Interleukin-6 and renal cell cancer: Production,regulation, and growth effects

Summary Interleukin-6 (IL-6) is a recently characterized pleiotropic cytokine with antitumor activity. We investigated the production of IL-6 by renal cell cancer (RCC) and the growth effects of IL-6 on RCC. Using immunoperoxidase staining, cytoplasmic IL-6 was detected in four of four renal tumor lines and in tumor cells from freshly nephrectomized RCC. We found that IL-6 mRNA was expressed at basal culture conditions by seven of ten RCC tumor lines tested. Biologically active IL-6, as measured by the B9 assay, was produced by all ten RCC tumor lines. The addition of tumor necrosis factor (TNF) significantly augmented the expression of IL-6 mRNA in five RCC tumor lines (P <0.05). The combination of interferon IFN and TNF further enhanced the augmented IL-6 mRNA accumulation seen with TNF alone (P <0.05). TNF also significantly stimulated the production of biologically active IL-6 (P <0.01). Furthermore, IFN and TNF were found to enhance IL-6 bioactivity synergistically (P <0.05). The growth effects of IL-6 on RCC were also investigated in two experimental systems: IL-6 was found to stimulate proliferative responses in six of six RCC tumor lines as measured by thymidine-uptake assays; however, only one of six tumor lines displayed an increase in proliferative response of greater than 21% (113%). The growth effect of IL-6 was further tested in clonogenic assays. One of the tumor lines tested displayed an enhanced growth response of up to 200%. We conclude that IL-6 is produced by RCC; this production is enhanced by TNF with synergistic effects seen with IFN at both mRNA and protein levels. In turn, IL-6 may have a modest stimulatory growth effect on certain RCC tumor lines.This work was supported in part by National Institutes of Health Grant CA 522 499-01, and the Margaret Early Foundation     

Interleukin-6 as an independent predictor of future cardiovascular events in high-risk Japanese patients: comparison with C-reactive protein

Inflammation is associated with the development of atherosclerotic vascular lesions and some inflammatory parameters are used as cardiovascular (CV) risk markers. The present study was designed to assess the predictive power of interleukin (IL)-6 for future CV events. In 121 Japanese patients with multiple CV risk factors and/or disease, serum concentrations of IL-6 and high sensitive C-reactive protein (hs-CRP) were measured. During follow-up periods (mean, 2.9 years) after the baseline assessment, 50 patients newly experienced CV events such as stroke/transient ischemic attack (n=10), heart failure hospitalization (n=6), acute coronary syndrome (n=7), and revascularization for coronary artery disease (n=15) and peripheral arterial disease (n=12). The serum level of IL-6, but not hs-CRP, was significantly higher in patients who had CV events than in event-free subjects (3.9±2.6 and 3.0±2.2 pg/mL, P=0.04). When the patients were divided into three groups by tertiles of basal levels of IL-6 (<1.85, 1.85-3.77, and ≥3.77 pg/mL), cumulative event-free rates by the Kaplan-Meier method were decreased according to the increase in basal IL-6 levels (65%, 50%, and 19% in the lowest, middle, and highest tertiles of IL-6, respectively; log-rank test, P=0.002). By univariate Cox regression analysis, previous CV disease, creatinine clearance, and serum IL-6 levels were significantly associated with CV events during follow-up. Among these possible predictors, the highest tertile of IL-6 was only an independent determinant for the morbidity in the multivariate analysis (hazard ratio 2.80 vs. lowest tertile, P=0.006). These findings indicate that IL-6 is a powerful independent predictor of future CV events in high-risk Japanese patients, suggesting its predictive value is superior to that of hs-CRP.     

Host immune response in renal cell cancer: Interleukin-4 (IL-4) and IL-10 mRNA are frequently detected in freshly collected tumor-infiltrating lymphocytes

Human renal cell cancer (RCC) is clearly responsive to immunotherapy. Clinical responses may be mediated by non-specific (e. g. natural killer, NK, cells) or specific MHC-class-I-restricted tumor-specific CD8⁺ T lymphocytes. Typically RCC progresses, however, despite significant infiltration of various lymphoid cells. We examined freshly isolated RCC tumor-infiltrating lymphocytes (TIL) derived from seven RCC patients for cytokine expression by the polymerase chain reaction (PCR). Established RCC tumor cell lines derived from these RCC patients were negative for interleukin-2 (IL-2), IL-4, IL-10, and interferon and found to be positive for tumor necrosis factor (TNF), IL-6, IL-1, granulocyte/macrophage-colony-stimulating factor (GM-CSF), and transforming growth factor 1 (TGF1) message as detected by PCR. An identical pattern of cytokine mRNA expression was identified in other long-term RCC lines and in normal human kidney cells upon culture, but not in two Wilms tumor cell lines tested. Short-term-, and long-term-established RCC lines, but not Wilms tumor lines, secreted substantial levels of GM-CSF, TNF, IL-1, and IL-6 as detected by enzyme-linked immunosorbent assay. Both RCC lines and Wilms tumor lines secreted TGF1. In comparison, normal kidney cells secreted IL-6 and GM-CSF, but not IL-1, or TFG1 under identical in vitro cell culture conditions. We applied PCR-based methods to characterize the cytokine mRNA expression pattern in immune cells infiltrating into renal cell cancer without the need for expansion of such effector cells in vitro. Examining freshly collected RCC TIL by PCR from patients with primary cell cell cancer, we could demonstrate that such cells, but not lympho-mononuclear cells harvested from normal human kidney tissue, typically exhibit IL-4 and IL-10 mRNA expression.     

Effect of different training mode on Interleukin-6 (IL-6) and C-reactive protein (CRP) in type 2 diabetes mellitus (T2DM) patients

[Purpose]

This study was carried out to investigate the effects of different training modes on IL-6 and CRP in patients with type 2 diabetes mellitus (T2DM).

[Methods]

The subjects consisted of 16 middle-aged women with type 2 diabetes mellitus (T2DM), all of whom had no other complications. The 16 subjects were randomly assigned to two experimental groups: the circuit training group (CTG, n = 8) and aerobic training group (ATG, n = 8). Based on measured THR (target heart rate) for maximum oxygen consumption rate, the circuit training group (CTG) exercised at 60% intensity, 60 min/day, 5 sets, 3 days/week for 12 weeks. Based on measured THR (target heart rate) for maximum oxygen consumption rate, the aerobic training group (ATG) exercised at 60% intensity (which was increased gradually in weeks 4, 7, and 10) 60 min/day, 3 days/week for 12 weeks.

[Results]

The results are as follows. Significant decreases in the post training values of weight, % Fat, BMI, IL-6 and CRP (p < .05) were observed in the CTG compared to pre-training. However, there were no differences in the physical characteristic and blood inflammatory factors between the groups (ATG & CTG).

[Conclusion]

In conclusion, the results of this study suggest that circuit training (CT) may be considered as an effective training mode for helping to decrease the blood inflammatory factors (IL-6 and CRP) in patients with type 2 diabetes mellitus (T2DM).     

Altered serum and salivary C-reactive protein levels in patients with oral premalignant lesions and oral squamous cell carcinoma

Chronic inflammation is associated with cancer development. C-reactive protein (CRP), an acute phase protein synthesized primarily in the liver, is a marker for inflammation and for the progression of many cancers. We compared serum and salivary CRP levels in 20 normal individuals, 20 patients with oral premalignant lesions and 20 patients with oral squamous cell carcinoma (OSCC) to assess its efficacy as a prognostic indicator for OSCC. Saliva and blood samples were obtained and evaluated for CRP levels. Mean CRP levels were higher in patients with oral premalignant lesions compared to controls. CRP levels in OSCC patients were elevated and were associated with advanced tumor stages.     

四七汤联合帕罗西汀治疗脑卒中后抑郁患者的疗效评价及对血清ox-LDL、CRP、IL-6的影响

目的:探讨四七汤联合帕罗西汀治疗脑卒中后抑郁患者的疗效及对血清氧化低密度脂蛋白(ox-LDL)、C反应蛋白(CRP)、白细胞介素-6(IL-6)的影响。方法:选择我院2014年9月～2016年9月收治的86例脑卒中后抑郁患者,按治疗方式分为对照组与实验组,每组43例。对照组予以帕罗西汀治疗,实验组在对照组基础上加用四七汤治疗,两组均持续治疗8周。比较两组的临床疗效,治疗前后中医症候积分、血清ox-LDL、CRP、IL-6、汉密顿抑郁量表(HAMD)、纳维亚神经卒中量表评分(SNSS)的变化及不良反应的发生情况。结果:治疗后,实验组治疗总有效率显著高于对照组(P0.05);两组中医症候积分、血清ox-LDL、CRP、IL-6、HAMD、SNSS评分均显著下降,且实验组以上指标均明显低于对照组,差异有统计学意义(P0.05)。两组不良反应的发生率比较差异无统计学意义(P0.05)。结论:四七汤联合帕罗西汀治疗脑卒中后抑郁患者的疗效优于单用帕罗西汀者,能够有效改善患者的临床症状,可能与其更有效降低患者血清ox-LDL、CRP、IL-6水平有关。     

Inhaled IL-2 induces systemic immunomodulation in patients with renal cell carcinoma and lung metastasis

The peripheral blood lymphocytes of eight patients with metastatic renal cell carcinoma, and of eight healthy volunteers were analyzed by four-color flow cytometry to characterize the immunophenotypic alterations manifested, determine the prevalence of lymphocyte apoptosis, and detect evidence of the systemic effect of inhaled IL-2. The T, B and NK lymphocytes of untreated patients were found to have undergone profound changes characterized by an increase in susceptibility to both spontaneous and mitogen-induced ex vivo apoptosis, a modified distribution of the main lymphocyte populations in the peripheral blood, and alterations in activation status. An increase in the proportion of regulatory T cells was also seen in these patients. Treatment with inhaled IL-2, however, normalized the rate of apoptosis in all the lymphocyte subpopulations studied, as well as their distribution and activation status. These findings demonstrate that inhaled IL-2 has systemic immunomodulatory effects.     

Immune function of patients receiving recombinant human interleukin-6 (IL-6) in a phase I clinical study: Induction of C-reactive protein and IgE and inhibition of natural killer and lymphokine-activated killer cell activity

Interleukin-6 (IL-6) is a cytokine that acts on a variety of cell types, including myeloid progenitor cells and B and T lymphocytes. It has been found to activate cytotoxic T cells and natural killer (NK) cells and to induce T-cell-mediated antitumour effects in animal models. In a phase I clinical trial of recombinant human IL-6, 20 patients with advanced cancer were entered to receive daily subcutaneous injections of IL-6 over 7 days followed by a 2-week observation period and another 4 weeks of daily IL-6 injections. Doses varied between 0.5 g/kg and 20 g/ kg body weight and immune functions were monitored throughout. At all dose levels IL-6 administration led to a marked increase in serum levels of C-reactive protein and a moderate rise in complement factor C3. The proportions of CD4, CD8 or HLA-DR lymphocytes in peripheral blood did not alter with IL-6 treatment nor did the in vitro proliferation of peripheral blood mononuclear cells induced by either phytohaemagglutinin, pokeweed mitogen or fixedStaphylococcus aureus. By contrast, NK cell activity, lymphokine-activated killer (LAK) cell activity and proliferation induced by in vitro culture with interleukin-2 (IL-2) were suppressed at doses exceeding 2.5 g/kg. Serum IgE levels were consistently elevated over the IL-6 dose range but IgM, IgG and IgA levels were unaffected. In summary there is a dose-dependent induction of acutephase proteins by in vivo IL-6 treatment. At higher IL-6 doses there is a suppressive effect on NK and LAK activity measured in vitro. IL-6 may thus be useful in combination cytokine therapies that seek to suppress LAK and favour cytotoxic T lymphocyte responses. The rise in IgE levels in response to IL-6 was unexpected and suggests a more pivotal role than previously known for the control of IgE production; this could include IgE-related diseases.Supported by a Mildred Scheel Research-Fellowship from the Deutsche Krebshilfe     

自杀未遂老年抑郁症患者血清5-羟色胺水平、总胆固醇、C反应蛋白及白介素-6检测的临床意义

目的:探讨自杀未遂老年抑郁症患者血清5-羟色胺(5-HT)水平、总胆固醇(TC)、C反应蛋白(CRP)及白介素-6(IL-6)检测的临床意义。方法:选取2015年5月至2018年5月我院收治的首次住院的老年抑郁症患者155例,依据入院前2周内是否曾有过自杀行为将其分为自杀未遂组(n=75)和无自杀行为组(n=80)。比较两组患者的临床指标及血清5-HT、TC、CRP及IL-6水平;分析不同病情严重程度自杀未遂老年抑郁症患者血清5-HT、TC、CRP及IL-6水平;采用Pearson相关分析血清5-HT、TC、CRP及IL-6水平与汉密尔顿抑郁量表(HAMD)评分的相关性。结果:自杀未遂组HAMD评分高于无自杀行为组(P<0.05)。自杀未遂组血清5-HT及TC水平均低于无自杀行为组(P<0.05),自杀未遂组血清CRP及IL-6水平均高于无自杀行为组(P<0.05)。与轻度组比较,中度组、重度组患者血清5-HT及TC水平均明显降低,且重度组低于中度组(P<0.05);与轻度组比较,中度组和重度组患者血清CRP及IL-6水平均明显升高,且重度组高于中度组(P<0.05)。5-HT、TC与HAMD评分呈负相关(P<0.05);CRP、IL-6与HAMD评分呈正相关(P<0.05)。结论:自杀未遂老年抑郁症患者血清5-HT、TC水平降低,CRP、IL-6水平升高,检测血清5-HT、TC、CRP及IL-6有助于评价其病情严重程度及出现自杀行为的风险。     

Lung squamous cell carcinoma and adenocarcinoma cell lines use different mediators to induce comparable phenotypic and functional changes in human monocyte-derived dendritic cells

Tumor-derived immunosuppressive factors contribute to the evasion of malignant cells from the immune response, partially by hampering dendritic cell (DC) differentiation. Here, we analyze whether soluble mediators released by the most frequent histological types of non-small cell lung carcinoma, squamous cell carcinoma (SCC), and adenocarcinoma (AD) cells, affect the development and functionality of DC. Monocytes from healthy donors were differentiated in vitro into DC with granulocyte–macrophage colony-stimulating factor (GM-CSF) and interleukin (IL)-4, in the absence or presence of soluble factors (SF) from SCC or AD cell lines. Monocytes were differentiated in parallel into macrophages (MΦ s) with macrophage colony-stimulating factor (M-CSF). SF-treated DC were phenotypically and functionally more similar to MΦ s than to untreated DC [control DC (Ctrl-DC)]. Both tumors increased myelomonocytic markers (CD14, CD16, CD32, and CD163) and impaired CD1a expression on DC. SF-treated DC increased their endocytic capacity, and released higher levels of IL-6, IL-10, and lower levels of IL-12, compared to Ctrl-DC. SF-treated DC were poor stimulators in mixed lymphocyte reactions, and naïve CD4⁺ T lymphocytes stimulated by SF-treated DC secreted lower levels of interferon (IFN)-γ and higher amounts of IL-10 than controls. In contrast to AD, the effects caused by SCC were mostly abolished by IL-6 neutralization during monocyte differentiation. However, tumor-derived prostanoid blockade recovered the IFN-γ levels secreted by lymphocytes stimulated with SF-treated DC, whereas prostanoid/IL-6 or prostanoid/IL-10 blockade decreased IL-10 production only by SCC-DC-stimulated lymphocytes. Thus, we provide evidence that lung SCC and AD cause comparable deficiencies on DC in vitro, skewing monocyte differentiation from DC to MΦ -like cells, but most of these changes occurred via different mediators.     

Quantitative proteomic analysis to discover potential diagnostic markers and therapeutic targets in human renal cell carcinoma

Renal cell carcinoma (RCC) is relatively resistant to chemotherapy and radiotherapy. Recent advances in drug development are providing novel agents for the treatment of RCC, but the effects are still minimal. In addition, there is an urgent need to identify diagnostic markers for RCC. In this report, to discover potential diagnostic markers and therapeutic targets, we subjected RCC samples to a quantitative proteomic analysis utilizing 2-nitrobenzenesulfenyl (NBS) reagent. Proteins were extracted from RCC and adjacent normal tissue, obtained surgically from patients, and labeled with NBS reagent containing six (12)C or (13)C. This was followed by trypsin digestion and the enrichment of labeled peptides. Samples were then subjected to analysis by MALDI-TOF MS. NBS-labeled peptides with a 6 Da difference were identified by MS/MS. Thirty-four proteins were upregulated in more than 60% of the patients of which some were previously known, and some were novel. The identity of a few proteins was confirmed by Western blotting and quantitative real time RT-PCR. The results suggest that NBS-based quantitative proteomic analysis is useful for discovering diagnostic markers and therapeutic targets for RCC.     

Reproductive and external hormonal factors and the risk of renal cell cancer in the Netherlands Cohort Study

BackgroundSeveral reproductive and hormonal factors, like age at menarche, parity, age at menopause, use of oral contraceptives and postmenopausal treatment, have been associated with the risk of renal cell cancer (RCC) in women, but results have not always been consistent. We therefore investigated the association between these factors and the risk of RCC in postmenopausal women participating in the Netherlands Cohort Study on Diet and Cancer.MethodsInformation on reproductive history, exogenous hormone use and gynecological surgery was obtained through a self-administered questionnaire at baseline in 1986. After 20.3 years of follow-up, 204 cases and 2280 subcohort members were available for case-cohort analysis. Multivariable hazard ratios (HR) were calculated using Cox Proportional Hazard analysis.ResultsWomen who reported a hysterectomy had an increased RCC risk compared to women who did not (HR, 1.42, 95%CI, 1.01–2.00). Women with a natural age at menopause between 45 and 49 years compared to 50–54 years had an increased RCC risk (HR, 1.61; 95%CI, 1.10–2.35). RCC risk was slightly and not statistically significant increased among parous women with three or more children and age at first birth before 25 years compared to nulliparous women (HR, 1.36; 95% confidence interval (CI), 0.84–2.20). No associations were observed with RCC risk for age at menarche, use of oral contraceptives and use of hormonal replacement therapy.ConclusionHysterectomy and age at natural menopause were associated with an increased RCC risk. Other hormonal and reproductive factors and RCC risk were not increased. Further studies are required to establish the mechanism(s) that explain the observed association.     

EGFR protein overexpression correlates with chromosome 7 polysomy and poor prognostic parameters in clear cell renal cell carcinoma

Background

The role of epidermal growth factor (EGF) and its receptor (EGFR) in the pathogenesis and progression of various malignant tumors has long been known, but there is still disagreement concerning prognostic significance of EGFR expression in clear cell renal cell carcinoma (CCRCC). The present study was designed to analyze more objectively the protein EGFR expression in CCRCC and to compare its value with EGFR gene copy number changes and clinicopathologic characteristics including patient survival.

Methods

The protein EGFR expression was analyzed immunohistochemically on 94 CCRCC, and gene copy number alterations of EGFR by FISH analysis on 41 CCRCC selected according to distinct membrane EGFR staining.

Results

Membrane EGFR expression in tumor cells was heterogeneous with respect to the proportion of positive cells and staining intensity. FISH analysis did not reveal EGFR gene amplification, while polysomy of chromosome 7 found in 41% was associated with higher EGFR membrane expression. Moreover, EGFR overexpression was associated with a higher nuclear grade, larger tumor size and shorter patient''s survival, while there was no connection with pathological stage.

Conclusion

In conclusion, the protein expression of EGFR had an impact on prognosis in patients with CCRCC, while an increased copy number of chromosome 7 could be the possible reason for EGFR protein overexpression in the absence of gene amplification.     

缺氧诱导因子(HIFs)在肾癌发生中的作用及其分子机制

肾癌是一种常见的泌尿系统肿瘤,但在临床上对转移性肾癌的治疗手段还非常有限。缺氧是实体肿瘤微环境的一个重要的基本特征。近年来基于分子机制和临床研究的数据表明,低氧诱导因子(hypoxia-inducible factors, HIFs)在肾细胞癌(renal cell carcinoma, RCC)的发生发展中发挥着至关重要的作用。HIF是一类介导细胞适应低氧状况必需的转录激活因子,由α亚基和β亚基组成。研究已经证实,在RCC中HIF-1α和HIF-2α具有相反的作用,前者作为肿瘤抑制因子,而后者作为癌基因发挥功能。本文综述了HIF信号通路在RCC发生发展中的作用及其分子机制,并对靶向HIF信号通路治疗RCC的进行了探讨,以期指导临床肾细胞癌的精准化治疗和进一步的研究。     

Interleukin-6 (IL-6) regulates claudin-2 expression and tight junction permeability in intestinal epithelium

In inflammatory bowel diseases (IBD), intestinal barrier function is impaired as a result of deteriorations in epithelial tight junction (TJ) structure. IL-6, a pleiotropic cytokine, is elevated in IBD patients, although the role of IL-6 in barrier function remains unknown. We present evidence that IL-6 increases TJ permeability by stimulating the expression of channel-forming claudin-2, which is required for increased caudal-related homeobox (Cdx) 2 through the MEK/ERK and PI3K pathways in intestinal epithelial cells. IL-6 increases the cation-selective TJ permeability without any changes to uncharged dextran flux or cell viability in Caco-2 cells. IL-6 markedly induces claudin-2 expression, which is associated with increased TJ permeability. The colonic mucosa of mice injected with IL-6 also exhibits an increase in claudin-2 expression. The claudin-2 expression and TJ permeability induced by IL-6 are sensitive to the inhibition of gp130, MEK, and PI3K. Furthermore, expression of WT-MEK1 induces claudin-2 expression in Caco-2 cells. Claudin-2 promoter activity is increased by IL-6 in a MEK/ERK and PI3K-dependent manner, and deletion of Cdx binding sites in the promoter sequence results in a loss of IL-6-induced promoter activity. IL-6 increases Cdx2 protein expression, which is suppressed by the inhibition of MEK and PI3K. These observations may reveal an important mechanism by which IL-6 can undermine the integrity of the intestinal barrier.     

加速康复外科理念联合腹腔镜技术对穿孔性阑尾炎患儿肠道功能恢复及外周血WBC、CRP、IL-6的影响

目的:探讨腹腔镜技术联合加速康复外科理念(ERAS)对穿孔性阑尾炎患儿肠道功能恢复及外周血白细胞计数(WBC)、C反应蛋白(CRP)、白介素-6(IL-6)的影响.方法:选取2017年8月～2019年8月期间我院收治的行腹腔镜下阑尾切除术的患儿120例,上述患儿根据随机数字表法分为对照组(n=60)和研究组(n=60)...     

Analgesic use and the risk of renal cell carcinoma – Findings from the Consortium for the Investigation of Renal Malignancies (CONFIRM) study

PurposeThe incidence of renal cell carcinoma (RCC) is rising. Use of analgesics such as non-steroidal anti-inflammatory drugs (NSAIDs) and paracetamol may affect renal function. The aim of this study was to assess associations between analgesic use and risk of RCC.MethodsA population-based case-control family design was used. Cases were recruited via two Australian state cancer registries. Controls were siblings or partners of cases. Analgesic use was captured by self-completed questionnaire. Logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI) for RCC risk associated with regular analgesic use (at least 5 times per month for 6 months or more) and duration and frequency of use.ResultsThe analysis included 1064 cases and 724 controls. Regular use of paracetamol was associated with an increased risk of RCC (OR 1.41, 95%CI 1.13–1.77). Regular use of NSAIDs was associated with increased risk of RCC for women (OR 1.71, 95% CI 1.23–2.39) but not men (OR 0.83, 95% CI 0.58–1.18; p-interaction=0.003). There was no evidence of a dose-response for duration of use of paracetamol (linear trend p = 0.77) and weak evidence for non- aspirin NSAID use by women (linear trend p = 0.054).ConclusionThis study found that regular use of paracetamol was associated with increased risk of RCC. NSAID use was associated with increased risk only for women.     

Interleukin-2 dose,blood monocyte and CD25+ lymphocyte counts as predictors of clinical response to interleukin-2 therapy in patients with renal cell carcinoma

Summary The purpose of this study was to determine immunological parameters in the peripheral blood that correlate with the clinical effect of interleukin-2 (IL-2) in patients with metastatic renal cell cancer. A group of 26 patients with metastatic renal cell cancer underwent IL-2 treatment using a 36-day schedule with continuous intravenous IL-2 infusion (3 × 10⁶ units m^–2 day^–1) administered from days 1 to 5 and days 12 to 16. The white blood cell count and the absolute and relative number of neutrophils, lymphocytes, eosinophils and monocytes were recorded six times in peripheral blood during the treatment. Also the blood counts of T cell and NK cell subsets and cells expressing the T cell activation markers IL-2R and VLA-1 were measured. The lymphokine-activated killer (LAK) cell cytotoxicity was measured either with or without additional in vitro stimulation by IL-2. Multivariate statistical analysis showed that the clinical responses were related to the administered dose of IL-2, to a low number of blood cells expressing IL-2 receptors and to a reduction in the blood monocyte count (P <0.05).