Nat. Med. 23, 1072–1079 (2017); published online 21 August 2017; corrected after print 11 October 2017

In the version of this article initially published, the representative images in Fig. 2n were inadvertently duplicated in Fig. 4h. A correct version of the images for Fig. 4h has been supplied. The authors wish to point out that this error did not affect the other data reported in the paper or the conclusions drawn. The error has been corrected in the HTML and PDF versions of the article.