Cytogenetic analysis was performed on peripheral blood cells stimulated with interleukin 6 (IL-6), lipopolysaccharide from Escherichia coli (LPS), phytohemagglutinin (PHA), pokeweed mitogen (PWM) and tetradecanoyl-phorbol-acetate (TPA), in a patient with B-chronic lymphocytic leukemia, showing a t(1;19;?) translocation as the sole abnormality. To our knowledge, this translocation has not been described before in any human neoplasia. In this case, the poor response to therapy (survival time 4 months) suggested that t(1;19;?) could be related to an aggressive course of the disease.