Low lymphocyte-to-monocyte ratio predicts unfavorable prognosis in non-germinal center type diffuse large B-cell lymphoma.

The peripheral blood lymphocyte to monocyte ratio (LMR) at diagnosis has been used to predict survival in diffuse large B-cell lymphoma (DLBCL) patients, but its prognostic significance with respect to different cell-of-origin (COO) subtypes remains unknown. We retrospectively analyzed 168 de novo DLBCL patients in this study and found that a low LMR (≤2.6) correlates with B symptoms, elevated LDH, advanced Ann Arbor stage and higher international prognostic index (IPI) score (p<0.05). The low LMR is a negative prognostic parameter for overall survival (OS) and event-free survival (EFS) in non-germinal center (GC) type DLBCL patients, as compared with the high LMR, especially in those treated with R-CHOP. However, the LMR has less correlation with the OS and EFS in GC type DLBCL patients (p=0.545 and 0.547, respectively). Multivariate analysis adjusting for IPI revealed that the low LMR indicates a shorter survival retain both OS and EFS in non-GC subtypes (p=0.023 and 0.005, respectively). In the non-GC DLBCL patients treated with R-CHOP a low LMR still showed a trend to predict poor EFS (p=0.052). In conclusion, these data suggest that a low LMR at diagnosis may imply a poor prognosis in non-GC subtype DLBCL patients, especially in those treated with R-CHOP, but not in those GC subtype DLBCL patients.