Editorial: Novel Insights into the Immunology of Pulmonary Granulomatous Diseases.

Pulmonary granulomatous disease encompasses both infectious and non-infectious disease forms. Presently, the immunopathogenesis of granulomatous inflammation is incompletely understood. This issue of Frontiers in Immunology explores recent insights concerning the clinical and immunological aspects of pulmonary granulomatous disease. Sarcoidosis is a complex multi-system disease of unknown cause which can be related to a diverse collection of environmental signals. The review by Judson summarizes current knowledge of the immunopathogenesis of sarcoidosis as well as the nature of varied environmental and occupational exposures, which could cause or affect the disease. Many infectious agents have been implicated in the disease, especially mycobacterium tuberculosis, and the review summarizes evidence for sarcoid patient immune responsiveness to such agents. A different perspective on pulmonary tuberculosis, another granulomatous disease, is provided by Muefong and Sutherland in their review of neutrophil activities in this deadliest of infectious diseases in humans. The authors raise the possibility that neutrophils may play a more central role in tuberculosis pathogenesis than previously thought. They propose that some neutrophil-related inflammatory mediators as potential targets for developing novel tuberculosis therapies. Hena reviews the effects of race on sarcoidosis epidemiology. The author presents data that show that in the United States, black patients with sarcoidosis experience more severe pulmonary disease, more multiorgan involvement, and an overall worse prognosis. The author proposes that epidemiologic concepts can be used to modulate and even prevent sarcoidosis in black Americans at risk of life-threatening disease phenotypes. Kraaijvanger et al. address the problem of identifying useful biomarkers for sarcoidosis diagnosis and prognosis. As noted by the authors, sarcoidosis is a heterogeneous disease, making treatment decisions problematic. Exploration of signaling pathways in sarcoidosis such as JAK/STAT and mTOR may result in the discovery of more specific biomarkers that may be relevant to prognosis. The authors stress that there is an unmet need for more specific and more sensitive biomarkers in sarcoidosis care. Gerke focuses on the deficiencies of the current treatment options for sarcoidosis. Sarcoidosis treatment decisions are problematic because of the marked heterogeneity of the disease. Clinical evidence is sparse because the disease is relatively rare and few clinical trials have been performed. Goals of treatment are to protect organ function and to decrease symptoms, but most clinical