Disclosed is the use of an anti-CD3 antibody or a functional anti-CD3 antibody fragment selected from the group consisting of anti-CD3 antibodies and functional fragments thereof which do not bind or have reduced binding to the Fc (gamma) receptors, for the manufacture of a pharmaceutical preparation for treating diabetes and psoriasis wherein over the course of a treatment, said anti-CD3 antibody, or a bioequivalent amount of a functional anti-CD3 antibody fragment, is to be administered in an amount wherein the total amount does not exceed 300 µg/kg when to be administered intravenously, and when to be administered other than intravenously the total amount administered does not exceed the bioequivalent of intravenous administration of 300 µg /kg.
