In experiments with rodents and PBMC isolated from SLE and HIV patients, HCQ attenuated Th17 differentiation, proliferation, and production of IL-17 while promoting the immunosuppressive effect of Tregs (Piconi et al., 2011; An et al., 2017; Yang et al., 2018; Kowatsch et al., 2023). The gene discussed is IL17A; the disease is systemic lupus erythematosus.