Specific antigen(s) in sarcoidosis: a link to autoimmunity?

Deconstructing Multiorgan Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown cause [...]

Orofacial sarcoidosis: report of three cases

Introduction: Sarcoidosis is a systemic non-caseating granulomatous disorder of unknown etiology that may affect multiple organ systems. Head and neck involvement can present in unusual and often nonspecific ways. Observations: We report three cases of sarcoidosis with orofacial manifestations: one African American patient with an existing diagnosis who presented with perioral cutaneous involvement by sarcoidosis, and two Caucasian patients with cases where the initial oral presentation – diffusely affected gingiva in one and intraosseous jaw involvement with resultant dental implant failure in the other – led to workup and establishment of the diagnosis of sarcoidosis. The patients were referred to rheumatology and dermatology for appropriate treatment. Conclusion: Although oral lesions of sarcoidosis are not common, they may be the first clinical manifestation of sarcoidosis. The practitioner should be aware of the possible manifestations and be able to formulate an informed clinical differential diagnosis.

Environmental Risk Factors for Sarcoidosis

Sarcoidosis is a multisystem granulomatous disease that may affect any body organ. Sarcoidosis is associated with many environmental and occupational exposures. Because the exact immunopathogenesis of sarcoidosis is unknown, it is not known whether these exposures are truly causing sarcoidosis, rendering the immune system more susceptible to the development of sarcoidosis, exacerbating subclinical cases of sarcoidosis, or causing a granulomatous condition distinct from sarcoidosis. This manuscript outlines what is known about the immunopathogenesis of sarcoidosis and postulates mechanisms whereby these exposures could cause or exacerbate the disease. We also describe the varied environmental and occupational exposures that have been associated with sarcoidosis. This includes potential infectious exposures such as mycobacteria and Propionibacterium acnes, a skin commensal bacterium, as well as non-infectious environmental exposures including inhaled bioaerosols, metal dusts and products of combustion. Further insights concerning the relationship of environmental exposures to the development of sarcoidosis may have a major impact on the prevention and treatment of this enigmatic disease.

Sarcoidosis: Causes, Diagnosis, Clinical Features, and Treatments

Sarcoidosis is a multisystem granulomatous disease with nonspecific clinical manifestations that commonly affects the pulmonary system and other organs including the eyes, skin, liver, spleen, and lymph nodes. Sarcoidosis usually presents with persistent dry cough, eye and skin manifestations, weight loss, fatigue, night sweats, and erythema nodosum. Sarcoidosis is not influenced by sex or age, although it is more common in adults (< 50 years) of African-American or Scandinavians decent. Diagnosis can be difficult because of nonspecific symptoms and can only be verified following histopathological examination. Various factors, including infection, genetic predisposition, and environmental factors, are involved in the pathology of sarcoidosis. Exposures to insecticides, herbicides, bioaerosols, and agricultural employment are also associated with an increased risk for sarcoidosis. Due to its unknown etiology, early diagnosis and detection are difficult; however, the advent of advanced technologies, such as endobronchial ultrasound-guided biopsy, high-resolution computed tomography, magnetic resonance imaging, and 18F-fluorodeoxyglucose positron emission tomography has improved our ability to reliably diagnose this condition and accurately forecast its prognosis. This review discusses the causes and clinical features of sarcoidosis, and the improvements made in its prognosis, therapeutic management, and the recent discovery of potential biomarkers associated with the diagnostic assay used for sarcoidosis confirmation.

New advances in the management of pulmonary sarcoidosis

Sarcoidosis is a highly variable granulomatous multisystem syndrome. It affects individuals in the prime years of life; both the frequency and severity of sarcoidosis are greater in economically disadvantaged populations. The diagnosis, assessment, and management of pulmonary sarcoidosis have evolved as new technologies and therapies have been adopted. Transbronchial needle aspiration guided by endobronchial ultrasound has replaced mediastinoscopy in many centers. Advanced imaging modalities, such as fluorodeoxyglucose positron emission tomography scanning, and the widespread availability of magnetic resonance imaging have led to more sensitive assessment of organ involvement and disease activity. Although several new insights about the pathogenesis of sarcoidosis exist, no new therapies have been specifically developed for use in the disease. The current or proposed use of immunosuppressive medications for sarcoidosis has been extrapolated from other disease states; various novel pathways are currently under investigation as therapeutic targets. Coupled with the growing recognition of corticosteroid toxicities for managing sarcoidosis, the use of corticosteroid sparing anti-sarcoidosis medications is likely to increase. Besides treatment of granulomatous inflammation, recognition and management of the non-granulomatous complications of pulmonary sarcoidosis are needed for optimal outcomes in patients with advanced disease.

A sarcoidosis clinician's perspective of MHC functional elements outside the antigen binding site

Sarcoidosis is a multisystem granulomatous disease of unknown cause. Evidence supports an integral role for interactions at the MHC binding site in the development of sarcoidosis. However, despite this evidence, there are clinical data that suggest that additional mechanisms are involved in the immunopathogenesis of this disease. This manuscript provides a brief clinical description of sarcoidosis, and a clinician's perspective of the immunopathogenesis of sarcoidosis in terms of the MHC binding site, MHC functional elements beyond the binding site, and other possible alternative mechanisms. Input from clinicians will be essential in establishing the immunologic cause of sarcoidosis as a detailed phenotypic characterization of disease will be required.

Expression of DROSHA and DICER genes in peripheral blood leukocytes in lung sarcoidosis

AIM

To study the expression level of the genes DROSHA and DICER in peripheral blood leukocytes (PBL) of patients with sarcoidosis of the lungs.

MATERIALS AND METHODS

The study included 32 patients diagnosed with persistent lung sarcoidosis (mean age 41.56±1.27 years) and 36 healthy donors (control; mean age 42.79±1.95 years). The level of expression of messenger RNA (mRNA) of the genes DROSHA and DICER were determined in PBL of healthy donors and patients with sarcoidosis of the lung by polymerase chain reaction in real time.

RESULTS

As a result of the conducted researches it is established that the level of drosha gene expression in PBL patients with sarcoidosis of lungs is significantly reduced in comparison with the control (p&lt;0.01). We also found a significant decrease in the number of Dicker gene transcripts in the PBL of the study group of patients (p&lt;0.01).

CONCLUSION

According to the results of the conducted studies, a significant decrease in the number of DROSHA and DICER transcripts in PBL patients with the development of lung sarcoidosis has been found, which can contribute to the pathogenesis of this disease.

Proteomic Analysis of Kveim Reagent Identifies Targets of Cellular Immunity in Sarcoidosis

Background

Kveim-reagent (Kv) skin testing was a historical method of diagnosing sarcoidosis. Intradermal injection of treated sarcoidosis spleen tissue resulted in a granuloma response at injection site by 4–6 weeks. Previous work indicates proteins as the possible trigger of this reaction. We aimed to identify Kv-specific proteins and characterise the ex vivo response of Peripheral Blood Mononuclear Cells (PBMCs) from sarcoidosis, tuberculosis and healthy control patients when stimulated with both Kv and selected Kv-specific proteins.

Methods

Kv extracts were separated by 1D-SDS-PAGE and 2D-DIGE and then underwent mass spectrometric analysis for protein identification. Sarcoidosis and control PBMCs were first stimulated with Kv and then with three selected recombinant protein candidates which were identified from the proteomic analysis. PBMC secreted cytokines were subsequently measured by Multiplex Cytokine Assay.

Results

We observed significantly increased IFN-γ and TNF-α secretion from Kv-stimulated PBMCs of sarcoidosis patients vs. PBMCs from healthy volunteers (IFN-γ: 207.2 pg/mL vs. 3.86 pg/mL, p = 0.0018; TNF-α: 2375 pg/mL vs. 42.82 pg/mL, p = 0.0003). Through proteomic approaches we then identified 74 sarcoidosis tissue-specific proteins. Of these, 3 proteins (vimentin, tubulin and alpha-actinin-4) were identified using both 1D-SDS-PAGE and 2D-DIGE. Data are available via ProteomeXchange with identifier PXD005150. Increased cytokine secretion was subsequently observed with vimentin stimulation of sarcoidosis PBMCs vs. tuberculosis PBMCs (IFN-γ: 396.6 pg/mL vs 0.1 pg/mL, p = 0.0009; TNF-α: 1139 pg/mL vs 0.1 pg/mL, p<0.0001). This finding was also observed in vimentin stimulation of sarcoidosis PBMCs compared to PBMCs from healthy controls (IFN-γ: 396.6 pg/mL vs. 0.1 pg/mL, p = 0.014; TNF-α: 1139 pg/mL vs 42.29 pg/mL, p = 0.027). No difference was found in cytokine secretion between sarcoidosis and control PBMCs when stimulated with either tubulin or alpha-actinin-4.

Conclusions

Stimulation with both Kveim reagent and vimentin induces a specific pro-inflammatory cytokine secretion from sarcoidosis PBMCs. Further investigation of cellular immune responses to Kveim-specific proteins may identify novel biomarkers to assist the diagnosis of sarcoidosis.

The Serum Expression of Selected miRNAs in Pulmonary Sarcoidosis with/without Löfgren's Syndrome

Purpose. Pulmonary sarcoidosis is associated with dysregulated expression of intracellular miRNAs. There is however only little information on extracellular miRNAs and their association with the disease course in sarcoidosis. We therefore assessed serum miRNAs in sarcoidosis classified according to the presence of Löfgren's syndrome (LS) as a hallmark of good prognosis in contrast to more advanced disease course. Methods. RT-PCR was used to assess 35 miRNAs in 13 healthy controls and 24 sarcoidosis patients (12 with X-ray (CXR) stage ≤ 1 and LS and 12 with insidious onset and CXR stage ≥ 3). Results. Compared to controls, we consistently observed dysregulated expressions of miR-146, miR-16, miR-425-5p, and miR-93-5p in both sarcoidosis groups irrespective of disease course. Specifically, patients without LS had dysregulated expressions of miR-150-5p, miR-1, and miR-212 compared to controls. Patients with LS had dysregulated expressions of miR-21-5p and miR-340-5p compared to controls. Bioinformatics predicted consistently "Pathways in cancer" to be modulated by both altered profiles in patients with/without LS. Three miRNAs (miR-21-5p, miR-340-5p, and miR-212-3p) differed between our patients with LS and those without LS; their cumulative effect may modulate "TGF-β signalling pathway." Conclusions. Further study should focus on possible applications of serum miRNAs for diagnostics follow-up and for prognosis.