The present invention relates to a specific antibody of a protein antigen capable of binding to nucleic acids, or a fragment or a derivative of such an antibody binding to the antigen, for use as a drug, in particular in the treatment or prevention of inflammation, due especially to an infection or an autoimmune disease, characterized in that the antibody, fragment or derivative has a reduced capacity to bind to the FcγRIIA receptor and/or an increased capacity to bind to the FcγRIIB receptor. The antibody, fragment or derivative is preferably without an Fc domain, or with a modified Fc domain with a reduced capacity to bind to FcγRIIA and optionally FcγRIIA (or even a reduced capacity to bind to all FcγR), and/or with a modified Fc domain with an increased capacity to bind to FcγRIIB.