Original Article Molecular analysis of interleukin-25 exons 1 and 2 and its serum levels in Iranian patients with multiple sclerosis

Overexpression of Interleukin-17 (IL-17) family has been shown in a variety of autoimmune diseases. IL- 25 (IL-17E), as a member of this family of cytokines, induces the overexpression of IL-13 and impedes Th17/IL-17 responses. In the present study potential single nucleotide polymorphisms (SNP) of IL-25, its serum level in Multiple Sclerosis (MS) patients have been surveyed. Blood samples were obtained from 100 Relapsing-Remitting MS cases, and 100 healthy controls. Serum levels of IL-25 were measured by ELISA. IL-25 exons 1 and 2 were sequenced. IL-25 serum levels investigation showed significant association in cases compared to controls. Molecular analysis of IL-25 exons 1 and 2 depicted significant differences in polymorphisms of exon 2 between two groups of study. However, no significant differences were found in polymorphisms for IL-25 exon. These results demonstrate that serum levels of IL-25 are reduced in MS patients compared to controls. This is the first study in Iran that shows polymorphisms in IL-25 among MS patients. Considering the role of IL-25 in suppression of the effects of IL-17A and active phase of Experimental Autoimmune Encephalomyelitis (EAE) in vivo, this cytokine seems to have therapeutic potentials for autoimmune diseases like MS.