MMP9 and Sjogren syndrome: In addition, expression of several genes known to be dysregulated in Sjögren's syndrome: CTSS, MHC-II, MMP9, Rab proteins (Rab3D, Rab27A, and Rab27B), IL12α, IFN-γ, TNF-α, and aquaporin 5 (Aq5), and the cholinergic muscarinic M3 receptor (M3R) were quantitatively measured using qPCR.