Editorial Expression of Concern: HoxC4 binds to the promoter of the cytidine deaminase AID gene to induce AID expression, class-switch DNA recombination and somatic hypermutation(Nature Immunology, 10.1038/ni.1725)

The Editor would like to alert the readers that concerns have been raised regarding some of the data presented in this article, specifically: • Fig. 3a, top two plots appear to share highly similar datapoints; • Fig. 8c, Human 2E2 (nil) blot appears to show repetitive features in the ‘empty’ lanes; • Fig. 8c, Mouse spleen (nil) lanes 6 and 8 appear to have repetitive features; • Supplementary Fig. 2, IgG3 LPS and IgA LPS+TGF-β+IL-4+IL-5+anti-δ mAb-dextran plots appear highly similar. The original data are no longer available due to the age of the article. Readers are therefore advised to interpret these date with caution. Egest J. Pone agrees to this Editorial Expression of Concern. Seok-Rae Park does not agree to this Editorial Expression of Concern. Paolo Casali has not explicitly stated whether they agree to this Editorial Expression of Concern. The other authors have not responded to any correspondence from the Editor or Publisher about this Editorial Expression of Concern.