Although several studies have evaluated the association between the rs12979860 and rs8099917 polymorphisms of the IL-28B gene and the diseases related to the HTLV-1, the results have been contradictory, but this is because that the information is limited; some reports suggest a significant association with the development of HAM/TSP or ATL, while others have not found statistically relevant differences between the genotypes, the reason for this may be due to the type of population studied, besides depending on their genetic and immunological profile [6,13]. The gene discussed is IFNL3; the disease is tropical spastic paraparesis.