BIOSYNTHESIS AND CHARACTERIZATION OF IGM-LAMBDA IN A CASE OF CHRONIC LYMPHOCYTIC-LEUKEMIA WITH INTRACELLULAR IMMUNOGLOBULIN INCLUSIONS

Lymphocytes from a patient with chronic lymphocytic leukaemia were found to contain crystalline inclusions in the cytoplasm. These crystals were characterised as IgMλ immunoglobulin. The cells did not have detectable surface immunoglobulin. No paraprotein was detected in the serum and no excess of immunoglobulin was detected in the urine. The cells incorporated radio-active leucine into μ and λ chains during an 18-hour culture. Studies of labelled lysate immunoglobulin revealed a molar excess of heavy chain over light chain while in contrast free light chain was the only detectable secreted immunoglobulin product during the culture period. These findings are discussed in relation to immunoglobulin synthesis by normal and other neoplastic lymphocyte preparations.