Innate lymphoid cells in peripheral blood of patients with American Cutaneous Leishmaniasis

Innate lymphoid cells (ILCs) are classified by the expression of specific transcription factors: ILC1 depending on T-bet for IFN-γ production; ILC2 depending on GATA3 for IL-5 and IL-13; and ILC3 depending on ROR-γτ and AHR for IL-17 and IL-22. This study aimed to determine circulating ILCs in 23 patients with localized (LCL) = 7, mucocutaneous (MCL) = 10, intermediate (ICL) = 3 and diffuse (DCL) = 3 cutaneous leishmaniasis and 17 healthy controls from endemic area (EC) = 9 and non-endemic area (HC) = 8. Results evidenced a higher proportion of ILC1 in LCL than controls and MCL. ILC2 was higher in DCL compared with controls. ILC3 s were abundant in MCL and DCL concerning controls. A prevalence ratio was calculated to approach cell plasticity: in LCL, the ratio showed a prevalence of ILC1/ILC3 (plasticity 1), in contrast to DCL, and controls, where ILC2/ILC3 (plasticity 3) is prevalent. Also, MCL and ICL showed higher ILC1/ILC2 (plasticity 2). These results suggest that ILC1 and ILC3 in LCL are associated with disease control and regulation of inflammation, while MCL and ICL are related to immunopathology and uncontrolled inflammation. In DCL, ILC2 is associated with the tolerogenic state of these patients.