ELISA was done for the assessment of IL-17A and 1L-17F, IL-22, IL-23A, IL6, IFN-gamma, and TGF-beta. Both type 1 and type 2 reactions are associated with a significant increase of IL17-A levels (mean in RR 219.8 ± 28.07 pg/ml, mean in ENL 650 ± 195.2 pg/ml) compared to matching stable forms of leprosy (mean in BT 101.9 ± 2.6 pg/ml, mean in LL 45.5 ± 22.7 pg/ml). This evidence concerns the gene IL17A and leprosy.