Cold agglutinin disease is a type of autoimmune hemolytic anemia (see this term) defined by the presence of cold autoantibodies (autoantibodies which are active at temperatures below 30°C).

Inflammatory changes in the synovial membranes and articular structures with widespread fibrinoid degeneration of the collagen fibers in mesenchymal tissues, as well as atrophy and rarefaction of bony structures.