Natural Killer (NK) cells are innate immune lymphocytes that play important roles in the clearance of viral infection and cellular malignancies.1 A critical effector function of NK cells is antibody-dependent cellular cytotoxicity (ADCC) in which FcγRIIIa (CD16a) binds to the fragment crystallizable (Fc) domain of immunoglobulin G (IgG) within immune complexes on the target cell surface, inducing NK cell activation and degranulation.2 ADCC activity is central to the efficacy of many therapeutic monoclonal antibodies (mAbs),3–5 which can be optimized for enhanced ADCC activity. Here, FCGR3A is linked to viral infectious disease.