[Cryoglobulinemia type II].

Cryoglobulinemia type II is a disease characterized by the presence of a monoclonal rheumatoid factor (mostly IgM) and by widespread deposition of immune aggregates that contain the monoclonal IgM RF. Complement and its receptor on erythrocytes, by transporting immune complexes in the circulation, are particularly adapted to protect the organism against immune deposition. This physiological system does not function appropriately in the presence of a monoclonal RF that depletes complement proteins, enhances immune aggregation and inhibits opsonization of circulating immune complexes. However many other factors are involved in the failure of normal clearance of immune complexes in this disease (excessive load of immune complexes, defective Fc-mediated clearance reactions, etc.) all of which concur to provide the most favorable conditions for the deposition of immune aggregates, or for the trapping of circulating immune complexes at the site of ongoing immune injury.