Functional immunophenotype of circulating T-cell subpopulations in patients with indolent B-cell malignancies. Whole blood samples were stained and analyzed by flow cytometry within 2 hours after phlebotomy. (A) Selected subpopulations of activated and senescent T cells compared with healthy donors. Horizontal bars, boxes, and whiskers represent median, 25%/75% quartiles, and range, respectively. FL/eMZL, n = 18; CLL, n = 9; MGUS, n = 6 patients. (B) Quantitative correlations between HLA-DR expression as activation marker with naive cells and senescence markers in CD4⁺ and CD8⁺ T cells of patients with FL/eMZL. (C) Quantitative correlation of activated HLA-DR⁺ cells between CD4⁺ and CD8⁺ T-cell compartments. (D) Retrospective analysis of data from the diagnostic immunophenotyping laboratory of the Freiburg Department of Hematology/Oncology. The fractions of activated HLA-DR⁺ T cells in 31 FL patients were compared between clinical stages as documented in the patients' records.