Conditioned alterations of specific blood leukocyte subsets are reconditionable

Behavioral conditioning has the ability to produce changes in immune functi on. However, it is unknown whether conditioned changes of immune function c an be recalled on multiple occasions, To address this issue we paired a nov el saccharin drinking solution with intraperitoneal cyclosporin A (CsA) inj ection in rats. Saccharin representation produced a reduction in splenocyte proliferation that mirrored the effect of CsA. Such functional changes wer e paralleled by a significant conditioned leukopenia in peripheral blood, w hich opposed the leukocytosis induced by CsA. Using the conditioned leukope nia in blood as a 'diagnostic window' of conditioned immunosuppression, the maintenance of CsA-induced changes was investigated by examining blood sam ples collected repeatedly. Experiments on the same group of animals over a period of 1 year showed that the conditioned leukopenia was reproducible on multiple occasions by reimplementing either the whole conditioning paradig m or reexposure to the saccharin solution only. These results demonstrate t hat behaviorally conditioned alterations of immune parameters are maintaine d in subsequent trials, indicating the potential clinical feasibility of be havioral conditioning procedures. Copyright (C) 2000 S. Karger AG, Basel.