The present invention is related to the branch of immunology and particularly with the generation of pharmaceutical compositions comprising a humanized monoclonal antibody recognizing the leukocyte differentiation antigen CD6. Accordingly with that statement, the purpose of this invention is to provide pharmaceutical compositions comprising a humanized anti-CD6 monoclonal antibody for the diagnosis and treatment of Lymphoproliferative Syndromes and particularly the B-Cell Chronic Lymphocytic Leukemia. The essence of the invention consist in the application of a humanized Monoclonal Antibody that recognizes the CD6 antigen, the generation of pharmaceutical compositions comprising that antibody being able to induce apoptosis of malignant cells from B-Cell Chronic Lymphocytic Leukemia patients, reaching a clinical and a histological antitumor efficacy. The field of application of the present invention extends to the Oncology.