The prognostic utility and the association of serum light chains (free and total) and absolute lymphocyte count in patients with newly diagnosed diffuse large B-cell lymphoma

• Elevated sFLC were more frequent than abnormal sTLC in patients with DLBCL.
• Patients with elevated sFLC more frequently showed adverse clinical features.
• Both elevated sFLC and κ/λ ratio were strongly associated with clinical outcomes.
• Not abnormal sTLC, but elevated sFLC was found to be associated with low ALC.
• sFLC and low ALC remain independent prognostic factors after adjusting for IPI.

In this study, serum free and total light chains (sFLC/sTLC) were measured in 108 serum samples of therapy-naïve patients with DLBCL. Clinicopathologic data and survival outcomes were analyzed according to the results of sFLC/sTLC measurements. Moreover, the association of sFLC/sTLC with absolute monocyte count (AMC) and absolute lymphocyte count (ALC) was evaluated. Elevated sFLC and abnormal κ/λ ratio was present in 42.6% (51/108) and 4.6% (5/108) of patients, respectively. sTLC was successfully measured in 107 serum samples, abnormal sTLC and abnormal κ/λ ratio was found in 28.0% (30/107) and 26.2% (28/107) of patients, respectively. Patients with elevated sFLC more frequently displayed adverse clinical characteristics, including age (P = 0.001), B symptoms (P = 0.022), low ALC (P = 0.024) and hyperglobulinemia (P = 0.012). Patients with elevated sFLC had an inferior overall survival (OS) (P = 0.012) and tended to have shorter progression-free survival (PFS) (P = 0.061) compared to patients with normal sFLC. Abnormal sTLC or abnormal sTLC ratio showed no significant association with clinical outcomes, with exception of abnormal concurrent κ and λ. Only association of sFLC and ALC with survival remained significant after adjusting for the International Prognostic Index (IPI). The measurement of sFLC and ALC at diagnosis might be useful for the prognostic stratification of patients and sTLC measurement was of little prognostic utility in DLBCL.