Front. Immunol. Frontiers in Immunology Front. Immunol. 1664-3224 Frontiers Media S.A. 10.3389/fimmu.2026.1809852 Retraction Retraction: The intra-nuclear SphK2-S1P axis facilitates M1-to-M2 shift of microglia via suppressing HDAC1-mediated KLF4 deacetylation Frontiers Editorial Office * Writing – original draft Correspondence: Frontiers Editorial Office, research.integrity@frontiersin.org 20 02 2026 2026 17 1809852 12 02 2026 12 02 2026 Copyright © 2026 Frontiers Editorial Office. 2026 Frontiers Editorial Office https://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms. A retraction of the Original Research article The intra-nuclear SphK2-S1P axis facilitates M1-to-M2 shift of microglia via suppressing HDAC1-mediated KLF4 deacetylation By Ji J, Wang J, Yang J, Wang X-P, Huang J-J, Xue T-F and Sun X-L (2019) Front. Immunol. 10:1241. doi: 10.3389/fimmu.2019.01241 section-at-acceptance Multiple Sclerosis and Neuroimmunology

The journal retracts the 04 June 2019 article cited above.

Following publication, concerns were raised about the integrity of images presented in the published figures, particularly duplicated images identified in Figures 3F, 4F, and 5F. Additional concerns were also noted regarding the integrity of the original western blot images provided during the subsequent investigation, which was carried out in compliance with Frontiers’ policies. As a result, the data and conclusions of the article have been deemed unreliable, and the article has been retracted.

The investigation followed Frontiers’ policies, and the retraction was approved by the Chief Executive Editor. The authors were informed about the retraction.

Approved by: Frontiers Editorial Office, Frontiers Media SA, Switzerland