Abstract: The invention concerns an extra-corporeal system and method to purify blood of pathogenic enzymes which initiate tumoral processes as well as evoke dystrophic muscular lesion, including enzymes of the group of cysteine peptidases, in particular of cathepsins B and L and calpain, this system being intended for removing these proteins from the blood in order to eliminate the degradation of the body's cells caused by the presence of these proteins in the blood.