Cisplatin induces serotonin release from human peripheral blood mononuclear cells of cancer patients and methylprednisolone inhibits this effect.

The aim of this study was to verify whether cisplatin (CDDP) can induce serotonin (5HT) release from peripheral blood mononuclear cells (PBMC) of cancer patients and determine whether methylprednisolone (MP) can inhibit such release. Ten patients (mean age 61.8 years) with cancer of different sites, all but one in advanced stage of disease were studied. Our study showed that unstimulated PBMC of cancer patients release a higher amount of 5HT than that of healthy subjects (57+/-5 nM vs 10+/-1 nM, p<0.001) and that similarly the stimulation with PHA or CDDP induces a higher amount of 5HT release by PBMC of cancer patients than that by PBMC of healthy subjects (74+/-6 vs 32+/-3 nM, p<0.001 and 91+/-8 vs 18+/-2 nM, p<0.001, respectively). The addition of MP to the culture in the presence of CDDP induced a significant decrease of 5HT levels: from 91+/-8 to 53+/-7 nM, p=0.002. This result obtained in cancer patients paralleled that previously obtained by us in healthy subjects. Our data confirm a new mechanism through which CDDP could induce emesis and provide a further possible explanation to the anti-emetic activity of corticosteroids, such as MP.