A new case of heavy mu-chain disease.

The tenth case of mu chain disease is described. The patient lives in Ivory Coast as in our previously reported case. He was not affected with chronic lymphocytic leukaemia and the main clinical feature was liver cirrhosis of unknown origin. The amount of abnormal protein in the serum was great enough to give an abnormal bond on the routine electrophoresis. The protein was devoid of light chains and was present in the form of disulfide linked polymers of incomplete mu chain. The molecular weight of the monomer was approximately 58,000. The protein comprised the Fc fragment and a part of the Fd segment. Bence Jones protein was not found in the urine.