MUC5AC and otitis media with effusion: Histologically, OME may be regarded as a chronic inflammatory condition, in which either a host or environmental/socioeconomic stimulus induces an inflammatory reaction in the middle ear mucosa [54] with an overproduction of mucin and production of altered more viscous mucin types [29], which overwhelms the normal mucociliary clearance system of the middle ear, resulting in functional blockage of the ET and subsequent accumulation of a thick, mucin-rich middle ear effusion [53].