Using a monoclonal antibody (MAb), chimeric, human or humanized, in which the glycan structure of the Fc region is of the two-branched type, to prepare a composition for treating patients with a CD16 polymorphism, partricularly V/F 158 or F/F 158, is new. Use of a monoclonal antibody (MAb), chimeric, human or humanized, in which the glycan structure of the Fc region is of the two-branched type, to prepare a composition for treating patients with a CD16 polymorphism, partricularly V/F 158 or F/F 158. The glycan structure has short chains； low degree of sialylation of mannose and GlcNAc at the terminal, non-intercalated point of attachment, and a low degree of fucosylation. Particularly patients are those for whom treatment with currently available antibodies has failed or who are suffering adverse side effects. ACTIVITY : Cytostatic； Antibacterial； Virucide； Schistomacide. No biological data given. MECHANISM OF ACTION : Ab induce secretion of cytokines (especially tumor necrosis factor； interferon-gamma ； IP 10 and interleukin-6) and antibody-dependent cellular cytotoxicity.
