Molecular analysis of sarcoidosis lymph nodes for microorganisms: a case–control study with clinical correlates

Robinson, Lary A; Smith, Prudence; SenGupta, Dhruba J; Prentice, Jennifer L; Sandin, Ramon L

Sarcoidosis is a multisystem, granulomatous disease whose etiology is obscure and controversial. Nevertheless, the condition is relatively common with a significantly higher ageadjusted annual incidence in African-Americans (35.5 cases per 100,000) versus Caucasian-Americans (10.9 cases per 100,000). An estimated one million people in the U. S. have this disease. Based on the current U.S. population of 315,556,000, there will be approximately 38,605 new cases of sarcoidosis this year and just over 1000 (2.6%) will die of the illness. 1, 2 The fundamental pathologic abnormality in the disease is the formation of non-caseating epitheliod granulomas, which usually confine poorly soluble foreign material that simply cannot be removed by a single phagocytic cell. The key feature in sarcoidosis is activated CD4+ T cells which differentiate into type 1 helper T cells (Th1), secreting interleukin-2 and interferon-γ, augmenting macrophage TNF-α, and amplifying the local cellular immune response. 3, 4 This granulomatous inflammation interferes with local tissue homeostasis leading to organ impairment.