The invention relates to the field of molecular medicine. In particular, it relates to compositions and methods to enhance the clearance of aberrant cells, e.g. cancer cells or virus-infected cells, by the host' s immune system. Provided is a composition comprising (i) a therapeutic compound that can trigger a host' s immune effector cells against an aberrant cell, such as a therapeutic antibody, and (ii) at least one agent capable of reducing or preventing inhibitory signal transduction initiated via SIRPalpha.