Clinical reviews in allergy & immunology
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The diagnosis of sarcoidosis, a systemic granulomatous disease, is based on a compatible clinical-radiological picture and the histological evidence of noncaseating granulomas. Other diseases mimicking sarcoidosis, mostly infections and other granulomatoses, have to be excluded. There is no single test for sarcoidosis, and the presence of granulomas alone does not establish the diagnosis. ⋯ Genetic testing, despite promising advances, has still not been included in routine care for sarcoidosis patients. The long-term prognosis of sarcoidosis depends on the different organ manifestations: Cardiac or central nervous involvement, together with respiratory complications, is critical. A multidisciplinary approach is necessary for comprehensive care of the sarcoidosis patient.
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Since sarcoidosis was first described more than a century ago, the etiologic determinants causing this disease remain uncertain. Studies suggest that genetic, host immunologic, and environmental factors interact together to cause sarcoidosis. Immunologic characteristics of sarcoidosis include non-caseating granulomas, enhanced local expression of T helper-1 (and often Th17) cytokines and chemokines, dysfunctional regulatory T-cell responses, dysregulated Toll-like receptor signaling, and oligoclonal expansion of CD4+ T cells consistent with chronic antigenic stimulation. ⋯ Despite these studies, there is no consensus on the nature of a microbial pathogenesis of sarcoidosis. Some groups postulate sarcoidosis is caused by an active viable replicating infection while other groups contend there is no clinical, pathologic, or microbiologic evidence for such a pathogenic mechanism. The authors posit a novel hypothesis that proposes that sarcoidosis is triggered by a hyperimmune Th1 response to pathogenic microbial and tissue antigens associated with the aberrant aggregation of serum amyloid A within granulomas, which promotes progressive chronic granulomatous inflammation in the absence of ongoing infection.
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Clin Rev Allergy Immunol · Aug 2015
ReviewThe Clinical Features of Sarcoidosis: A Comprehensive Review.
Sarcoidosis has innumerable clinical manifestations, as the disease may affect every body organ. Furthermore, the severity of sarcoidosis involvement may range from an asymptomatic state to a life-threatening condition. This manuscript reviews a wide variety of common and less common clinical characteristics of sarcoidosis. ⋯ Pulmonary fibrosis from sarcoidosis is usually slowly progressive but may be life-threatening because of the development of respiratory failure, pulmonary hypertension, or hemoptysis related to a mycetoma or bronchiectasis. Some manifestations of sarcoidosis are not organ-specific and probably are the result of a release of mediators from the sarcoid granuloma. Two such manifestations include small fiber neuropathy and fatigue syndromes, and they are observed in a large percentage of patients.