Surgery-induced decline in circulating dendritic cells in operable cancer patients: A possible explanation of postoperative immunosuppression

Background/Aims: The recent advances in the immunobiology of tumor have dem onstrated the essential role of dendritic cells in anticancer Immunity. Den dritic cells activate anticancer immunity by secreting interleukin-12 and b y activating T helper lymphocytes, with the following production of interle ukin-a. Since surgery-induced immunosuppression has been proven to be assoc iated with a decline in the blood levels of both interleukin-2 and interleu kin-12, it could depend at least in part on a transient deficiency of dendr itic cells system. Unfortunately, at present there are no data about change s in circulating dendritic cell number during the postoperative period. Thi s preliminary study was performed to evaluate the influence of surgery on d endritic cell number in the peripheral blood. Methodology: The study included 14 consecutive operable gastrointestinal tr act cancer patients, who were evaluated before and at day 7 of the postoper ative period. The control group consisted of 50 healthy subjects. Immature (CD 123(+)) and mature (CD 11(+)) dendritic cell subsets were measured by F AGS and monoclonal antibodies. Results: Cancer patients showed a significantly lower mean number of immatu re dendritic cells with respect to that found in controls. The mean number of mature dendritic cells:was also lower in patients than in controls, with out, however, significant differences. Finally, surgery induced a statistic ally significant decline in the mean number of both immature and mature den dritic cells, and the decrease was particularly pronounced for immature den dritic cells. Conclusions: In addition to the well-demonstrated surgery-induced lymphocyt openia, this preliminary study shows that the surgical treatment may determ ine a significant decrease in circulating immature and mature dendritic cel ls. Because of the fundamental role of dendritic cells in regulating the im mune responses, surgery-induced decline in circulating dendritic cells numb er could play a role in determining the immunosuppressive status, which cha racterizes the postoperative period.