Understanding the Immunopathogenesis of Sarcoidosis through Gene Expression Profiling
Christopher Curtiss, George Christophi, Steve Landas. SUNY Upstate Medical University, Syracuse, NY; Washington University in St. Louis, St. Louis, MO
Background: Sarcoidosis is a multisystemic, granulomatous disease of unresolved pathogenesis with broad, variable clinical features. While several environmental agents have been proposed as potential disease triggers, the lack of a single proven etiologic agent suggests that the affected patients may mount an aberrant immune response to various environmental triggers, which result in sarcoidosis. The role of inflammatory cytokine pathways in sarcoidosis pathogenesis has also been suggested by the elevation of inflammatory cytokine profiles in previous studies.
Design: A retrospective review of archived pathology specimens and confirmation of diagnosis of sarcoid granulomas, infectious granulomas, suture granulomas, and normal (non-granulomatous) lung tissue was performed. Formalin-fixed paraffin-embedded (FFPE) tissue was used to isolate mRNA followed by gene-specific quantitative real time RT-PCR using a modified method that accounted for RNA fragmentation. The expression of several genes including cytokines, signaling modulators, chemokines, proteolytic and oxidative enzymes, and adhesion molecules were quantified.
Results: Forty total cases were analyzed and consisted of 13 sarcoid granulomas, 7 infectious granulomas, 8 suture granulomas, and 12 normal lung specimens.We successfully amplified expression of several genes and many of those genes were differentially regulated among sarcoid granulomas and normal lymph nodes or suture granulomas. These genes included the cytokines IFN-γ and IL-12, the chemokines IP-10 and RANTES, and inducible nitric oxide synthase while housekeeping genes like GAPDH and actin were expressed in similar amounts in all tissues.
Conclusions: Our study demonstrated that it is feasible to use FFPE specimens of granulomatous inflammation and normal tissue to assess gene expression via quantitative real time RT-PCR. Furthermore, preliminary results suggest that specific genes are differentially regulated in sarcoid granulomas, which might provide new molecular or immunohistopathologic diagnostic avenues.
Category: Special Category - Pan-genomic/Pan-proteomic approaches to Cancer
Monday, March 19, 2012 9:30 AM
Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 3, Monday Morning