Erucic acid improves the progress of pregnancy complicated with systemic lupus erythematosus by inhibiting the effector function of CD8(+) T cells

Pathogenic CD8(+) T cells are pivotal contributors to the onset of systemic lupus erythematosus (SLE). Erucic acid (EA) has been proven to have anti‐inflammatory activity. However, the capacity of EA to regulate pathogenic CD8(+) T cells in the context of pregnancy complicated with SLE (pSLE) remains unclear. In our investigation, we observed augmented CD8(+) T cell effector function juxtaposed with diminished EA levels in pSLE patients relative to healthy pregnant controls. Significantly, plasma EA levels exhibited a negative correlation with the severity of pSLE‐associated complications. In blood from patients with pSLE, EA inhibited the effector function of CD8(+) T cells, concurrently dampening the maintenance of stem cell‐like memory CD8(+) T cells. Mechanistically, EA orchestrated the inhibition of CD8(+) T cell effector function by impeding signal transducer and activator of transcription 3 phosphorylation and promoting ferroptosis. Moreover, EA supplementation in pregnant MRL/lpr mice manifested as the attenuation of uterine CD8(+) T cell effector function, culminating in the mitigation of placental pathological damage. Our findings uncover the immune response modulatory effects of EA upon pathogenic CD8(+) cells, thereby unveiling new perspectives for therapeutic strategies targeting pSLE patients.