CD4 and hepatocellular carcinoma: At concentrations up to 20 μg/mL, AFP did not alter the in vitro generation, maturation and T cell stimulation of DC. Higher AFP concentration ( >20 μg/ml) led to phenotypic changes in DC without impair its ability to stimulate CD4+ T cells. Independent of serum AFP levels, the frequency and function of DC and AFP-specific T cells did not decrease in HCC patients.