High levels of regulatory T cells in blood are a poor prognostic factor in patients with diffuse large B-cell lymphoma

Objectives: Host immunity likely plays a role in preventing progression of diffuse large B-cell lymphoma (DLBCL). Analysis of host immune cells may provide useful information for assessing prognosis or possibly clinical management. Methods: Peripheral blood samples from 77 patients with DLBCL and 30 healthy volunteers were analyzed using flow cytometry immunophenotyping. CBC counts, T-cell subsets, and dendritic cells (DCs) were detected, and the results were correlated with clinicopathologic characteristics. Results: Compared with healthy volunteers, patients with DLBCL had significantly higher leukocyte and monocyte counts (P <.001); higher percentages of neutrophils (P <.001), "natural" regulatory T cells (Tregs; CD3+Foxp3+, P <.001), and immature DCs (CD83-CD1a+, P =.005); and lower percentages of lymphocytes (P <.001) and helper T cells (P =.038). In univariate analysis, high neutrophil counts (≥6,000/μL, P =.014) and "induced" Tregs (CD4+CD25+, P =.026) were poor survival factors along with high International Prognostic Index scores (P <.001) and other high-risk clinical parameters. In multivariate analysis, high Tregs retained significance. Suppression of lymphocytes correlated with poor clinical factors; higher natural Tregs correlated with a lower CD4+/CD8+ ratio (P =.035) and more immature DCs (P =.055). Conclusions: Changes in blood immune cells occur in patients with DLBCL. The results also support a suppressive role of Tregs in adaptive immunity and correlate with poor-risk prognostic factors.