TP53 and systemic lupus erythematosus: In our study, tested by immunofluorescence staining, we observed that p53 and p21 were mainly localized in the nuclei of the BM-MSCs from SLE patients, whereas lower levels were found in the cytoplasm of the BM-MSCs from SLE patients than that of the normal control (Figures 3(a) and 3(d)).