Urinary light chain excretion in leukaemia and lymphoma.

Immunoglobulins are produced by plasma cells. However, tissue culture and fluorescent antibody techniques have also demonstrated that other leucocytes, mainly lymphocytes, may synthesize immunoglobulins. In the aberrant protein synthesis of myeloma there is often excessive production of electrophoretically homogeneous light polypeptide chains, appearing in the urine as Bence Jones protein. Among a group of seventy-six patients with leukaemia and lymphoma, nineteen showed quantitatively increased excretion of urinary light chains (> 100 mg/24 hr). In all instances the light chain excretion of one dominating light-chain group (κ) was present. Studies of the κ/λ ratio in serum and isolated γG-globulin were made and appeared normal in the expected 2:1 range. By cellulose acetate electrophoresis these light polypeptide chains from the leukaemia–lymphoma group appeared considerably more heterogeneous than Bence Jones proteins from multiple myeloma.