Response to the letter to the editor by M. Elsner et al: "Comment on Binhai Ren et al (2013;15:28–41). Long term reversal of diabetes in non‐obese diabetic mice by liver‐directed gene therapy". (20th September 2013) - Simpson, Ann M.; Ren, Binhai; O'Brien, Bronwyn A.; Nassif, Najah T.