Light Chains in Chronic Cold Haemagglutinin Disease

THE chronic cold haemagglutinin disease (CHAD) is a rare illness of unknown aetiology characterized by the presence in the serum of an autoantibody which causes marked agglutination of both patient's and normal red cells at temperatures below 37° C. The antibody is known to be a macroglobulin of the IgM sub-group of immunoglobulins 1 . There is often a spike in the β to γ 1 globulin area on serum-protein electrophoresis owing to the presence of a large amount of electrophoretically homogeneous antibody 2 .