In summary, UbMPO can induce the reactivation of Th1 and Th17 cells, producing IFNγ and IL-17A; enhanced proliferation in SLE patients, as well as dampened activation and proliferation in healthy donors T cells, highlighting the presence of changes in the intrinsic dynamics of MPO when conjugated with ubiquitin. Here, IFNG is linked to systemic lupus erythematosus.