T_H17 cells, interleukin‐17 and interferon‐ γ in patients and households contacts of leprosy with multibacillary and paucibacillary forms before and after the start of chemotherapy treatment

[[[ Background: ]]] Studies on the immunology of leprosy are fundamental to the understanding of the various forms of clinical manifestation of the disease. In some diseases, lymphocytes TH17 and one of its key cytokines, interleukin-17 has been shown to be essential in developing an effective immune response. In leprosy, involvement of lymphocyte TH17 and interleukin-17 remains understudied. [[[ Objectives: ]]] This study is the first investigation to examine the association between TH17 cells, interleukin-17 and interferon- γ in patients and households contacts of leprosy. [[[ Methods: ]]] To document the participation of TH17 cells and interleukin-17 in the immunology of leprosy, to observe the behavior of interferon-γ in relation to interleukin-17 and to verify the differences found between individuals paucibacillary, multibacillary and household contacts, we analyzed samples peripheral blood to identify TH-17 cells, interleukin-17 and IFN-γ; establishing relationships between all the groups. [[[ Results: ]]] There was a significant difference in the results found in the comparison between the paucibacillary and multibacillary groups of patients (P < 0.001), as well with the household contacts (P < 0.005). The polychemotherapeutic treatment modified the profile of immune response in multibacillary patients compared to what was observed before the start of treatment. [[[ Conclusion: ]]] The principal finding was that TH17 lymphocytes and interleukin-17 actively participating in the immune response of Hansen’s disease as well these cells can stimulate the cellular immunity.