Restoration by levamisole of E-rosette formation and its abrogation by autochthonous serum from patients with bladder cancer.

Incubation in vitro of lymphocytes from bladder cancer patients with levamisole (40 microgram/ml) resulted in a rise of the number of E-rosette forming cells from 39.2 +/- 11.8% to 57.5 +/- 11.3% (p less than 0.005). The same effect was observed when levamisole was administrated 150 mg/day for 3 days to the patients. The stimulatory effect of levamisole was abrogated when the lymphocytes were first incubated with levamisole and afterwards with 50% autochthonous serum from the patient. With more diluted serum concentrations (from 0.5% to 1%), the response decreased, and the response was not observed with allogeneic serum. When lymphocytes from healthy donors were incubated with 50% serum from bladder cancer patients, there were no significant changes in numbers of E-rosette forming cells. It was presumed that the suppression of E-rosette forming cells from the patients with bladder cancer was caused by blocking the receptor sites for sheep red blood cells by autochthonous serum components and that levamisole eliminated such substances from the cryptic sites on the surface of the lymphocytes.