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Noncoding RNAs (ncRNAs) are coded by 98% of human genomic DNA. They are grouped into two major classes according to length: small ncRNAs and long ncRNAs. They regulate genome organization, stability, and physiological processes that maintain cellular homeostasis. Recently, great interest has emerged in ncRNAs because of their significant roles in the development of inflammatory diseases, including sarcoidosis. Some have been introduced as novel markers for disease activity, such as increased levels of microRNA-34a in peripheral blood mononuclear cells of patients with sarcoidosis, re-emphasizing the inflammatory component in sarcoidosis. They are also important factors in the outcome of sarcoidosis. Dysregulation of microRNA-let7f leads to overexpression of profibrotic factors and could be related to the pathogenesis of pulmonary fibrosis in patients with sarcoidosis, owing to their stimulatory effect on collagen expression and deposition. However, many unanswered questions remain about the association of ncRNAs and sarcoidosis. By understanding the functions of ncRNAs in T-helper cell type 1 and T-helper cell type 17, we may uncover the mechanism of action of those cells in sarcoidosis. Further translational research is needed to define the RNA gene fingerprint of different sarcoidosis stages.

Sarcoidosis is a systemic granulomatous disorder of unidentified etiology, with a heterogeneous clinical presentation. It is characterized by a reduced delayed-type hypersensitivity to tuberculin and common antigens. The balance between Th1, Th17 and Regulatory T(Treg) cells controls T-cell proliferation and activation.The Th17/Treg ratio in the peripheral blood and bronchoalveolar lavage fluidis increased in patients with active sarcoidosis. Amplified IL-17A expression in granulomas and the presence of IL-17A+, IL-17A+IL-4+ and IL-17A+IFN-γ+ memory T helper cells in the circulation and BAL indicate Th17 cell involvement in granuloma induction and/or maintenance in sarcoidosis. Sarcoidosis should therefore be considered as a Th1/Th17 multisystem disorder and anti-IL-17/Th17 approaches that control and reduce IL-17Amay be an option, therefore, for the treatment of sarcoidosis.Here we provide a short overview as to the role of Th17 cells as critical cells in the pathogenesis of sarcoidosis.

The immunopathology of sarcoidosis remains elusive despite years of research into this multiorgan disease.However, recent studies have provided new insights into the genetics and immune components involved in the clinical manifestation of the disease. Granulomatous inflammation is due to the host immune response to a persistent poorly degradable unknown antigen.Mycobacterium tuberculosis (MTB) is the major disease driver in many patients. The immune mechanisms that cause this disease start with the antigenic stimulus, followed by T-cell, macrophage and dendritic cell activation via a classic MHC II-mediated pathway. In addition, the profile of immune mediators reported in sarcoidosis indicates that the inflammasome pathway plays a critical role in disease pathogenesis. Increased understanding of the signal transductions pathways involved in the induction of inflammatory processes in sarcoidosis could give rise to new therapeutic approaches in future.

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Background: The neutrophil-to-lymphocyte ratio (NLR) has emerged as a new marker of inflammation associated with the severity of several respiratory and cardiac diseases. Materials and Methods: We investigated whether the degree of systemic inflammation in sarcoidosis patients as measured by the NLR is associated with pulmonary hypertension (PH). Results: A NLR > 3.5 occurred with a significantly higher frequency in sarcoidosis patients with PH (50% vs. 24%, P=0.016) yielding a sensitivity of 50%, specificity of 78%, positive predictive value (PPV) of 41.9% and negative predictive value (NPV) of 81.4% and remained independently associated with PH in multivariate analysis (OR: 3.254, 95% CI: 1.094- 9.678, P=0.034). Conclusion: We conclude that level of inflammation in sarcoidosis patients may be associated with the development of PH. Owing to the relatively good specificity and NPV, NLR may be a good negative test, which is a simple, inexpensive and widely available in office-based setting to predict the risk of PH in sarcoidosis patients. [ABSTRACT FROM AUTHOR]

The authors focus on epigenetic similarities between obstructive lung diseases (COPD), severe asthma, and treatment unresponsive sarcoidosis. They mention evidence suggesting that epigenetic mechanisms are involved in inflammation and immune cell function control in cancer and reflects on diseases associated with mesenchymal and epithelial cell remodeling within the alveoli and airways. They comment on the association of acetylated histone marks deposited by histone acetyltransferases with enhanced immune and inflammatory gene expression.

Sarcoidosis is a granulomatous inflammatory disease that is induced by unknown antigen(s) in a genetically susceptible host. Although the direct link between Mycobacterium tuberculosis (MTB) infection and sarcoidosis can be excluded on the basis of current knowledge, non-infectious mechanisms may explain the causative role of mycobacterial antigens. Ever since sarcoidosis was first described, its relationship with tuberculosis (TB) has been under-investigated. Whereas some researchers consider sarcoidosis and TB as two examples of the same disease process, others have rejected mycobacteria as playing any causative role in sarcoidosis. Whether they are linked causally or not, clinical evidence makes a differential diagnosis between the two conditions very challenging, particularly in countries with high burden of TB. The present study analyzes the relationship between sarcoidosis and TB and its implications in clinical practice. The coincidence of TB and sarcoidosis and the higher incidence of mycobacterial DNA in biological samples of sarcoid patients have been reported by many authors. In addition, new evidence of a similarity in MTB phenotype in sarcoidosis is provided. Overall, these observations suggest that TB and sarcoidosis may not only share the same etiology, but may even be different aspects of one disease. [ABSTRACT FROM AUTHOR]

Aims and objectives: Sarcoidosis and tuberculosis (TB) are two granulomatous inflammatory diseases with several common symptoms. The aim of the present study was to compare the serum levels of biomarkers including interleukin-4 (IL-4) and IL-13, calcium (Ca), hemoglobin, sedimentation rate, and lymphocyte-to-neutrophil ratio between patients with pulmonary TB, patients with sarcoidosis, and control group. Methods: This case–control study was performed on patients referred to the Masih Daneshvari Hospital, Tehran, from April 2017 to 2018. In this study, 24 newly diagnosed patients with active pulmonary TB, 34 patients with pulmonary sarcoidosis, and 30 healthy individuals as the control group were enrolled. Demographic data, erythrocyte sedimentation rate (ESR), the ratio of neutrophil-to-lymphocyte (NLR), serum Ca level, hemoglobin (Hb), and IL-4 and IL-13 were compared between the study groups. Receiver operating characteristic (ROC) curve analysis, sensitivity, and specificity were also calculated using SPSS 16.0 software. Results: The mean age was 47.71 ± 10.88 and 55.25 ± 21.58 years in the sarcoidosis and TB. The mean ESR in sarcoidosis patients was 21.45 ± 13.37 mm/h and 41.4 ± 17 mm/h in the TB group. The percentage of peripheral blood lymphocytes in sarcoidosis and TB patients was 28.02 ± 12.20 and 21.41 ± 12.49, respectively, which was significantly higher among patients with sarcoidosis. NLR was also 2.4 ± 1.6 and 4.4 ± 2.9 in sarcoidosis and TB patients, respectively, which showed a significant difference among the groups. Regarding the evaluation of the level of IL-4 and IL-13 in patients, it is worth noting that IL-4 in patients with sarcoidosis was 90 pg/ml compared to 20 pg/ml for TB patients (P < 0.001). There was no significant difference in the levels of IL-13 in the TB and control groups, which varied between 20 and 80 pg/ml (P = 0.35). However, its value was significantly higher in patients with sarcoidosis (P = 0.01) than in the healthy control group and TB (P = 0.01). The ROC curves showed that the diagnostic cutoff of ESR level, Ca, NLR, and Hb could be valuable due to the area under the curves. The cutpoint of 34 mm/h for ESR had a sensitivity of 86% as well as 80% specificity to distinguish TB from the sarcoidosis. Conclusions: Serum levels of the biomarkers indicated a stronger immunological background in sarcoidosis using NLR, Ca, ESR, and Hb. [ABSTRACT FROM AUTHOR]

Tuberculosis (TB) is a disease caused by Mycobacterium tuberculosis . Despite the availability of novel therapeutic approaches, TB is considered as one of the leading causes of death due to infectious diseases worldwide. Alveolar macrophages are the first line of defense against M. tuberculosis ; they ingest and sequester the bacilli within granulomatous structures. Control and resolution of the infection requires activated T lymphocytes as well as Th1 cytokines. There are two forms of TB: active TB and latent TB. Latent TB is a state in which M. tuberculosis survives in the body without causing overt signs and symptoms. People with latent TB are noncontagious. However, M. tuberculosis can become active in the body, multiply, and cause overt TB. Sarcoidosis, on the other hand, is an autoimmune disease of unknown etiology which can affect multiple systems of the body. Nonspecific constitutional symptoms, such as fever, fatigue, malaise, and weight loss, are present in approximately one-third of patients. Chest X-ray usually shows hilar and mediastinal lymphadenopathy. Although the lungs are the most common sites of inflammation, sarcoidosis can also involve other organs, such as the eyes (intraocular and adnexal), skin, lymph nodes, salivary glands, heart, spleen, liver, and the nervous system. Recent investigations have provided further insights into the genetic basis of sarcoidosis and the way genotype determines the clinical presentation and phenotype of patients. Histopathologic features are usually insufficient for diagnosis of sarcoidosis. Diagnosis of sarcoidosis in endemic areas for TB can become a great challenge. Both TB and sarcoidosis are granulomatous diseases; TB is characterized by caseating granulomas, whereas sarcoidosis is characterized by noncaseating granulomas. New cases of sarcoidosis are increasingly being diagnosed in areas endemic for TB due to increased orientation of physicians and availability of diagnostic modalities. However, it is often difficult to differentiate sarcoidosis from TB, especially when caseous necrosis is not seen and acid-fast staining is negative in the biopsy specimen of patient with TB. Granulomatous inflammation in sarcoidosis is believed to be caused by the presence of a persistent poorly degradable unknown antigen in combination with a nonresolving host response. M. tuberculosis has been extensively studied as a possible cause of sarcoidosis. Results suggest that granulomas form in the lungs as a result of the immune response to inhaled M. tuberculosis and serve as the central site of host–pathogen interaction during M. tuberculosis infection. M. tuberculosis DNA detection in sarcoidosis samples by traditional polymerase chain reaction (PCR) has been used for the pathological study of sarcoidosis; however, it is likely that real time quantitative PCR analysis of specific mRNAs and microRNAs will be necessary as a sensitive, precise, and rapid diagnostic test for detecting trace of TB in Sarcoidosis. In conclusion, diagnosis of sarcoidosis in areas with a high burden of TB poses a significant challenge. Improved diagnostic tests including genetic tests can improve our knowledge and help in distinguishing these two diseases. [ABSTRACT FROM AUTHOR]