In this sense, the negative correlations detected between Il17 levels in the spleen vs the phenotypic parasitic markers used in this work, i.e. number of liver flukes detected in the bile duct, suggest a protective role of the IL-17 and Th17 response previously unappreciated in fascioliasis, but described in other helminthic infections in association with a Th2 response. This evidence concerns the gene IL17A and helminthiasis.