The Bak protein expression in germinal centers of hypertrophied adenoids in children

The aim of this study was to evaluate pro-apoptotic Bak expression in the germinal centers of adenoid in children on the assumption of the potential usefulness of Bak as adenoid function marker. The study involved 95 children undergoing adenoidectomy; divided into three age groups: aged up to 5 years (25 children), 5-10 years (54 children) and over 10 years (16 children). The analyzed material was adenoids removed on the ground of hypertrophy. Immunohistochemical analyses were carried out using goat polyclonal Bak antibodies (DAKO) directed against human Bak protein. The presence of Bak positive lymphocytes within germinal centers and Bak immunostaining were scored. The immunohistochemical staining showed the Bak positive lymphocytes mainly within the germinal centers of the lymphoid follicles. The Bak reactivity was also present in hyperplastic lymphoid tissue within the subepithelial B lymphocytes. We have not found statistically significant correlation between Bak expression and clinical status and change in Bak expression level according to age. The apoptotic presence within the germinal centers are the manifestation of which is Bak expression and its lack in the mantle zone, what we confirmed in our former study by describing Bcl-2 expression, seems to be a proper B cells maturation marker within lymphoid follicles. Our finding shows that these processes are not influenced by age and supports our thesis that adenoid involution is rather the effect of changes in the number of lymphoid follicles that changes in them.