TGFB1 and systemic lupus erythematosus: The adoptive transfer of 2.5 × 106 TGF-β−sufficient NK cells into BDF1 lupus mice at the time of disease induction did not affect serum creatinine levels that were instead increased in BDF1 mice receiving an identical number of NK cells but TGF-β−deficient (TGF-β siRNA) (Figure 4C).