Cryocrystalglobulinemia: pH-dependent precipitation of a monoclonal IgG-kappa-immunoglobulin.

Cryoglobulinemia is seen in a minority of patients with plasma cell dyscrasias and can be of clinical relevance if intravascular gelling or precipitate formation occurs at low temperatures. We observed a patient suffering from IgG-kappa multiple myeloma which was complicated by instability of the immunoglobulin forming crystalline precipitates at low pH and low temperature. Short exposure to extreme cooling initiated an unusual course terminating in disseminated vascular occlusion and fatal outcome which was connected with an adverse effect of blood exchange. Crystal formation was noticed in anticoagulated blood samples even at 37 degrees C. In vitro studies showed a critical pH dependency of solubility of the immunoglobulin close to the physiological pH of the blood. These observations suggest that the fatal outcome was due to a vicious circle of ischemia, metabolic acidosis and intravascular precipitations, initiated not only by low acral temperatures but by cold-induced ischemic tissue acidosis as well. Serum of patients with monoclonal gammopathy and cryoglobulinemia should be tested for pH dependent immunoglobulin insolubility.