Bence-jones Proteinemia in Multiple Myelomai

The term "Bence-Jones protein" refers to an ill-defined group of proteins having a molecular weight of approximately 37,000 (1), and the characteristic properties of precipitating out of solution when warmed to 45 to 58° C. and of redissolving completely or partially on boiling. This peculiar behavior on heating has long served as a useful test for Bence-Jones proteins in the urine of patients with multiple myeloma. When applied to serum, however, particularly to those sera where hyperproteinemia is associated with myeloma, the heat test has been found generally inadequate because it does not sufficiently differentiate BenceJones proteins from the serum euglobulins (2, 3). More convincing evidence of Bence-Jones proteinemia can be obtained by extraction (4, and others), protein solubility curves (5), and ultracentrifugation (6, 7, and others). However, to establish satisfactorily the frequency and degree of Bence-Jones proteinemia in multiple myeloma, and its relation to hyperproteinemia in that disease, more adequate methods recently devised for characterizing proteins would appear to be necessary. Any generalizations so derived should be based upon a series of cases large enough to be representative. In a recent study combining electrophoretic with salting-out techniques (8), it was found that 38 cases of multiple myeloma, presenting the most varied quantitative and qualitative differences in serum proteins, could be classified into 3 major groups: 1. Those with hyperglobulinemia due to y components which precipitated out chiefly with the Howe "euglobulin," and partly with the Howe "pseudoglobulin I" fraction. 2. Those with a variety of unusual serum protein patterns, not encountered in any other disease. 3. Those with apparently normal serum proteins. It was suggested that the protein increment in the first group