The Laryngoscope Lippincott Williams & Wilkins, Inc. © 2006 The American Laryngological, Rhinological and Otological Society, Inc. Up-Regulation of MUC5AC and MUC5B Mucin Genes in Nasopharyngeal Respiratory Mucosa and Selective Up- Regulation of MUC5B in Middle Ear in Pediatric Otitis Media with Effusion Mohamed Nasser Elsheikh, MD; Magdy ElSayed Mahfouz, PhD Objectives: Mucins are the major component re- sponsible for the gel-like properties of mucus secre- tion. Currently, little is known about the regulation of mucins in otitis media with effusion (OME). We inves- tigated the expression of MUC5AC and MUC5B mucin gene messenger (m)RNAs in middle ear effusions as well as in tissue biopsies of the respiratory mucosa of the nasopharynx by means of reverse-transcription polymerase chain reaction (RT-PCR). Study Design: A prospective, controlled, clinical trial. Methods: The study group consisted of 25 children with a diagnosis of OME who were to undergo bilateral ventilation tube insertion with adenoidectomy. A sample of mid- dle ear effusion (n  50) as well as tissue biopsy from nasopharyngeal respiratory mucosa (n  25) were ob- tained from each patient. For the nasopharyngeal mucosal biopsies, two control groups were made up from 30 children with healthy ears who underwent tonsillectomy  adenoidectomy operation; control A, 15 children with adenoid hypertrophy, and control B, 15 children with healthy nasopharynx. RNAs were extracted from effusion and tissue samples, and semi- quantitative RT-PCR was performed for MUC5AC and MUC5B to investigate their expression. Results: In the middle ear effusions, MUC5B mRNA expression was detected in 48 (96%), whereas MUC5AC mRNA was detected in 8 (16%). On semiquantitative analysis, MUC5AC/glyceraldehyde 3-phosphate dehydroge- nase (GAPDH) and MUC5B/GAPDH mRNA ratios in the study group were significantly increased com- pared with those in both control groups (P < .05). Conclusions: The results suggest that the middle ear has a unique mucin gene expression pattern when compared with that of the nasopharynx. Up- regulation of MUC5B in the ear may play an im- portant role in the pathogenesis of middle ear effusions. Key Words: Otitis media with effusion, mucin genes, MUC5AC, MUC5B, RT-PCR. Laryngoscope, 116:365–369, 2006 INTRODUCTION Otitis media with effusion (OME) is one of the fre- quently encountered diseases in children. It leads to a conductive type hearing loss (HL) with its negative impact on acquisition and development of speech and success in school of young children. The economic burden of the medications and surgical procedures used for the treat- ment of OME is significant. 1 The causes of OME have been the source of much controversy, and numerous studies have been generated in an effort to clarify the issue. However, the onset and longevity of the disease can be traced in most cases to some nasopharyngeal or upper respiratory pathologic conditions. 2 Although OME is strongly related to adenoid hyper- trophy, it appears that adenoids do not play an obstructive role at the level of the eustachian tube (ET) opening into the nasopharynx (NP) and that their removal does not prompt immediate mucus clearance from the middle ear (ME). However, long-term follow-up has recorded that patients with OME recover better after adenoidectomy and ventilation tube insertion than without adenoidec- tomy. The reason is only partly known and may be ex- plained by the adenoids playing an infective role, with the infection ascending through the ET into the ME and lead- ing to OME. 3 In addition, the bacteria involved in OME have been shown to originate from the NP because they show a close genetic relatedness with their nasopharyn- geal counterparts. 4 Similarly, in atopic patients with OME, the allergic inflammation occurs on both sides of the ET, both in the ME and in the NP, supporting the concept From the Departments of Otolaryngology (M.N.E.) and Biological Sciences (M.E.M.), Tanta University, Egypt. Editor’s Note: This Manuscript was accepted for publication October 25, 2005. Send Correspondence to Dr. Mohamed Nasser Elsheikh, P.O. Box 34, Tanta, Egypt. E-mail: mnel_sheikh@hotmail.com DOI: 10.1097/01.MLG.0000195290.71090.A1 Laryngoscope 116: March 2006 Nasser Elsheikh and Mahfouz: Up-Regulation of MUC5AC and MUC5B 365