Mucosa-Associated Lymphoid Tissue in Middle Ear and Eustachian Tube

Abstract

The presence of mucosa-associated lymphoid tissue (MALT) was investigated histopathologically in every 20th section from 99 vertically cut, celloidin-embedded temporal bone-eustachian tube (ET) specimens. Among specimens from infants and children between 1 month and 7 years of age, MALT was found in 22 of 44 (50%). However, in 26 adults over 18 years of age, MALT was found in only 2 specimens (7.7%), a significantly lower incidence than that in infants and children. Moreover, MALT did not appear in any of the 21 neonates under the age of 1 month. All 99 specimens were classified into 2 groups: 41 specimens with otitis media (OM) and 58 specimens without OM. The presence of MALT was significantly higher in specimens with OM (43.9%) than in specimens without OM (13.8%). Mucosa-associated lymphoid tissue was found in the ET, middle ear, and mastoid process in 18 specimens (43.9%). 5 specimens (12.2%), and 1 specimen (2.4%) with OM, respectively, and in 8 (13.8%), 0, and 0 specimens without OM. In regard to the distribution of MALT, it occurred more frequently in the pharyngeal half of the cartilaginous portion of the ET than in the rest of the ET, middle ear, and mastoid; the presence was significantly greater in the inferior half of the cartilaginous portion of the ET than in the superior half. Inflammatory cell infiltration in the cartilaginous and bony portions of the ET was significantly greater in specimens with OM than in specimens without OM with no MALT. However, even in some specimens without OM, inflammatory cells were found in the ET, particularly in the pharyngeal half of the cartilaginous portion of the ET. These findings suggest that MALT has a close relationship to OM and that it may be a local response to repeated infection.

Cytokine Expression in Experimental Chronic Otitis Media With Effusion in Mice

“…In addition, mononuclear cell infiltration was found in the ET of patients with OME, particularly in the pharyngeal half of the cartilaginous portion of the ET, and was increased by repeated infection. 8 These pathological findings in humans are similar to those observed in our endotoxin-treated mice, suggesting that inflammatory changes in the middle ear mucosa affected by chronic OME might involve inflammatory factors such as endotoxin.…”

“…In a human study, Kitajiri et al 7 showed the histopathological appearance of OME in infants to be characterized by the formation of pseudostratified, cuboidal, or cylindrical epithelium in the middle ear mucosa. In addition, mononuclear cell infiltration was found in the ET of patients with OME, particularly in the pharyngeal half of the cartilaginous portion of the ET, and was increased by repeated infection 8 . These pathological findings in humans are similar to those observed in our endotoxin‐treated mice, suggesting that inflammatory changes in the middle ear mucosa affected by chronic OME might involve inflammatory factors such as endotoxin.…”

Gene expression profiles of early pneumococcal otitis media in the rat

“…Arrow, activation; oval arrow, inhibition; dashed line, indirect action. important for development of peripheral lymphoid tissue [50], thus it may be responsible for the development of mucosa-associated lymphoid tissue that has recently been observed in sections of temporal bones in human cadavers with history of otitis media [51]. The multiple roles of Id-2 make it a promising avenue for future work.…”

MALT und Epithel der Mittelohrschleimhaut. Morphologische Untersuchung

“…Es spielt hier eine entscheidende Rolle bei der Abwehr akuter Infektionen und ist insgesamt als ein wichtiger Teil der Immunabwehr zu werten. Eine Studie von Kamimura et al [11,12] und eigene Untersuchungen an menschlichen Felsenbeinen ergaben, dass bei Neugeborenen MALT in der Schleimhaut des Mittelohres und der Tube nicht vorkommt, w ä hrend es sich in der Gruppe der Kleinkinder im Alter von einem Monat bis zu 3 Jahren sehr h ä ufi g -in fast 70 % der F ä lle -nachweisen l ä sst. Beim Erwachsenen ist es selten; eigene Untersuchungen wiesen MALT in der Altersgruppe ab 18 Jahren nur in rund 17 % der F ä lle in der knorpeligen Tube nach.…”

“…Es kommt also in einer Altersgruppe am h ä ufi gsten vor, in der sich der menschliche Organismus oft mit Infektionen des oberen Respirationstraktes auseinandersetzen muss [13 -15] . Zudem wurde MALT bei Personen mit positiver Anamnese einer Otitis media sowohl in eigenen Untersuchungen als auch in der Studie von Kamimura [12] [11,12,16] hinsichtlich seines Vorkommens in verschiedenen Altersstufen und bei entz ü ndlichen Erkrankungen der Mittelohrschleimhaut legen nahe, dass es sich hierbei nicht um eine angeborene Struktur handelt, sondern dass diese sich erst in der Auseinandersetzung mit entz ü ndlichen Reizen bildet. Sie ist also als eine Umbildung der Schleimhaut zu werten, die immer wieder Entz ü ndungen abwehren muss und sich dementsprechend in ihrer Struktur ä ndert.…”