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

Abstract

<b><i>Introduction:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> DLBCL patients had a higher proportion of CD4⁺CD25⁺ Treg (<i>p</i> &#x3c; 0.001) and lower absolute lymphocyte count than those of healthy controls. Lymphopenia at diagnosis was associated with advanced-stage disease (<i>p</i> = 0.001), a high-intermediate/high-risk International Prognostic Index (IPI) (<i>p</i> &#x3c; 0.001), and older age (<i>p</i> = 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. <b><i>Conclusion:</i></b> 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.