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Lymphocytopenia is one of the most negative biological prognostic factors in cancer patients. Lymphocytopenia may depend on tumor progression, or on various anticancer therapies. In particular, radiotherapy (RT) may induce direct lymphocyte damage. The present study was carried out to evaluate the influence of pelvic irradiation on lymphocyte number and lymphocyte subpopulations in patients with gynecologic tumors. The study included 40 patients affected by locally limited or advanced uterine tumors, who underwent pelvic irradiation for a total dose of 50.4 Gy. RT induced a significant decline in total lymphocyte number, with values lower than 500/mm3 in 29/40 (73%) patients and with a mean decrease of 71 +/- 4%. In the same way, T lymphocyte, CD4, CD8 and NK cell mean numbers significantly decreased under RT. The decline in NK and CD8 cells was limited to the first 2-3 weeks of irradiation, whereas that involving T lymphocytes and CD4 cells was progressive and persistent until the end of RT. Finally, the decline in total lymphocyte number was significantly greater in patients who had no tumor regression in response to RT. This study confirms that pelvic RT may induce severe lymphocytopenia which could negatively influence the efficacy of RT itself.

Despite the well demonstrated fundamental role of dendritic cells (DC) in generating antitumor immunity in experimental conditions, to date there are only few preliminary studies which investigate the percent of DC in the peripheral blood of cancer patients. Several cell surface markers have now been described which are specific to cultured DC, however their expression in vivo is still controversial. Recently, however, two DC subsets, consisting of immature and mature DC, have been shown to be present in peripheral blood, which can be recognized as CD123+ and CD11c+ cells, respectively. On this basis, we decided to investigate the presence of both mature and immature DC in the peripheral blood of early or advanced cancer patients. The study included 40 solid tumor patients, 18 of whom had a locally limited disease, while the other 22 showed distant organ metastases. CD123+ and CD11c+ cells were detected by FACS using monoclonal antibodies, and expressed as the percent of total leukocytes. The control group consisted of 50 healthy subjects. The mean percent of both CD123+ and CD11c+ cells was significantly lower in cancer patients than in controls. Moreover, the mean percent of both DC subsets was significantly lower in metastatic patients than in the non-metastatic ones. This study, demonstrating significantly lower percents of both immature and mature DC in the peripheral blood of cancer patients, particularly in those with distant organ metastases, suggests that DC deficiency may play a role in inducing cancer-related immunosuppression. Therefore, the demonstration of a diminished percent of DC in peripheral blood may represent a new interesting biological marker predicting a poor prognosis in human neoplasms, as with lymphocytopenia, the unfavourable prognostic significance of which has been well demonstrated.

Experimental studies have shown that IL-12 plays an important role in the activation of the anticancer immune defenses. Unfortunately, at present the behavior of IL-12 secretion in human neoplasms remain to be established. In an attempt to draw some preliminary data about IL-12 secretion in human cancer, in the present study we have evaluated serum levels of IL-12 in a group of non-metastatic and metastatic solid tumor patients in relation to the survival time, and their changes in surgically treated cancer patients and in metastatic patients undergoing immunotherapy with IL-2. Mean serum levels of IL-12 were significantly higher metastatic patients (n = 40) than in those with locally limited solid neoplasm (n = 16). Moreover, within the metastatic group, the percent of 1-year survival was significantly higher in patients with abnormally elevated blood concentrations of IL-12 than in those with normal values. In the group of 10 patients surgically treated for gastrointestinal tract tumors, the surgical operation induced a significant decline in IL-12 mean serum levels. Finally, in a group of 23 metastatic renal cell cancer patients treated with IL-12 immunotherapy (6 million IU/day S.C. for 6 days/week for 4 weeks), the treatment was associated with a significant and progressive increase in IL-12 mean values. Moreover, serum mean levels of IL-12 observed in therapy in patients with response or stable disease were significantly higher than those found in progressing patients. This preliminary study seems to suggest that the evidence of high levels of IL-12 may have a favourable prognostic significance in solid tumor patients, either in baseline conditions or in response to IL-2 cancer immunotherapy.

Several experiments have suggested that the pineal hormone melatonin (MLT) may regulate cancer growth by exerting both oncostatic and immunomodulating effects. In particular, MLT would stimulate the anticancer immunity induced by interleukin-2 (IL-2). Recent studies seem to suggest that the activation of the inflammatory response may counteract the anticancer efficacy of IL-2 immunotherapy because of the immunosuppressive action of inflammatory-related cytokines, mainly IL-6. At present, it is still unknown whether MLT may influence host immune antitumor defences by modulating the inflammatory response. To analyze this hypothesis, we have evaluated the effects of a chronic administration of MLT on some of the commonly used markers of inflammation, including erythrosedimentation rate (ESR), IL-6, neopterin and SIL-2R, in patients with evidence of activation of the inflammatory response due to advanced solid neoplasms or auto-immune diseases. The study included 14 patients (solid tumors: 9; autoimmune diseases: 5). MLT was given orally at 20 mg/day during the dark phase of the day for 7 consecutive days. Mean serum levels of IL-6, neopterin and SIL-2R significantly decreased in both groups of patients. ESR values also decreased on therapy, without, however, significant differences. This preliminary study shows that the pineal hormone MLT may inhibit the acute inflammatory reaction. Therefore, because of the immunosuppressive section of inflammation-related cytokines, this study could suggest that MLT may contribute to the generation of the immune reaction against cancer at least in part by removing the immunosuppression related to the activation of the inflammatory response.

Despite the great importance of IL-2 and IL-12 in activating the anticancer immune response in humans, cancer-related physiopathology of their secretion needs to be better investigated. IL-2 blood levels have been proven to decrease in the advanced neoplastic disease, whereas preliminary data would suggest an enhanced secretion of IL-12 in metastatic cancer patients. This study was performed to analyze IL-2 levels in relation to those of IL-12 in metastatic solid neoplasms. The study included 40 untreated metastatic cancer patients. Serum levels of both IL-2 and IL-12 were measured by ELISA. Abnormally low blood levels of IL-2 and elevated values of IL-12 were observed in 16/40 and in 18/40 patients, respectively. Moreover, patients with IL-2 deficiency showed significantly higher mean levels of IL-12 than patients with normal values of IL-2. This preliminary result, by showing an increased secretion of IL-12 in advanced cancer patients with IL-2 endogenous deficiency, would suggest the existance of a possible feedback mechanism operating between macrophage release of IL-12 and T lymphocyte secretion of IL-2.