The clinical and laboratory features of the seven known patients with heavy chain disease showed that all but one had chronic lymphocytic leukemia. Two common and striking features are the presence of κ-type Bence Jones proteins and vacuolated plasma cells in the marrow.
Franklin EC. µ-Chain Disease. Arch Intern Med. 1975;135(1):71-72. doi:10.1001/archinte.1975.00330010073010