Cellular phenotypes and immunity in acquired aural cholesteatoma

ABSTRACT

Middle ear cholesteatoma is characterized by the presence or a keratinizing squamous epithelium with proliferative features and associated with marked bone destruction. Aims of this study to detect the cellular phenotypes and their immunological functional state in aquired aural cholesteatoma. So, cellular membranous expression of CD4, CD8 and HLA-DR antigens on the infilterated mononuclear cells in cholesteatoma were studied through immunohistochemical method. Nine formalin-fixed cholesteatoma specimens were obtained from patients of chronic otitis media during their ear surgery. The patients' ages ranged between 11 to 43 years [mean age=22 yrs. and SD +/- 6.5] and they involved 15 males and 12 females. All patients had dry ears with no signs of bacterial infections for at least 2 weeks preoperatively. Also, three normal skin specimens from external auditory canals of these patients were taken as a control. All tissue specimens were subjected to Hematoxylin and Eosin staining and immunohistochemical [strept-avidin-peroxidase] method staining. The results showed CD4 positive [=T- helper or inducer] lymphocytes in 24 out of 27 specimens [88.8%] with subepithelial distribution and at the periphery of lymphoid follicles in 15 cases [55.5%].While, CD 8 positive [=T-suppressor or cytotxic] lymphocytes were seen only in 6 out of 27 specimens [22.2%] with diffuse distribution pattern. On the other hand, HLA-DR expression was observed in both cholesteatoma matrix and perimatrix cellular components indicating their immunocompetent activity. Keratinocytes of cholesteatoma matrix were HLA-DR positive in 18 specimens [66.6%] while, "epidermal Langerhans" cells were positive in 12 specimens [44.4%]. In the perimatrix of all specimens, infilterated lymphocytes and macrophages were positive for HLA-DR expression. Also, [either intact or degranulated mast cells] were demonstrated in all specimens scattered in the cholesteatoma perimatrix. Active T-helper cells are directly correlated to the expression HLA-DR has a certain playing. Role in epithelial proliferation and participating in bone resorption rather than cytotoxic T-lymphocytes. Also, activated keratinocytes and Langerhans' cells and sensitized mast cells contribute to the biologic features of cholesteatoma