Current status of interleukin-2 therapy in cancer

Beyond Promoter: The Role of Macrophage in Invasion and Progression of Renal Cell Carcinoma

Renal cell carcinoma (RCC) is one of the common urologic neoplasms, and its incidence has been increasing over the past several decades; however, its pathogenesis is still unknown up to now. Recent studies have found that in addition to tumor cells, other cells in the tumor microenvironment also affect the biological behavior of the tumor. Among them, macrophages exist in a large amount in tumor microenvironment, and they are generally considered to play a key role in promoting tumorigenesis. Therefore, we summarized the recent researches on macrophage in the invasiveness and progression of RCC in latest years, and we also introduced and discussed many studies about macrophage in RCC to promote angiogenesis by changing tumor microenvironment and inhibit immune response in order to activate tumor progression. Moreover, macrophage interactes with various cytokines to promote tumor proliferation, invasion and metastasis, and it also promotes tumor stem cell formation and induces drug resistance in the progression of RCC. The highlight of this review is to make a summary of the roles of macrophage in the invasion and progression of RCC; at the same time to raise some potential and possible targets for future RCC therapy.

Comprehensive analysis of current approaches to inhibit regulatory T cells in cancer

CD4⁺CD25⁺Foxp3⁺ regulatory T cells (Treg) have emerged as a dominant T cell population inhibiting anti-tumor effector T cells. Initial strategies used for Treg-depletion (cyclophosphamide, anti-CD25 mAb…) also targeted activated T cells, as they share many phenotypic markers. Current, ameliorated approaches to inhibit Treg aim to either block their function or their migration to lymph nodes and the tumor microenvironment. Various drugs originally developed for other therapeutic indications (anti-angiogenic molecules, tyrosine kinase inhibitors,etc) have recently been discovered to inhibit Treg. These approaches are expected to be rapidly translated to clinical applications for therapeutic use in combination with immunomodulators.

Nanomaterials for T-cell cancer immunotherapy

T-cell-based immunotherapies hold promise for the treatment of many types of cancer, with three approved products for B-cell malignancies and a large pipeline of treatments in clinical trials. However, there are several challenges to their broad implementation. These include insufficient expansion of adoptively transferred T cells, inefficient trafficking of T cells into solid tumours, decreased T-cell activity due to a hostile tumour microenvironment and the loss of target antigen expression. Together, these factors restrict the number of therapeutically active T cells engaging with tumours. Nanomaterials are uniquely suited to overcome these challenges, as they can be rationally designed to enhance T-cell expansion, navigate complex physical barriers and modulate tumour microenvironments. Here, we present an overview of nanomaterials that have been used to overcome clinical barriers to T-cell-based immunotherapies and provide our outlook of this emerging field at the interface of cancer immunotherapy and nanomaterial design.

Developments in Intralesional Therapy for Metastatic Melanoma

BACKGROUND

Locoregional advanced melanoma poses a complex clinical challenge that requires a multidisciplinary, patient-centered approach. Numerous agents have been studied for their suitability as intralesional therapy in the past decades, but few have successfully completed phase 3 clinical trial testing.

METHODS

The relevant medical literature was searched for articles regarding use of intralesional therapies in metastatic melanoma. Therapies with data from phase 2 or higher studies were selected for review. This review also summarizes the mechanisms of action, adverse-event profiles, and clinical data for these agents.

RESULTS

Intralesional therapies demonstrate promising effects in select patients with advanced melanoma. The optimal approach should be individually tailored and consist of a combination of intralesional therapies, regional perfusions, systemic immunotherapies, targeted therapies, and surgery, if necessary.

CONCLUSIONS

Due to its relatively good local response rates and tolerable adverse-event profile, intralesional therapy may be a treatment option for select patients with unresectable, locally advanced or metastatic melanoma.

Prevention of post-traumatic clinical capillary leak syndrome

Systemic capillary leak is an early feature of the inflammatory response to localized injury, and is proportional to the severity of the inflammatory insult. Loss of local control of inflammation leads to an exaggerated systemic inflammatory response known as systemic inflammatory response syndrome (SIRS). SIRS is associated with multiple organ failure and death when there is failure to maintain homeostasis.

Whilst the application of molecular biology and recombinant techniques have produced major advances in our understanding of the mediation of the inflammatory response, there is no agent currently available which will prevent SIRS and reduce the incidence of post-traumatic multiple organ failure. In the meantime, a more practical approach to the avoidance of SIRS and its attendant capillary leak syndrome is to attempt to reduce the deleterious effects of interstitial oedema by tailoring treatment to the rapid changes in capillary permeability.

NK Cell-Mediated Antibody-Dependent Cellular Cytotoxicity in Cancer Immunotherapy

Natural killer (NK) cells play a major role in cancer immunotherapies that involve tumor-antigen targeting by monoclonal antibodies (mAbs). NK cells express a variety of activating and inhibitory receptors that serve to regulate the function and activity of the cells. In the context of targeting cells, NK cells can be "specifically activated" through certain Fc receptors that are expressed on their cell surface. NK cells can express FcγRIIIA and/or FcγRIIC, which can bind to the Fc portion of immunoglobulins, transmitting activating signals within NK cells. Once activated through Fc receptors by antibodies bound to target cells, NK cells are able to lyse target cells without priming, and secrete cytokines like interferon gamma to recruit adaptive immune cells. This antibody-dependent cell-mediated cytotoxicity (ADCC) of tumor cells is utilized in the treatment of various cancers overexpressing unique antigens, such as neuroblastoma, breast cancer, B cell lymphoma, and others. NK cells also express a family of receptors called killer immunoglobulin-like receptors (KIRs), which regulate the function and response of NK cells toward target cells through their interaction with their cognate ligands that are expressed on tumor cells. Genetic polymorphisms in KIR and KIR-ligands, as well as FcγRs may influence NK cell responsiveness in conjunction with mAb immunotherapies. This review focuses on current therapeutic mAbs, different strategies to augment the anti-tumor efficacy of ADCC, and genotypic factors that may influence patient responses to antibody-dependent immunotherapies.

Trial Watch: Therapeutic vaccines in metastatic renal cell carcinoma

Despite the renaissance of cancer immunotherapy, no novel immunotherapy has been approved for the treatment of renal cell cancer (RCC) since the availability of recombinant cytokines (interleukin-2, interferon-α). All vaccine trials have failed to meet their endpoints although they have highlighted potential predictive biomarkers (e.g., pre-existing immune response, hematological parameters, tumor burden). Recent advances in immunomodulatory therapies have prompted the study of combination treatments targeting the tumor immunosuppressive microenvironment consisting of regulatory T-cells (Treg), myeloid suppressor cells, and cytokines. Approaches under investigation are use of inhibitors to curb the overexpression of immune checkpoint ligands by tumor cells (e.g., anti-CTLA-4, anti-PD-1/PD-L1) and exploiting the immunomodulatory effects of anti-angiogenic agents that are the current standard of metastatic RCC care. Phase III trials are focusing on the possible synergy between therapeutic vaccines (e.g., IMA-901 and AGS-003) and anti-angiogenic agents.

Clinical validation of IFNγ/IL-10 and IFNγ/IL-2 FluoroSpot assays for the detection of Tr1 T cells and influenza vaccine monitoring in humans

The type of T cell polarization and simultaneous production of multiple cytokines have been correlated with vaccine efficacy. ELISpot is a T cell detection technique optimized for the measurement of a secreted cytokine at the single cell level. The FluoroSpot assay differs from ELISpot by the use of multiple fluorescent-labeled anticytokine detection antibodies, allowing optimal measurement of multiple cytokines. In the present study, we show that an IFNγ/IL-10 FluoroSpot assay is more sensitive than flow cytometry to detect Tr1 regulatory T cells, an immunosuppressive T cell population characterized by the production of IL-10 and IFNγ. As many tolerogenic vaccines are designed to induce these Tr1 cells, this FluoroSpot test could represent a standard method for the detection of these cells in the future. The use of an IFNγ/IL-2 FluoroSpot assay during influenza vaccine monitoring showed that the influenza-specific IL-2-producing T-cell response was the dominant response both before and after vaccine administration. This study therefore questions the rationale of using the single-color IFNγ ELISpot as the standard technique to monitor vaccine-specific T-cell response. Using this same test, a trend was also observed between baseline levels of IFNγ T cell response and T cell vaccine response. In addition, a lower IFNγ+IL-2+ T-cell response after vaccine was observed in the group of patients treated with TNFα inhibitors (P=0.08). This study therefore supports the use of the FluoroSpot assay due to its robustness, versatility and the complementary information that it provides compared with ELISpot or flow cytometry to monitor vaccine-specific T-cell responses.

[At the crossroads of cancer]

Since the introduction of the concept of immunosurveillance in 1970 by Macfarlane Burnet and Lewis Thomas, cancer immunology has known a significant revolution and an explosion of discoveries. In this regard, manipulation of the immune system in cancer pathology has been a succession of enthusiasms and failures. Thanks to the fundamental achievements during the past three decades, non-specific passive immunotherapy of cancer has shifted to active specific immunotherapy. Thanks to the immunological arsenal (tumor peptides, dendritic cells), the clinical trials have increased but the results were not encouraging. It became clear that the escape of immunosurveillance by tumor cells is under the control of the complex tumor microenvironment and its heterogeneity, complexity and plasticity. The future of immunotherapy lies in an integrative approach to simultaneously boost the immune system and target the tumor microenvironment or combine immunotherapy with conventional treatments. In this review, we will focus on the development of cancer immunotherapy, its realities, failure and hope it raises as the fourth modality of cancer therapy.

NK cells from pleural effusions are potent antitumor effector cells

Natural killer (NK) cells express a set of activating and inhibitory receptors which, after interaction with their ligands, determine whether or not the target cell will be lysed. Many studies have clearly demonstrated that NK cells have the capacity to lyse stressed cells (such as tumor or virally-infected cells). However, NK cells that infiltrate tumors usually exhibit phenotypic and functional defects. In this issue of the European Journal of Immunology, Vacca et al. [Eur. J. Immunol. 2013. 43: 550-561] show that NK cells in pleural effusions of primary and metastatic tumors of various origins are not anergic, possibly because the downregulation of activating receptors and the upregulation of inhibitory receptors does not occur, as previously reported for tumor NK cells. Another major finding of this study is the capacity of these pleural NK cells to respond to IL-2 stimulation, as the authors demonstrate that pleural NK cells stimulated by IL-2 in long-term culture acquire the capacity to lyse autologous tumor cells isolated from pleural effusions. These results support the treatment of primary or metastatic pleural tumors with IL-2 or other innovative strategies currently being developed to stimulate NK cells in cancer patients as discussed in this Commentary.

Trial Watch: Adoptive cell transfer for anticancer immunotherapy

Adoptive cell transfer (ACT) represents a prominent form of immunotherapy against malignant diseases. ACT is conceptually distinct from dendritic cell-based approaches (which de facto constitute cellular vaccines) and allogeneic transplantation (which can be employed for the therapy of hematopoietic tumors) as it involves the isolation of autologous lymphocytes exhibiting antitumor activity, their expansion/activation ex vivo and their reintroduction into the patient. Re-infusion is most often performed in the context of lymphodepleting regimens (to minimize immunosuppression by host cells) and combined with immunostimulatory interventions, such as the administration of Toll-like receptor agonists. Autologous cells that are suitable for ACT protocols can be isolated from tumor-infiltrating lymphocytes or generated by engineering their circulating counterparts for the expression of transgenic tumor-specific T-cell receptors. Importantly, lymphocytes can be genetically modified prior to re-infusion for increasing their persistence in vivo, boosting antitumor responses and minimizing side effects. Moreover, recent data indicate that exhausted antitumor T lymphocytes may be rejuvenated in vitro by exposing them to specific cytokine cocktails, a strategy that might considerably improve the clinical success of ACT. Following up the Trial Watch that we published on this topic in the third issue of OncoImmunology (May 2012), here we summarize the latest developments in ACT-related research, covering both high-impact studies that have been published during the last 13 months and clinical trials that have been initiated in the same period to assess the antineoplastic profile of this form of cellular immunotherapy.

Trial Watch: Adoptive cell transfer immunotherapy

During the last two decades, several approaches for the activation of the immune system against cancer have been developed. These include rather unselective maneuvers such as the systemic administration of immunostimulatory agents (e.g., interleukin-2) as well as targeted interventions, encompassing highly specific monoclonal antibodies, vaccines and cell-based therapies. Among the latter, adoptive cell transfer (ACT) involves the selection of autologous lymphocytes with antitumor activity, their expansion/activation ex vivo, and their reinfusion into the patient, often in the context of lymphodepleting regimens (to minimize endogenous immunosuppression). Such autologous cells can be isolated from tumor-infiltrating lymphocytes or generated by manipulating circulating lymphocytes for the expression of tumor-specific T-cell receptors. In addition, autologous lymphocytes can be genetically engineered to prolong their in vivo persistence, to boost antitumor responses and/or to minimize side effects. ACT has recently been shown to be associated with a consistent rate of durable regressions in melanoma and renal cell carcinoma patients and holds great promises in several other oncological settings. In this Trial Watch, we will briefly review the scientific rationale behind ACT and discuss the progress of recent clinical trials evaluating the safety and effectiveness of adoptive cell transfer as an anticancer therapy.

[Cancer immunotherapy: recent breakthroughs and perspectives]

Immunotherapy of cancer has long been considered as an attractive therapeutic approach but with no impact on clinical practice. Two clinical protocols of immunotherapy, one based on a cancer vaccine in patients with prostate cancer or melanoma and the other using an immunomodulator targeting T cells (anti-CTLA4 mAb) in melanoma patients, have demonstrated clinical efficacy in two phase III clinical trials. To improve these encouraging clinical results, biomarkers to better select patients which may benefit from this therapy are actively searched. In addition, immunosuppression associated with cancer has to be overcome to allow a better immunostimulation. In contrast to chemotherapy, clinical variables to monitor the efficacy of immunotherapy has to be revisited and overall survival appears to be a better endpoint than clinical response defined by the RECIST criteria. Combination of immunotherapy with conventional treatments (chemotherapy, anti-angiogenic, etc.) should further improve this approach both in its effectiveness and in its clinical indications.

Angiogenesis and immunity: a bidirectional link potentially relevant for the monitoring of antiangiogenic therapy and the development of novel therapeutic combination with immunotherapy

The immune system regulates angiogenesis in cancer with both pro- and antiangiogenic activities. The induction of angiogenesis is mediated by tumor-associated macrophages and myeloid-derived suppressor cells (MDSC) which produce proinflammatory cytokines, endothelial growth factors (VEGF, bFGF…), and protease (MMP9) implicated in neoangiogenesis. Some cytokines (IL-6, IL-17…) activated Stat3 which also led to the production of VEGF and bFGF. In contrast, other cytokines (IFN, IL-12, IL-21, and IL-27) display an antiangiogenic activity. Recently, it has been shown that some antiangiogenic molecules alleviates immunosuppression associated with cancer by decreasing immunosuppressive cells (MDSC, regulatory T cells), immunosuppressive cytokines (IL-10, TGFβ), and inhibitory molecules on T cells (PD-1). Some of these broad effects may result from the ability of some antiangiogenic molecules, especially cytokines to inhibit the Stat3 transcription factor. The association often observed between angiogenesis and immunosuppression may be related to hypoxia which induces both neoangiogenesis via activation of HIF-1 and VEGF and favors the intratumor recruitment and differentiation of regulatory T cells and MDSC. Preliminary studies suggest that modulation of immune markers (intratumoral MDSC and IL-8, peripheral regulatory T cells…) may predict clinical response to antiangiogenic therapy. In preclinical models, a synergy has been observed between antiangiogenic molecules and immunotherapy which may be explained by an improvement of immune status in tumor-bearing mice after antiangiogenic therapy. In preclinical models, antiangiogenic molecules promoted intratumor trafficking of effector cells, enhance endogenous anti-tumor response, and synergyzed with immunotherapy protocols to cure established murine tumors. All these results warrant the development of clinical trials combining antiangiogenic drugs and immunotherapy.

Big tumor regression induced by GM-CSF gene-modified 3LL tumor cells via facilitating DC maturation and deviation toward CD11c+CD8alpha+ subset

Granulocyte-macrophage colony-stimulating factor (GM-CSF) is a powerful immune-stimulating factor that helps to generate a systemic, strong, and long-lasting immune response. However, whether the transduction of GM-CSF to tumor cell results in tumor regression and optimizes local immune microenvironment remains to be investigated. In this study, using an experimental murine tumor model, we demonstrated that the in vivo growth of 3LL tumor cells modified with the GM-CSF gene (3LL-GM) was inhibited even when the tumor diameter was over 7 mm (big tumor), and mice inoculated with GM-CSF gene-modified 3LL cells survived over 90 days, whereas mice inoculated with control parental 3LL cells and 3LL cells transduced with control vector all succumbed to the tumor by day 17 after tumor inoculation. Further analysis showed that targeted expression of GM-CSF in 3LL tumor cells markedly enhanced the systemic antitumor effect, including specific lymphocytes proliferation, cytotoxicity against 3LL tumor, and increased production of IFN-gamma. GM-CSF gene-modified 3LL cells significantly protected the mice from the parental 3LL tumor challenge. More importantly, the percentage of dendritic cells (DCs) in tumor site was greatly increased and the DCs differentiated into CD11c(+)CD8alpha(+) cells, which were reported to be able to benefit the induction of CD8(+) cytotoxic T lymphocytes (CTLs) that contribute to tumor regression. Our research indicated that GM-CSF could optimize the immune microenvironment in the tumor site, which provides a potent approach for immunotherapy of tumors.

Restoring immune defenses via lymphotoxin signaling: lessons from cytomegalovirus

Although primary infection with human cytomegalovirus (HCMV), a beta-herpesvirus, is widespread and acquired early in life, it rarely causes disease in immune-competent individuals. However, in immune-compromised patients HCMV infection or reactivation invariably leads to serious disease, the effective treatment of which remains a difficult clinical problem. Current antiviral therapy is limited not only by toxicity but also by the continual emergence of drugresistant viruses. The limitations of these current therapeutics provides a strong impetus to develop novel approaches that will enhance the host's immune responsiveness while at the same time effectively controlling virus replication. Type I interferon (IFN) plays a critical role in initiating innate antiviral defenses and promoting adaptive responses and lymphotoxin (LT)-alphabeta has recently been identified as an essential effector cytokine regulating the induction of type I IFN during CMV infection. In particular, CMV infection of immune-compromised mice has revealed the immunotherapeutic potential of the lymphotoxin-beta receptor (LTbetaR) signaling pathway to restore immune function and provide protection from CMV mortality. In this review, we discuss the potential benefits and risks associated with LTbetaR-directed immunotherapy for CMV disease and other persistent viral infections.

Phase I clinical trial with IL-2-transfected xenogeneic cells administered in subcutaneous metastatic tumours: clinical and immunological findings

Various studies have emphasized an immunodepression state observed at the tumour site. To reverse this defect and based upon animal studies, we initiated a phase I clinical trial of gene therapy in which various doses of xenogeneic monkey fibroblasts (Vero cells) genetically engineered to produce human IL-2 were administered intratumorally in 8 patients with metastatic solid tumours. No severe adverse effect was observed in the 8 patients analysed during this clinical trial even in the highest dose (5 yen 107 cells) group. This absence of toxicity seems to be associated with rapid elimination of Vero-IL-2 cells from the organism. Indeed, exogenous IL-2 mRNA could no longer be detected in the peripheral whole blood 48 hours after Vero-IL-2 cell administration. In addition, we did not find any expression of exogenous IL-2 mRNA in post-therapeutic lesions removed 29 days after the start of therapy. A major finding of this trial concerns the two histological responses of two treated subcutaneous nodules not associated with an apparent clinical response. The relationship between local treatment and tumour regression was supported by replacement of tumour cells by inflammatory cells in regressing lesions and marked induction of T and natural killer cell derived cytokines (IL-2, IL-4, IFNg ...) in post-therapeutic lesions analysed 28 days after the start of Vero-IL-2 administration. Gene therapy using xenogeneic cells as vehicle may therefore present certain advantages over other vectors, such as its complete absence of toxicity. Furthermore, the in vivo biological effect of immunostimulatory genes, i.e IL-2-, may be potentiated by the xenogeneic rejection reaction.

Target cell-induced apoptosis in IL-2-activated human natural killer cells

We demonstrated that tumor cells induce cell death in lymphokine-activated NK (LAK) cells, but not in non-activated NK cells. Cell death in LAK cells involves nuclear condensation and DNA cleavage, all of which are characteristic features of apoptosis. The mechanism involves signaling through integrins and requires src family tyrosine kinases and protease activities. Engagement of an apoptotic signal molecule, Fas, may also trigger LAK cell death by apoptosis. It appears that LAK cells rapidly die by apoptosis after attacking tumor cells. This phenomenon may provide a means for potential tumor target cells to escape from natural immunosurveillance during therapeutic interventions such as those using IL-2 or LAK cells.

Cytokines and cancer

The relationships between cytokines and cancer are multiple and bidirectional. On the one hand, cytokines may directly influence carcinogenesis and metastasis by modifying the tumor phenotype. On the other hand, during tumor progression, modifications of the cytokine expression in the tumor environment may be induced by the tumor cells, leading to a state of immunosuppression reflected by low cytokine expression in tumor stroma. Cytokines also play a role by stimulating the host immune system to generate anti-tumor specific responses. Finally, the use of cytokines as anti-tumor agents has led to objective clinical responses in about 15-25% of patients with metastatic melanoma or renal cell carcinoma, which presents the basis for the development of promising immunotherapeutic approaches for cancer therapy.

Vascular leak syndrome: a side effect of immunotherapy

The major dose-limiting toxicity of interleukin-2 (IL-2) and of immunotoxin (IT) therapies is vascular leak syndrome (VLS). VLS is characterized by an increase in vascular permeability accompanied by extravasation of fluids and proteins resulting in interstitial edema and organ failure. Manifestations of VLS include fluid retention, increase in body weight, peripheral edema, pleural and pericardial effusions, ascites, anasarca and, in severe form, signs of pulmonary and cardiovascular failure. Symptoms are highly variable among patients and the causes are poorly understood. The pathogenesis of endothelial cell (EC) damage is complex and can involve activation or damage to ECs and leukocytes, release of cytokines and of inflammatory mediators, alteration in cell-cell and cell-matrix adhesion and in cytoskeleton function. VLS restricts the doses of IL-2 and of ITs which can be administered to humans and, in some cases, necessitates the cessation of therapy. This review discusses the diversity of clinical manifestation, possible mechanisms and therapeutic modalities for VLS induced by IL-2 and ITs.

Possibilities of gene therapies for cancer

Cancer is an acquired disease in which it is possible to identify a variety of abnormalities at a genetic level. This holds a promise that genetic manipulation of tumour cells will lead to novel therapies. As yet these approaches are constrained by available methods for obtaining gene transfer and subsequent genetic control. However, a number of strategies are already reaching the clinic, including attempts at immunotherapy, prodrug activation and improving host defence against conventional chemotherapy. Further clinical opportunities will occur with improved vector development.

Neurotoxicity induced by interleukin-2: involvement of infiltrating immune cells

Interleukin-2 (IL-2), a key regulator of immune functions, also has potent effects on neurons and glia. IL-2 modulates neural cell growth and survival and transmitter and hormone releases and is thought to mediate neuroimmune interactions. Investigating the neuroendocrine consequences of chronically elevated central nervous system (CNS) levels of IL-2, we recently observed marked neurotoxicity [Hanisch et al. (1994) Endocrinology 135:2465-2472]. In the present study, we characterize in detail the modifications in brain tissue architecture as they result in Sprague-Dawley rats from intracerebroventricular (i.c.v.) administration of low amounts of IL-2 (5 and 15 U/h, respectively, delivered by means of osmotic minipumps for up to 14 days). Histological inspection of the brains revealed massive cellular infiltrates in the ipsilateral hemisphere. The infiltrates were associated with pronounced angiogenesis and changes in the composition of the extracellular matrix. These anatomical changes apparently developed between day 7 and 14. They were specific for IL-2 and were not seen in animals treated, for example, with heat-inactivated IL-2 (controls). We further show that chronic central administration of IL-2 let to T and B lymphocyte invasion of the brain and an intracranial agglomeration of large numbers of MHC class II-positive cells. Immunocytochemistry revealed a widespread inundation of CNS tissue and a decoration of glial cells and neurons by endogenous antibodies. Tissue regions around the IL-2-induced infiltrates showed myelin destruction and neuronal cell loss. Chronically elevated CNS levels of IL-2 may, thus, not only interfere with neurotransmission and endocrine functions but also severely disturb tissue homeostasis. Therefore, the present findings could be relevant to brain injuries, CNS disorders, and clinical treatments associated with increased IL-2 levels or involving an immune component.

Carpal tunnel syndrome associated with interleukin-2 therapy

BACKGROUND

Interleukin (IL-2) has been extensively used in our institution in the treatment of cancer and has protean neurologic side effects. Carpal tunnel syndrome developing in patients receiving IL-2 appears to have a good prognosis and may spare the patient unneeded investigation.

METHODS

A retrospective evaluation was undertaken for all patients using our institution's Patient Studies database. The patients were examined and their charts reviewed.

RESULTS

We found eight patients with renal cell carcinoma who developed carpal tunnel syndrome (CTS) during treatment with IL-2, fluorouracil (5-FU), and alpha-interferon (alpha-IFN). The symptoms were bilateral in five patients and all patients improved with cessation of therapy. Three patients had recurrent symptoms with subsequent courses of therapy. Symptoms occurred during or shortly after IL-2 infusion and resolved after therapy was completed with conservative management. The number of courses given did not seem to correlate with development of symptoms. Neurophysiologic studies demonstrated conduction velocity slowing without evidence of acute denervation.

CONCLUSIONS

IL-2 can produce focal entrapment of the median nerve at the wrist, which reverses with drug withdrawal. IL-2 mediates the inflammatory response and can cause interstitial edema that likely causes CTS to develop in predisposed patients undergoing treatment.

Interleukin-2 as a neuroregulatory cytokine

Interleukin-2 (IL-2), the cytokine also known as T-cell growth factor, has multiple immunoregulatory functions and biological properties not only related to T-cells. In the past decade, substantial evidence accumulated to suggest that IL-2 is also a modulator of neural and neuroendocrine functions. First, extremely potent effects of IL-2 on neural cells were discovered, including activities related to cell growth and survival, transmitter and hormone release and the modulation of bioelectric activities. IL-2 may be involved in the regulation of sleep and arousal, memory function, locomotion and the modulation of the neuroendocrine axis. Second, the concept that IL-2 could act as a neuroregulatory cytokine has been supported by reports on the presence in rodent and human brain tissues of IL-2-like bioactivity, IL-2-like immunoreactivity, IL-2-like mRNA, IL-2 binding sites, IL-2 receptor (IL-2R alpha) and beta chain mRNA and IL-2R immunoreactivity. IL-2 and/or IL-2R molecules mainly localize to the frontal cortex, septum, striatum, hippocampal formation, hypothalamus, locus coeruleus, cerebellum, the pituitary and fiber tracts, such as the corpus callosum, where they are likely expressed by both neuronal and glial cells. Although the molecular biology of the brain IL-2/IL-2R system (including its relation to IL-15/IL-15R alpha) is not yet fully established by cloning and complete sequencing of all respective components, similarities (and to some extent differences) to peripheral counterparts are now apparent. The ability of IL-2 to readily penetrate the blood-brain barrier further suggests that this cytokine could regulate interactions between peripheral tissues and the central nervous system. Taken together, these data suggest that IL-2 of either immune and CNS origin can have access to functional IL-2R molecules on neurons and glia under normal conditions. Additionally, dysregulation of the IL-2/IL-2 receptor system could lead or contribute to functional and pathological alterations in the brain as in the immune system. Understanding the neurobiology of the IL-2/IL-2 receptor system should also help to explain neurologic, neuropsychiatric and neuroendocrine side effects occurring during IL-2 treatment of peripheral and brain tumors. Immunopharmacological manipulation either aiming at the activation or suppression of IL-2 signaling should consider functional interference with constitutive and inducible IL-2 receptors on brain cells in order to fulfil the high expectations associated with the use of this cytokine as a promising agent in immunotherapies, especially of brain tumors.

Prognostic value of cytokine and soluble Fc gamma receptor assays in oncology

The clinical course of a cancer is influenced by the interaction of tumour cells with the patient's immune system. It is thus conceivable that immunological parameters may be used as markers of prognostic or predictive value. We report here that increased serum levels of IL-6 is a signal of poor prognosis and predicts unresponsiveness to immunotherapy in patients with metastatic melanoma. In cervical cancer, IL-6 produced by infiltrating macrophages is a marker of invasive cancer. In patients with multiple myeloma, the plasmatic levels of soluble Fc gamma receptors are markers of the disease, sCD16 being drastically decreased and sCD32 being slightly increased.