Levamisole augments roxatidine's immune modulatory effects in the graft-versus-host reaction (GVHR).

Levamisole is known to have anti-anergic properties in immune compromised, but no or only marginal effects in immunologically competent subjects. In this study the possibility that levamisole would act as an 'immunoadjuvant' with roxatidine, a histamine H2 receptor blocker, is explored in healthy animals. Sixteen female, inbred Sprague-Dawley rats acted as lymphocyte donors and were treated for 8 days with either a roxatidine-levamisole combination, or levamisole alone, or roxatidine alone or placebo. Five randomly bred guinea pigs and eight inbred BD IX rats acted as lymphocyte acceptors. The in vivo effects of the four treatment modalities on transferred lymphocytes were expressed as the sizes of the allogeneic and xenogeneic graft-versus-host reactions as well as the radioactivity in each AGVHR. The combination of levamisole and roxatidine significantly augmented the cell mediated immune response in vivo and resulted in the most reactive lymphocytes as indicated by the AGVHR's and XGVHR's. These cells mediated reactions with significantly larger wheals as well as more lymphocyte proliferation in each reaction site than those caused by either levamisole or placebo treatment.