Light-chain heterogeneity of cold agglutinins.

Cold agglutinins with specificity to I or to i antigens of humanadult or cord-blood erythrocytes produced during the course of Mycoplasma pneumoniae infection and infectious mononucleosis contain light chains of K and L types. However, cold agglutinin isolated from the serums of patients with chronic cold-agglutinin hemolytic anemia contains only type K light chains. The experimental evidence suggests that some cold agglutinins contain both types of light chains in the same molecule.