Prognostic Impact of Peripheral Blood T-Cell Subsets at the Time of Diagnosis on Survival in Patients with Diffuse Large B-Cell Lymphoma.

INTRODUCTION The effects of lymphocyte subtypes, including helper (Th), natural killer (NK), and regulatory (Treg) cells, and other T-cell subtypes on treatment outcomes in diffuse large B-cell lymphoma (DLBCL) patients are not clearly established. METHODS Among 151 consecutive patients diagnosed with DLBCL, we collected peripheral blood samples at diagnosis from 91 patients who received at least 1 cycle of R-CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone plus rituximab) chemotherapy and analyzed lymphocyte subsets by flow cytometry. RESULTS DLBCL patients had a higher proportion of CD4+CD25+ Treg (p < 0.001) and lower absolute lymphocyte count than those of healthy controls. Lymphopenia at diagnosis was associated with advanced-stage disease (p = 0.001), a high-intermediate/high-risk International Prognostic Index (IPI) (p < 0.001), and older age (p = 0.060). High-intermediate/high-risk IPI, high proportion of CD3+CD4+ Th cells, and extranodal site ≥2 correlated with unfavorable prognostic factors for survival. High proportion of Th cells was associated with fewer cytotoxic T cells and NK cells at the time of diagnosis. CONCLUSION This study showed an association between circulating lymphocyte subsets including Th cells, Tregs, and NK cells and clinical outcomes in DLBCL; however, further confirmation is needed via prospective trials.