Likewise, functional impairments in GrB-producing Breg cells have also been found in patients with rheumatoid arthritis (RA) and SLE, which can be reversed after clinical remission.19 20 Rabani et al35 also found a reduced proportion of GrB-producing Breg cells in patients with SLE, which may promote the development of lupus nephritis. Here, GZMB is linked to lupus nephritis.