γδ T lymphocytes from NHL patients produce IL-4. (A) Human IL-4 measured in the sera of HD and patients using the FlowCytomix Multiplex kit. Samples were then run on a flow cytometer (FACScan), analyzed with BMS FlowCytomix software, and referred to a standard curve. Results are expressed as picograms per milliliter and are the mean ± SD from 15 FL, 4 MT, 4 MZ lymphomas, 4 DLCL, 10 B-CLL patients, and 6 HDs. *P < .01 versus HD or B-CLL or DLCL; **P < .01 versus HDs or B-CLL or DLCL, or MZ or MT. (B-C) PBMCs were separated from HDs and FL, B-CLL, and DLCL patients and stained with Alexa Fluor-488–conjugated anti-γδ (B) or anti-Vδ1 or anti-Vδ2 (C) mAb and, after fixation and permeabilization, cytoplasmic staining with PE–anti-IL-4 was performed. (B) Top dot plots are one representative FL staining of PB (i) or LN cells (ii); bottom dot plots are one representative HD (iii) and one representative B-CLL (iv). Results are expressed as log red fluorescence intensity versus log green fluorescence intensity (au). (C) Percentage of IL-4⁺ cells, among Vδ1 or Vδ2 T cells, calculated as percentage of red cells (PE–anti-IL-4 mAb) after gating on green cells detected by immunofluorescence staining with specific anti-Vδ1 or anti-Vδ2 mAbs. Results are the mean ± SD from 15 FL, 4 MT, 4 MZ lymphomas, 4 DLCL, and 10 B-CLL patients, and 6 HDs. *P < .01 versus Vδ2.