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 granulomatous disease primarily involving the lungs, lymph nodes and other organs that appears to be the result of an exuberant T cell and macrophage immunologic response to the continued presentation of a poorly degradable antigen. Numerous non-infective agents have been implicated based on epidemiologic basis but none have stood up to scrutiny. 1, 3, 5 The focus over the last two decades has been on infective agents that might trigger sarcoidosis, with the strongest suspects found in the mycobacteria family and the common commensal Propionibacterium acnes. And like classical tuberculosis where up to 90% of people infected with Mycobacterium tuberculosis remain in remission without treatment, 17 sarcoidosis also has a 65-80% spontaneous remission rate without treatment. 1 One may speculate that similar to tuberculosis, the immune system, after its initial response to a triggering microorganism, is successful in eradicating the agent and the immune response subsides. Then in the 20% or so with persistent and progressive sarcoidosis, the organism remains viable and perpetuates the destructive immune response.