Transient immune activation without loss of intraepidermal innervation and associated Schwann cells in patients with complex regional pain syndrome.

"Declarations Ethics approval and consent to participatePatient recruitment followed the ResolvePAIN study protocol registered in the German clinical trial register (registration number DRKS00016790). Ethical approval was obtained from the responsible ethics committees of the University of Würzburg. All animal experiments were approved by the Government of Lower Franconia, Germany (Regierung von Unterfranken). Consent for publicationAll authors of the manuscript have agreed to publish this article. Competing interestsThe authors declare that they have no competing interests. Competing interests The authors declare that they have no competing interests."

"Funding Open Access funding enabled and organized by Projekt DEAL. The study was supported by the German Research Foundation (DFG) for the Clinical Research Group KFO5001 ResolvePAIN (HLR, CS, KD) and the Graduate School of Life Sciences of the Julius-Maximilians-Universität Würzburg (SS, KM)."

"In this monocentre study at the Centre for Interdisciplinary Pain Medicine (ZiS) at the University Hospital Würzburg, patient recruitment (between 2017 and 2021) followed the ResolvePAIN study protocol registered in the German clinical trial register (https://drks.de/—registration number DRKS00016790). Patients were included at their first visit at the ZiS. Ethical approval was obtained from the responsible ethics committees of the University of Würzburg. Study participants were over 18 years old, of both sexes and gave written informed consent. We only included patients with CRPS of the upper extremity. Pre-existing severe neurological diseases, diabetes, current or past malignancies, surgeries within the last 4 weeks at the affected extremity, and current infections were exclusion criteria. As controls, sex- and aged-matched healthy volunteers were recruited for a unilateral finger biopsy. Declarations: Ethics approval and consent to participatePatient recruitment followed the ResolvePAIN study protocol registered in the German clinical trial register (registration number DRKS00016790). Ethical approval was obtained from the responsible ethics committees of the University of Würzburg. All animal experiments were approved by the Government of Lower Franconia, Germany (Regierung von Unterfranken).: Consent for publicationAll authors of the manuscript have agreed to publish this article.: Competing interestsThe authors declare that they have no competing interests. Ethics approval and consent to participate: Patient recruitment followed the ResolvePAIN study protocol registered in the German clinical trial register (registration number DRKS00016790). Ethical approval was obtained from the responsible ethics committees of the University of Würzburg. All animal experiments were approved by the Government of Lower Franconia, Germany (Regierung von Unterfranken)."