Low-dose IL-2 treatment: activation of discrete T- and NK-cell sub-populations in vivo

Development in the Study of Natural Killer Cells for Malignant Peritoneal Mesothelioma Treatment

Malignant peritoneal mesothelioma (MPeM) is a rare primary malignant tumor originating from peritoneal mesothelial cells. Insufficient specificity of the symptoms and their frequent reappearance following surgery make it challenging to diagnose, creating a need for more efficient treatment options. Natural killer cells (NK cells) are part of the innate immune system and are classified as lymphoid cells. Under the regulation of activating and inhibiting receptors, NK cells secrete various cytokines to exert cytotoxic effects and participate in antiforeign body, antiviral, and antitumor activities. This review provides a comprehensive summary of the specific alterations observed in NK cells following MPeM treatment, including changes in cell number, subpopulation distribution, active receptors, and cytotoxicity. In addition, we summarize the impact of various therapeutic interventions, such as chemotherapy, immunotherapy, and targeted therapy, on NK cell function post-MPeM treatment.

Epirubicin and Gemcitabine as First-Line Treatment in Malignant Pleural Mesothelioma

Malignant pleural mesothelioma represents a rare disease, for which chemotherapy actually remains unsatisfactory. From August 1998 to November 2001, 28 chemo-radio-immunonaive patients were consecutively enrolled in the trial: 22/6 males/females; median age 63 years (range, 45-79); median ECOG PS 1 (range, 0-2). They were treated with epirubicin (100 mg/m2 iv on day 1) plus gemcitabine (1000 mg/m2 iv on days 1 and 8) every 4 weeks for 6 cycles. Patients who responded to chemotherapy (n = 6) were subsequently treated with interleukin-2 (4,500,000 IU) subcutaneously every other day, until progression. A total of 124 epirubicin-gemcitabine cycles were administered (median, 6/patient; range, 2-6). Twenty-six patients were evaluated for toxicity. According to WHO criteria, we observed grade III-IV hematological and gastrointestinal toxicity respectively in 3 patients (11%) and 1 patient (3%). No red cell transfusions were required and no toxic deaths occurred. Two patients (8%) could not be evaluated for response (no therapy performed). According to WHO criteria, the final responses were: partial in 4 patients (14%), stable disease in 19 patients (69%), and progression in 3 patients (10%). In 26 patients, the median survival was 55 weeks (range, 7-222) and median time to progression 30 weeks (range, 4-156). At the time of this writing, no patient is alive. The 1-year survival was 32%, 2-year survival 11%, and 4% at 3 and 4 years. All patients were at stage III, and time to progression was 58 weeks and survival 63.5 weeks, without any toxicity. This multi-center phase II clinical trial showed that epirubicin plus gemcitabine, as a first-line treatment in malignant pleural mesothelioma, has promising activity with a good tolerability profile and symptom palliation. The role of interleukin-2 in maintenance therapy for malignant pleural mesothelioma is encouraging and requires further study.

Combined Epirubicin and Interleukin-2 Regimen in the Treatment of Malignant Mesothelioma: A Multicenter Phase II Study of the Italian Group on Rare Tumors

The Italian Group on Rare Tumors undertook a phase II study of a combination of epirubicin and interleukin-2 in 21 chemotherapy-naive patients with malignant mesothelioma. All patients had bidimensionally measurable disease at CT scan. Treatment included intravenous administration of epirubicin at a dose of 110 mg/m2 i.v. on day 1, and interleukin-2 at a dose of 9 MU subcutaneously from day 8 to day 12 and from day 15 to day 19. Cycles were repeated every three weeks, up to six times in the absence of progressive disease. Treatment response was evaluated after two cycles of therapy. Only one patient achieved a partial response, resulting in an overall response rate of 5% (1/21) with a median progression-free and overall survival of 5 and 10 months, respectively. Toxicity was relevant and caused treatment discontinuation in many patients. These results do not support the use of such a combination in the management of malignant mesothelioma.

The Society for Immunotherapy of Cancer consensus statement on tumour immunotherapy for the treatment of cutaneous melanoma

Immunotherapy is associated with durable clinical benefit in patients with melanoma. The goal of this article is to provide evidence-based consensus recommendations for the use of immunotherapy in the clinical management of patients with high-risk and advanced-stage melanoma in the USA. To achieve this goal, the Society for Immunotherapy of Cancer sponsored a panel of melanoma experts--including physicians, nurses, and patient advocates--to develop a consensus for the clinical application of tumour immunotherapy for patients with melanoma. The Institute of Medicine clinical practice guidelines were used as a basis for this consensus development. A systematic literature search was performed for high-impact studies in English between 1992 and 2012 and was supplemented as appropriate by the panel. This consensus report focuses on issues related to patient selection, toxicity management, clinical end points and sequencing or combination of therapy. The literature review and consensus panel voting and discussion were used to generate recommendations for the use of immunotherapy in patients with melanoma, and to assess and rate the strength of the supporting evidence. From the peer-reviewed literature the consensus panel identified a role for interferon-α2b, pegylated-interferon-α2b, interleukin-2 (IL-2) and ipilimumab in the clinical management of melanoma. Expert recommendations for how to incorporate these agents into the therapeutic approach to melanoma are provided in this consensus statement. Tumour immunotherapy is a useful therapeutic strategy in the management of patients with melanoma and evidence-based consensus recommendations for clinical integration are provided and will be updated as warranted.

Development and application of a multiplexable flow cytometry-based assay to quantify cell-mediated cytolysis

Although target cell cytolysis has been widely employed to describe effector function of cells, cytolysis assays as commonly employed do not generate quantitative data. In this report we describe the development and application of a statistically supported flow cytometry-based assay to quantify cell-mediated cytolysis. The assay depends on the use of the fluorescent dye CFSE to distinguish target from effector cells, the DNA intercalating dye 7AAD to distinguish dead from live cell events, and on the establishment of a cytolysis curve that allows for the derivation of statistically robust data. We demonstrate that the cytolysis curve is well described by a four parameter logistic regression model provided that (i) the range of effector to target (E:T) ratios studied allows for full description of the logistic curve, and (ii) an adequate number of data points are collected to estimate the model parameters. We show that the assay is highly reproducible and accurate, and comparable in sensitivity with the standard (51)Cr assay. We report on the potential for this assay to generate quantitative data on the cytolytic activity of both CD8 T and NK cells; describe a relationship between the efficiency of effector cell degranulation and target cell cytolysis throughout a range of E:T ratios, and demonstrate the potential to multiplex with other platforms to obtain broader datasets for the effector phenotype of cells. Appropriate use of this assay will enhance the ability to derive quantitative and integrated correlative datasets from basic, translational, and clinical studies.

IL-2 and IL-18 attenuation of airway hyperresponsiveness requires STAT4, IFN-gamma, and natural killer cells

IL-18 is known to induce IFN-gamma production, which is enhanced when combined with IL-2. In the present study, we investigated whether the combination of exogenous IL-2 and IL-18 alters airway hyperresponsiveness (AHR) and airway inflammation. Sensitized mice exposed to ovalbumin (OVA) challenge developed AHR, inflammatory cells in the bronchoalveolar lavage (BAL) fluid, and increases in levels of Th2 cytokines and goblet cell numbers. The combination of IL-2 and IL-18, but neither alone, prevented these changes while increasing levels of IL-12 and IFN-gamma. The combination of IL-2 and IL-18 was ineffective in IFN-gamma-deficient and signal transducer and activator of transcription (STAT)4-deficient mice. Flow cytometry analysis showed significant increases in numbers of IFN-gamma-positive natural killer (NK) cells in the lung after treatment with the combination therapy, and transfer of lung NK cells isolated from sensitized and challenged mice treated with the combination significantly suppressed AHR and BAL eosinophilia. These data demonstrate that the combination of IL-2 and IL-18 prevents AHR and airway inflammation, likely through IL-12-mediated induction of IFN-gamma production in NK cells.

Phase I study of adoptive T-cell therapy using antigen-specific CD8+ T cells for the treatment of patients with metastatic melanoma

PURPOSE

The adoptive transfer of in vitro generated tumor antigen-specific cytotoxic T lymphocytes (CTL) provides a promising approach to the immunotherapy of cancer. A phase I study was conducted to test the feasibility, safety, and survival of adoptively transferred Melan-A-specific CTL lines in melanoma patients.

PATIENTS AND METHODS

Eleven HLA-A2+ patients with metastatic melanoma received at least three intravenous infusions of Melan-A-specific CTL at 2-week intervals. CTL were generated by four rounds of in vitro stimulation of purified CD8+ peripheral blood lymphocytes with autologous dendritic cells pulsed with an HLA-A2 binding Melan-A peptide. Each T-cell infusion was accompanied by a 6-day course of low-dose interleukin-2.

RESULTS

A total of 52 T-cell infusions were administered, averaging 2.1 x 10(8) Melan-A-specific CTL per infusion. Clinical adverse effects were mild and consisted of chills and low-grade fever in seven of 11 patients. Clinical and immunologic responses revealed an antitumor response in three of 11 patients (one complete regression, one partial regression, one mixed response), an elevated frequency of circulating Melan-A tetramer+ T cells up to 2 weeks in all the patients with a maximal frequency of 2% of total CD8+ T cells, an increase in eosinophils to up to 50% in seven of 11 patients, and a selective loss of Melan-A expression in lymph node metastases in two evaluated patients after T-cell transfer.

CONCLUSION

Our data indicate that the adoptive transfer of antigen-specific T cells in melanoma patients can induce clinical tumor-specific immune responses without major adverse effects.

Autoimmune Toxicities Associated with the Administration of Antitumor Vaccines and Low-Dose Interleukin-2

The purpose of this investigation was to evaluate the occurrence of autoimmune toxicities associated with the administration of low-dose IL-2 in conjunction with vaccines for melanoma. Ninety-three patients with stage IIB, III, or IV melanoma were enrolled in three clinical trials and received anti-melanoma vaccines on days 1, 8, 15, 29, 36, and 43. The vaccines comprised peptide-pulsed dendritic cells, autologous tumor cells with GM-CSF in Montanide ISA-51, or synthetic peptides with GM-CSF in Montanide ISA-51. In conjunction with the vaccines, all patients were administered 3 x 10(6) IU/m2/d IL-2 subcutaneously for 42 days, either days 8 to 49 or 29 to 70. Clinical and laboratory data from these studies were reviewed in aggregate to evaluate the occurrence of autoimmune toxicities. Of 91 evaluable patients, vitiligo was documented in 6 patients (7%). In addition, one patient experienced transient severe insulin-dependent diabetes that resolved after discontinuing IL-2, and another experienced an exacerbation of his pre-existing diabetes; these occurrences are consistent with an autoimmune insulitis. Four occurrences (4%) of transient minor ocular toxicity were documented, but no autoimmune ocular toxicities or changes in visual acuity were found. Of 55 evaluable patients, 14 experienced thyroid abnormalities (25%). These were attributed to an autoimmune thyroiditis, which was supported by findings of antithyroid antibodies in three of the seven patients evaluated. Overall, autoimmune toxicities affecting several organ systems were observed in patients receiving melanoma vaccines in conjunction with low-dose IL-2. None of these toxicities caused major long-term effects, though one was acutely life-threatening and others contributed to treatment-related morbidity. Peptide- or cell-based vaccines administered in combination with low-dose IL-2 appear to be capable of breaking tolerance to self-antigens; despite the associated toxicities, these combinations may still be useful to administer as an immunotherapy for cancer. However, careful monitoring for autoimmune toxicities should be incorporated in future clinical studies incorporating low-dose IL-2.

Immunologic and clinical outcomes of vaccination with a multiepitope melanoma peptide vaccine plus low-dose interleukin-2 administered either concurrently or on a delayed schedule

PURPOSE

A phase II trial was performed to test whether systemic low-dose interleukin-2 (IL-2) augments T-cell immune responses to a multipeptide melanoma vaccine. Forty patients with resected stage IIB-IV melanoma were randomly assigned to vaccination with four gp100- and tyrosinase-derived peptides restricted by human leukocyte antigen (HLA) -A1, HLA-A2, and HLA-A3, and a tetanus helper peptide plus IL-2 administered daily either beginning day 7 (group 1), or beginning day 28 (group 2).

PATIENTS AND METHODS

T-cell responses were assessed by an interferon gamma ELIspot assay in peripheral blood lymphocytes (PBL) and in a lymph node draining a vaccination site (sentinel immunized node [SIN]). Patients were followed for disease-free and overall survival.

RESULTS

T-cell responses to the melanoma peptides were observed in 37% of PBL and 38% of SINs in group 1, and in 53% of PBL and 83% of SINs in group 2. The magnitude of T-cell response was higher in group 2. The tyrosinase peptides DAEKSDICTDEY and YMDGTMSQV were more immunogenic than the gp100 peptides YLEPGPVTA and ALLAVGATK. T-cell responses were detected in the SINs more frequently, and with higher magnitude, than responses in the PBL. Disease-free survival estimates at 2 years were 39% (95% CI, 18% to 61%) for group 1, and 50% (95% CI, 28% to 72%) for group 2 (P = .32).

CONCLUSION

The results of this study support the safety and immunogenicity of a vaccine composed of four peptides derived from gp100 and tyrosinase. The low-dose IL-2 regimen used for group 1 paradoxically diminishes the magnitude and frequency of cytotoxic T lymphocyte responses to these peptides.

Assessment of the Toxicities of Systemic Low-Dose Interleukin-2 Administered in Conjunction with a Melanoma Peptide Vaccine

In this phase 2 study, the authors assessed the hematologic and clinical toxicities of a melanoma peptide vaccine administered in conjunction with low-dose interleukin-2 (IL-2) therapy. Forty patients were randomized to receive a weekly vaccine paired with a regimen of subcutaneous IL-2 (3 x 10(6) IU/m2/day) administered daily for 6 weeks beginning either at week 1 or at week 4 of vaccine therapy. The differences in the time course of the IL-2 between the two groups permitted assessment of the cause of the toxicities, due either to IL-2 or to vaccine components. Both treatment regimens were well tolerated in the outpatient setting. Toxicities attributable to the vaccine components were principally limited to grade 1 injection site reactions. Systemic clinical toxicities correlated with the initiation of IL-2 therapy. These toxicities coincided temporally and in magnitude with changes in circulating eosinophil counts, suggesting that systemic clinical toxicities and eosinophilia may have common etiologic pathways. Other minor toxicities attributable to this low-dose IL-2 regimen were clinically insignificant hepatic toxicity, mild anemia, and mild thrombocytosis. The hematologic effects of this therapy were delayed in time between the two treatment groups, without dramatic differences in magnitude, which suggests minimal modulation of the IL-2 toxicity by components of the vaccine.

Phase I studies of interleukin (IL)-2 and rituximab in B-cell non-hodgkin's lymphoma: IL-2 mediated natural killer cell expansion correlations with clinical response

PURPOSE

Expansion and activation of natural killer (NK) cells with interleukin-2 (IL-2) may enhance antibody-dependent cellular cytotoxicity (ADCC), an important mechanism of rituximab activity. Two parallel Phase I studies evaluated combination therapy with rituximab and IL-2 in relapsed or refractory B-cell non-Hodgkin's lymphoma (NHL).

EXPERIMENTAL DESIGN

Thirty-four patients with advanced NHL received rituximab (375 mg/m(2) i.v. weekly, weeks 1-4) and escalating doses of s.c. IL-2 [2-7.5 MIU daily (n = 19) or 4.5-14 million international units three times weekly (n = 15), weeks 2-5]. Safety, tolerability, clinical responses, NK cell counts, and ADCC activity were evaluated.

RESULTS

Maximally tolerated doses (MTD) of IL-2 were 6 MIU daily and 14 million international units thrice weekly. The most common adverse events were fever, chills, and injection site reactions. Dose-limiting toxicities were fatigue and reversible liver enzyme test elevations. Of the 9 patients enrolled at the daily schedule MTD, 5 showed clinical response. On the thrice-weekly schedule at the MTD, 4 of 5 patients responded. Responders showed median time to progression of 14.9 and 16.1 months, respectively, for the two studies. For the same total weekly dose, thrice-weekly IL-2 administration induced greater increases in NK cell counts than daily dosing, and NK cells correlated with clinical response on the thrice-weekly regimen. ADCC activity was increased and maintained after IL-2 therapy in responding and stable disease patients.

CONCLUSIONS

Addition of IL-2 to rituximab therapy is safe and, using thrice-weekly IL-2 dosing, results in NK cell expansion that correlates with response. This combination treatment regimen merits additional evaluation in a randomized clinical trial.

Clinical and Immunologic Results of a Randomized Phase II Trial of Vaccination Using Four Melanoma Peptides Either Administered in Granulocyte-Macrophage Colony-Stimulating Factor in Adjuvant or Pulsed on Dendritic Cells

Purpose: To determine clinical and immunologic responses to a multipeptide melanoma vaccine regimen, a randomized phase II trial was performed.

Patients and Methods: Twenty-six patients with advanced melanoma were randomly assigned to vaccination with a mixture of four gp100 and tyrosinase peptides restricted by HLA-A1, HLA-A2, and HLA-A3, plus a tetanus helper peptide, either in an emulsion with granulocyte-macrophage colony-stimulating factor (GM-CSF) and Montanide ISA-51 adjuvant (Seppic Inc, Fairfield, NJ), or pulsed on monocyte-derived dendritic cells (DCs). Systemic low-dose interleukin-2 (Chiron, Emeryville, CA) was given to both groups. T-lymphocyte responses were assessed, by interferon gamma ELIspot assay (Chiron, Emeryville, CA), in peripheral-blood lymphocytes (PBLs) and in a lymph node draining a vaccine site (sentinel immunized node [SIN]).

Results: In patients vaccinated with GM-CSF in adjuvant, T-cell responses to melanoma peptides were observed in 42% of PBLs and 80% of SINs, but in patients vaccinated with DCs, they were observed in only 11% and 13%, respectively. The overall immune response was greater in the GM-CSF arm (P < .02). Vitiligo developed in two of 13 patients in the GM-CSF arm but in no patients in the DC arm. Helper T-cell responses to the tetanus peptide were detected in PBLs after vaccination and correlated with T-cell reactivity to the melanoma peptides. Objective clinical responses were observed in two patients in the GM-CSF arm and one patient in the DC arm. Stable disease was observed in two patients in the GM-CSF arm and one patient in the DC arm.

Conclusion: The high frequency of cytotoxic T-lymphocyte responses and the occurrence of clinical tumor regressions support continued investigation of multipeptide vaccines administered with GM-CSF in adjuvant.

Evaluation of peptide vaccine immunogenicity in draining lymph nodes and peripheral blood of melanoma patients

Many peptide epitopes for cytotoxic T lymphocytes (CTLs) have been identified from melanocytic differentiation proteins. Vaccine trials with these peptides have been limited mostly to those associated with HLA-A2, and immune responses have been detected inconsistently. Cases of clinical regression have been observed after peptide vaccination in some trials, but melanoma regressions have not correlated well with T-cell responses measured in peripheral blood lymphocytes (PBLs). We vaccinated stage IV melanoma patients with a mixture of gp100 and tyrosinase peptides restricted by HLA-A1 (DAEKSDICTDEY), HLA-A2 (YLEPGPVTA and YMDGTMSQV) and HLA-A3 (ALLAVGATK) in an emulsion with GM-CSF and Montanide ISA-51 adjuvant. CTL responses were assessed in PBLs and in a lymph node draining a vaccine site (sentinel immunized node, SIN). We found CTL responses to vaccinating peptides in the SIN in 5/5 patients (100%). Equivalent assays detected peptide-reactive CTLs in PBLs of 2 of these 5 patients (40%). CTLs expanded from the SIN lysed melanoma cells naturally expressing tyrosinase or gp100. We demonstrated immunogenicity for peptides restricted by HLA-A1 and -A3 and for 1 HLA-A2 restricted peptide, YMDGTMSQV. Immune monitoring of clinical trials by evaluation of PBLs alone may under-estimate immunogenicity; evaluation of SIN provides a new and sensitive approach for defining responses to tumor vaccines and correlating these responses with clinical outcomes. This combination of an immunogenic vaccine strategy with a sensitive analysis of CTL responses demonstrates the potential for inducing and detecting anti-tumor immune responses in the majority of melanoma patients.

A combination of interleukin-2 and 60 nm cationic supramolecular biovectors for the treatment of established tumours by subcutaneous or intranasal administration

The Supramolecular Biovector (SMBV) KY is a drug delivery nanocarrier which consists of a discretely sized, ionically charged, cross-linked polysaccharide core surrounded by a lipid membrane. We used the non-immunogenic spontaneous mammary adenocarcinoma TS/A tumour to test the efficacy on tumour growth of low (10(4) IU) or ultra-low (10(3) IU) doses of interleukin-2 (IL-2) adsorbed to these 60 nm cationic synthetic particles. In comparison with the progressive growth of TS/A cells in syngeneic mice, KY/IL-2 particles coinjected with TS/A cells or administered at a distance from the tumour, inhibited tumour growth while free IL-2, even at 10-100 times the dose used in the KY/IL-2 formulations, had no effect. Studies performed on implanted tumours (treatment at day 6 (D6)) showed that KY/IL-2 administered subcutaneously (s.c.) at five sites distant from the tumour (10(3) IL-2 IU per site) induced rejection of the implanted tumours. Six out of 10 mice were cured while the other four had residual tumours only. In the same experiment, free IL-2 induced only tumoral growth reduction. Protection induced by KY/IL-2 administered s.c. at five sites involved recruitment of a CD8(+) T cell response since nu/nu mice and CD8-depleted mice did not reject the tumours. Mice cured were protected significantly to completely against a rechallenge with TS/A tumour cells, and a systemic tumour-specific CTL activity was induced. Finally, we showed that repeated intranasal (i.n.) administration of KY/IL-2 (low-dose) also led to complete regression of pre-established tumours and partial protection from tumour rechallenge. We therefore suggest that, in contrast to free IL-2, a KY/IL-2 formulation could be used as a systemic immunostimulant leading to the eradication of non-immunogenic, established tumours.

Expression of SART3 antigen and induction of CTLs by SART3-derived peptides in breast cancer patients

We recently reported the SART3 tumour-rejection antigen as possessing tumour epitopes capable of inducing HLA-class I-restricted cytotoxic T lymphocytes (CTLs). This study investigated expression of the SART3 antigen in breast cancer to explore an appropriate molecule for use in specific immunotherapy of breast cancer patients. The SART3 antigen was detected in all of the breast cancer cell lines tested, 30 of 40 (75%) breast cancer tissue samples, and 0 of 3 non-tumourous breast tissue samples. SART3 derived peptides at positions 109-118 and 315-323 induced HLA-A24 restricted CTLs that reacted to breast cancer cells from the peripheral blood mononuclear cells (PBMCs) of breast cancer patients. Therefore, the SART3 antigen and its peptides could be an appropriate molecule for use in specific immunotherapy of the majority of HLA-A24-positive breast cancer patients.

Palliative and therapeutic activity of IL-2 immunotherapy in unresectable malignant pleural mesothelioma with pleural effusion: Results of a phase II study on 31 consecutive patients

Malignant pleural mesothelioma is often unresectable at diagnosis, is refractory to cytotoxic agents and is frequently complicated by pleural effusion. The expected survival range for patients with or without involvement of visceral pleura is respectively 1-9 and 9-12 months; mesothelioma-related pleural effusion severely impairs the patients' quality of life and easily relapses after conservative treatments. Intrapleural administration of IL-2 is reported to be effective both in tumor-associated malignant pleurisy and on primary mesothelioma, whereas few data exist about IL-2 systemic administration. In order to assess the palliative and therapeutic activity of IL-2 in unresectable pleural malignant mesothelioma with pleural effusion, we performed a phase II study on 31 consecutive patients (M/F 16/15; median age 61 years, range 40-84; PS ECOG 0 n=7; ECOG 1 n=15; ECOG 2 n=9; stage IA n=13; IB n=9; II n=7; IV=2) who received first-line therapy with intrapleural repeated instillation of 9000000 I.U. IL-2 twice/weekly for 4 weeks, after needle thoracenthesis. In nonprogressing patients, 3000000 I.U. IL-2 were subcutaneously administered thrice weekly for up to 6 months. Toxicity (WHO criteria) with intrapleural IL-2 consisted of grade 3 fever in 6/31 (19%) patients and of cardiac toxicity (failure) grade 3 in one patient (3%); toxicity during subcutaneous treatment was mild to moderate, mainly a flu-like syndrome. In 28/31 (90%) of patients there was no further or minimal (asymptomatic) pleural fluid collection (according to Paladine criteria); pleurisy relapsed only in 1/28 patients after 19 months. Tumor objective response (WHO criteria), evaluated by CT, occurred in seven patients (one CR and six PR; ORR 22%); ten patients achieved SD and 14 patients progressed. Median overall survival was 15 months (range 5-39) in all patients. IL-2 intrapleural administration followed by low-dose IL-2 subcutaneously in pleurisy-complicated malignant mesothelioma is feasible and active both in palliation of pleural effusion and on primary tumor, with manageable toxicity. The overall survival observed in nonprogressing patients warrants further randomized studies with IL-2 aimed to the patient outcome.

Induction of HIV-1-specific T cell responses by administration of cytokines in late-stage patients receiving highly active anti-retroviral therapy

Highly active anti-retroviral therapy (HAART) is associated with reduction in the morbidity and mortality of patients with advanced HIV-1 disease. The ability of such treatment to improve immune responses against HIV-1 and opportunistic pathogens is variable and limited. Addition of cytokine immunotherapy to this treatment may improve immune responses. IL-2 with or without granulocyte-macrophage colony-stimulating factor (GM-CSF) was administered to HIV-1+ individuals receiving HAART with undetectable viral loads, and CD4 counts < 100 cells/microl. In one patient presenting with Mycobacterium avium complex (MAC) infection, we evaluated the effect of cytokine immunotherapy on lymphocyte phenotype; plasma viral load; proliferative responses to mitogens, recall and HIV-1 antigens; cytokine production and message in response to non-specific and specific stimuli; and natural killer (NK) cell activity. Proliferation assays were performed in two similar patients. Before cytokine immunotherapy the predominant CD8+ population was mainly CD28-. No proliferation or IL-2 production was seen in response to mitogens, recall or HIV-1 antigens; and no HIV-1 peptide-specific interferon-gamma (IFN-gamma)-secreting cells were present. Low levels of IL-4 were detected in response to antigens to which patients had been exposed, associated with up-regulated expression of costimulatory molecules influenced by IL-4. Following IL-2 administration, loss of IL-4 was associated with increased NK cell activity and HIV-1 peptide-specific and non-specific IFN-gamma-producing cells. Proliferative responses associated with IL-2 production and responsiveness were only seen after subsequent concomitant administration of GM-CSF with IL-2. These changes mirrored clinical improvement. An imbalance of lymphocyte subsets may account for immune unresponsiveness when receiving HAART. Restoration of responses following immunotherapy suggests a shift towards a lymphocyte profile with anti-pathogen activity.

Influence of low dose rIL-2 treatment on endogenous cytokine production, expression of surface IL-2R and the level of soluble IL-2R in patients with minimal residual disease

This study was designed to investigate the immunomodulatory effect of low-dose IL-2 therapy (100 microg/day for 3 weeks) on interferon (IFN), tumor necrosis factor (TNF) production in vivo and in vitro and on the expression of IL-2Ralpha/beta and soluble form of IL-2Ralpha. Patients enrolled in the study suffered from multiple myeloma (MM), Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) All of them were in remission after chemotherapy or radiotherapy. Our results indicated that IL-2 given subcutaneously at a low dose of 100 microg/day for 3 weeks induced IFN-gamma and TNF-alpha in plasma (measured 24 hrs after the last dose of IL-2) and affected the ability of blood leukocytes to produce cytokines. Production of IFN-gamma induced in vitro with PHA was enhanced, but TNF-alpha production induced by lipopolysaccharide (LPS) and virus (Newcastle Disease Virus) was depressed. The expression of both: surface IL-2R, especially beta subunit on total population of lymphocytes and NK cells, and soluble form of IL-2R, of chain were significantly enhanced after low-dose IL-2 therapy. Low dose IL-2 therapy was well tolerated by all patients, and side effects not exceeding II grade of toxicity according to WHO scale were observed. Five patients with MM relapsed 3-10 month after cessation of IL-2 therapy, but all patients with Hodgkin's and non-Hodgkin's lymphomas are still in remission (20 months of observation).

In vivo biological response following low-dose interleukin-2 in complete remission B-cell non-Hodgkin's lymphoma patients. Italian Lymphoma Study Group (GISL)

The aim of the present study is to verify whether recombinant interleukin-2 (rIL-2) at low doses is well tolerated in aggressive lymphoma in complete remission (CR), and if there may be a biological justification for its use as a remission-maintenance therapy able to reduce the percentage of relapses. We treated 6 patients with B-cell non-Hodgkin's lymphoma (B-NHL) in CR following PM-Cytabom with rIL-2 3 IMU s.c. x 5 d per wk, every other wk for 8 wk. Our results show that this treatment provokes statistically significant changes in the absolute number of lymphocytes, eosinophils, CD25+ and CD122+ cells and soluble IL-2 receptors; these doses, however, are not sufficient to modify CD3+, CD16+ and CD56+ cell values or natural killer and lymphokine activated killer cell activity. Thus these findings do not appear to constitute a biological rationale for the use of rIL-2 at this dose and schedule as a remission-maintenance therapy in B-cell NHL. Nevertheless, the results are a valid basis for further study of the use of the same rIL-2 doses for a longer period of time in combination with other cytokines, in the hope that the biological effects can be augmented without increasing the toxic side effects.

Clonal T cell expansion induced by interleukin 2 therapy in blood and tumors

In a phase I clinical trial on the effects of preoperative adjuvant IL-2 therapy given to patients undergoing hepatic resection of colorectal adenocarcinoma metastases, we monitored the putative induction of T cell clonal expansion in both tissues and blood. The presence of T cell clonotypes was analyzed with a PCR-based method that determines V-D-J junction size patterns in T cell receptor (TCR) V beta subfamilies in samples before and after a 5-d IL-2 infusion. This high resolution method analyzing CDR3 sizes of TCR transcripts was used in conjunction with FACS analysis of the corresponding T cell subpopulations with TCR V beta-specific mAb. At time of surgery (day 8 after starting IL-2), we found in the three patients analyzed with V beta-C beta primers multiple dominant T cell clonotypes in the tumor and peritumoral tissues which had probably expanded as a result of therapy. In three control patients not treated with IL-2, multiple oligoclonal patterns were not observed with this set of primers. In the fourth control patient a unique V beta 21-C beta CDR3 pattern which corresponds to two dominant clonotypes was found in the tumor. The same dominant clonotypes identified in the tumor after IL-2 were also detectable in the blood and comparison of the profiles obtained before and after IL-2 therapy indicates that they were induced by IL-2. The relative expansion of the corresponding T cell subpopulations was maintained for varying periods of time after surgery (4-7 d and almost 2 yr in one case). Together, these results indicate that IL-2 induces marked expansion of several T cell clones. Systemic IL-2 administration may represent, either alone or as a vaccine adjuvant, an appropriate way of boosting antigen-specific immune responses.