Introduction: The immunopathogenesis of multiple sclerosis (MS) is a main field of
research, together with the mechanism of action of most immune therapies in this disease, such as
interferon beta. Interleukin (IL)-17 is considered to play a central part in the initial immune cascade in
MS, though there are numerous interactions between other cytokines that might explain the
heterogeneity of disease evolution and treatment response.
Material and Methods: We tested the serum levels of IL-17A, IL-10 and transforming growth factor (TGF-β) using the
enzyme-linked immunosorbent assay method in three small groups of relapsing-remitting MS patients: 10 being naïve
without treatment, 10 patients receiving Avonex treatment early in the MS evolution (≤ one year from the MS onset) and
12 MS patients who received Avonex later in the disease evolution. The values were compared with those obtained from
32 healthy subjects using statistical analysis.
Results: In the naive multiple sclerosis group: IL-17A values were statistically higher than among healthy subjects; IL-
17A inversely correlated with MS duration; serum IL-17A negatively correlated with TGF-β. A direct correlation was
found between the serum titre of IL-17A and IL-10 in the early treated multiple sclerosis group; the titre of IL-17A was
significantly reduced compared with that from the late treated multiple sclerosis group.
Conclusion: The role in MS pathology of IL-17A, IL-10 and TGF-β is only partially elucidated. IL-17 plays an important
role in the inflammatory phase of relapsing-remitting MS and is diminished by Avonex mainly if this disease modifying
treatment is administered early in the evolution of MS.