The expression of several mucins has been detected in OME. 53, 57 However, overproduction of only two mucins has been observed in otitis media; namely, the membrane-bound MUC4 53 and the secreted MUC5B. 53, 55, 58, 59 Another secreted mucin (MUC5AC) is always presented in effusions, but in varying amounts, 53, 55, 57, 60 and its levels maybe linked to levels of the pro-inflammatory cytokines TNF-a, IL-6 and IL-8, which can promote different levels of MUC5AC secretion. 61, 62 The initial step in the pathogenesis of OME is the inflammatory process in the middle ear mucosa. Bacteria, 63, 64 viruses, 65,66 allergic reactions 67,68 and even gastroesophageal reflux 69 Á 71 in tandem with predisposing factors such as eustachian tube dysfunction, 72 cleft palate 73 and obstructive adenoids 74 can stimulate the middle ear inflammation.