Orbital pseudotumor can be a localized form of granulomatosis with polyangiitis as revealed by gene expression profiling.

Biopsies and ANCA testing for limited forms of granulomatosis with polyangiitis (GPA) are frequently non-diagnostic. We characterized gene expression in GPA and other causes of orbital inflammation. We tested the hypothesis that a sub-set of patients with non-specific orbital inflammation (NSOI, also known as pseudotumor) mimics a limited form of GPA. Formalin-fixed, paraffin-embedded orbital biopsies were obtained from controls (n=20) and patients with GPA (n=6), NSOI (n=25), sarcoidosis (n=7), or thyroid eye disease (TED) (n=20) and were divided into discovery and validation sets. Transcripts in the tissues were quantified using Affymetrix U133 Plus 2.0 microarrays. Distinct gene expression profiles for controls and subjects with GPA, TED, or sarcoidosis were evident by principal coordinate analyses. Compared with healthy controls, 285 probe sets had elevated signals in subjects with GPA and 1472 were decreased (>1.5-fold difference, false discovery rate adjusted p<0.05). The immunoglobulin family of genes had the most dramatic increase in expression. Although gene expression in GPA could be readily distinguished from gene expression in TED, sarcoidosis, or controls, a comparison of gene expression in GPA versus NSOI found no statistically significant differences. Thus, forms of orbital inflammation can be distinguished based on gene expression. NSOI/pseudotumor is heterogeneous but often may be an unrecognized, localized form of GPA.

Pneumocystis jiroveci pneumonia prophylaxis in patients with autoimmune hepatitis.

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Axial spondyloarthritis patients have altered mucosal IgA response to oral and fecal microbiota.

Axial spondyloarthritis (axSpA) is an inflammatory arthritis involving the spine and the sacroiliac joint with extra-articular manifestations in the eye, gut, and skin. The intestinal microbiota has been implicated as a central environmental component in the pathogenesis of various types of spondyloarthritis including axSpA. Additionally, alterations in the oral microbiota have been shown in various rheumatological conditions, such as rheumatoid arthritis (RA). Therefore, the aim of this study was to investigate whether axSpA patients have an altered immunoglobulin A (IgA) response in the gut and oral microbial communities. We performed 16S rRNA gene (16S) sequencing on IgA positive (IgA+) and IgA negative (IgA-) fractions (IgA-SEQ) from feces (n=17 axSpA; n=14 healthy) and saliva (n=14 axSpA; n=12 healthy), as well as on IgA-unsorted fecal and salivary samples. PICRUSt2 was used to predict microbial metabolic potential in axSpA patients and healthy controls (HCs). IgA-SEQ analyses revealed enrichment of several microbes in the fecal (Akkermansia, Ruminococcaceae, Lachnospira) and salivary (Prevotellaceae, Actinobacillus) microbiome in axSpA patients as compared with HCs. Fecal microbiome from axSpA patients showed a tendency towards increased alpha diversity in IgA+ fraction and decreased diversity in IgA- fraction in comparison with HCs, while the salivary microbiome exhibits a significant decrease in alpha diversity in both IgA+ and IgA- fractions. Increased IgA coating of Clostridiales Family XIII in feces correlated with disease severity. Inferred metagenomic analysis suggests perturbation of metabolites and metabolic pathways for inflammation (oxidative stress, amino acid degradation) and metabolism (propanoate and butanoate) in axSpA patients. Analyses of fecal and salivary microbes from axSpA patients reveal distinct populations of immunoreactive microbes compared to HCs using the IgA-SEQ approach. These bacteria were not identified by comparing their relative abundance alone. Predictive metagenomic analysis revealed perturbation of metabolites/metabolic pathways in axSpA patients. Future studies on these immunoreactive microbes may lead to better understanding of the functional role of IgA in maintaining microbial structure and human health.

Estrogen protection against EAE modulates the microbiota and mucosal-associated regulatory cells.

Sex hormones promote immunoregulatory effects on multiple sclerosis. In the current study we evaluated the composition of the gut microbiota and the mucosal-associated regulatory cells in estrogen or sham treated female mice before and after autoimmune encephalomyelitis (EAE) induction. Treatment with pregnancy levels of estrogen induces changes in the composition and diversity of gut microbiota. Additionally, estrogen prevents EAE-associated changes in the gut microbiota and might promote the enrichment of bacteria that are associated with immune regulation. Our results point to a possible cross-talk between the sex hormones and the gut microbiota, which could promote neuroprotection.

Intestinal Metabolites Are Profoundly Altered in the Context of HLA-B27 Expression and Functionally Modulate Disease in a Rat Model of Spondyloarthritis.

OBJECTIVE: HLA-B27-associated spondyloarthritides are associated with an altered intestinal microbiota and bowel inflammation. We undertook this study to identify HLA-B27-dependent changes in both host and microbial metabolites in the HLA-B27/ß2 -microglobulin (ß2 m)-transgenic rat and to determine whether microbiota-derived metabolites could impact disease in this major model of spondyloarthritis. METHODS: Cecal contents were collected from Fischer 344 33-3 HLA-B27/ß2 m-transgenic rats and wild-type controls at 6 weeks (before disease) and 16 weeks (with active bowel inflammation). Metabolomic profiling was performed by high-throughput gas and liquid chromatography-based mass spectrometry. HLA-B27/ß2 m-transgenic rats were treated with the microbial metabolites propionate or butyrate in drinking water for 10 weeks, and disease activity was subsequently assessed. RESULTS: Our screen identified 582 metabolites, of which more than half were significantly altered by HLA-B27 expression at 16 weeks. Both microbial and host metabolites were altered, with multiple pathways affected, including those for amino acid, carbohydrate, xenobiotic, and medium-chain fatty acid metabolism. Differences were even observed at 6 weeks, with up-regulation of histidine, tyrosine, spermidine, N-acetylmuramate, and glycerate in HLA-B27/ß2 m-transgenic rats. Administration of the short-chain fatty acid propionate significantly attenuated HLA-B27-associated inflammatory disease, although this was not associated with increased FoxP3+ T cell induction or with altered expression of the immunomodulatory cytokines interleukin-10 (IL-10) or IL-33 or of the tight junction protein zonula occludens 1. HLA-B27 expression was also associated with altered host expression of messenger RNA for the microbial metabolite receptors free fatty acid receptor 2 (FFAR2), FFAR3, and niacin receptor 1. CONCLUSION: HLA-B27 expression profoundly impacts the intestinal metabolome, with changes evident in rats even at age 6 weeks. Critically, we demonstrate that a microbial metabolite, propionate, attenuates development of HLA-B27-associated inflammatory disease. These and other microbiota-derived bioactive mediators may provide novel treatment modalities in HLA-B27-associated spondyloarthritides.

Gene Expression Profiling and Heterogeneity of Nonspecific Orbital Inflammation Affecting the Lacrimal Gland.

Importance: Although a variety of well-characterized diseases, such as sarcoidosis and granulomatosis with polyangiitis, affect the lacrimal gland, many patients with dacryoadenitis are diagnosed as having nonspecific orbital inflammation (NSOI) on the basis of histology and systemic disease evaluation. The ability to further classify the disease in these patients should facilitate selection of effective therapies. Objective: To test the a priori hypothesis that gene expression profiles would complement clinical and histopathologic evaluations in identifying well-characterized diseases and in subdividing NSOI into clinically relevant groups. Design, Setting, and Participants: In this cohort study, gene expression levels in biopsy specimens of inflamed and control lacrimal glands were measured with microarrays. Stained sections of the same biopsy specimens were used for evaluation of histopathology. Tissue samples of patients were obtained from oculoplastic surgeons at 7 international centers representing 4 countries (United States, Saudi Arabia, Canada, and Taiwan). Gene expression analysis was done at Oregon Health & Science University. Participants were 48 patients, including 3 with granulomatosis with polyangiitis, 28 with NSOI, 7 with sarcoidosis, 4 with thyroid eye disease, and 6 healthy controls. The study dates were March 2012 to April 2017. Main Outcomes and Measures: The primary outcome was subdivision of biopsy specimens based on gene expression of a published list of approximately 40 differentially expressed transcripts in blood, lacrimal gland, and orbital adipose tissue from patients with sarcoidosis. Stained sections were evaluated for inflammation (none, mild, moderate, or marked), granulomas, nodules, or fibrosis by 2 independent ocular pathologists masked to the clinical diagnosis. Results: Among 48 patients (mean [SD] age, 41.6 [19.0] years; 32 [67%] female), the mclust algorithm segregated the biopsy specimens into 4 subsets, with the differences illustrated by a heat map and multidimensional scaling plots. Most of the sarcoidosis biopsy specimens were in subset 1, which had the highest granuloma score. Three NSOI biopsy specimens in subset 1 had no apparent granulomas. Thirty-two percent (9 of 28) of the NSOI biopsy specimens could not be distinguished from biopsy specimens of healthy controls in subset 4, while other examples of NSOI tended to group with gene expression resembling granulomatosis with polyangiitis or thyroid eye disease. The 4 subsets could also be partially differentiated by their fibrosis, granulomas, and inflammation pathology scores but not their lymphoid nodule scores. Conclusions and Relevance: Gene expression profiling discloses clear heterogeneity among patients with lacrimal inflammatory disease. Comparison of the expression profiles suggests that a subset of patients with nonspecific dacryoadenitis might have a limited form of sarcoidosis, while other patients with NSOI cannot be distinguished from healthy controls.

Perturbed Mucosal Immunity and Dysbiosis Accompany Clinical Disease in a Rat Model of Spondyloarthritis.

OBJECTIVE: The HLA-B27/ß2 -microglobulin (ß2 m)-transgenic (Tg) rat is a leading model of B27-associated spondyloarthritis (SpA), and the disease is dependent on the presence of intestinal bacteria. Previous studies have shown that adult HLA-B27/ß2 m-Tg rats have an altered intestinal microbiota. This study sought to better define the age-dependent changes to both mucosal immune function and dysbiosis in this rat model of SpA. METHODS: Intestinal contents were collected from wild-type and HLA-B27/ß2 m-Tg rats postweaning (ages 3 and 6 weeks), at disease onset (age 10 weeks), and after the establishment of disease (ages ≥16 weeks). The microbial community structure was determined by 16S ribosomal RNA sequencing and quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Mucosal and systemic Th1, Th17, and Treg cell responses were analyzed by flow cytometry, as was the frequency of IgA-coated intestinal bacteria. Intestinal expression of inflammatory cytokines and antimicrobial peptides (AMPs) was determined by qRT-PCR. RESULTS: An inflammatory cytokine signature and elevated AMP expression during the postweaning period preceded the development of clinical bowel inflammation and dysbiosis in HLA-B27/ß2 m-Tg rats. An early and sustained expansion of the Th17 cell pool was specifically observed in the cecal and colonic mucosa of HLA-B27/ß2 m-Tg rats. Strongly elevated intestinal colonization of Akkermansia muciniphila and an increased frequency of IgA-coated fecal bacteria were significantly associated with expression of HLA-B27 and arthritis development. CONCLUSION: HLA-B27/ß2 m expression in this rat model renders the host hyperresponsive to microbial antigens from infancy. Early activation of innate immunity and expansion of a mucosal Th17 signature are soon followed by dysbiosis in HLA-B27/ß2 m-Tg animals. The pathologic processes of perturbed mucosal immunity and dysbiosis strongly merit further study in both prediseased and diseased populations of patients with SpA.

Does the Urinary Microbiome Play a Role in Urgency Urinary Incontinence and Its Severity?

OBJECTIVES: Traditionally, the urinary tract has been thought to be sterile in the absence of a clinically identifiable infection. However, recent evidence suggests that the urinary tract harbors a variety of bacterial species, known collectively as the urinary microbiome, even when clinical cultures are negative. Whether these bacteria promote urinary health or contribute to urinary tract disease remains unknown. Emerging evidence indicates that a shift in the urinary microbiome may play an important role in urgency urinary incontinence (UUI). The goal of this prospective pilot study was to determine how the urinary microbiome is different between women with and without UUI. We also sought to identify if characteristics of the urinary microbiome are associated with UUI severity. METHODS: We collected urine from clinically well-characterized women with UUI (n = 10) and normal bladder function (n = 10) using a transurethral catheter to avoid bacterial contamination from external tissue. To characterize the resident microbial community, we amplified the bacterial 16S rRNA gene by PCR and performed sequencing using Illumina MiSeq. Sequences were processed using the workflow package QIIME. We identified bacteria that had differential relative abundance between UUI and controls using DESeq2 to fit generalized linear models based on the negative binomial distribution. We also identified relationships between the diversity of the urinary microbiome and severity of UUI symptoms with Pearson's correlation coefficient. RESULTS: We successfully extracted and sequenced bacterial DNA from 95% of the urine samples and identified that there is a polymicrobial community in the female bladder in both healthy controls and women with UUI. We found the relative abundance of 14 bacteria significantly differed between control and UUI samples. Furthermore, we established that an increase in UUI symptom severity is associated with a decrease in microbial diversity in women with UUI. CONCLUSIONS: Our study provides further characterization of the urinary microbiome in both healthy controls and extensively phenotyped women with UUI. Our results also suggest that the urinary microbiome may play an important role in the pathophysiology of UUI and that the loss of microbial diversity may be associated with clinical severity.

The Role of the Immune Response in the Pathogenesis of Thyroid Eye Disease: A Reassessment.

BACKGROUND: Although thyroid eye disease is a common complication of Graves' disease, the pathogenesis of the orbital disease is poorly understood. Most authorities implicate the immune response as an important causal factor. We sought to clarify pathogenesis by using gene expression microarray. METHODS: An international consortium of ocular pathologists and orbital surgeons contributed formalin fixed orbital biopsies. RNA was extracted from orbital tissue from 20 healthy controls, 25 patients with thyroid eye disease (TED), 25 patients with nonspecific orbital inflammation (NSOI), 7 patients with sarcoidosis and 6 patients with granulomatosis with polyangiitis (GPA). Tissue was divided into a discovery set and a validation set. Gene expression was quantified using Affymetrix U133 Plus 2.0 microarrays which include 54,000 probe sets. RESULTS: Principal component analysis showed that gene expression from tissue from patients with TED more closely resembled gene expression from healthy control tissue in comparison to gene expression characteristic of sarcoidosis, NSOI, or granulomatosis with polyangiitis. Unsupervised cluster dendrograms further indicated the similarity between TED and healthy controls. Heat maps based on gene expression for cytokines, chemokines, or their receptors showed that these inflammatory markers were associated with NSOI, sarcoidosis, or GPA much more frequently than with TED. CONCLUSION: This is the first study to compare gene expression in TED to gene expression associated with other causes of exophthalmos. The juxtaposition shows that inflammatory markers are far less characteristic of TED relative to other orbital inflammatory diseases.

Parallel Gene Expression Changes in Sarcoidosis Involving the Lacrimal Gland, Orbital Tissue, or Blood.

IMPORTANCE: Sarcoidosis is a major cause of ocular or periocular inflammation. The pathogenesis of sarcoidosis is incompletely understood and diagnosis often requires a biopsy. OBJECTIVE: To determine how gene expression in either orbital adipose tissue or the lacrimal gland affected by sarcoidosis compares with gene expression in other causes of orbital disease and how gene expression in tissue affected by sarcoidosis compares with gene expression in peripheral blood samples obtained from patients with sarcoidosis. DESIGN, SETTING, AND PARTICIPANTS: In a multicenter, international, observational study, gene expression profiling of formalin-fixed biopsy specimens, using GeneChipp U133 Plus 2 microarrays (Affymetrix), was conducted between October 2012 and January 2014 on tissues biopsied from January 2000 through June 2013. Participants included 12 patients with orbital sarcoidosis (7 in adipose tissue; 5 affecting the lacrimal gland) as well as comparable tissue from 6 healthy individuals serving as controls or patients with thyroid eye disease, nonspecific orbital inflammation, or granulomatosis with polyangiitis. In addition, results were compared with gene expression in peripheral blood samples obtained from 12 historical individuals with sarcoidosis. MAIN OUTCOMES AND MEASURES: Significantly differentially expressed transcripts defined as a minimum of a 1.5-fold increase or a comparable decrease and a false discovery rate of P < .05. RESULTS: Signals from 2449 probe sets (transcripts from approximately 1522 genes) were significantly increased in the orbital adipose tissue from patients with sarcoidosis. Signals from 4050 probe sets (approximately 2619 genes) were significantly decreased. Signals from 3069 probe sets (approximately 2001 genes) were significantly higher and 3320 (approximately 2283 genes) were significantly lower in the lacrimal gland for patients with sarcoidosis. Ninety-two probe sets (approximately 69 genes) had significantly elevated signals and 67 probe sets (approximately 56 genes) had significantly lower signals in both orbital tissues and in peripheral blood from patients with sarcoidosis. The transcription factors, interferon-response factor 1, interferon-response factor 2, and nuclear factor κB, were strongly implicated in the expression of messenger RNA upregulated in common in the 3 tissues. CONCLUSIONS AND RELEVANCE: Gene expression in sarcoidosis involving the orbit or lacrimal gland can be distinguished from gene expression patterns in control tissue and overlaps with many transcripts upregulated or downregulated in the peripheral blood of patients with sarcoidosis. These observations suggest that common pathogenic mechanisms contribute to sarcoidosis in different sites. The observations support the hypothesis that a pattern of gene expression profiles could provide diagnostic information in patients with sarcoidosis.

Fibrosis, gene expression and orbital inflammatory disease.

BACKGROUND/AIMS: To clarify the pathogenesis of fibrosis in inflammatory orbital diseases, we analysed the gene expression in orbital biopsies and compared our results with those reported for idiopathic pulmonary fibrosis. METHODS: We collected 140 biopsies from 138 patients (58 lacrimal glands; 82 orbital fat). Diagnoses included healthy controls (n=27), non-specific orbital inflammation (NSOI) (n=61), thyroid eye disease (TED) (n=29), sarcoidosis (n=14) and granulomatosis with polyangiitis (GPA) (n=7). Fibrosis was scored on a 0-3 scale by two experts, ophthalmic pathologists. Gene expression was quantified using Affymetrix U133 plus 2.0 microarray. RESULTS: Within orbital fat, fibrosis was greatest among subjects with GPA (2.75±0.46) and significantly increased in tissue from subjects with GPA, NSOI or sarcoidosis (p<0.01), but not for TED, compared with healthy controls (1.13±0.69). For lacrimal gland, the average score among controls (1.36±0.48) did not differ statistically from any of the four disease groups. Seventy-three probe sets identified transcripts correlating with fibrosis in orbital fat (false discovery rate <0.05) after accounting for batch effects, disease type, age and sex. Transcripts with increased expression included fibronectin, lumican, thrombospondin and collagen types I and VIII, each of which has been reported upregulated in pulmonary fibrosis. CONCLUSIONS: A pathologist's recognition of fibrosis in orbital tissue correlates well with increased expression of transcripts that are considered essential in fibrosis. Many transcripts implicated in orbital fibrosis have been previously implicated in pulmonary fibrosis. TED differs from other causes of orbital fat inflammation because fibrosis is not a major component. Marked fibrosis is less common in the lacrimal gland compared with orbital adipose tissue.

HLA-B27 and human ß2-microglobulin affect the gut microbiota of transgenic rats.

The HLA-B27 gene is a major risk factor for clinical diseases including ankylosing spondylitis, acute anterior uveitis, reactive arthritis, and psoriatic arthritis, but its mechanism of risk enhancement is not completely understood. The gut microbiome has recently been shown to influence several HLA-linked diseases. However, the role of HLA-B27 in shaping the gut microbiome has not been previously investigated. In this study, we characterize the differences in the gut microbiota mediated by the presence of the HLA-B27 gene. We identified differences in the cecal microbiota of Lewis rats transgenic for HLA-B27 and human ß2-microglobulin (hß2m), compared with wild-type Lewis rats, using biome representational in situ karyotyping (BRISK) and 16S rRNA gene sequencing. 16S sequencing revealed significant differences between transgenic animals and wild type animals by principal coordinates analysis. Further analysis of the data set revealed an increase in Prevotella spp. and a decrease in Rikenellaceae relative abundance in the transgenic animals compared to the wild type animals. By BRISK analysis, species-specific differences included an increase in Bacteroides vulgatus abundance in HLA-B27/hß2m and hß2m compared to wild type rats. The finding that HLA-B27 is associated with altered cecal microbiota has not been shown before and can potentially provide a better understanding of the clinical diseases associated with this gene.

IgG4 immunostaining and its implications in orbital inflammatory disease.

OBJECTIVE: IgG4-related disease is an emerging clinical entity which frequently involves tissue within the orbit. In order to appreciate the implications of IgG4 immunostaining, we analyzed gene expression and the prevalence of IgG4- immunostaining among subjects with orbital inflammatory diseases. METHODS: We organized an international consortium to collect orbital biopsies from 108 subjects including 22 with no known orbital disease, 42 with nonspecific orbital inflammatory disease (NSOI), 26 with thyroid eye disease (TED), 12 with sarcoidosis, and 6 with granulomatosis with polyangiitis (GPA). Lacrimal gland and orbital adipose tissue biopsies were immunostained for IgG4 or IgG secreting plasma cells. RNA transcripts were quantified by Affymetrix arrays. RESULTS: None of the healthy controls or subjects with TED had substantial IgG4 staining. Among the 63 others, the prevalence of significant IgG4-immunostaining ranged from 11 to 39% depending on the definition for significant. IgG4 staining was detectable in the majority of tissues from subjects with GPA and less commonly in tissue from subjects with sarcoidosis or NSOI. The detection of IgG4+ cells correlated with inflammation in the lacrimal gland based on histology. IgG4 staining tissue expressed an increase in transcripts associated with inflammation, especially B cell-related genes. Functional annotation analysis confirmed this. CONCLUSION: IgG4+ plasma cells are common in orbital tissue from patients with sarcoidosis, GPA, or NSOI. Even using the low threshold of 10 IgG4+ cells/high powered field, IgG4 staining correlates with increased inflammation in the lacrimal gland based on histology and gene expression.