The present invention relates to the field of medicine, in particular of research and diagnosis. It relates more particularly to a novel tool for detecting antibodies in a biological sample originating from a mammal. This tool, which is in the form of a protein chip, can be used in screening for new targets of interest involved in the occurrence of an autoimmune disease, in particular of a disease affecting the nervous system of a mammal, and also in the diagnosis or the monitoring of the progression of such an autoimmune disease. The invention also relates to a method for producing such a tool and also to kits comprising it and enabling its use.