Lupus TC mice possess an expanded population of HSPCs with enhanced self-renewal capacity. (A) The total number of nucleated BM cells from lupus TC and age-matched B6 mice were enumerated. Each symbol shows data from 1 mouse. (B) Lineage-negative BM cells from lupus TC and B6 control mice are displayed by c-Kit and Sca-1 staining in the contour plots. The LSK population in the rectangular gate is shown with percentages ± SD. The absolute number of LSK cells (middle panel) and long-term HSCs (right panel) in the BM from each mouse is shown by each dot. ***P < .001; **P < .01. (C) Irradiated B6.SJL mice were engrafted with 2 × 10⁶ BM cells of lupus TC or B6 mice, and analyzed for donor-derived LSK cells in the BM 4 to 5 months after transplantation. Each dot corresponds to the percentage of BM LSK cells in each mouse. (D) The frequencies of donor-derived peripheral blood leukocytes (PBL) in recipients at each round of serial transplantation are shown by gray bars representing the mean ± SD (n = 10). (E) Survival curve of recipient mice after quaternary transplantation with BM cells of B6 or lupus TC origin (B6, n = 20; TC, n = 25). BMT, bone marrow transplantation; ns, not significant.