Systemic lupus erythematosus (SLE) is an autoimmune disease in which circulating immune complexes can cause different types of glomerulonephritis, according to immune deposits and to the type of glomerular cell injury. Proliferative lesions represent the most severe form of lupus nephritis (LN) and often lead to kidney failure and death. Mucosal-associated invariant T (MAIT) are a subset of innate-like T cells that recognize microbial-derived ligands from the riboflavin synthesis pathway. Now the inventors analyzed the phenotype and function of peripheral blood MAIT cells by flow cytometry in 26 patients with LN and in a control group of 16 healthy volunteers. The inventors found that MAIT cell frequencies are markedly reduced in blood of LN patients. More particularly, among LN patients, baseline MAIT cell frequency, Ki-67 expression evaluating proliferative activity and granzyme B production measuring cytotoxicity represent promising prognostic factors of renal response one year after induction therapy. In conclusion, the inventors showed that baseline frequency and cytotoxic profile of MAIT cells may represent a promising prognostic factor of renal remission one year after induction therapy.