Prognostic significance of CD8 and CD4 T cells in chronic lymphocytic leukemia

Abstract

The prognostic value of the number of T cells and NK cells at diagnosis in CLL was analyzed in a cohort of 256 patients with CLL diagnosed between 1997 and 2007. Patients with leukemia showed elevated NK cells and T cell populations and CD4/CD8 ratio was inverted in 39.7% cases. Prognostic significance of lymphocytes was analyzed as a ratio of relative number of T cells to the size of the malignant monoclonal B-cell pool (T/NK cells:Malignant monoclonal B-cells ratio). Patients showed higher relative number of CD4 (p = 0.03), CD8 (p = 0.02), and NK cells (p = 0.01) in early Rai stage of disease. The multivariate Cox analysis identified the relative number of CD8 (hazard ratio (HR) = 1.464; p = 0.006) and CD4 T cells (HR = 0.091; p < 0.01) as independent predictors for survival. Additionally, patients with relative CD8 count > 0.074 or CD4 count > 0.1 had higher 10-year overall survival than patients with CD8 count ≤ 0.074 or CD4 count ≤ 0.1 (p = 0.002). Higher CD8 count was associated with significantly higher median time of survival of patients (149.33 vs. 82.06 months). Finally, association of the good prognostic factor of leukemia cells (CD38⁻) with high relative CD8 count identified a group of patients with an indolent clinical course with an overall survival probability at 10 years of 95%.

Keywords:

• Chronic lymphocytic leukemia
• T cells
• CD4
• CD8
• NK cells

Declaration of interest: This work was supported by the Spanish grants of Fondo de Investigaciones Sanitarias PI06/0841 and PS09/00420. AL holds a predoctoral fellowship from FYCIT of Asturias (BP06-99).