Updated project metadata. Through this comparative proteomic study of equine CD4+ cells 376 membrane proteins could be identified. Several proteins showed changed abundance in horses affected by a spontaneous autoimmune disease (equine recurrent uveitis, ERU). Findings provide novel knowledge about changes in the CD4+ immune cell membrane proteome in a spontaneously and naturally occurring autoimmune disease in horses. The data is highly relevant for veterinary medicine and has proven translational quality for autoimmune uveitis in man.