Diseases of the digestive system such as gastroduodenal disorders (GDD) and hepatobiliary diseases (HBD) are fairly common among children. At the same time, intestinal parasites are widespread gastrointestinal tract infectious agents. We examined 108 children with GDD (n = 54) and HBD (n = 54) (mean age 11.8 ± 4.3 years) who were treated in a children's hospital. The following were performed: blood test for specific Ig to Ascaris lumbricoides, Toxocara canis; feces analysis for helminth eggs, Giardia cysts; and pinworm test. The serum level of interleukin-4 (Il-4) was measured in 97 of 108 children. overall parasitic co-infections were found in 60.2% of children: giardiasis in 30.6%, toxocariasis in 17.6%, ascariasis seropositivity in 13.9% and enterobiasis in 8.3% of cases. Parasitic infections (PIs) occurred in 72.2% of the HBD group and in 48.2% of the GDD group (P = 0.01). Among the PIs only ascariasis was found more often in the HBD group (22.2%) compared with the GDD group (5.6%) (P = 0.01). The mean age of children who were positive for PI (PI+) was 9.9 ± 4.6 years; while in the PI negative (PI-) group the mean age was 12.8 ± 3.3 years (P < 0.001). In GDD the Il-4 level in PI+ group was 9.3 ± 0.9 pg/ml in the versus 6.9 ± 1.8 pg/ml in the PI-group (P = 0.02). Children with HBD and PI had higher .8 pg/ml) compared to those without PI (7.5 ± 2.4 pg/ml) (P = 0.03). The differing impact on the course and immune response in children depending on co-infection with PIs indicates the need for additional testing for these infections. K e y w o r d s: children, parasitic infections, digestive diseases, interleukin-4.

Toxocariasis is common among children and causes digestive diseases. The aim of the work was to study the development of toxocariasis in children with digestive diseases. The serum levels of specific IgG to Toxocara canis and Ascaris, levels of IL-4 and TNF-α were determined in 63 children. In addition, tests for parasites and a retrospective survey in order to assess sanitation and hygiene practices were conducted. All children were divided into two groups: group I includes 19 (30.2%) patients seropositive for toxocariasis, and group II – 44 (69.8%) children without any parasites. The level of IL-4 was higher in group I (18.0 ± 6.4 pg/ml) than in group II (7.2 ± 2.0 pg/ml) (P < 0.001. While the level of TNF-α did not differ significantly between groups I (4.5 ± 2.1 pg/ml) and II (3.6 ± 1.1 pg/ml) (P > 0.05). A higher incidence of Toxocara was observed among rural residents (78.9%). Children with toxocariasis more often had soil-pica (42.1%), played with dogs (100%), and did not wash their hands (84.2%) compared to the group of uninfected children. It was noted that hygienic habits and place of living contribute to Toxocara canis infection. IL-4 levels were considerably higher in group I than in group II that can be accounted for the host immune response activation, at the same time, the levels of TNF-α did not differ. Children without toxocariasis had also increased levels of IL-4, which may be related to past helminthic infection. Keywords: children., digestive diseases, interleukin-4, toxocariasis, tumor necrosis factor - α