Activity of soluble aminopeptidase A and dipeptidyl peptidase IV and membrane-bound aminopeptidase B and pyroglutamyl peptidase I in adenoid hyperplasia, tonsillar hyperplasia and chronic tonsillitis

ObjectiveTo analyze soluble and membrane-bound peptidase activities in the tonsils and adenoids removed from patients with adenoid hyperplasia, tonsillar hyperplasia and chronic tonsillitis.MethodsA total of 48 tissue samples from patients undergoing adenoidectomy and tonsillectomy for adenoid hyperplasia, tonsillar hyperplasia or chronic tonsillitis were analyzed. The catalytic activity of a pool of peptidases in the soluble (dipeptidyl peptidase IV, aminopeptidase A, aminopeptidase N and cystinyl aminopeptidase) and membrane-bound (prolyl endopeptidase, aspartyl aminopeptidase, aminopeptidase B and pyroglutamyl peptidase I) fractions was measured fluorometrically.ResultsThe activity of membrane-bound aminopeptidase B was higher in cases of chronic tonsillitis and adenoid hyperplasia than in tonsillar hyperplasia, p = 0.004. Soluble dipeptidyl peptidase IV and membrane-bound pyroglutamyl peptidase I were found to be more active in tissues from male chronic tonsillitis tissues, p < 0.05, while membrane-bound aminopeptidase B activity was higher in tissues of females with tonsillar hyperplasia, p < 0.001. In the case of chronic tonsillitis, soluble aminopeptidase A was found to have a higher level of activity in tissues from children than those from adults, p = 0.005.ConclusionsOur results suggest a potential role of soluble aminopeptidase A, soluble dipeptidyl peptidase IV, membrane-bound aminopeptidase B and membrane-bound pyroglutamyl peptidase I in the pathobiology of adenoid hyperplasia, tonsillar hyperplasia and chronic tonsillitis that is differently regulated as a function of gender. These finfings may modify in the future the clinical approach to these diseases.