Disclosed is the use of a humanized anti-CD4 antibody capable of activating CD4+CD25+ regulatory T cells for the manufacture of a pharmaceutical composition for treating an autoimmune disease in a subject, wherein the humanized anti-CD4 antibody comprises an H chain V domain, an L chain V domain and an IgG 1 constant domain wherein: (a) the H chain V domain compnses the sequences DCRMY, VISVKSENYGANYAESVRG and SYYRYDVGAWFAY, and the L chain Vdomain compnses the sequences RASKSVSTSGYSYIY, LASILES and QHSRELPWT and/or (b) the H chain V domain has at least 90% sequence identity with SEQ ID No: 1 and the L chain V domain has at least 90% sequence identity with SEQ ID No: 2, and wherein the composition is to be administered to the subject in a dose of the humanized anti-CD4 antibody of from 20 mg to 200 mg 8 to 60 mg/m2 body surface area of the subject or 0.2 to 2 mg/kg. Further disclosed is a pharmaceutical composition comprising the antibody as defined above wherein the composition is in a volume of 1 ml to 3 ml and the humanized anti-CD4 antibody is present in the composition at a concentration of from 20 to 150 mg/ml or (ii) the composition is in a volume of 15 to 25 ml and the humanized anti-CD4 antibody is present in the composition at a concentration of approximately 10 mg/ml or approximately 12.5 mg/ml.
