute anterior uveitis (AAU), Behçet's disease (BD), Vogt-Koyanagi-Harada (VKH) disease, birdshot chorioretinopathy (BSCR), sarcoid uveitis. In addition, a few monogenic autoinflammatory disorders can also cause uveitis, such as Blau Syndrome and haploinsufficiency of A20 (HA20). Although the exact pathogenesis of non-infectious uveitis is still unclear, it is well-recognised that it involves both genetic and environmental risk factors. A hallmark of uveitis is its strong associations with human leucocyte antigens (HLA). For examples, AAU, BD and BSCR are strongly associated with HLA-B27, HLA-B51, and HLA-A29, respectively. In uveitis studies, multiple GWAS have successfully been conducted and led to identification of novel susceptibility loci, for example, IL23R has been identified in BD, VKH and AAU. In this review, we summarize the latest progress on the genetic associations of both HLA and non-HLA genes with major forms of uveitis, including AAU, BD, VKH, BSCR, sarcoid uveitis, Blau Syndrome and HA20, and potential future research directions.

Genetic and Clinical Features of Blau Syndrome among Chinese Patients with Uveitis.

PURPOSE: The American College of Medical Genetics and Genomics (ACMG) and the Association for Molecular Pathology call for cautious interpretation of variants as causative of a monogenic disorder by stringent standards. We aimed to reclassify the pathogenicity of nucleotide binding oligomerization domain containing 2 (NOD2) variants according to the ACMG guidelines and to characterize clinical features in patients whose ocular disease might actually be explained by Blau syndrome. DESIGN: Genetic analysis and descriptive study. PARTICIPANTS: A total of 1003 unrelated healthy individuals and 3921 sporadic patients who presented with uveitis. METHODS: Whole-exome sequencing was performed on all healthy participants and 551 patients with uveitis, and targeted NOD2 resequencing was performed on the remaining 3370 patients with uveitis. Pathogenicity for Blau syndrome was classified for NOD2 variants identified by sequencing in study participants according to the ACMG guidelines. Clinical manifestations were compared among NOD2 variants of different levels of classification. MAIN OUTCOME MEASURES: Pathogenicity of variants. RESULTS: Eight NOD2 gain-of-function mutations, p.R334W, p.R334Q, p.E383K, p.G481D, p.W490S, p.M513T, p.R587C, and p.N670K, were classified as pathogenic, and 66 patients (1.7%) with uveitis were diagnosed with Blau syndrome due to these mutations. Of 66 with Blau syndrome, anterior uveitis accounted for 39.4%, posterior uveitis for 9.1%, and panuveitis for 51.5%. A proportion of 21.2% of Blau syndrome presented as multifocal choroiditis, 48.5% had papillitis, and 74.2% showed retinal microvasculitis detected by fundus fluorescein angiography. Six NOD2 variants, p.P268S, p.R311W, p.R471C, p.A612T, p.R702W, and p.V955I, were considered nonpathogenic for Blau syndrome and were identified in 96 patients with uveitis. The incidence of bilateral uveitis (86.4%), secondary glaucoma (47.0%), epiretinal membrane (7.6%), choroidal neovascularization (4.6%), retinal atrophy (10.6%), arthritis (69.7%), joint deformity (51.5%), and skin rash (40.9%) was higher in Blau syndrome than in patients with uveitis carrying non-Blau-causing NOD2 variants. Patients with Blau syndrome permanently experienced overall poorer best-corrected visual acuity. Several rare NOD2 mutations, p.I722L (2 cases), p.T476P (1 case), p.T476del (1 case), and p.R439H (1 case), were newly identified. CONCLUSIONS: Pathogenic NOD2 variants for Blau syndrome were limited to those gain-of-function mutations and were associated with a high risk for arthritis, skin rash, permanent visual loss, and ocular complications in patients with uveitis.

Predictive potential of ACE phenotyping in extrapulmonary sarcoidosis.

Elevated ACE expression in tissues (reflected by blood ACE levels) is associated with increased risk of cardiovascular diseases and is also a marker for granulomatous diseases. We developed a new approach for characterization of ACE status in the blood-ACE phenotyping and established normal values of ACE levels 50-150% of control pooled plasma. ACE phenotyping was performed in citrated plasma of 120 patients with known interstitial lung diseases. In the 1st set of 100 patients we found 22 patients with ACE levels > 150%; ACE phenotyping also objectively identified the presence of ACE inhibitors in the plasma of 15 patients. After excluding these patients and patient with ACE mutation that increases ACE shedding, 17 patients were identified as a suspicious for systemic sarcoidosis based on elevation of blood ACE (> 150% of mean). A new parameter that we have established-ACE immunoreactivity (with mAb 9B9)-allowed us to detect 22 patients with decreased values (< 80%) of this parameter, which may indicate the presence of ACE in the blood that originates from macrophages/dendritic cells of granulomas. In the remaining 20 patients, this new parameter (mAbs binding/activity ratio) was calculated using 3 mAbs (9B9, 3A5 and i1A8-having overlapping epitopes), and 8 patients were identified as having decreases in this parameter, thus increasing dramatically the sensitivity for detection of patients with systemic sarcoidosis. Whole body PET scan confirmed extrapulmonary granulomas in some patients with lower immunoreactivity towards anti-ACE mAbs. ACE phenotyping has novel potential to noninvasively detect patients with systemic sarcoidosis.

Clinical phenotyping in sarcoidosis using cluster analysis.

BACKGROUND: Most phenotyping paradigms in sarcoidosis are based on expert opinion; however, no paradigm has been widely adopted because of the subjectivity in classification. We hypothesized that cluster analysis could be performed on common clinical variables to define more objective sarcoidosis phenotypes. METHODS: We performed a retrospective cohort study of 554 sarcoidosis cases to identify distinct phenotypes of sarcoidosis based on 29 clinical features. Model-based clustering was performed using the VarSelLCM R package and the Integrated Completed Likelihood (ICL) criteria were used to estimate number of clusters. To identify features associated with cluster membership, features were ranked based on variable importance scores from the VarSelLCM model, and additional univariate tests (Fisher's exact test and one-way ANOVA) were performed using q-values correcting for multiple testing. The Wasfi severity score was also compared between clusters. RESULTS: Cluster analysis resulted in 6 sarcoidosis phenotypes. Salient characteristics for each cluster are as follows: Phenotype (1) supranormal lung function and majority Scadding stage 2/3; phenotype (2) supranormal lung function and majority Scadding stage 0/1; phenotype (3) normal lung function and split Scadding stages between 0/1 and 2/3; phenotype (4) obstructive lung function and majority Scadding stage 2/3; phenotype (5) restrictive lung function and majority Scadding stage 2/3; phenotype (6) mixed obstructive and restrictive lung function and mostly Scadding stage 4. Although there were differences in the percentages, all Scadding stages were encompassed by all of the phenotypes, except for phenotype 1, in which none were Scadding stage 4. Clusters 4, 5, 6 were significantly more likely to have ever been on immunosuppressive treatment and had higher Wasfi disease severity scores. CONCLUSIONS: Cluster analysis produced 6 sarcoidosis phenotypes that demonstrated less severe and severe phenotypes. Phenotypes 1, 2, 3 have less lung function abnormalities, a lower percentage on immunosuppressive treatment and lower Wasfi severity scores. Phenotypes 4, 5, 6 were characterized by lung function abnormalities, more parenchymal abnormalities, an increased percentage on immunosuppressive treatment and higher Wasfi severity scores. These data support using cluster analysis as an objective and clinically useful way to phenotype sarcoidosis subjects and to empower clinicians to identify those with more severe disease versus those who have less severe disease, independent of Scadding stage.