A Department of Error was published in The Lancet for the article Gao J, Li M, Sun M et al. entitled Efficacy and safety of allogeneic CD19 CAR NK-cell therapy in systemic lupus erythematosus: a case series in China. The article was published in volume 406 on pages 2968–79 in 2025. In Figure 3A, the data from the first graph was erroneously added to the second graph. Appendix 2 has also been fixed. These corrections were made to the online version as of 18 December 2025. The print version of the article is correct.