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

Abstract

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 PARTICIPANTSIn 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 MEASURESSignificantly 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.

Molecular diagnosis: Implications for ophthalmology

“…Similarly we use normal adipose tissue as a comparator to learn what transcripts are up or down regulated in orbital fat affected by sarcoidosis. Our observations indicate that there is a great deal of overlap between genes expressed in the sarcoidosis-affected lacrimal gland compared to the sarcoidosis-affected orbital adipose tissue (Rosenbaum et al, 2015b). More importantly many of the transcripts that are up or down regulated in both lacrimal gland and orbital adipose tissue as a result of sarcoidosis are similarly affected in an assay based on whole blood (Rosenbaum et al, 2015b).…”

“…Could this technology be extrapolated such that a blood sample alone would allow accurate diagnosis of orbital inflammation? We tested this hypothesis as it relates to sarcoidosis involving the orbit (Rosenbaum et al, 2015b). We characterized the genes expressed in the lacrimal gland affected by sarcoidosis in comparison to genes expressed in orbital adipose tissue affected by sarcoidosis.…”

“…About 50% of patients with Graves’ disease develop some symptoms of ophthalmopathy, although it is severe in only about ten per cent of those affected (Bartalena and Tanda, 2009). Other non-malignant, non-contagious causes of orbital swelling include sarcoidosis (Rosenbaum et al, 2015b), GPA (Rosenbaum et al, 2015c) (previously known as Wegener’s granulomatosis and also known as ANCA associated vasculitis), histiocytoses like Erdheim Chester disease (Hayden et al, 2007), and xanthogranulomas. A common diagnosis for orbital inflammation is nonspecific orbital inflammation (NSOI), which is also known as idiopathic orbital inflammation or orbital pseudotumor (Yuen and Ruin, 2003).…”

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

“…All tissues had been reviewed by an ophthalmic pathologist from the contributing center and then further reviewed by two additional pathologists (DJW and HEG) who collaborated in the preparation of this report. These centers and the pathologists have previously used a similar method of tissue collection to analyze gene expression from a variety of orbital diseases including TED 13 , GPA 12 , sarcoidosis 16 , and nonspecific orbital inflammation 14 . Control tissue from healthy individuals was obtained at the time of cosmetic surgery or blepharoplasty.…”

“…All tissue was sent to Oregon Health & Science University, Portland, Oregon, for RNA extraction and microarray as previously described 12,13,16 . In brief, cDNA was synthesized from purified RNA, amplified, labeled, and hybridized to Affymetrix U 133 plus 2.0 arrays, which include probe sets for about 45,000 transcripts.…”