Baiocchi et Caligiuri demonstrated that very low doses of polyethylene glycol-modified rh-IL-2 therapy could counteract the immune deficiencies leading to EBV-associated lymphoproliferative diseases by using an in vivo model of severe combined immunodeficiency (SCID) mice reconstituted with human peripheral blood lymphocytes [48]. Here, IL2 is linked to Immunodeficiency.