Prognostic value of the immunomonitoring of patients with renal cell carcinoma under therapy with IL-2/IFN-alpha-2 in combination with 5-FU

Clinical potential of PD-1/PD-L1 blockade therapy for renal cell carcinoma (RCC): a rapidly evolving strategy

Programmed death-1 (PD-1)/programmed death-ligand 1 (PD-L1) blockade therapy has become a game-changing therapeutic approach revolutionizing the treatment setting of human malignancies, such as renal cell carcinoma (RCC). Despite the remarkable clinical activity of anti-PD-1 or anti-PD-L1 monoclonal antibodies, only a small portion of patients exhibit a positive response to PD-1/PD-L1 blockade therapy, and the primary or acquired resistance might ultimately favor cancer development in patients with clinical responses. In light of this, recent reports have signified that the addition of other therapeutic modalities to PD-1/PD-L1 blockade therapy might improve clinical responses in advanced RCC patients. Until, combination therapy with PD-1/PD-L1 blockade therapy plus cytotoxic T lymphocyte antigen 4 (CTLA-4) inhibitor (ipilimumab) or various vascular endothelial growth factor receptors (VEGFRs) inhibitors axitinib, such as axitinib and cabozantinib, has been approved by the United States Food and Drug Administration (FDA) as first-line treatment for metastatic RCC. In the present review, we have focused on the therapeutic benefits of the PD-1/PD-L1 blockade therapy as a single agent or in combination with other conventional or innovative targeted therapies in RCC patients. We also offer a glimpse into the well-determined prognostic factor associated with the clinical response of RCC patients to PD-1/PD-L1 blockade therapy.

Long-Term Survival in Patients with Metastatic Renal Cell Carcinoma Treated with Continuous Intravenous Infusion of Recombinant Interleukin-2: The Experience of a Single Institution

Aim and background

Metastatic renal cell carcinoma is one of the few tumors for which a clear benefit of immunotherapy has been demonstrated. The aim of this study was to evaluate the long-term survival of patients with metastatic renal cell carcinoma, along with response rate and other prognostic and predictive factors.

Patients and methods

Between July 1989 and May 1995, 56 patients with metastatic renal cell carcinoma were treated in a single institution with high-dose recombinant interleukin-2 in continuous infusion. Survival was measured by the Kaplan and Meier method. Prognostic factors were assessed by univariate and multivariate analyses of survival (Cox proportional hazard ratio model).

Results

Of 56 patients, 15 had objective responses (26.8%), 16 stable disease (28.6%), 18 disease progressions (32.1%), and 7 (12.5%) were not valuable for response. Median overall survival was 20 months, and probability of 2- and 5-year survival was 41% and 21%, respectively. At multivariate analysis, the increased risk of death for: performance status ≥2 vs 0 (HR = 6.20), stable disease (HR = 1.87), disease progression (HR = 10.61) vs partial or complete remission, and for hypotension and oliguria toxicity, G3 + G4 vs G1 + G2 (HR = 2.19).

Conclusions

Our study confirms the activity of IL-2 based immunotherapy in renal cell carcinoma. Moreover, ECOG performance status, clinical response, hypotension and oliguria toxicity resulted as independent survival prognostic factors.

CD40 expression in renal cell carcinoma is associated with tumor apoptosis, CD8(+) T cell frequency and patient survival

The co-stimulatory molecule, CD40, is expressed in renal cell carcinoma (RCC) and a variety of inflammatory diseases in the kidney. We investigated the relationship between tumor-associated CD40 expression, immune milieu of the tumor microenvironment, tumor stage and survival of patients with RCC. The expression of CD40, TUNEL and CD8 in human renal cell carcinomas was analyzed by immunohistochemistry performed on tissue samples obtained at the time of surgery. Computer-assisted quantitation of protein expression was used to analyze results in connection with patient survival and tumor stage. We show for the first time that tumor-associated CD40 expression is associated with prolonged survival in RCC patients. Tumor apoptosis (TUNEL) and CD8 immunostaining were also associated with patient survival. No relation was observed between CD40 expression and tumor stage. Our results suggest CD40 may be a prognostic biomarker indicative of prolonged RCC patient survival. Strategies that up-regulate CD40 expression in some RCC patients may thus improve survival, supporting further studies of agonistic CD40 antibodies in RCC.

Changes in Lymphocyte Count Induced by Repeated Cycles with Low-Dose Interleukin-2 and Interferon-α in 146 Patients with Renal Cell Carcinoma

Aims and Background

The exact mechanism by which recombinant interleukine-2 and interferon-a modulate the immunological response, inducing long-term responses in metastatic renal cell carcinoma, is still not clear. The aim of the study was to analyze the modifications in peripheral blood lymphocytes during cycles of low-dose immunotherapy as a marker of the biological response to the treatment in 146 patients with renal cell carcinoma (advanced and localized disease).

Methods and Study Design

Peripheral blood lymphocytes were evaluated before and after every cycle of treatment.

Results

We found a statistically significant overall difference between pre- and post-cycle values (mean increase of 39%). The differences between pre- and post-cycle lymphocyte counts for each cycle were significant. Also, the post-cycle lymphocyte count of each cycle remained higher than the baseline value. Furthermore, pre-cycle lymphocyte counts of each cycle were still higher than the baseline value, with no difference between a pre-cycle lymphocyte mean value and the other one (except that between the first and second cycle). From the end of each cycle, but before starting the next one, the absolute value of lymphocytes fell on the average by 15–30%, concurring with the fact that, even starting from pre-cycle values higher than baseline, the immune system remains sensitive to chronically repeated stimulation by immunotherapy. We also found that non-metastatic patients had a higher number of peripheral blood lymphocytes than metastatic patients, whereas the latter had a lower immune response to therapy.

Conclusions

The results support the idea that “maintenance” immunotherapy may not develop resistance over time in terms of biological response and thus may have a role as chronic therapy in combination with other drugs such as target therapy. We suppose that the immune system of patients with metastases is in a state of relative impairment, resulting in less sensitivity to immunostimulating agents.

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.

The longitudinal relationship between the systemic inflammatory response, circulating T-lymphocytes, interleukin-6 and -10 in patients undergoing immunotherapy for metastatic renal cancer

OBJECTIVE

To examine the longitudinal relationship between the systemic inflammatory response, circulating T-lymphocyte subpopulations, interleukin-6 and -10 in patients undergoing immunotherapy for metastatic renal cancer, as the inflammation-based Glasgow Prognostic Score (GPS) provides additional prognostic information in patients with advanced renal cancer, but the basis of the relationship between the systemic inflammatory response and poorer survival is not clear, and nor is the effect of immunotherapy on related variables.

PATIENTS AND METHODS

The study included 23 patients with metastatic renal cancer and starting immunotherapy. Samples of blood were drawn for routine laboratory analysis and to quantify cytokines using enzyme-linked immunosorbent assays before immunotherapy, and repeated after 2 weeks of treatment.

RESULTS

Most patients had a good performance status, favourable or intermediate Memorial Sloane-Kettering Cancer Center (MSKCC) risk scores, and with elevated C-reactive protein (>10 mg/L), GPS (1 or 2), interleukin-6 (>4 pg/mL) and interleukin-10 (>10 pg/mL). Patients who completed one cycle of immunotherapy were more likely to have a normal MSKCC (P < 0.05) or GPS (P < 0.05) scores, whilst the percentage of lymphocytes was lower (P < 0.05). The MSKCC and the GPS scores did not alter significantly during one cycle of immunotherapy. Similarly, leukocyte counts, CD4+ and CD8+ T-lymphocytes, interleukin-6 and -10 concentrations did not change significantly.

CONCLUSIONS

The pretreatment systemic inflammatory response and its related lymphopenia are important in determining the tolerance to immunotherapy in patients with metastatic renal cancer. Immunotherapy is not associated with changes in circulating T-lymphocytes, nor the systemic inflammatory response.

Cytotoxic markers and frequency predict functional capacity of natural killer cells infiltrating renal cell carcinoma

PURPOSE

Renal cell carcinoma harbors high numbers of infiltrating lymphocytes with apparent limited efficacy in tumor control. This study focused on the natural killer (NK) cells infiltrating renal cell carcinoma.

EXPERIMENTAL DESIGN

Tumor-infiltrating lymphocytes (TIL) were isolated from renal cell carcinoma and analyzed for NK cell frequency and phenotype (n = 34). NK cells were enriched and tested for effector function.

RESULTS

Two renal cell carcinoma subtypes were identified, one containing high (>20% of the lymphocyte population, n = 14), the other low (<20%, n = 20), NK cell numbers. NK cells of both groups were noncytolytic ex vivo but differed in CD16 and cytotoxic effector molecule expression as well as in their capacity to acquire cytotoxic activity: The majority of NK cells from tumors with high NK cell content (high NK-TIL) were CD16(bright), whereas few CD16bright NK cells were found in tumors with low NK cell frequencies (low NK-TIL). The CD16 dichotomy correlated with different capacities to develop cytotoxicity after short-term activation with interleukin-2 ex vivo: Low NK-TIL remained noncytolytic against K562 and unresponsive to signals via the activating receptor NKp46 despite expression of receptor and adaptor molecules. In contrast, high NK-TIL acquired cytotoxic function. As described for peripheral CD16bright NK cells, NK cells from high-NK tumors showed high per cell expression of granzyme A, granzyme B, and perforin. NK cells from low NK-TIL resembled CD16(neg/dim) peripheral NK cells with few cytotoxin+ cells and lower expression of perforin.

CONCLUSION

The extent of NK cell infiltration and the expression of markers (CD16 and cytotoxins) predict the functional capacity of NK cells infiltrating renal cell carcinoma and can be used to characterize subgroups of renal cell carcinoma.

Activated anti-tumor immunity in cancer patients after high intensity focused ultrasound ablation

T cell-mediated immune responses represent the main cellular antitumor immunity in cancer patients. Recent studies have shown that that both surgical procedure and radiation therapy could cause the functional suppression of lymphocyte-mediated cellular immunity. The purpose of current study is to evaluate whether high intensity focused ultrasound (HIFU) might change a systemic antitumor immunity, particularly T lymphocyte-mediated immunity in cancer patients. A total of 16 patients with solid malignancies were treated with HIFU. Among them, six patients had osteosarcoma (Enneking stage, II(B)4, III(B) 2), five had hepatocellular carcinoma (TNM stage, III 3, IV 2), and five had renal cell carcinoma (TNM stage, III 2, IV 3). Using flow cytometry technique, T lymphocyte and subset, B lymphocyte and natural killer cell (NK) in the peripheral blood were measured in these patients on the day before HIFU and 7 to 10 d after HIFU. The statistical significance of any observed difference is evaluated by Student's t-test. The results showed a significance increase in the population of CD4(+) lymphocytes (p < 0.01) and the ratio of CD4(+) /CD8(+) (p < 0.05) in the circulation of cancer patients after HIFU treatment. The abnormal levels of CD3(+) lymphocytes returned toward the normal range in two patients, CD4(+)/CD8(+) ratio in 3, CD19(+) lymphocytes in one and cytotoxic NK in one, respectively, in comparison to control values. It is concluded that HIFU could enhance a systemic antitumor cellular immunity in addition to local tumor destruction in patients with solid malignancies.

Subcutaneous interleukin-2 in combination with medroxyprogesterone acetate and antioxidants in advanced cancer responders to previous chemotherapy: phase II study evaluating clinical, quality of life, and laboratory parameters

We carried out an open, non-randomized phase II study including all patients treated with whatever chemotherapy or combined modality regimen for whatever cancer who were in clinical objective response (complete response, CR, or partial response, PR) or stable disease (SD). The treatment consisted of administration of recombinant interleukin-2 (rIL-2) at a dose of 1.8 MIU subcutaneously three times/week (every other day) for the first 2 weeks of every month plus medroxyprogesterone acetate (MPA) 500 mg/day every other day plus antioxidant agents alpha-lipoic acid 300 mg/day and N-acetyl cysteine 1800 mg/day or carbocysteine lysine salt oral solution 2.7 g/day. The treatment was administered for 1 year except when progression of disease occurred. The primary study endpoints were to define clinical outcome, i.e. duration of response, survival (overall survival, OS and progression-free survival, PFS), the toxicity profile, and the evaluation of quality of life (QL). As secondary endpoints, we measured the changes of lymphocyte count, serum levels of proinflammatory cytokines, IL-2, C-reactive protein (CRP) and leptin, blood levels of reactive oxygen species (ROS) and antioxidant enzymes (glutathione peroxidase, GPx and superoxide dismertase, SOD). From July 1998 to June 2003, 42 patients were enrolled in the study (M/F ratio, 39/3; mean age, 62.5 years). Twenty (47.6%) patients were elderly (> 65 years). The majority of patients had either head and neck cancer or lung cancer, 88% had locally advanced or metastatic disease at diagnosis, and 76% had ECOG 0. Forty patients were previously treated with chemotherapy (27 also with radiotherapy), two with IL-2 and interfiron (IFN), one with endocrine therapy and one with only surgery. We obtained an objective response to maintenance treatment of 50%. Median duration of response was 19 months and median PFS was 33 months. Median duration of maintenance treatment was 12 months, median follow-up duration from diagnosis to June 2003 was 40 months, and median follow-up duration from study entry to June 2003 was 17 months. The median overall survival has not been reached. Toxicity was negligible. As for QL, a significant improvement of cognitive functions was observed, whereas all other functioning and symptom scales did not change significantly. As for laboratory parameters, absolute lymphocyte count increased significantly, IL-6, IL-1 beta, tumor necrosis factor-alpha, CRP, and fibrinogen decreased significantly whereas IL-2 and leptin increased significantly after treatment. ROS decreased significantly, whereas GPx increased significantly after treatment. Patients alive at study end showed a significant increase in absolute lymphocyte count, IL-2, leptin, and GPx and a significant decrease of proinflammatory cytokines, CRP, fibrinogen, and ROS, whereas patients who died before study end exhibited only a significant increase in absolute lymphocyte count, IL-2, and GPx and a significant decrease of ROS. Long-term combined maintenance therapy with rIL-2 + MPA + antioxidant agents is feasible, has a very low toxicity, and results in the improvement of clinical outcome, QL, and laboratory parameters.

Fibrinogen: a novel predictor of responsiveness in metastatic melanoma patients treated with bio-chemotherapy: IMI (italian melanoma inter-group) trial

Purpose

To evaluate a panel of pretreatment clinical and laboratory parameters in metastatic melanoma (MM) in order to verify their impact on response and survival in a single prospective multi-institutional phase III study comparing out-patient chemotherapy (CT) vs bioCT.

Methods

A total of 176 patients were randomised to receive CT (cisplatin, dacarbazine, optional carmustine) or bioCT (the same CT followed by subcutaneous IL-2 plus intramuscular α-IFN-2b). Pretreatment total leucocytes, lymphocytes, eosinophyls, C-reactive protein (CRP), lactate dehydrogenase (LDH), erytrosedimentation rate (ESR), and fibrinogen were analyzed. Some clinical parameters (performance status, age, sex, and disease site) were also considered. As we found a positive trend for bio-CT with no statistical significance in OR (25.3% vs 20.2%) and OS (11 Mo vs 9.5 Mo), all analyses are stratified by treatment arm.

Results

In univariate analysis, higher value of lymphocytes percentage (P < .0001), lower value of total leucocytes (P=.005), CRP (P=.003), LHD (P < .0001), ESR (P < .027), fibrinogen (P < .0001), and no liver disease were strongly related to a better survival. In a multivariate analysis, using the Cox proportional hazards model, only fibrinogen (P=.004), LDH (P=.009) and liver disease (P=.04) were found to have an independent role on clinical outcome in metastatic melanoma patients.

Conclusion

Liver disease and higher LDH and fibrinogen levels had an important impact on survival in MM patients. In particular, fibrinogen has been recently reconsidered both for its determinant role in the host hemostatic system, and for its capability to provide protection against NK and LAK-cell-induced lysis. These observations could have some important implications for therapeutic approaches, in particular when immunological strategies are used.

The potential palliative role and possible immune modulatory effects of low-dose total body irradiation in relapsed or chemo-resistant non-Hodgkin's lymphoma

In a group of 35 patients with relapsed and/or chemo-resistant non-Hodgkin's lymphoma (NHL), low-dose total body irradiation (LTBI) (+involved-field radiotherapy to bulky sites) achieved a complete remission rate of 29%, 2-years progression-free survival of 32% and a median progression-free survival of 12 months. The 2-year survival was 42% and the median survival was 17 months. Immuno-staining and flow cytometry of peripheral blood in 14 patients showed that LTBI leads to a significant increase in the percentage of CD4+ cells with a consequent significant increase in the CD4+/CD8+ ratio. High lymphocytic percent and a high percentage of CD4+ cells before LTBI were significantly correlated with longer response duration and overall survival. These data may suggest that the palliative potential of LTBI should be investigated as an alternative to chemotherapy in NHL patients. The pre-treatment percentage of lymphocytes and CD4+ cells may be used as predictors for response to LTBI.

Lymphocyte counts independently predict overall survival in advanced cancer patients: a biomarker for IL-2 immunotherapy

Interleukin-2 (IL-2) targets cells bearing IL-2 receptors and induces different degrees of lymphocytosis. This study retrospectively evaluated whether lymphocytosis, in addition to clinical characteristics at baseline and to tumor objective response, may predict overall survival in metastatic renal cell carcinoma patients who received IL-2 subcutaneously (s.c.). Overall survival, clinical characteristics, tumor response, and total lymphocyte count at baseline and during the first treatment cycle of 266 advanced renal cell cancer patients, treated with 1 of 4 different first-line s.c. IL-2-based protocols, were studied using the Cox multivariate analysis. Median IL-2 cumulative dose and length of treatment (+/-SD) were 232 +/- 282 x 10(6)/m(2) in 7 +/- 5.9 weeks, respectively. Median overall survival (os) was 13.1 months (range 0.7-86.9+) in all. Tumor outcome consisted of: 9 CR (3%) (os = NR); 35 PR (13%) (os = 19.7 months.); 117 SD (44%) (os = 15.1 months); 105 PD (39%) (os = 6.4 months). Median lymphocyte counts were 1400/mm(3) at baseline (25th-75th, 900-1900/mm(3)) and 3600/mm(3) as a maximum value (25th-75th, 2600-4800/mm(3)). Death risk significantly decreased by 11% for each 1,000 lymphocytes/mm(3) (RR 0.89; 95% CI 0.82-0.97), after correcting for clinical characteristics (PS ECOG 0 versus > or =1, time from primary diagnosis > or =2 years versus <2 years, number of metastatic sites 1 versus >1) and tumor response (CR, PR). A two-step bootstrapping procedure confirmed such predictive performance. Lymphocyte count monitoring represents a biomarker of the host response to subcutaneous IL-2 treatment useful for multimodal clinical assessment, as it predicts overall survival in advanced cancer patients independently from tumor response and from main clinical characteristics.

Intratumoural and peripheral blood lymphocyte subsets in patients with metastatic renal cell carcinoma undergoing interleukin-2 based immunotherapy: association to objective response and survival

The aim of the present study was to analyse lymphocyte subsets in consecutive peripheral blood samples and consecutive tumour tissue core needle biopsies performed before and during interleukin-2 based immunotherapy, and to correlate the findings with objective response and survival. Twenty-six patients with metastatic renal cell carcinoma were treated with low dose s.c. interleukin-2, interferon-alpha and histamine. A total of 250 blood samples and 62 core needle biopsies from 23 and 19 of these patients, respectively, were analysed. After 2 weeks of treatment, a significant positive correlation between absolute number of peripheral blood lymphocytes (P=0.028), CD3 (P=0.017), CD57 (P=0.041) and objective response was demonstrated. There was no correlation between any peripheral blood leukocyte subsets and survival. Cytotoxicity of peripheral blood mononuclear cells was not correlated to objective response or survival. Within the tumour tissue at baseline, a significant positive correlation between CD4 (P=0.027), CD8 (P=0.028), CD57 (P=0.007) and objective response was demonstrated. After one month of immunotherapy, a significant positive correlation between intratumoral CD3 (P=0.026), CD8 (P=0.015), CD57 (P=0.009) and objective response was demonstrated. A significant positive correlation between intratumoral baseline CD4 (P=0.047), baseline CD57 (P=0.035), CD3 at one month (P=0.049) and survival was demonstrated. These data provide novel in vivo evidence of the possible contribution of lymphocyte subsets in the tumour reduction in responding patients during interleukin-2 based immunotherapy. Confirmation of the results requires further studies including a larger number of patients.

Malignancy: Changes in Circulating Immature and Mature Dendritic Cells During IL-2 Cancer Immunotherapy and Their Relation with Lymphocyte Increase and Clinical Response

Lymphocytosis is the main biomarker predicting the efficacy of subcutaneous IL-2 anticancer immunotherapy. In addition, it has been demonstrated the fundamental role of dendritic cells (DC) in the generation of an effective anticancer immunity. However, the relation between IL-2 and DC system needs to be further understood. This preliminary study was performed in an attempt to analyze changes in circulating DC during IL-2 cancer immunotherapy in relation to lymphocyte variations and clinical efficacy of treatment. The study included 20 metastatic renal cell cancer patients, who underwent subcutaneous low-dose IL-2 immunotherapy (6.000.000 IU/day for 6 days/week for 4 weeks). To evaluate DC, venous blood samples were collected before and after 2 weeks of IL-2 injections, corresponding to the period of maximum lymphocytosis. Immature (CD123(+) ) and mature (CD11c(+) ) DC were measured by FACS and monoclonal antibodies. IL-2 induced a significant increase in the mean number of circulating mature DC, whereas no substantial change occurred in immature DC mean number. The increase in mature DC was associated with a control of disease, whereas no rise was observed in patients who had progressed on IL-2 immunotherapy. Moreover, the increase in mature DC mean number was significantly higher in patients showing evident lymphocytosis, with lymphocyte enhancement greater than 1000 cells/mmc, than in patients with less pronounced lymphocytosis, even though no significant correlation was seen in between mature DC and lymphocyte increase. This preliminary study would suggest that IL-2 may stimulate DC system and that the clinical anticancer efficacy of IL-2 is associated with the increase in circulating mature DC, which could be considered as a new favourable biomarker during IL-2 immunotherapy.

Alleviating oxidative stress in cancer immunotherapy: a role for histamine?

Interleukin-2 is a remarkable activator of lymphocytes with anti-neoplastic properties such as T-cells or natural killer cells, but tumor regression only rarely occurs in interleukin-2-treated cancer patients. In this review, we focus on interactions between monocytes/macrophages and T-cells/natural killer-cells, and in particular the role of such interactions for the outcome of cancer immunotherapy with interleukin-2. We propose that interleukin-2 therapy should be supplemented with compounds that alleviate toxicity inflicted by monocyte/macrophage-derived reactive oxygen metabolites within and around tumors. The hypothesis is founded on data demonstrating that (i) functions of intratumoral lymphocytes in many human malignant tumors are inhibited by reactive oxygen metabolites, generated by neighboring monocytes/macrophages, (ii) interleukin-2 only weakly activates T-cells or natural killer cells in an environment of oxidative stress, and (iii) inhibitors of the formation of reactive oxygen metabolites or scavengers of reactive oxygen metabolites synergize with interleukin-2 to activate these lymphocyte subsets. We also review the preclinical background to the use of histamine dihydrochloride, an inhibitor of reactive oxygen metabolite formation in monocytes/macrophages, as a supplement to cancer immunotherapy with interleukin-2.

Histamine: a novel approach to cancer immunotherapy

The functions of intratumoral lymphocytes in many human malignant tumors are inhibited by reactive oxygen species (ROS), generated by adjacent monocytes/macrophages (MO). In vitro data suggest that immunotherapeutic cytokines such as interleukin-2 (IL-2) or interferon-alpha (IFN-alpha) only weakly activate T cells or natural killer (NK) cells in a reconstituted environment of oxidative stress and that inhibitors of the formation of ROS or scavengers of ROS synergize with IL-2 and IFN-alpha to activate T cells and NK cells. In this review, we focus on the immunoenhancing properties of histamine, a biogenic amine. Histamine inhibits ROS formation in MO via H2-receptors; thereby, histamine protects NK cells from MO-mediated inhibition and synergizes with IL-2 and IFN-alpha to induce killing of NK cell-sensitive human tumor cells in vitro. Histamine also optimizes cytokine-induced activation of several subsets of T cells by affording protection against MO-inflicted oxidative inhibition. The putative clinical benefit of histamine as an adjunct to immunotherapy with IL-2 and/or IFN-alpha is currently evaluated in clinical trials in metastatic malignant melanoma and acute myelogenous leukemia.

Adjuvant histamine in cancer immunotherapy

Interleukin-2 (IL-2) is an effective activator of lymphocytes with anti-neoplastic properties such as T-cells or natural killer cells, and this property of IL-2 has formed the basis for its widespread used as an immunotherapeutic agent in human neoplastic disease. In recent years, IL-2 therapy for solid neoplastic diseases and hematopoietic cancers has been supplemented with histamine dihydrochloride with the aim of counteracting immunosuppressive signals from monocytes/macrophages. Here we review the preclinical basis for the use of histamine as an adjunct to IL-2 in cancer immunotherapy.

Lymphocyte subsets as prognostic markers for cancer patients receiving immunomodulative therapy

Immunogenic features of some malignancies have aroused interest in immunotherapy of cancer. Immunotherapy seems most effective in patients with a small tumour burden, and the focus of immunotherapy trials has, thus, lately been on adjuvant treatment. To enable further development of immunotherapy we need to know more about the mechanisms involved in host defence, especially when the system is influenced by extrinsic factors, that is, immunomodulative agents. T lymphocytes play an important role in the host defence against tumour cells trying to escape from immune surveillance. The mechanisms that regulate the host defence systems are complex, and the influence of extrinsic factors such as immunotherapeutic agents is poorly understood. Most data on lymphocyte subsets in malignant disease originate from melanoma or renal cell carcinoma (RCC) studies, although there are scattered data on lymphocyte subsets also in other malignancies. There are several studies implying that the relative amount of CD4+, CD8+, and natural killer (NK) cells may be important and that, by reducing the tumour burden or by using different therapeutic agents, we can stimulate the host defence. However, only some of these studies imply that these changes can have an impact on clinical outcome and prognosis. The findings of the studies reviewed in this paper are mostly encouraging, but whether the lymphocyte subsets have any value as prognostic markers in patients with malignancies receiving immunotherapy is still unclear. Large randomized immunotherapy trials including an observation arm give an ideal opportunity to recognize those immunological changes that are due to therapy, related to the natural host defence, or whether they have any prognostic value.

Pretreatment serum markers and lymphocyte response to interleukin-2 therapy

Lymphocytosis is a marker of subcutaneous interleukin (IL)-2 therapy efficacy, whereas baseline elevated inflammatory indices were noticed in IL-2-resistant disease. The aim of this study was to analyse the relationship between pretreatment circulating values of IL-6, neopterin, sIL-2R, ESR and the changes in lymphocyte number in response to IL-2 administration. Twenty metastatic renal cell cancer patients were treated with subcutaneous IL-2 immunotherapy (6 000 000 IU day(-1) for 6 days per week for 4 weeks); tumour response consisted of partial response (PR) in four patients, stable disease (SD) in eight patients and progressive disease (PD) in eight patients. Abnormally high pretreatment values of each marker were found as follows: IL-6 in seven patients, neopterin in nine patients, sIL-2R in 13 patients. In response to IL-2 immunotherapy, a significantly higher mean increase in lymphocyte number and a higher percentage of patients with tumour response or stable disease were observed when pretreatment values of IL-6, neopterin and sIL-2R were within the normal range, in comparison to patients with high values for these markers. The pretreatment excess of these serum inflammatory markers seems to negatively influence both the host and tumour response to IL-2 administration, by preventing the IL-2-induced lymphocytosis and resulting in tumour progression. Further studies are requested to verify if overall survival and quality of life may depend on pretreatment host immune status and/or lymphocyte response after IL-2 administration.