A plasma IL-17 concentration <1 pg/mL or if the IL-17 concentration was >1 pg/mL an IL-10 concentration of >0.8 pg/mL identified ATL with 78.5% sensitivity and 85% specificity whilst an IL-17 concentration of ≥ 1 pg/mL with an IL-10 concentration between 0.16 and 0.8 pg/mL identified HAM with 82.1% sensitivity and a specificity of 71.8%. The gene discussed is IL17A; the disease is tropical spastic paraparesis.