Effect of levamisole on E-rosette-forming cells in vivo and in vitro in Hodgkin's disease.

Incubation in vitro of lymphocytes from patients with Hodgkin's disease with 40 mug per milliliter of levamisole resulted in a rise in the number of E-rosette-forming cells from 33.6 +/- 12.5 per cent (mean +/- S.D.) to 56.7 +/- 14.6 per cent. The drug had no effect on normal lymphocytes. Ten patients with Hodgkin's disease treated six months previously with levamisole were restudied. The positive skin tests to PPD, candida and mumps persisted. However, the E-rosette-forming cells decreased to the pretreatment levels (34.7 +/- 6.4 per cent). Readministration of 150 mg of levamisole for three days raised the number of E-rosette-forming cells to 54.1 +/- 5.6 per cent. This effect was observed for at least two months. However, the drug had no effect in vitro as long as the in vivo effect persisted. These results demonstrate a clear immunologic effect of levamisole in Hodgkin's disease and indicate that the low number of E-rosette-forming cells is not due to a real T-cell depletion.