Dual Analysis for Mycobacteria and Propionibacteria in Sarcoidosis BAL

Abstract

Purpose Sarcoidosis is a non-caseating granulomatous disease for which a role for infectious antigens continues to strengthen. Recent studies have reported molecular evidence of mycobacteria or propionibacteria. We assessed for immune responses against mycobacterial and propionibacterial antigens in sarcoidosis bronchoalveolar lavage (BAL) using flow cytometry, and localized signals consistent with microbial antigens with sarcoidosis specimens, using matrix-assisted laser desorption ionization imaging mass spectrometry (MALDI-IMS). Methods BAL cells from 27 sarcoidosis, 14 PPD- controls, and 9 subjects with nontuberculosis mycobacterial (NTM) infections were analyzed for production of IFN-γ after stimulation with mycobacterial ESAT-6 and Propionibacterium acnes proteins. To complement the immunological data, MALDI-IMS was performed to localize ESAT-6 and Propionibacterium acnes signals within sarcoidosis and control specimens. Results CD4+ immunologic analysis for mycobacteria was positive in 17/27 sarcoidosis subjects, compared to 2/14 PPD-subjects, and 5/9 NTM subjects (p=00.008 and p=00.71 respectively, Fisher's exact test). There was no significant difference for recognition of P. acnes, which occurred only in sarcoidosis subjects that also recognized ESAT-6. Similar results were also observed for the CD8+ immunologic analysis. MALDI-IMS localized signals consistent with ESAT-6 only within sites of granulomatous inflammation, whereas P. acnes signals were distributed throughout the specimen. Conclusions MALDI-IMS localizes signals consistent with ESAT-6 to sarcoidosis granulomas, whereas no specific localization of P. acnes signals is detected. Immune responses against both mycobacterial and P. acnes are present within sarcoidosis BAL, but only mycobacterial signals are distinct from disease controls. These immunologic and molecular investigations support further investigation of the microbial community within sarcoidosis granulomas.

Blockade of the Programmed Death-1 Pathway Restores Sarcoidosis CD4+ T-Cell Proliferative Capacity

“…The lung is a unique environment with constant exposure to foreign antigens. Mycobacterial antigens or signals consistent with mycobacterial antigens have been localized to sarcoidosis granulomas (34,35) The distinction in local versus peripheral PD-1 expression could reflects distinction in microbial antigen load, which has been shown to affect immune function and drive PD-1 up-regulation (36). Thus, the observation of high spontaneous cytokine production and increased PD-1 expression likely reflects the consequences of the host immune system attempting to clear persistent, foreign antigen while minimizing organ destruction.…”

Interferon Gamma Release Assays Based on M. tuberculosis-specific Antigens in Sarcoidosis Patients

“…The same author in his subsequent paper reported that ESAT-6 induces the most frequent stimulation of Th1 immune response in these patients, as compared to katG, Ag85A, sodA and Hsp70 [19]. Recently, Oswald-Richter et al, using matrix-assisted laser desorption ionization imaging mass spectrometry localized signal consistent with antigen ESAT-6 in sarcoidosis granulomas [20].…”

Etiologies of Sarcoidosis

“…Dubaniewicz and colleagues identified mycobacterial heat shock proteins in lymph nodes from patients with sarcoidosis using immunohistochemistry [94]. Using a directed candidate approach, Drake and colleagues screened sarcoidosis tissue samples by mass spectrometry and detected a mass-tocharge (m/z) signal compatible with the mycobacterial protein, ESAT6 [95].…”