IL10 and B-cell chronic lymphocytic leukemia: IL-10, produced by Th2 cells and by CLL clones themselves, is a powerful inhibitor of the Th1 cytokine synthesis—including IFN-γ, TNF-α, IL-2 and lymphotoxin-α [149]—and stimulates B cell proliferation and differentiation, thus further promoting the skewing toward a Th2 response [150].