ABSTRACT
INTRODUCTION: Systemic lupus erythematosus (SLE) is a chronic autoimmune disease. Lupus nephritis (LN) is a common type of organ damage which occurs in SLE patients and is characterized by recurrent proteinuria. Activation of B lymphocytes can lead to refractory LN, which is an important pathogenic factor in SLE. B lymphocyte stimulator (BLyS) and A proliferation-inducing ligand (APRIL) are predominantly produced by myeloid cells (monocytes, dendritic cells, neutrophils, etc) to regulate B lymphocyte function. Telitacicept was the first dual-targeting biological drug which targeted both BLyS and APRIL. Telitacicept has passed a phase II clinical trial and has since been approved for the treatment of SLE. CASE PRESENTATION: We report a case of SLE confirmed by renal biopsy as proliferative lupus nephritis (PLN) with massive proteinuria, which was treated with telitacicept (European League Against Rheumatism / American College of Rheumatology 2019 standard). During the 19 months of follow-up, the patient's renal function was stable, massive proteinuria was relieved, and creatinine and blood pressure did not increase. CONCLUSIONS: During the 19 months of telitacicept treatment (160 mg once weekly), PLN reduced blood system damage and proteinuria without increasing the risk of infection.