CD4 and diffuse large B-cell lymphoma: In summary, the increased regulatory T (Treg) cells along with decreased CD8+ T cells, CD4+ memory activated T cells, gamma delta T cells, M1 macrophages, and resting mast cells in high-risk DLBCL patients may facilitate tumor progression by hampering overall anti-tumor immune responses, increasing chemoresistance, etc., leading to poorer prognosis in this subset of patients.