Molecular profiling and gene expression analysis in cutaneous sarcoidosis: the role of interleukin-12, interleukin-23, and the T-helper 17 pathway

Abstract

Background: Cutaneous sarcoidosis (CS) skin provides relatively noninvasive access to granulomatous sarcoidosis tissue.

Objective: We sought to explore the role of the T-helper (Th)1 and Th17 pathways in sarcoidosis.

Methods: We used molecular profiling and gene expression analysis to analyze the Th1 and Th17 pathways and other immune-mediated pathways in CS. Molecular profiles were obtained from sarcoidosis skin lesions (lesional skin [LS]), unaffected skin from patients with CS (non-LS), and the skin of healthy control subjects. Whole blood was collected to compare the molecular profile of sarcoidosis skin lesions and whole blood.

Results: Twenty participants were enrolled: 15 with active CS and 5 healthy volunteers. Microarray analyses comparing non-LS and healthy volunteer skin with LS showed several thousand genes differentially expressed (≥2-fold change false discovery rate, P < .01). Targeted selections of genes associated with Th1 and Th17 phenotypes showed a strong Th1 profile of sarcoidosis and expression of interleukin (IL)-23 and IL-23R with limited expression of other Th17 pathway genes. IL-21 and signal transducer and activator of transcription 3 (STAT3) were also dysregulated in skin and whole blood, providing additional evidence for involvement of the IL-12 pathway and potential activation of the Th17 pathway.

Limitations: Measurements were made at a single point in time and may not identify mechanisms that may be identified in patients followed up longitudinally.

Conclusion: These findings provide novel insight into the dysregulated pathways that may be involved in the pathogenesis of sarcoidosis.