Serum soluble interleukin-2 receptor alpha levels in patients with gynecologic cancers: early effect of surgery

Potential prophylactic measures against postoperative immunosuppression: could they reduce recurrence rates in oncological patients?

BACKGROUND

Removing the primary tumor is indispensable for eliminating the major pool of metastasizing cells, but the surgical procedure itself is suspected of promoting metastases. This adverse effect is attributed to several mechanisms acting in synergy, including mechanical release of tumor cells, enhanced angiogenesis, secretion of growth factors, and immunosuppression. Here we provide new insights into mechanisms of postoperative immunosuppression and assess the assumptions underlying the hypothesis that, by suppressing cell-mediated immunity (CMI), surgery may render the patient vulnerable to metastases that otherwise could have been controlled.

METHODS

An extensive review of relevant articles in English identified by using the MEDLINE database and cross-referencing.

RESULTS

Current literature suggests that (1) CMI can control minimal residual disease, especially if surgery is performed early; (2) major surgery transiently but markedly suppresses CMI through multiple mechanisms now better understood; (3) surgical stress promotes experimental metastasis through immunosuppression, but the clinical evidence remains indirect because of ethical limitations.

CONCLUSIONS

Minimizing postoperative immunosuppression seems feasible, may limit recurrence, and should be introduced into the broader array of considerations when planning oncological surgeries. In the short run, physicians could try to avoid immunosuppressive anesthetic approaches, inadvertent hypothermia, excessive blood transfusions, and untended postoperative pain. When feasible, minimally invasive surgery should be considered. In the long run, clinical trials should evaluate prophylactic measures, including perioperative immunostimulation and several antagonists to cytokines and hormones specified herein.

Immuno-gene therapy with interferon-β before surgical debulking delays recurrence and improves survival in a murine model of malignant mesothelioma

OBJECTIVES

Immuno-gene therapy of mesothelioma with an adenovirus encoding interferon-beta mediated strong antitumor responses in murine models with low but not high tumor burden. Our goals were to determine the mechanisms responsible for this loss of efficacy and to test the hypothesis that the combination of preoperative adenovirus encoding interferon-beta and surgical resection would be effective in treating bulky tumors.

METHODS

Flank tumors of a mouse mesothelioma cell line were treated with adenovirus encoding interferon-beta or adenoviral vector encoding the bacterial protein beta-galactosidase. Cytotoxic T lymphocytes and tumor infiltration by T lymphocytes were measured. Tumors were surgically excised 72 hours later and tumor cells were injected in the contralateral flank to create a model of a metastatic focus. Tumor-free survival and distant metastatic disease were assessed.

RESULTS

Immuno-gene therapy effectively treated small tumors (<200 mm(3)) but did not reduce the size of large (>800 mm(3)) flank tumors. Although treatment with adenovirus encoding interferon-beta resulted in the generation of tumor-neutralizing splenocytes in large tumors, the number of T cells visualized within the tumors was minimal. Tumors treated with adenovirus encoding interferon-beta (versus adenoviral vector encoding the bacterial protein beta-galactosidase or phosphate-buffered saline solution) prior to debulking increased long-term tumor-free survival and resulted in two- to sixfold smaller foci of implanted tumor cells at 2 weeks postoperatively.

CONCLUSIONS

The use of adenovirus encoding interferon-beta or surgical debulking alone is ineffective in treating large tumors, but combining preoperative adenovirus encoding interferon-beta and surgical debulking significantly reduces tumor recurrence and improves long-term tumor-free survival. We postulate that adenovirus encoding interferon-beta amplifies the cytotoxic T-lymphocyte antitumor response, allowing elimination of residual tumor cells.

Immunological effects following administration of interferon-alpha in patients with chronic hepatitis C virus (cHCV) infection

The immunological effects of interferon (IFN)-alpha administration were evaluated in 15 patients with cHCV infection. Individuals were treated with 6 MU of lymphoblastoid IFN-alpha three times a week for 6 months and with 3 MU three times a week for an additional 6 months. Patients were divided into responders (12 subjects) and nonresponders (3 subjects), respectively, according to alanine aminotransferase serum levels at the end of treatment. Before therapy (T0), absolute numbers of CD3+, CD4+, CD8+, CD14+ and CD16+ cells were significantly reduced in both groups when compared to normal values. At the same time, all patients displayed a profound decrease of phagocytosis and killing exerted by both polymorphonuclear cells (PMN) and monocytes (MO). However, MO Killing resulted to be normal in the responder group. With special reference to T cell function, T cell mediated antibacterial activity, using Salmonella typhi as a target, was also significantly reduced. After therapy (T12), in responder patients a significant increase of CD3+, CD4+, CD14+ and CD16+ cell absolute numbers was observed, while phagocytic and T cell functions were still depressed. Among the nonresponders, in two of three patients IFN-alpha administration gave rise to an increase (above normality) of CD3+, CD4+, CD8+, CD14+, CD16+ and CD20+ cell absolute numbers, while in one patient the same markers dramatically dropped below normal range. In two patients, antibacterial activity was significantly augmented by IFN-alpha treatment, whereas in one patient no modification was observed. Finally, in the same patients IFN-alpha did not correct PMN and MO pretreatment deficits.

A critical analysis of soluble interleukin-2 receptor levels in kidney allograft recipients

Soluble interleukin-2 receptor (sIL-2R) was measured by the Cellfree Kit (T Cell sciences) in 103 pretransplant and 1590 posttransplant samples from 103 patients with cadaveric kidney allografts. The mean values (+/- SD) detected in pretransplant sera were significantly higher (1932 +/- 1389 U/ml) than in 72 healthy adults (267 +/- 139 U/ml), but after transplantation they continuously fell towards normal levels within the first 3 postoperative weeks. Recipients with acute rejection episodes showed higher sIL-2R levels (1762 +/- 904 U/ml) than those with stable transplants at discharge (937 +/- 398 U/ml). Highest values were detected during antirejection therapy with antithymocyte globulin (4996 +/- 2166 U/ml) or OKT3 (5905 +/- 3910). Increases were also observed during bacterial and viral infections and even, in some cases, without any apparent cause. Because of this lack of specificity, elevated sIL-2R levels should be interpreted cautiously. Nevertheless, sIL-2R level can be useful for monitoring kidney allograft recipients. Increases point to a cellular immune activation process and can predict rejections or infections.

Evaluation of cellular immune responses and soluble mediators in patients with chronic hepatitis C virus (cHCV) infection

In 54 patients with cHCV infection, peripheral immune responsiveness and soluble mediator release were evaluated. Results demonstrate that in these patients phagocytosis and killing capacities exerted by polymorphonuclear cells and monocytes were profoundly depressed. At the same time, absolute numbers of CD3+, CD8+ and CD16+ cells were reduced, while the CD4(+)-CD8+ dependent antibacterial activity was also impaired. With special reference to soluble mediators, elevated amounts of both soluble interleukin-2 receptor and soluble intercellular adhesion molecule-1 were detected in sera of patients. By contrast, serum levels of tumor necrosis factor-alpha were within normal ranges, whereas interferon-gamma serum concentrations were decreased. Of note, in 18.5% of cHCV patients circulating levels of bacterial lipopolysaccharides (LPS) were detected by means of Limulus assay. In the Limulus+subset of patients, absolute numbers of CD14+ cells were reduced in a significant manner, this implying a putative monocyte-LPS interaction. In conclusion, the overall results indicate a condition of peripheral immune depression in cHCV patients with an exaggerated shedding of various mediators endowed with noxious effects for the host.