Negative prognostic impact of low absolute CD4⁺ T cell counts in peripheral blood in mantle cell lymphoma

Tumor microenvironment and host immunity are closely related to outcome in patients with mantle cell lymphoma (MCL). However, few researchers have focused on the prognostic value of peripheral blood lymphocyte subsets counts. The purpose of this study was to investigate the prognostic value of lymphocyte subsets and absolute monocyte counts. Sixty-eight patients were analyzed retrospectively. Absolute CD4⁺ T cell counts (ACD4C), CD8⁺ T cell counts, nature killer cell counts, and CD4/CD8 ratios were assessed by peripheral blood flow cytometry and correlated with clinical parameters and long-term outcomes. The median follow-up for all patients was 21 months and the median survival time was 44 months. The overall survival (OS) rate at 1, 3, and 5 years was 80%, 51%, and 41%, respectively. In our cohort, high absolute monocyte count, and low ACD4C and CD4/CD8 ratio were associated with unfavorable OS (P = 0.029, P = 0.027, and P = 0.045, respectively) by univariate analysis. Multivariate analysis indicated that low ACD4C was a significant predictor of unfavorable OS (P = 0.004) independent of the simplified MCL International Prognostic Index (P = 0.048) in patients treated with or without rituximab (P = 0.011). Low CD4⁺ T cell counts proved to be a significant predictor of unfavorable OS in patients with MCL.