Sarcoidosis Th17 cells are ESAT-6 antigen specific but demonstrate reduced IFN-γ expression.

RATIONALE: Sarcoidosis is a granulomatous disease of unknown etiology. Many patients with sarcoidosis demonstrate antigen-specific immunity to mycobacterial virulence factors. Th-17 cells are crucial to the immune response in granulomatous inflammation, and have recently been shown to be present in greater numbers in the peripheral blood and bronchoalveolar lavage (BAL) fluid (BALF) of sarcoidosis patients than healthy controls. It is unclear whether Th-17 cells in sarcoidosis are specific for mycobacterial antigens, or whether they have similar functionality to control Th-17 cells. METHODS: Flow cytometry was used to determine the numbers of Th-17 cells present in the peripheral blood and BALF of patients with sarcoidosis, the percentage of Th-17 cells that were specific to the mycobacterial virulence factor ESAT-6, and as well as to assess IFN-γ expression in Th-17 cells following polyclonal stimulation. RESULTS: Patients with sarcoidosis had greater numbers of Th-17 cells in the peripheral blood and BALF than controls and produced significantly more extracellular IL-17A (p = 0.03 and p = 0.02, respectively). ESAT-6 specific Th-17 cells were present in both peripheral blood and BALF of sarcoidosis patients (p < 0.001 and p = 0.03, respectively). After polyclonal stimulation, Th-17 cells from sarcoidosis patients produced less IFN-γ than healthy controls. CONCLUSIONS: Patients with sarcoidosis have mycobacterial antigen-specific Th-17 cells peripherally and in sites of active sarcoidosis involvement. Despite the Th1 immunophenotype of sarcoidosis immunology, the Th-17 cells have reduced IFN-γ expression, compared to healthy controls. This reduction in immunity may contribute to sarcoidosis pathogenesis.

The WASOG Sarcoidosis Organ Assessment Instrument: An update of a previous clinical tool.

INTRODUCTION: A Case Control Etiology of Sarcoidosis Study (ACCESS) sarcoidosis organ assessment instrument has been used for more than a decade to establish uniform standards for the probability of sarcoidosis organ involvement. The ACCESS instrument has become increasingly outdated as new technologies have been developed. Furthermore, the ACCESS instrument failed to address all possible organs involved with sarcoidosis. For these reasons, the World Association of Sarcoidosis and Other Granulomatous Diseases (WASOG) developed a new sarcoidosis organ assessment instrument. METHODS: Clinical sarcoidosis experts assessed various clinical manifestations for the probability of sarcoidosis organ involvement. Two criteria were required to apply this assessment: 1) histologic evidence of granulomatous inflammation of unknown cause in an organ that was not being assessed; 2) the clinical manifestation being addressed required that alternative causes other than sarcoidosis had been reasonably excluded. Clinical manifestations were assessed as either: a) highly probable: likelihood of sarcoidosis causing this manifestation of at least 90%.; b) probable: likelihood of sarcoidosis causing this manifestation of between 50 and 90%; c) possible: likelihood of sarcoidosis causing this manifestation of less than 50%. The sarcoidosis experts voted on the likelihood of sarcoidosis causing each manifestation using Delphi study methodology where at least 70% agreement of the experts was needed for consensus. RESULTS: Various clinical manifestations were classified as highly probable, at least probable, possible, or indeterminate when no consensus could be reached. CONCLUSION: An instrument was developed by expert opinion that may be useful for the clinician and researcher in establishing criteria for sarcoidosis organ involvement.