Inhibition of lymphocyte proliferation by sera from patients with hepatocellular carcinoma: lack of correlation with serum alpha-fetoprotein levels.

Sera from 23 hepatocellular carcinoma (HCC) patients were studied for their effects on lymphocyte proliferation during polyclonal mitogen stimulation and one-way mixed lymphocyte culture (MLC). The effect of 25% HCC serum on tritiated thymidine uptake of cultures varied from slight augmentation to 95% inhibition; however, no relationship was found between the potency of inhibition and serum alpha-fetoprotein (AFP) concentration. Purified AFP from the ascitic fluid of an HCC patient had no effect on MLC or cultures containing pokeweed mitogen; but at a concentration of 200 micro g/ml, AFP inhibited up to 30% of the proliferative responses in cultures containing phytohemagglutinin or concanavalin A. Results strongly suggest that the AFP in HCC sera is not inhibitory in itself.