CD4 and lymphoma: Immune subsets of prognostic interest include, among others: CD68+ lymphoma-associated macrophages [9–12], CD3+ T cells [10, 12–14], CD4+ T helper cells [12–14], CD8+ cytotoxic T cells [12–15], CD4+FOXP3+ T regulatory cells (Tregs) [12, 14, 16–18], CD21+ dendritic cells [12], mast cells [19], and PD-1 expressing T-cells [12, 14, 20].