Blood clonal B cell excess at diagnosis in multiple myeloma: Relation to prognosis

Abstract

112 patients with multiple myeloma have been studied at diagnosis for the presence of blood clonal B‐cell excess (CBE), defined as a ratio between k+ and λ+ lymphocytes outside the normal range (0.9‐3.5). 48 patients (43%) had CBE. The increase in light chain‐bearing lymphocytes was always that of the M component light chain isotype. The proportions of patients exhibiting CBE were the same in different stages. The response frequency was not influenced by the presence of CBE. However, patients with CBE had a shorter remission duration time (p < 0.001) and total survival (p < 0.05) than those without CBE. This was also noticed when each clinical stage was analyzed separately. Moreover, survival was shorter in patients with a large fraction of CBE than in those with a small one. Cox regression analysis revealed that CBE was a much stronger predictor of remission duration than age, clinical stage and renal dysfunction. CBE and response to initial treatment independently were the best factors to indicate survival. It is suggested that analysis of CBE should be included in the clinical characterization of untreated patients with multiple myeloma.