ACC EPT

Distribution of dipeptidyl peptidase IV in chronic tonsillitis In the pathogenesis of recurrent tonsillitis (RT) and tonsillar hypertrophy (TH) different immunological mechanisms are involved. Dipeptidyl peptidase IV (DPP IV) and aminopeptidase N (APN) participate in the regulation of the immune response during infla-mmation. In this study the localization of DPP IV and enzymatic activity of DPP IV and APN were investigated in 32 patients, 13 with RT and there were 19 with TH, who underwent tonsillectomy. The localization of DPP IV in tonsils was studied using histochemical and immunohistochemical methods. The enzymatic activity of DPP IV and APN in tonsillar lymphocytes and the patient's serum was determined kinetically at 37°C using Gly-Pro-p-nitroanilide (for DPP IV) and Ala-p-nitroanilide (for APN) as chromogenic substrate. In both RT and TH, the localization of DPP IV was found mainly in extrafollicular areas of tonsillar tissue corresponding to the T cells distribution. A significantly higher (p < 0.001) serum DPP IV and APN activities have been found in patients with TH compared to those with RT. The correlation of DPP IV activities in serum and tonsillar lymphocytes was also found in TH (r