Macro creatine kinase BB: evidence for specific binding between creatine kinase BB and immunoglobulin G

In the sera of four female patients with proven IgG-linked creatine kinase BB (macro creatine kinase BB) we studied the nature of the binding between creatine kinase isoenzymes and immunoglobulin G. The specificity towards the isoenzyme bound, the recombination of the complex after treatment with acid buffer, the site of the binding between both partners and an apparently monoclonal nature of the immunoglobulin G involved in the complex indicate that a specific antigen-antibody reaction is responsible for the existence of macro creatine kinase BB in the sera investigated.