Efficacy of mebendazole in the spontaneous NZBxNZWF1 animal model of systemic lupus erythematosus.

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease with a complex etiology involving both innate and adaptive immune dysregulation. Among several perturbed signaling pathways, decreased ERK activity in CD4⁺ T-cells has been linked to DNA hypomethylation and aberrant gene expression in SLE. Mebendazole (MBZ), an anti-helminthic drug with a well-established safety profile, has shown immunomodulatory effects in preclinical studies, including activation of the MEK/ERK pathway and inhibition of MAPK14 (p38), a known driver of inflammation. To evaluate the therapeutic potential of MBZ in SLE, we tested its efficacy in NZBxNZWF1 mice, a spontaneous and well-characterized SLE model. MBZ treatment resulted in reduced proteinuria, lower anti-dsDNA antibody levels, and diminished glomerular IgG deposition, both in preventive and therapeutic settings. Exploratory in vitro data suggest that MBZ may also influence ERK signaling in B cells, while the mechanistic basis of these effects remains to be clarified. Our findings demonstrate robust phenotypic improvements and support further investigation of MBZ as a repositioned candidate for SLE.