The invention relates to negative functional modulators of erythropoietin (EPO) for use in the treatment of cancers, in the therapy of autoimmune -based and non-autoimmune based chronic inflammatory diseases, and in the treatment of patients under-going organ or tissue transplant, or for the treatment of hemophilic arthropathy, hemophilia A and B, von Willebrand disease, angiodysplasia, proliferative disorders and neurological diseases characterized in their pathogenesis by primary neuroinflammation and/or neuroinflammation secondary to other causes. Such modulators are anti-EPO antibodies and their derivatives: anti-EPO receptor antibodies (EPOR), antisense oligonucleotides, decoy DNA, decoy RNA, ribozyme, antagomir, shRNA, LNA and/or siRNAs that inhibit the expression of the gene encoding EPO or EPOR.