The Combined Evaluation of Neutrophil, T-Lymphocyte and Monocyte Counts Provides New Prognostic Information in CLL Patients

The recent advances in cytogenetic and molecular diagnostic techniques has provided a better understanding of biology of CLL and a better prediction of disease progression and refractoriness but they are not easily accessible to all Institutions.

CLL cells depend on microenvironmental interactions for proliferation and survival that are at least partially mediated through B cell receptor (BCR) signaling. An increased number of studies describe the emerging role of neutrophils and monocytes as mediators of the inflammation process and antitumor immunity modulation that support tumorigenesis and tumor progression. The neutrophil to lymphocyte ratio (NLR), has been recently published as new marker of systemic inflammation associated with outcome in different cancer types.

In our study we retrospectively evaluated the prognostic significance of peripheral blood neutrophils, monocytes and non-neoplastic lymphocytes in a unicentric, unselected, CLL cohort of 400 CLL patients (160 were treated). The study was approved by the institutional board review;informed consent was obtained from patients.

Using the blood count and the Flow cytometric analysis reports, peripheral blood absolute neutrophil count (ANC), absolute monocyte count (AMC) and absolute T-lymphocyte count (ALC-CD3+) were evaluated and the neutrophil to T-lymphocyte ratio (NLR), the monocyte to T-lymphocyte ratio (MLR) and the neutrophil to monocyte ratio (NMR) were calculated. Clinical and biological data from all patients were also retrieved. Serial count and ratio were evaluated at diagnosis, during follow up and at relapse to make a better comparison with the major clinical and prognostic markers commonly used.

The median ratio for NLR 2.67 and patients with pre-treatment NLR > 3 had a shorter time from diagnosis to treatment initiation. CLL patients showed an increase in the absolute number of monocytes compared to normal controls (788±65 cells/μL vs 469±51 cells/μL, p=0.005) and MLR appeared higher in advanced stage (stage Binet C) and bulky disease (p=0.06). High level of both NLR and MLR (cut off >3) correlated with the presence of a complex karyotype detected by FISH (p=0.03, p=0.016). NLR ratio was associated with the absence of serum prognostic markers, such as the expression of CD38, ZAP-70 and CD49d. This result, apparently conflicting, could strengthen the NLR as an independent prognostic factor.

NMR was higher in asymptomatic patients (absence vs. presence of B symptoms, p=0.02) and this data resulted independent from disease stage. NMR median value was significantly higher in untreated patients than in patients who received treatment (p=0.01), strengthening the hypothesis that this ratio is associated with a more indolent form of disease. In this contest, the subset of patients with CD49d positive disease showed the lowest NMR value. This data seems of relevance, being CD49d a recently discovered and validated prognostic marker.

ANC/ALC and AMC/ALC ratio significantly increased at relapse compare to baseline (NLR average onset 2.3±0.4 vs 3.4±0.6 at relapse). The median NMR value showed conversely the opposite trend: NMR is reduced in first relapse (NMR average onset 7.2±0.4 vs. 5.4±0.5 at relapse).

These combined ratios reflect both the inflammatory status, the immune response and the microenviromental network that contribute to aggressive tumor biology and disease progression. They are simple, cheap, easily measured and reproducible and can be integrated into daily clinical practice as new prognostic markers for CLL.