AIM:Intestinal parasitic diseases are commonly accompaniedwith diarrhoeal symptoms and allergic reactions.Eosinophiliaoccurs as a result of IL-5 synthesized from Th2 cells duringallergic reactions.IL-5 acts as a factor activating eosinophils.The aim of this study was to compare the IL-5 cytokinemeasurements in serum samples and cell cultures.Andalso to compare eosinophilia observed in helminth infectionsand protozoon infections accompanied with allergy.METHODS:Twenty-three patients who presented withdiarrhoeal symptoms and allergic complaints were testedpositive for intestinal parasites,as well as 21 controls withallergic complaints who did not have any intestinal parasiteswere included in this study.IL-5 production in in vitro cellcultures prepared by using phytohemaglutinin (PHA) tostimulate peripheral blood mononuclear cells (PBMC)obtained from the blood samples taken from these patientswere compared with the IL-5 level in serum.Furthermore,the IL-5 production in protozoon and helminth infectionswas also compared.Absolute eosinophil values in 1 mm~3of blood were calculated by means of peripheral smear inboth groups within the scope of the study.RESULTS:Parasites such as helminth detected in 15(65.2%) and protozoon in 8 (34.8%) of the patients wereincluded in this study.As regards the values of the sera inboth patients with parasite infection and controls,the IL-5production was found to be higher in the cell culturesupernatant (P<0.001 and P<0.05).When the IL-5 level ofthe patients with helminth parasites was compared withthat of those with protozoon,it was determined that theIL-5 level in serum was more significant in the patientswith protozoon than in those with helminth (P<0.05).Inthe study group,the patients were found to have parasites,the percentage of eosinophil was 7.0% compared to 6.5%in the control group.Thus,there was no significant differencebetween the eosinophil values (P>0.05).CONCLUSION:It was found that IL-5 cytokine levels inserum samples from the patients with helminth andprotozoon displayed more measurable values as comparedto the IL-5 levels after stimulation with mitogen.It is concludedthat IL-5 acts as a triggering factor in the toxiallergic complaints commonly seen in helminth and protozoon infections. AIM: Intestinal parasitic diseases are accompanied accompanied by diarrhea symptoms and allergic reactions. Eosinophilia activity as a result of IL-5 synthesized from Th2 cells duringallergic reactions. IL-5 acts as a factor activating activating eosinophils. AIM of this study was to compare the IL- 5 cytokine measurements in serum samples and cell cultures. Andalso to compare eosinophilia observed in helminth infections and protozoon infections accompanied with allergy. METHODS: Twenty-three patients who presented with diarrhea symptoms and allergic complaints were tested positive for intestinal parasites, as well as 21 controls withallergic who did not have any intestinal parasiteswere included in this study. IL-5 production in vitro cellcultures prepared by using phytohemaglutinin (PHA) tostimulate peripheral blood mononuclear cells (PBMC) obtained from the blood samples taken from these patientswere compared with the IL-5 level in serum.Furthermore, the IL-5 production in protozoon and helmi nthsuseswas also compared.Absolute eosinophil values ​​in 1 mm ~ 3of blood were calculated by means of peripheral smear inboth groups within the scope of the study .RESULTS: Parasites such as helminth detected in 15 (65.2%) and protozoon in 8 (34.8% ) of the patients wereincluded in this study. Aspects of values ​​of the sera inboth patients with parasite infection and controls, the IL-5 production was found to be higher in the cell cultures supernatant (P <0.001 and P <0.05) .When the IL -5 level of the patients with helminth parasites was compared with that of those with protozoon, it was determined that theIL-5 level in serum was more significant in the patients with protozoon than those with helminth (P <0.05). Inthe study group, the patients were found to have parasites, the percentage of eosinophil was 7.0% compared to 6.5% in the control group.Thus, there was no significant difference between the eosinophil values ​​(P> 0.05) .CONCLUSION: It was found that IL-5 cytokine levels inserum samples from the patients with helminth and prototozoon displayed more measurable values ​​as compared to the IL-5 levels after stimulation with mitogen. It is concluded that IL-5 acts as a triggering factor in the toxiallergic laws commonly seen in helminth and protozoon infections.