Nephelometry of the kappa/lambda light-chain ratio in serum of normal and diseased children.

We determined, immunonephelometrically, the ratio between the two types of light chains of immunoglobulins, kappa and lambda, in serum of 94 children, ages 0.4 to 14 years, with no manifest immunological disorders. Children with an abnormal protein pattern by immunoelectrophoresis show other values for this ratio than do children in this reference group. We also determined the ratios for children with IgA deficiency (I), juvenile rheumatic arthritis (II), and acute lymphoblastic leukemia (III). Children with I show the same kappa/lambda ratios as for the children in the reference group. Children with II also show the same mean kappa/lambda ratios, but a significantly wider range of ratios. In children with III, the ratio during chemotherapy is slightly depressed, significantly lower than after cessation of therapy. All groups--healthy children and patients--show an increase in kappa-chain-bearing immunoglobulins with age, but the concentration of lambda-chain-bearing immunoglobulins remains relatively constant.