CCL4 as an adjuvant for DNA vaccination in a Her2/neu mouse tumor model.

Chemokines are key regulators of both innate and adaptive immune responses. CCL4 (macrophage inflammatory protein-1ß, MIP-1ß) is a CC chemokine that has a broad spectrum of target cells including immature dendritic cells, which express the cognate receptor CCR5. We asked whether a plasmid encoding CCL4 is able to improve tumor protection and immune responses in a Her2/neu+ mouse tumor model. Balb/c mice were immunized twice intramuscularly with plasmid DNA on days 1 and 15. On day 25, a tumor challenge was performed with 2 × 10(5) syngeneic Her2/neu+ D2F2/E2 tumor cells. Different groups of mice were vaccinated with pDNA(Her2/neu) plus pDNA(CCL4), pDNA(Her2/neu), pDNA(CCL4) or mock vector alone. Our results show that CCL4 is able to (i) improve tumor protection and (ii) augment a TH1-polarized immune response against Her2/neu. Although Her2/neu-specific humoral and T-cell immune responses were comparable with that induced in previous studies using CCL19 or CCL21 as adjuvants, tumor protection conferred by CCL4 was inferior. Whether this is due to a different spectrum of (innate) immune cells, remains to be clarified. However, combination of CCL19/21 with CCL4 might be a reasonable approach in the future, particularly for DNA vaccination in Her2/neu+ breast cancer in the situation of minimal residual disease.

Impact of prior treatment on outcome of transformed follicular lymphoma and relapsed de novo diffuse large B cell lymphoma: a retrospective multicentre analysis.

Transformation of follicular lymphoma (FL) into aggressive disease and relapse of de novo diffuse large B cell lymphoma (DLBCL) are considered highly unfavourable events. However, most published data were acquired when rituximab was not routinely used. We retrospectively analysed 50 patients with transformed FL (tFL) in a multicenter study and compared them to 50 individuals with relapsed DLBCL (rDLBCL) who all obtained rituximab for the treatment of their disease. Our goal was to identify factors that predict a more favourable prognosis. After a median follow-up of 5.4 years from diagnosis, there was no significant difference in median overall survival (OS) from the date of transformation (tFL) or date of the first relapse (rDLBCL) (1.9 versus 3.9 years, P = .542). Of note, 5-year OS of patients with tFL was 46 %. Follicular lymphoma patients, treatment naïve prior to transformation, fared significantly better than pretreated patients (median not reached versus 1.4 years, P = .014). Regarding rDLBCL, female gender (13.9 versus 1.8 years, P = .019) and absence of rituximab prior to the first relapse (14.0 versus 1.8 years, P = .035) were favourable prognostic factors in a uni- and multivariate analysis. Only a proportion of patients received high-dose chemotherapy with autologous stem cell transplantation (HDT-ASCT), i.e. 38 and 52 % of patients with tFL and rDLBCL, respectively. Our data indicate that a favourable prognosis is conferred by treatment naivety in tFL and by rituximab naivety in rDLBCL. In contrast, we did not find a prognostic impact of HDT-ASCT in our series.

Influence of comorbidity, age and performance status on treatment efficacy and safety of cetuximab plus irinotecan in irinotecan-refractory elderly patients with metastatic colorectal cancer.

BACKGROUND: We investigated the influence of comorbidity, Eastern Cooperative Oncology Group (ECOG) performance status and age on the efficacy and safety profile of cetuximab and irinotecan in elderly irinotecan-pretreated patients with mCRC. METHODS: 497 patients with mCRC were entered in the database of this non-interventional study (NIS). Comorbid conditions were recorded. RESULTS: A total of 247 and 250 patients aged <65 and >65 years, respectively, with a median age of 66 y were documented; 78% of the patients showed a reduced ECOG status. Grade III/IV toxicities occurred in 18% of patients without any difference between age groups although older patients had more comorbidities with a higher Charlson Comorbidity Index (CCI) (p = 0.002). Skin rash was strongly related to response (p = 0.006). Age, line of therapy, ECOG, gender and CCI had no influence on response. The objective response rates were similar: 38.1% for age <65 years versus 36.4% for age >65 years (p = 0.57). Progression-free survival (PFS) did not differ between patients 18-65 years (6.0 months) and patients >65 years (6.2 months; p = 0.99). Only PS had a negative impact on PFS (hazard ratio (HR): 0,499; 95% confidence interval (CI) 0.34-0.72; p=0.002), whereas the presence of skin toxicity (grade>1) influenced PFS and response rate (RR) positively (HR: 2.04; 95% CI, 1.6-2.6; p<0.001). CONCLUSIONS: Only PS and age had a negative influence on PFS irrespective of CCI or age. There were no significant differences in response rate and safety profile for elderly patients when treated with cetuximab and irinotecan. Comorbidities and age had no influence on efficacy or toxicity.

Transformation and additional malignancies are leading risk factors for an adverse course of disease in marginal zone lymphoma.

BACKGROUND: Marginal zone lymphoma (MZL) is a non-Hodgkin lymphoma that occurs as extra nodal, nodal, or splenic. While MZL is generally considered an indolent disease, a substantial percentage of patients follow an unfavorable course. The objective of this retrospective analysis was to identify predictors for a reduced overall survival (OS), or conversely an increased OS. PATIENTS AND METHODS: One hundred and ninety-seven MZL patients were analyzed. Apart from assessing previously published risk factors, concomitant morbidity at diagnosis, transformation into aggressive lymphoma, and occurrence of additional malignancies were evaluated. RESULTS: Next to the known risk factors, i.e. above 60 years of age and elevated serum lactate dehydrogenase (LDH), we demonstrate that transformation into aggressive lymphoma, as well as additional malignancies, are important independent risk factors for a shortened OS in a multivariate analysis, irrespective of the MZL localization. Impressively, in the group of patients lacking LDH elevation, transformation, and/or additional malignancies, only 1 of 63 patients died during follow-up compared with 37 of 87 patients in the high-risk group (HR = 22.8; 95% confidence interval 3.1-167.0; P = 0.002). CONCLUSIONS: Our analysis proposes novel risk factors and warrants for a continuous follow-up to detect the occurrence of transformation and additional malignancies early on.

Influence of age, performance status, cancer activity, and IL-6 on anxiety and depression in patients with metastatic breast cancer.

Depression and anxiety are the core disorders causing emotional distress in patients (pts) with metastatic breast cancer. The aim of our study was to screen metastatic breast cancer outpatients for anxiety and depression, and to investigate the influence of age, Karnofsky Performance Status (KPS), cancer activity, and inflammation as represented by IL-6 levels on these two mood disorders. Pts treated with chemotherapy for metastatic breast cancer (n = 70) were assessed using the Hospital Anxiety and Depression Scale (HADS) for symptoms (scores 0-21) and caseness (score ≥11) of clinical depression and anxiety. Blood samples for IL-6 concentrations were collected at 10:00 a.m. A total of 22 (31.4 %) pts were diagnosed with caseness of clinical depression and 23 (32.9 %) pts with clinical anxiety, while 12 pts were diagnosed positive for both mood disorders. Depression and anxiety were positively but moderately correlated (Spearman's r (2) = 0.24, p < 0.001). IL-6 was significantly correlated with symptoms of depression (r (2) = 0.42, p < 0.001) and to a lesser extent to symptoms of anxiety (r (2) = 0.16, p = 0.001). In addition, IL-6 was positively associated with tumor progression (p < 0.001). Multiple linear regression analysis showed that tumor progression (standardized b = 0.226, p = 0.047), symptoms of anxiety (b = 0.292, p = 0.016), and IL-6 (b = 0.314, p = 0.007) were independently associated with clinical depression, whereas anxiety was linked to tumor progression (b = 0.238, p = 0.030), symptoms of depression (b = 0.407, p < 0.001) and age (b = -0.381, p < 0.001), but not to IL-6 (b = 0.168, p = 0.134). Even though a positive correlation between depression and anxiety exists, clinical parameters like age, cancer activity, KPS, and IL-6 do influence depression and anxiety differently. Unlike clinical depression, anxiety is not associated with increased IL-6 levels, however, shows a reciprocal correlation with age.

CCL19 as an adjuvant for intradermal gene gun immunization in a Her2/neu mouse tumor model: improved vaccine efficacy and a role for B cells as APC.

The aim of this study was to evaluate the efficacy of the chemokine CCL19 (ELC) as an adjuvant for intradermal gene gun delivery of Her2/neu DNA and to investigate the role of B cells in CCL19-mediated enhancement of immune responses. Balb/c mice were immunized intramuscularly (i.m.) on days 1 and 15 with plasmid DNA (pDNA) (100 µg DNA) or intradermally (i.d.) by gene gun delivery (1-2 µg DNA). Administration of pDNA encoding Her2/neu (pDNA(Her2/neu) was compared with pDNA(Her2/neu) plus pDNA(CCL19), pDNA(CCL19), mock vector or uncoated gold particles/phosphate-buffered saline (PBS). Tumor challenge was performed subcutaneously on day 25 with syngeneic Her2/neu(+) tumor cells (D2F2/E2). Intradermal immunization by gene gun led to an enhancement of tumor protection by the DNA vaccine as compared with i.m. immunization. The protective effect of the vaccine was further enhanced by coadministration of pDNA(CCL19) both after i.m. and i.d. immunization. Tumor protection was associated with Her2/neu-specific T cell and humoral immune responses. Experiments in B-cell-deficient µMT mice showed that B cells are crucial for CCL19-mediated enhancement of tumor rejection, most likely as antigen-presenting B cells. DNA vaccines against Her2/neu may play a future role in the treatment of Her2/neu-positive breast cancer patients in a clinical situation of minimal residual disease.

CCL21 (SLC) improves tumor protection by a DNA vaccine in a Her2/neu mouse tumor model.

Secondary lymphoid-tissue chemokine (SLC/CCL21) is a CC chemokine that is constitutively expressed in various lymphoid tissues and binds to chemokine receptor CCR7 on mature dendritic cells (DCs) and distinct T-and B-cell sub-populations. In vivo, CCL21 regulates the encounters between DC and T cells and thus is a key regulator of adaptive immune responses. We asked whether CCL21 is able to augment immunogenicity of a DNA-based vaccine against Her2/neu in a Balb/c mouse model with syngeneic Her2/neu+ tumor cells (D2F2/E2). Mice were vaccinated intramuscularly with plasmid DNA (pDNA) on day 1 and boosted on day 15; tumor challenge was performed subcutaneously on day 25. Coexpression of CCL21 and Her-2/neu resulted in induction of a TH1-polarized immune response and substantial improvement of the protective effect of the DNA vaccine. Coexpression of tumor antigen pDNA(Her2/neu) with both pDNA(GM-CSF) and pDNA(CCL21) as adjuvants led to further improvement of protection by the vaccine (70% tumor-free mice on day 35 vs 40% with either adjuvant alone vs 5-10% with tumor antigen alone). Our results show that CCL21 is a potent adjuvant for DNA vaccination, particularly in combination with granulocyte-macrophage colony-stimulating factor (GM-CSF). Clinical use of a pDNA(Her2/neu/CCL21/GM-CSF) vaccine might be particularly promising in minimal residual Her2/neu+ breast cancer.

Allogeneic gene-modified tumor cells (RCC-26/IL-7/CD80) as a vaccine in patients with metastatic renal cell cancer: a clinical phase-I study.

Despite novel targeted agents, prognosis of metastatic renal cell cancer (RCC) remains poor, and experimental therapeutic strategies are warranted. Transfection of tumor cells with co-stimulatory molecules and/or cytokines is able to increase immunogenicity. Therefore, in our clinical study, 10 human leukocyte antigen (HLA)-A(*)0201(+) patients with histologically-confirmed progressive metastatic clear cell RCC were immunized repetitively over 22 weeks with 2.5-40 × 10(6) interleukin (IL)-7/CD80 cotransfected allogeneic HLA-A(*)0201(+) tumor cells (RCC26/IL-7/CD80). Endpoints of the study were feasibility, safety, immunological and clinical responses. Vaccination was feasible and safe. In all, 50% of the patients showed stable disease throughout the study; the median time to progression was 18 weeks. However, vaccination with allogeneic RCC26/IL-7/CD80 tumor cells was not able to induce TH1-polarized immune responses. A TH2 cytokine profile with increasing amounts of antigen-specific IL-10 secretion was observed in most of the responding patients. Interferon-γ secretion by patient lymphocytes upon antigen-specific and non-specific stimulation was substantially impaired, both before and during vaccination, as compared with healthy controls. This is possibly due to profound tumor-induced immunosuppression, which may prevent induction of antitumor immune responses by the gene-modified vaccine. Vaccination in minimal residual disease with concurrent depletion of regulatory cells might be one strategy to overcome this limitation.

A phase II study of enzastaurin, a protein kinase C beta inhibitor, in patients with relapsed or refractory mantle cell lymphoma.

BACKGROUND: Protein kinase C beta (PKCbeta), a pivotal enzyme in B-cell signaling and survival, is overexpressed in most cases of mantle cell lymphoma (MCL). Activation of PI3K/AKT pathway is involved in pathogenesis of MCL. Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through PKCbeta/PI3K/AKT pathways, induces apoptosis, reduces proliferation, and suppresses tumor-induced angiogenesis. PATIENTS AND METHODS: Patients with relapsed/refractory MCL, and no more than four regimens of prior therapy, received 500 mg enzastaurin, orally, once daily. RESULTS: Sixty patients, median age 66 years (range 45-85), Eastern Cooperative Oncology Group performance status of zero to two (48% had baseline International Prognostic Index of 3-5), were enrolled. Most patients had prior CHOP-like chemotherapy and/or rituximab (median = 2 regimens). No drug-related deaths occurred. There was one case each of grade 3 anemia, diarrhea, dyspnea, vomiting, hypotension, and syncope. Fatigue was the most common toxicity. Although no objective tumor responses occurred, 22 patients (37%, 95% CI 25% to 49%) were free from progression (FFP) for > or =3 cycles (one cycle = 28 days); 6 of 22 were FFP for >6 months. Two patients remain on treatment and FFP at >23 months. CONCLUSION: Freedom from progression for >6 months in six patients and a favorable toxicity profile with minimal hematological toxicity indicate that enzastaurin warrants evaluation as maintenance therapy and combination chemotherapy in MCL.

Assessment of free light chains in the cerebrospinal fluid of patients with lymphomatous meningitis - a pilot study.

BACKGROUND: Lymphomatous meningitis (LM) represents a severe complication of malignant lymphomas. While clinical suspicion is raised by symptoms ranging from mild disturbances of sensation to severe pain or impaired consciousness, the definite diagnosis of LM is often difficult to obtain. Since B-cell lymphomas are clonally restricted to express either kappa or lambda immunoglobulin light chain, we hypothesised that analysis of free light chain (FLC) ratios might facilitate the diagnosis of LM. METHODS: Kappa and lambda FLC were measured using a novel nephelometric assay in cerebrospinal fluid (CSF) and serum from 17 patients. 5/17 suffered from LM as demonstrated by cytology, immunocytology, and/or imaging procedures. RESULTS: Measurement of FLC concentrations in CSF was achieved for all 17 patients. FLC levels in CSF were lower than serum FLC levels in samples for the same patient obtained at the same time (p < 0.01). CSF and serum FLC concentrations correlated weakly in all patients irrespective of LM status. Significantly more patients with cytopathologically and immunohistochemically proven LM displayed abnormal kappa/lambda FLC ratios in CSF compared to individuals with no LM (p < 0.01). CONCLUSION: This is the first report demonstrating that a significant proportion of LM patients display an abnormal kappa/lambda FLC ratio in the CSF.

CCL19 (ELC) as an adjuvant for DNA vaccination: induction of a TH1-type T-cell response and enhancement of antitumor immunity.

Coexpression of tumor antigens together with immunomodulatory molecules is a strategy in DNA vaccination aiming at an amplification of the antitumor immune response. Epstein-Barr virus-induced-molecule-1-ligand-chemokine (ELC/CCL19) is a CC chemokine that binds to the chemokine receptor CCR7. CCR7 is expressed on mature dendritic cells (DC) and distinct T- and B-cell subpopulations. CCL19 (ELC) is mainly expressed in secondary lymphoid organs and plays a central role in regulating the encounters between DC and T cells. We asked whether CCL19 is able to augment immunogenicity of a DNA vaccine in a C57BL/6 mouse model with syngeneic MCA205 (beta-gal) tumor cells. Mice were vaccinated twice intramuscularly on days 1 and 15 and tumor challenge was performed subcutaneously on day 25. Coadministration of plasmid DNA (pDNA) (beta-gal) plus pDNA (CCL19) was compared with pDNA (beta-gal), pDNA (CCL19), mock vector and phosphate-buffered saline (PBS) alone. Coexpression of CCL19 resulted in enhancement of a Th1-polarized immune response with substantial improvement of the protective effect of the DNA vaccine. Immunohistochemical staining revealed an increased CD8+ T-cell infiltration in the tumor tissue of mice that had been immunized with pDNA (beta-gal) plus pDNA (CCL19). We conclude that CCL19 is an attractive adjuvant for DNA vaccination able to augment antitumor immunity and that this effect is partially caused by enhanced CD8+ T-cell recruitment.

Trimethoprim-sulfamethoxazole exacerbates posthypoxic action myoclonus in a patient with suspicion of Pneumocystis jiroveci infection.

We describe a 58-year-old patient with relapsing high-grade non-Hodgkin's lymphoma who exhibited exacerbation of posthypoxic action myoclonus during high-dose intravenous trimethoprim-sulfamethoxazole (TMP-SMX) treatment for highly suspicious Pneumocystis jiroveci pneumonia (PCP). Three months previously the patient had experienced a hypoxic insult caused by respiratory arrest due to an anaphylactic reaction to antibiotic therapy. He had developed posthypoxic action myoclonus (Lance-Adams syndrome), which was well controlled by oral treatment with piracetam. However, after TMP-SMX therapy (115 mg/kg daily) was started for suspicion of newly developed PCP, posthypoxic action myoclonus worsened dramatically resulting in complete disability. Anti-myoclonic therapy with increased doses of piracetam and valproic acid did not significantly improve his clinical condition. Only when TMPSMX doses were reduced (38 mg/kg daily) on day 12 did action myoclonus cease within 2 to 3 days. We suggest that TMP-SMX can exacerbate posthypoxic action myoclonus.

Flt-3 ligand as adjuvant for DNA vaccination augments immune responses but does not skew TH1/TH2 polarization.

Since transfection of dendritic cells (DC) plays a key role in DNA vaccination, in vivo expansion of DC might be a tool to increase vaccine efficacy. We asked whether Fms-like tyrosine kinase-3 ligand (Flt-3L), a growth factor for DC, can be used as an adjuvant for DNA vaccination. Beta-galactosidase (beta-gal) was used as a model antigen in C57BL/6 mice. Mice were immunized i.m. with DNA coding for beta-gal with or without additional injection of Flt-3L. In both cases, antigen-specific CD4+ and CD8+ T cells were detectable after vaccination. Compared with DNA alone, additional administration of Flt-3L led to a significant increase in the antigen-specific proliferative response. However, increased cytotoxicity by T cells was not observed. The cytokines secreted by splenocytes of immunized mice upon in vitro stimulation with antigen had a TH2 profile. Humoral responses against beta-gal preferentially consisted of IgG1 antibodies. Analysis of DC from Flt-3L-treated mice revealed an immature phenotype with low or absent expression levels of CD80, CD86 and CD40. We conclude that Flt-3L does not generally skew immune responses towards a TH1 type. More likely, factors determined by the antigen and/or the vaccination procedure itself are crucial for the resulting type of immune response. Flt-3L - under circumstances such as the one we have investigated - can also lead to suppression of TH1 T cell immunity, possibly by expansion of immature/unactivated DC.

Risk-adapted postremission therapy in acute myeloid leukemia: results of the German multicenter AML HD93 treatment trial.

The objective of the AML HD93 treatment trial was to evaluate the outcome in young adults with acute myeloid leukemia (AML) after postremission therapy was stratified according to cytogenetically defined risk. The rationales for the study design were based (i) on previous favorable results with high-dose cytarabine in AML with t(8;21), inv/t(16q22) and in AML with normal karyotype, and ii) on encouraging results obtained in several phase II trials using autologous stem cell transplantation (SCT). Between July 1993 and January 1998, 223 eligible patients, 16-60 years of age with newly diagnosed AML other than French-American-British type M3/M3v, were entered into the trial. Risk groups were defined as follows: low risk: t(8;21) or inv/t(16q22); intermediate risk: normal karyotype; high risk: all other chromosomal abnormalities. Following intensive double induction therapy with idarubicin, cytarabine and etoposide, all patients in complete remission (CR) received a first consolidation therapy with high-dose cytarabine and mitoxantrone (HAM). A second consolidation therapy was stratified according to the risk group: low risk: HAM; intermediate risk: related allogeneic SCT or sequential HAM; high risk: related allogeneic or autologous SCT. Double induction therapy resulted in a high CR rate of 74.5%, and 90% of the responding patients were eligible for consolidation therapy. Survival for all 223 trial entrants was 40%, and for the 166 patients who entered CR, disease-free (DFS) and overall survival were 40 and 51% after 5 years, respectively. Within the low-, intermediate- and high-risk groups, DFS and survival after 5 years were 62.5 and 87, 40 and 49 and 17 and 26% respectively, without advantage for allogeneic transplantation in the intermediate- and high-risk groups. Postremission therapy-related mortality was 0, 7 and 14%, respectively. This study demonstrates the feasibility of cytogenetically defined risk-adapted consolidation therapy. The overall trial results are at least equivalent to those of published trials supporting the risk-adapted treatment strategy.

Tumor necrosis factor-alpha regulates the expression of inducible costimulator receptor ligand on CD34(+) progenitor cells during differentiation into antigen presenting cells.

The inducible costimulator receptor (ICOS) is a third member of the CD28 receptor family that regulates T cell activation and function. ICOS binds to a newly identified ligand on antigen presenting cells different from the CD152 ligands CD80 and CD86. We used soluble ICOSIg and a newly developed murine anti-human ICOS ligand (ICOSL) monoclonal antibody to further characterize the ICOSL during ontogeny of antigen presenting cells. In a previous study, we found that ICOSL is expressed on monocytes, dendritic cells, and B cells. To define when ICOSL is first expressed on myeloid antigen presenting cells, we examined ICOSL expression on CD34(+) cells in bone marrow. We found that CD34(bright) cells regardless of their myeloid commitment were ICOSL(-), whereas ICOSL was first expressed when CD34 expression diminished and the myeloid marker CD33 appeared. However, acute myeloid leukemia cells were ICOSL-negative, whereas among B-cell malignancies only some cases of the most mature tumors such as prolymphocytic leukemia and hairy cell leukemia were positive. Next, we investigated purified CD34(+) hematopoietic progenitor cells that did not constitutively express ICOSL but were induced to express ICOSL within 12 h after granulocyte/macrophage colony-stimulating factor/tumor necrosis factor alpha (TNF-alpha) stimulation. Interestingly, ICOSL was induced prior to CD80/CD86 induction on CD34(+) cells so that ICOSL was expressed in the absence of CD80/CD86. This suggests that ICOSL is an early differentiation marker along the monocytic/dendritic maturation pathway. Induction of ICOSL was dependent on TNF-alpha and was regulated via NF-kappa B as revealed by use of inhibitors specific for I kappa B alpha phosphorylation such as BAY 11-7082 and BAY 11-7085. The antigen presenting capacity of TNF-alpha stimulated CD34(+) cells was strongly inhibited by ICOSIg fusion proteins or by NF-kappa B inhibition. Thus, TNF-alpha-induced ICOSL expression seemed to be functionally important for the costimulatory capacity of CD34(+) hematopoietic progenitor cells.

Granulocyte/macrophage-colony-stimulating-factor plus interleukin-2 plus interferon alpha in the treatment of metastatic renal cell carcinoma: a pilot study.

Granulocyte/macrophage-colony-stimulating factor (GM-CSF) plays a central role in the differentiation and function of dendritic cells, which are crucial for the elicitation of MHC-restricted T cell responses. Preclinical and the first clinical data provide a rationale for the application of GM-CSF in immunotherapy of cancer. Ten patients with renal cell carcinoma stage IV (Holland/ Robson) were treated in this pilot study. Therapy was started with GM-CSF alone (2 weeks). Interleukin (IL-2) and interferon alpha (IFNalpha) were added sequentially (3 weeks GM-CSF plus IL-2 or IFNalpha, 3 weeks GM-CSF plus IL-2 plus IFNalpha). Therapy was performed on an outpatient basis. The cytokine regimen was evaluated for toxicity, clinical response and immunomodulatory effects [fluorescence-activated cell sorting analysis of peripheral blood mononuclear cells (PBMC), mixed-lymphocyte reaction and cytotoxicity of PBMC]. GM-CSF treatment caused a significant increase in the number of PBMC expressing costimulatory molecules. Addition of IL-2 and IFNalpha led to an increase in CD3 , CD4+, CD8+ and CD56+ PBMC in week 9. In an autologous mixed-lymphocyte reaction a 2.1-fold increase in T cell proliferation was observed after 2 weeks of GM-CSF treatment, and cytotoxicity assays showed changes in natural-killer-(NK)- and non-NK-mediated cytotoxicity in some patients. Two patients achieved partial remission, one patient had a mixed response. The toxicity of the regimen was mild to moderate with fever, flu-like symptoms and nausea being observed in most patients. Severe organ toxicity was not observed. We conclude that GM-CSF might be useful for immunotherapy of renal cell carcinoma, especially in combination with T-cell-active cytokines. Further studies are warranted.

Bcr/abl+ autologous dendritic cells for vaccination in chronic myeloid leukemia.

In chronic myeloid leukemia (CML) ex vivo generated DC are characterized by constitutive expression of bcr/abl and possibly other yet undefined leukemia-associated antigens, since these DC share a common progeny with leukemic cells. Induction of anti-leukemic T cell responses has been described in vitro. For a phase I vaccination study, autologous bcr/abl+ DC are generated under GMP conditions mainly from monocyte precursors in chronic phase CML patients. Lin-, CD80+, CD86+, CD83+, DR+ DC could be generated in sufficient numbers for s.c. vaccination with 1 x 10(6)-5 x 10(7) DC. Using monocyte precursors, the yield of DC per seeded PBMC was in the range of 1-6%. Furthermore, we could demonstrate in vitro that the T cell stimulatory ability of CD34+-derived DC can be augmented by a factor 2-3 by retroviral transduction with a gene coding for interleukin-7. DC-based vaccination strategies are a promising clinical approach, particularly as postremission immunotherapy in the setting of autologous stem cell transplantation.

Allogeneic vaccination for renal cell carcinoma: development and monitoring.

An allogeneic tumor cell vaccine should display a natural immunogenicity that allows the stimulation of tumor-reactive effector cells in patients. Furthermore, the vaccine should express antigens that are shared by many tumors to which patients are not tolerant. A variety of tumor peptides should be presented by different HLA-molecules due to limited MHC matching with recipients and last but not least, the vaccine should have a strong growth potential in vitro to allow adequate amounts of vaccine to be generated for long-term usage. In vitro and in situ studies with the renal cell carcinoma cell line RCC-26 demonstrate: (1) RCC-26 can induce complex allospecific responses through direct priming; (2) RCC-26 can not only reactivate cytotoxic T lymphocytes (CTL) of a memory phenotype but they also can induce de novo tumor-antigen associated responses in normal donors; (3) these cells present epitopes restricted by several MHC molecules, allowing the vaccination of patients matched for different HLA alleles; and (4) they stimulate HLA-A*0201-restricted T cells bearing characteristic T cell receptors (TCR). Thus, in addition to using limiting dilution killer and ELISPOT assays, molecular tracking of a tumor-specific TCR can be used to judge the development of antitumor reactivity and vaccine efficiency.

Characterization of human inducible costimulator ligand expression and function.

The inducible costimulator (ICOS) is the newest member of the CD28/CD152 receptor family involved in regulating T cell activation. We constructed a soluble-Ig fusion protein of the extracellular domain of human ICOS and used it as a probe to characterize expression patterns of the ICOS ligand (ICOSL). ICOSIg did not bind to CD80- or CD86-transfected Chinese hamster ovary cell lines, demonstrating that ICOSL is distinct from those ligands identified for CD28/CD152. ICOSIg showed selective binding to monocytic and B cell lines, whereas binding was undetectable on unstimulated monocytes and peripheral blood T and B cells. Expression of ICOSL was induced on monocytes after integrin-dependent plastic adhesion. Pretreatment of monocytes with mAb to the beta2-integrin subunit CD18 decreased adhesion and abolished ICOSL up-regulation but had no effect on CD80/86 (CD152 ligand (CD152L)) expression. Both ICOSL and CD152L were up-regulated on monocytes by IFN-gamma but by distinct signaling pathways. Unlike CD152L expression, ICOSL expression did not change when monocytes were differentiated into dendritic cells (DCs) or after DCs were induced to mature by LPS, TNF-alpha, or CD40 ligation. Addition of ICOSIg to allogeneic MLRs between DCs and T cells reduced T cell proliferative responses but did so less efficiently than CTLA4Ig (CD152Ig) did. Similarly, ICOSIg also blocked Ag-specific T cell proliferation to tetanus toxoid. Thus, ICOSL, like CD80/86, is expressed on activated monocytes and dendritic cells but is regulated differently and delivers distinct signals to T cells that can be specifically inhibited by ICOSIg.