Non symptomatic hypercalcemia in a myeloma patient.

An asymptomatic hypercalcemic IgG-Kappa myeloma patient is presented. A calcium-IgG complex was isolated and purified from the serum by column chromatography. Following further purification on a Sepharose protein A column, the IgG-Kappa molecule did not contain any detectable amount of calcium, indicating that calcium is loosely bound to IgG. The monoclonal IgG demonstrated a strong calcium binding capacity in vitro. The calcium-IgG complex in the serum was shown not to be saturated and thus could absorb more ionized calcium. In view of the presence of an abnormal monoclonal IgG capable of binding excess calcium, and the fact that the asymptomatic patient did not respond to the antihypercalcemic drugs, the treatment was stopped.