The present disclosure relates to monovalent antibodies and chimeric proteins (comprising the monovalent antibodies) for the treatment of an auto-immune inflammatory disorder or condition. The monovalent antibody moiety lacks a Fc region, is specific for an activating Fc receptor and is for limiting or avoiding the activation of an immune cell induced in the presence and upon the binding of a ligand of the activating Fc receptor to the activating Fc receptor. The monovalent antibodies and chimeric proteins are especially useful for the prevention, treatment or alleviation of symptoms associated with an auto-immune inflammatory disorder caused or maintained by the engagement of an auto-antibody having a Fc region capable of engaging the activating Fc receptor to mediate the pathological destructions of cells or tissues.
