The clinical significance of pure Bence Jones proteinuria at low concentration.

The clinical significance of Bence Jones (BJ) proteinuria at low concentration (less than 0.2 g/24 hours) was investigated in 33 unselected patients who had no intact monoclonal immunoglobulin in their serum. The great majority (79%) of the patients were recognized as having malignant lymphoproliferative diseases, such as chronic lymphocytic leukemia (46%), hairy cell leukemia (6%), and non-Hodgkin's lymphoma (27%), whereas only two patients (6%) had multiple myeloma or systemic amyloidosis. Five patients (15%) had no evidence of definite malignant immunoproliferative disorders at the time of recognition of BJ proteinuria. Three of them, who were excreting steadily low amounts of BJ protein in their urine for 47, 61, and 73 months, respectively, without development of any B-lymphocytic malignancy, were classified as having a monoclonal gammopathy of undetermined significance. In the remaining two patients, BJ protein disappeared spontaneously 14 and 18 months, respectively, after its recognition. The study indicates that pure BJ proteinuria, even when occurring at low concentration, is most consistently associated with malignant proliferations of B-lymphocytic origin. However, the possibility should be considered that the clinical spectrum of the monoclonal gammopathy of the light chain type also includes benign and transient forms.

The clinical spectrum of pure Bence Jones proteinuria. A study of 66 patients.

Sixty-six consecutive patients exhibiting isolated urinary excretion of monoclonal free light chains, i.e. Bence Jones protein (BJP), on screening investigation for serum and urine monoclonal immunoglobulins were studied in order to better define the spectrum of immunoproliferative disorders associated with such a protein abnormality. The typical plasma cell neoplasms accounted for only one third of the cases, multiple myeloma (MM) and systemic amyloidosis (AL) being diagnosed in 18% and 15% of the patients, respectively. Eighteen (27%) of the patients were recognized as having malignant nonHodgkin's lymphomas (NHL), 21 (32%) had chronic lymphocytic leukemia (CLL), and 2 (3%) had hairy cell leukemia (HCL). Three patients (5%) without apparent evidence of any malignant immunoproliferative disease were classified as having a monoclonal gammopathy of undetermined significance (MGUS). The greatest urinary concentrations of BJP were found in plasmacytic neoplasms, the daily excretion of MM patients being significantly higher than that of AL patients. Considerably lower BJP outputs were recorded in the other diseases, the lowest ones being associated with MGUS. NHL patients had a daily excretion four times higher as compared with that of CLL patients. The distribution of NHL by histologic type was: follicular center cell lymphomas (FCCL) 39%, small lymphocytic lymphoma (SLL) 33%, immunoblastic lymphoma (IBL) 17%, and plasmacytoid lymphocytic lymphoma (PLL) 11%. The highest BJP levels were found in PLL, and the lowest ones in FCCL. In CLL patients the amount of urinary BJP correlated significantly with the tumor load, as estimated by the number of enlarged lymphoid areas. The study suggests that detection and measurement of isolated urinary BJP may provide useful data for the clinical evaluation of a wide spectrum of immunoproliferative disorders.