MUC5AC and congenital rubella syndrome: Neutrophil elastase, a serine protease released from the neutrophils has been found to affect goblet cells proliferation and mucin overproduction in patients with CRS (101, 102), EMT is a phenomenon involved in tissue remodeling that can eventually result in the local pools of fibroblasts, abnormal extracellular matrix deposition and the formation of nasal polyps (9).