[Prognostic value of prolymphocyte percentage in chronic lymphocytic leukemia]

Objective: To investigate the impact of peripheral blood prolymphocyte percentage on the prognosis of patients with chronic lymphocytic leukemia (CLL) . Methods: This study included 300 patients diagnosed with CLL at the Department of Hematology of Jiangsu Provincial People's Hospital from October 2011 to December 2020. The association between prolymphocyte percentage and other parameters was analyzed, and the optimal cutoff prolymphocyte percentage was determined by X-tile analysis. Further survival analysis and prognostic model construction were used to validate the predictive value of prolymphocyte percentage. Results: Of the 300 eligible patients with CLL who were enrolled, 50 received Bruton tyrosine kinase inhibitors (BTKi) as first-line treatment. The group with higher prolymphocyte percentage comprised more patients in the advanced stages (P=0.010) and had higher β(2)-microglobulin (P<0.001), unmutated immunoglobulin heavy-chain variable region gene (P<0.001), and TP53 aberration (P=0.004). The optimal cutoff percentage of prolymphocytes was 1%. Patients with a prolymphocyte percentage >1% had significantly shorter treatment-free survival (TFS) (P<0.001) and overall survival time (P=0.007) than patients with a prolymphocyte percentage ≤1%. On multivariate analysis, prolymphocyte percentage >1% tended to have an independent prognostic value for TFS [HR=1.405 (95% CI 0.971~2.032), P=0.071]. Compared with the nomogram of CLL international prognostic index (CLL-IPI) alone, the nomogram of CLL-IPI combined with prolymphocyte percentage showed better discrimination (area under the curve: 0.778 vs. 0.637; P=0.006). In addition, patients with a prolymphocyte percentage >1% were more likely to progress after BTKi treatment (P=0.038) . Conclusion: Peripheral blood prolymphocyte percentage was associated with various clinical and biological parameters and prognosis among patients with treatment-naive CLL.