Clinical significance of plasma diamine oxidase activity in pediatric patients: influence of nutritional therapy and chemotherapy.

The aims of this study were to determine the normal values of plasma diamine oxidase (pDAO) activity in children and to examine the influence of several factors (nutritional management, dietary fiber, and chemotherapy) on pDAO activity. The activity of pDAO was measured in 138 healthy children with minor surgical conditions such as inguinal hernia or undescended testis. In order to define normal values patients were subdivided into 5 groups according to age. Next, changes in pDAO activity under different nutritional conditions were studied in 14 patients with adhesive ileus. The influence of chemotherapeutic drugs on pDAO activity was also studied in 19 neuroblastoma patients. I. The normal values of pDAO activity at year < 1, 1 < or = years < 3, 3 < or = years < 6.6 < or = years < 12, 12 < or = years were 6.65 +/- 1.75, 7.70 +/- 2.29, 6.53 +/- 1.68, 5.85 +/- 1.87, 5.06 +/- 1.84 units/l, respectively. II. The pDAO activities in patients with ileus were 4.73 +/- 1.02 (total parenteral nutrition), 6.84 +/- 1.18 (enteral, nutrition), 7.62 +/- 0.67 (soluble dietary fiber added enteral nutrition) and 8.82 +/- 1.26 units/l (oral feeding). The difference in pDAO activity at enteral or oral feeding vs. total parenteral nutrition was significant (p < .0001). III. The pDAO activity decreased significantly and remained low during the first 4 days after cyclophosphamide administration in neuroblastoma patients. The preadministration of dietary fiber inhibited the influence of cyclophosphamide. Plasma DAO activity was greatly influenced by nutritional management and administration of dietary fiber and/or cyclophosphamide. Plasma DAO activity may be a sensitive marker of intestinal function in children.