Nivolumab and ipilimumab in recurrent or refractory cancer of unknown primary: a phase II trial

Cancer of unknown primary has a dismal prognosis, especially following failure of platinum-based chemotherapy. 10-20% of patients have a high tumor mutational burden (TMB), which predicts response to immunotherapy in many cancer types. In this prospective, non-randomized, open-label, multicenter Phase II trial (EudraCT 2018-004562-33; NCT04131621), patients relapsed or refractory after platinum-based chemotherapy received nivolumab and ipilimumab following TMBhigh vs. TMBlow stratification. Progression-free survival (PFS) represented the primary endpoint; overall survival (OS), response rates, duration of clinical benefit and safety were the secondary endpoints. The trial was prematurely terminated in March 2021 before reaching the preplanned sample size (n = 194). Among 31 evaluable patients, 16% had a high TMB ( > 12 mutations/Mb). Overall response rate was 16% (95% CI 6-34%), with 7.7% (95% CI 1-25%) vs. 60% (95% CI 15-95%) in TMBlow and TMBhigh, respectively. Although the primary endpoint was not met, high TMB was associated with better median PFS (18.3 vs. 2.4 months) and OS (18.3 vs. 3.6 months). Severe immune-related adverse events were reported in 29% of cases. Assessing on-treatment dynamics of circulating tumor DNA using combined targeted hotspot mutation and shallow whole genome sequencing as part of a predefined exploratory analysis identified patients benefiting from immunotherapy irrespective of initial radiologic response.

REFLECT: prospective multicenter non-interventional study evaluating the effectiveness and safety of Sandoz rituximab (SDZ-RTX; Rixathon®) in combination with CHOP for the treatment of patients with previously untreated CD20-positive diffuse large B-cell lymphoma

Background

REFLECT is the first prospective study of Sandoz biosimilar rituximab (SDZ-RTX) in patients with diffuse large B-cell lymphoma (DLBCL).

Objective

To evaluate the 2-year effectiveness and safety of SDZ-RTX as first-line treatment for DLBCL.

Design

Real-world, multicenter, open-label, single-arm, non-interventional, post-approval study of SDZ-RTX in combination with cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP) in patients with treatment-naïve CD20‑positive DLBCL.

Methods

Treatment-naïve, CD20-positive adult patients (⩾18 years) with DLBCL eligible for therapy with R-CHOP were treated with SDZ-RTX-CHOP every 2 or 3 weeks for 6-8 cycles. The effectiveness of SDZ-RTX was measured by the complete response (CR) rate at the end of R-CHOP treatment, as assessed by the treating physician. Progression-free survival (PFS) was assessed at 24 months.

Results

A total of 169 patients [52.1% female, median (range) age 70 (24-94) years] with DLBCL were included in the full analysis set. At baseline, 19.5% and 24.3% of patients had Ann Arbor disease stage III or IV, respectively, and most patients (80.5%) had Eastern Cooperative Oncology Group Performance Status of 0 or 1. A total of 100 (59.2%) patients completed the 24-month observation period. In total, 110 [65.1%; 95% confidence interval (CI): 57.4-72.3] patients achieved CR as best response and 50 (29.6%; 95% CI: 22.8-37.1) patients achieved partial response. Overall best response rate was 94.7% (95% CI: 90.1-97.5). One-year PFS was 84.9% (95% CI: 78.2-89.6), while 2-year PFS was 78.5% (95% CI: 70.9-84.4); median PFS was not reached within the observational period. A total of 143 (84.6%) patients experienced ⩾1 adverse event, 53 (31.4%) of which were suspected to be related to study drug.

Conclusion

This real-world, 2-year study reconfirms that first-line treatment of CD20-positive DLBCL with R-CHOP using SDZ-RTX is effective and well tolerated.

Registration

N/A.

B‐cell receptors of EBV‐negative Burkitt lymphoma bind modified isoforms of autoantigens

Burkitt lymphoma (BL) represents the most aggressive B‐cell‐lymphoma. Beside the hallmark of IG‐MYC‐translocation, surface B‐cell receptor (BCR) is expressed, and mutations in the BCR pathway are frequent. Coincidental infections in endemic BL, and specific extra‐nodal sites suggest antigenic triggers. To explore this hypothesis, BCRs of BL cell lines and cases were screened for reactivities against a panel of bacterial lysates, lysates of Plasmodium falciparum, a custom‐made virome array and against self‐antigens, including post‐translationally modified antigens.

An atypically modified, SUMOylated isoform of Bystin, that is, SUMO1‐BYSL was identified as the antigen of the BCR of cell line CA46. SUMO1‐BYSL was exclusively expressed in CA46 cells with K139 as site of the SUMOylation. Secondly, an atypically acetylated isoform of HSP40 was identified as the antigen of the BCR of cell line BL41. K104 and K179 were the sites of immunogenic acetylation, and the acetylated HSP40 isoform was solely present in BL41 cells. Functionally, addition of SUMO1‐BYSL and acetylated HSP40 induced BCR pathway activation in CA46 and BL41 cells, respectively. Accordingly, SUMO1‐BYSL‐ETA’ immunotoxin, produced by a two‐step intein‐based conjugation, led to the specific killing of CA46 cells. Autoantibodies directed against SUMO1‐BYSL were found in 3 of 14 (21.4%), and autoantibodies against acetylated HSP40 in 1/14(7.1%) patients with sporadic Burkitt‐lymphoma. No reactivities against antigens of the infectious agent spectrum could be observed.

These results indicate a pathogenic role of autoreactivity evoked by immunogenic post‐translational modifications in a subgroup of sporadic BL including two EBV‐negative BL cell lines.

Identification of the atypically modified autoantigen Ars2 as the target of B-cell receptors from activated B-cell-type diffuse large B-cell lymphoma

It has been suggested that stimulation of B-cell receptors (BCR) by specific antigens plays a pathogenic role in diffuse large B-cell lymphoma (DLBCL). Here, it was the aim to screen for specific reactivities of DLBCL-BCR in the spectrum of autoantigens and antigens of infectious origin. Arsenite resistance protein 2 (Ars2) was identified as the BCR target of three of five activated B-cell type DLBCL cell lines and two of 11 primary DLBCL cases. Compared to controls, Ars2 was hypophosphorylated exclusively in cases and cell lines with Ars2-specific BCR. In a validation cohort, hypophosphorylated Ars2 was found in eight of 31 activated B-cell type DLBCL, but in only one of 20 germinal center B-cell like type DLBCL. Incubation with Ars2 induced BCR-pathway activation and increased proliferation, while an Ars2/ETA’ toxin conjugate induced killing of cell lines with Ars2-reactive BCR. Ars2 appears to play a role in a subgroup of activated B-cell-type DLBCL. Moreover, transformed DLBCL lines with Ars2-reactive BCR still showed growth advantage after incubation with Ars2. These results provide knowledge about the pathogenic role of a specific antigen stimulating the BCR pathway in DLCBL.

HANNA: Real-world outcomes from an observational study with nivolumab in patients with recurrent or metastatic squamous cell carcinoma of the head and neck in Germany

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Background: Nivolumab has demonstrated efficacy in clinical trials of recurrent or metastatic squamous cell carcinoma of the head and neck (R/M SCCHN). As only limited real-world data are available, we describe the use of nivolumab and its outcomes in routine clinical practice. Methods: HANNA is a prospective, observational study of patients with R/M SCCHN treated with nivolumab in 56 hospitals and practices in Germany. In total, 385 patients will be followed for ≤ 5 years from treatment initiation until death, withdrawal of consent, loss of follow-up/record, or end of study. The primary objective is overall survival (OS). Secondary objectives include baseline characteristics, safety profiles, and quality of life (QOL) assessment. Results: By November 2019, data from 311 patients were available. Median follow-up was 3.5 months. Baseline characteristics were male, 81.7%; median age, 63 years; history of smoking, 73.3%; Eastern Cooperative Oncology Group performance status (ECOG PS) 0/1, 60.8%; ECOG PS 2/3, 29.6%. Location of primary tumor was oropharynx, 38.3%; hypopharynx, 20.9%; oral cavity, 22.8%; larynx, 11.6%; others, 6.4%. 55.6% of R/M SCCHN patients progressed ≤ 6 months after platinum-based therapy, whereas 43.4% were platinum-sensitive (progressed > 6 months after platinum-based therapy). Nivolumab was received by 25.1% of patients as first therapy after platinum-based chemo- or radiochemotherapy, by 62.1% as second therapy, and by 12.9% as later line therapy. Median treatment duration was 4.6 months. OS at 1 year was 43.3%. 1-year OS for patients with ECOG PS 0 was 75.9%; ECOG PS 1, 41.2%; and ECOG PS 2, 27.3%. Platinum-sensitive patients had higher 1-year OS probability (51.6%). Drug-related adverse events (grade 1/2) and serious adverse events (grade 3/4) were observed in 28.9% and 10.0% of patients, respectively. Interim QOL data (per FACT-H&N and EQ-5D questionnaire) indicated a tendency toward stabilization or slight improvement. We will present an update of the data with longer follow-up (data cut March 2020). Conclusions: HANNA represents one of the largest real-world datasets for nivolumab in R/M SCCHN and comprises a more diverse set of patients than the phase 3 CheckMate 141 trial, including patients with higher ECOG PS, age, and platinum sensitivity. Outcomes from HANNA show that the improved OS, safety, and QOL seen with nivolumab in the real-world setting are consistent with the outcomes from CheckMate 141. Clinical trial information: NCT03114163 .

[Periodic fever and pancytopenia in a 35-year-old patient]

MEDICAL HISTORY AND INITIAL PRESENTATION

A 35-year-old patient with a previous history of persistent episodic fever, sore throat, myalgia, and cephalgia presented for evaluation of pancytopenia. He had no recent travel history, except for a stay in Italy 1 year prior to admission and in Spain several years in the past.

DIAGNOSTIC WORKUP

Laboratory evaluation confirmed pancytopenia, agranulocytosis, and elevated infection parameters without indicative serological results en par with lymphadenitis colli. Computed tomography scanning revealed cervical lymphadenopathy, hepatosplenomegaly, and colitis with occult perforation of the sigmoid colon. Bone marrow biopsy showed an infiltration of polyclonal plasma cells. Lymph node biopsy was compatible with necrotizing lymphadenitis.

DIAGNOSIS

Polymerase chain reaction analysis of a lymph node specimen confirmed the presence of Leishmania species, thereby enabling the diagnosis of visceral Leishmania.

THERAPY COURSE

Treatment with liposomal amphotericin B was initiated. Both fever and lymphadenopathy quickly resolved.

CONCLUSION

VL is a clinically pleiotropic, severe disease with fatal outcome if left untreated. It often presents with distinct similarities to hematologic malignancies. Exacerbation can occasionally occur as fulminant macrophage activation syndrome. Disease incidence is globally increasing and has not peaked as yet. A complex interplay between pathogen and the immune system is the key pathophysiological mechanism.

KIT D816 mutated/CBF-negative acute myeloid leukemia: a poor-risk subtype associated with systemic mastocytosis

KIT D816 mutations (KIT D816mut) are strongly associated with systemic mastocytosis (SM) but are also detectable in acute myeloid leukemia (AML), where they represent an adverse prognostic factor in combination with core binding factor (CBF) fusion genes. Here, we evaluated the clinical and molecular features of KIT D816mut/CBF-negative (CBFneg) AML, a previously uncharacterized combination. All KIT D816mut/CBFneg cases (n = 40) had histologically proven SM with associated AML (SM-AML). Molecular analyses revealed at least one additional somatic mutation (median, n = 3) beside KIT D816 (e.g., SRSF2, 38%; ASXL1, 31%; RUNX1, 34%) in 32/32 (100%) patients. Secondary AML evolved in 29/40 (73%) patients from SM ± associated myeloid neoplasm. Longitudinal molecular and cytogenetic analyses revealed the acquisition of new mutations and/or karyotype evolution in 15/16 (94%) patients at the time of SM-AML. Median overall survival (OS) was 5.4 months. A screen of two independent AML databases (AMLdatabases) revealed remarkable similarities between KIT D816mut/CBFneg SM-AML and KIT D816mut/CBFneg AMLdatabases (n = 69) with regard to KIT D816mut variant allele frequency, mutation profile, aberrant karyotype, and OS suggesting underlying SM in a significant proportion of AMLdatabases patients. Bone marrow histology and reclassification as SM-AML has important clinical implications regarding prognosis and potential inclusion of KIT inhibitors in treatment concepts.

Learning from the failures of drug discovery in B-cell non-Hodgkin lymphomas and perspectives for the future: chronic lymphocytic leukemia and diffuse large B-cell lymphoma as two ends of a spectrum in drug development

INTRODUCTION

Despite substantial recent advances, there is still an unmet need for better therapies in B-cell non Hodgkin lymphomas (B-NHL), especially in relapsed or refractory disease. Many novel targeted drugs have been developed based on a better molecular understanding of B-NHL. Areas covered: This article focuses on chronic lymphocytic leukemia (CLL) as a representative for indolent lymphomas and paradigmatic for the tremendous progress in treating B-NHL on the one hand and diffuse large B-cell lymphoma (DLBCL) as a representative for aggressive lymphomas and paradigmatic for many unsolved problems in lymphoma treatment or the other hand. We highlight salient points in current therapies targeting genetic, epigenetic, immunological and microenvironmental alterations. Possible reasons for drug failure in clinical trials like tumor heterogeneity, clonal evolution and drug resistance mechanisms are discussed. Based thereon, some perspectives for further drug discovery are given. Expert opinion: In view of the pathogenetic complexity of lymphomas, therapies targeting exclusively a single alteration may fail because resistance mechanisms are present either initially or evolve during treatment. Therefore, future therapies in B-NHL may have to target the greatest possible number of genetic, immunological or epigenetic alterations still allowing tolerability and to monitor these alterations during therapy.

Autoantibodies against lamin C, NA14 and CK15 in primary vasculitides or autoimmune diseases with secondary vasculitis

OBJECTIVES

Autoantibodies may play a role in the pathogenesis of primary vasculitides (PVs) like giant cell arteritis (GCA). We recently identified 3 cytoskeletal proteins (lamin C [laC], nuclear autoantigen of 14kD [NA14] and cytokeratin 15 [CK15]) as autoantigens in GCA and postulated a frequent autoantibody response against these antigens in PVs.

METHODS

To test this hypothesis we studied a cohort of patients with PVs (n=61) and healthy individuals (n=27) for the presence of these autoantibodies using a recombinant cDNA expression library. To define their specifity for PV, we also examined patients with other autoimmune diseases such as rheumatoid arthritis (RA) and connective tissue diseases (CTD).

RESULTS

We found no statistically significant differences in autoantibody responses between patients with PV and healthy controls, although there was a trend for an association between PVs and the occurrence of antibodies against laC and CK15. However, in patients with RA (n=33) or Sjögren's syndrome (SS, n=11) with vasculitides we observed more frequently autoantibodies against NA14, laC and CK15 compared to healthy controls. In patients with systemic lupus erythematosus (SLE, n=23) autoantibodies against laC were more frequent. The presence of autoantibodies in RA, SS and SLE was associated with systemic secondary vasculitis (SSV). In RA, laC- and NA14-seropositive patients were in a more advanced disease stage than seronegative patients with more frequent extraarticular manifestations (p=0.004). In SLE laC-autoantibody-positive patients had a higher SLE activity index (p<0.001).

CONCLUSIONS

Serum autoantibodies against laC and NA14 are frequent in patients with RA and CTD and are associated with extensive disease and SSV. The potential pathogenic and prognostic role of these antibodies should be further investigated.

The molecular basis for development of proinflammatory autoantibodies to progranulin

Recently we identified in a wide spectrum of autoimmune diseases frequently occurring proinflammatory autoantibodies directed against progranulin, a direct inhibitor of TNFR1 & 2 and of DR3. In the present study we investigated the mechanisms for the breakdown of self-tolerance against progranulin. Isoelectric focusing identified a second, differentially electrically charged progranulin isoform exclusively present in progranulin-antibody-positive patients. Alkaline phosphatase treatment revealed this additional progranulin isoform to be hyperphosphorylated. Subsequently Ser81, which is located within the epitope region of progranulin-antibodies, was identified as hyperphosphorylated serine residue by site directed mutagenesis of candidate phosphorylation sites. Hyperphosphorylated progranulin was detected exclusively in progranulin-antibody-positive patients during the courses of their diseases. The occurrence of hyperphosphorylated progranulin preceded seroconversions of progranulin-antibodies, indicating adaptive immune response. Utilizing panels of kinase and phosphatase inhibitors, PKCβ1 was identified as the relevant kinase and PP1 as the relevant phosphatase for phosphorylation and dephosphorylation of Ser81. In contrast to normal progranulin, hyperphosphorylated progranulin interacted exclusively with inactivated (pThr320) PP1, suggesting inactivated PP1 to cause the detectable occurrence of phosphorylated Ser81 PGRN. Investigation of possible functional alterations of PGRN due to Ser81 phosphorylation revealed, that hyperphosphorylation prevents the interaction and thus direct inhibition of TNFR1, TNFR2 and DR3, representing an additional direct proinflammatory effect. Finally phosphorylation of Ser81 PGRN alters the conversion pattern of PGRN. In conclusion, inactivated PP1 induces hyperphosphorylation of progranulin in a wide spectrum of autoimmune diseases. This hyperphosphorylation prevents direct inhibition of TNFR1, TNFR2 and DR3 by PGRN, alters the conversion of PGRN, and is strongly associated with the occurrence of neutralizing, proinflammatory PGRN-antibodies, indicating immunogenicity of this alternative secondary modification.

CD4⁺ T cells in chronic autoantigenic stimulation in MGUS, multiple myeloma and Waldenström's macroglobulinemia

Hyperphosphorylated paratarg-7 (pP-7) carrier state is the strongest and most frequent molecular risk factor for MGUS, multiple myeloma (MM) and Waldenström's macroglobulinemia (WM), inherited autosomal-dominantly and, depending on the ethnic background, found in up to one third of patients with MGUS/MM. Since P-7 is the antigenic target of paraproteins that do not distinguish between wtP-7 and pP-7, we investigated CD4(+) T-cell responses in pP-7(+) patients and controls. Peptides spanning amino acids 1-35 or 4-31 containing phosphorylated or nonphosphorylated serine17 were used for stimulation. CD4(+) cells from 9/14 patients (65%) showed a pP-7 specific HLA-DR restricted response. These results demonstrate that pP-7 specific CD4(+) cells can mediate help for pP-7 specific chronic antigenic stimulation of P-7 specific B cells, which might ultimately result in the clonal evolution of a B cell into MGUS/MM/WM producing a P-7 specific paraprotein. Prerequisites for pP-7 specific stimulation of CD4(+) cells appear to be both a pP-7 carrier state and an HLA-DR subtype able to present and recognize pP-7. Our results serve as an explanation for the exclusive autoimmunogenicity of the hyperphosphorylated variant of P-7 and for the different hazard ratios of pP-7 carriers from different ethnic origins to develop MGUS/MM/WM.

Management of diffuse large B-cell lymphoma (DLBCL)

Diffuse large B-cell lymphoma (DLBCL) is the most common non-Hodgkin lymphoma. While CHOP was the standard combination chemotherapy for 25 years, the incorporation of the CD20 antibody rituximab at the beginning of this century has considerably improved the outcome of all patients with DLBCL: Depending on the prognostic subgroup, only half to one-third of the patients die of their DLBCL compared to pre-rituximab era. Treatment is usually tailored according to the individual risk profile of a DLBCL patient according to the International Prognostic Index (IPI). Assignment of DLBCL according to the gene expression profile into DLBLC originating from a germinal center B cell (GC type) or from an activated B cell (ABC type) has provided novel insights into the pathogenesis of the respective DLBCL, identified molecules which are indispensable for the survival of the lymphoma cells and provided targets for novel "targeted therapies" drugs. Incorporating these new drugs into combination immunochemotherapy or substituting single drugs in the R-CHOP combination will result in even higher cure rates of and/or less toxicity for patients with DLBCL in the decade to come.

Sumoylated HSP90 is a dominantly inherited plasma cell dyscrasias risk factor

Posttranslationally modified proteins serve as autoimmunogenic targets in a wide spectrum of autoimmune diseases. Here, we identified a posttranslationally modified paraprotein target (paratargs) in monoclonal gammopathies of undetermined significance (MGUS), multiple myelomas (MM), and Waldenstrom's macroglobulinemias (WM) using protein macroarrays that were sumoylated and screened for reactivity with paraproteins from MGUS, MM, and WM patients. We found that paraproteins from a proportion of European, African-American, and Japanese patients specifically reacted with the sumoylated heat-shock protein 90 β isoform-α (HSP90-SUMO1, where SUMO indicates small ubiquitin-like modifier), while no reactivity with HSP90-SUMO1 was detected in over 800 controls. HSP90-SUMO1 was present in blood cells from all patients with HSP90-SUMO1-binding paraproteins. We determined that the HSP90-SUMO1 carrier state is autosomal-dominantly inherited and caused by the inability of SUMO peptidase sentrin/SUMO-specific protease 2 (SENP2) to desumoylate HSP90-SUMO1. HSP90-SUMO1 was detected in a small percentage of healthy individuals from all backgrounds; however, only MGUS, MM, and WM patients who were HSP90-SUMO1 carriers produced HSP90-SUMO1-specific paraproteins, suggesting that sumoylated HSP90 promotes pathogenesis of these diseases through chronic antigenic stimulation. This study demonstrates that harboring HSP90-SUMO1 identifies healthy individuals at risk for plasma cell dyscrasias and that dominant inheritance of posttranslationally modified autoantigenic paratargs is one of the strongest molecular defined risk factors for MGUS, MM, and WM.

EBV-transformed lymphoblastoid cell lines as vaccines against cancer testis antigen-positive tumors

EBV-transformed lymphoblastoid cell lines (LCL) are potent antigen-presenting cells. To investigate their potential use as cancer testis antigen (CTA) vaccines, we studied the expression of 12 cancer testis (CT) genes in 20 LCL by RT-PCR. The most frequently expressed CT genes were SSX4 (50 %), followed by GAGE (45 %), SSX1 (40 %), MAGE-A3 and SSX2 (25 %), SCP1, HOM-TES-85, MAGE-C1, and MAGE-C2 (15 %). NY-ESO-1 and MAGE-A4 were found in 1/20 LCL and BORIS was not detected at all. Fifteen of 20 LCL expressed at least one antigen, 9 LCL expressed ≥2 CT genes, and 7 of the 20 LCL expressed ≥4 CT genes. The expression of CT genes did not correlate with the length of in vitro culture, telomerase activity, aneuploidy, or proliferation state. While spontaneous expression of CT genes determined by real-time PCR and Western blot was rather weak in most LCL, treatment with DNA methyltransferase 1 inhibitor alone or in combination with histone deacetylase inhibitors increased CTA expression considerably thus enabling LCL to induce CTA-specific T cell responses. The stability of the CT gene expression over prolonged culture periods makes LCL attractive candidates for CT vaccines both in hematological neoplasias and solid tumors.

Mutated Ras-transfected, EBV-transformed lymphoblastoid cell lines as a model tumor vaccine for boosting T-cell responses against pancreatic cancer: a pilot trial

Genetically modified lymphoblastoid cell lines (LCL) have been shown to be an attractive alternative source of antigen-presenting cells for cancer vaccination in vitro. We tested their application in patients with pancreatic cancer in a phase I clinical trial. As a model tumor antigen, we selected the point-mutated (codon 12) Ki-Ras p21 oncogene (muRas) frequently (∼85%) present in pancreatic adenocarcinoma. Autologous LCLs were established in vitro by spontaneous outgrowth from peripheral blood lymphocytes of seven pancreatic carcinoma patients and were genetically modified with an episomal Epstein-Barr virus (EBV)-based expression vector to express muRas (muRas-LCL). Weekly vaccinations with subcutaneous injection of 5×10(6) muRas-LCL were done. In six of seven patients, therapeutic vaccination elicited a T-cell response with an increase in the frequency of muRas-specific precursor cytotoxic T lymphocytes in the peripheral blood and positive delayed-type hypersensitivity reactions at the injection site. Besides local reactions and flu-like symptoms, there were no signs of toxicity and no acute EBV infection, onset of EBV-associated lymphoma, or other severe complications. A clinical response (stable disease) was observed for a short time period (2-4 months) in four of seven patients (57%), mostly in earlier tumor stages. Our results indicate that LCL presenting genetically modified antigen represent a valuable and easily available tool for in vivo autologous tumor vaccination. LCL can be transfected with any known tumor antigen and therefore should be further clinically investigated.

A peptide epitope derived from the cancer testis antigen HOM-MEL-40/SSX2 capable of inducing CD4⁺ and CD8⁺ T-cell as well as B-cell responses

BACKGROUND

Antigen-derived HLA class I-restricted peptides can generate specific CD8(+) T-cell responses in vivo and are therefore often used as vaccines for patients with cancer. However, only occasional objective clinical responses have been reported suggesting the necessity of CD4(+) T-cell help and possibly antibodies for the induction of an effective anti-tumor immunity in vivo. The SSX2 gene encodes the cancer testis antigen (CTA) HOM-MEL-40/SSX2, which is frequently expressed in a wide spectrum of cancers. Both humoral and cellular immune responses against SSX2 have been described making SSX2 an attractive candidate for vaccine trials.

METHODS

SYFPEITHI algorithm was used to predict five pentadecamer peptides with a high binding probability for six selected HLA-DRB1 subtypes (*0101, *0301, *0401, *0701, *1101, *1501) which are prevalent in the Caucasian population.

RESULTS

Using peripheral blood cells of 13 cancer patients and 5 healthy controls, the HOM-MEL-40/SSX2-derived peptide p101-111 was identified as an epitope with dual immunogenicity for both CD4(+) helper and cytotoxic CD8(+) T cells. This epitope also reacted with anti-SSX2 antibodies in the serum of a patient with breast cancer. Most remarkably, SSX2/p101-111 simultaneously induced specific CD8, CD4, and antibody responses in vitro.

CONCLUSIONS

p101-111 is the first CTA-derived peptide which induces CD4(+), CD8(+), and B-cell responses in vitro. This triple-immunogenic peptide represents an attractive vaccine candidate for the induction of effective anti-tumor immunity.

Recombinant NY-ESO-1 protein with ISCOMATRIX adjuvant induces broad antibody responses in humans, a RAYS-based analysis

Antibody responses to tumor antigens play an important role in initiating a cellular antitumor response with respect to antigen cross-presentation and T cell cross-priming. Successful vaccination strategies rely on an optimally timed activation of the humoral and cellular immune system by using appropriate adjuvant stimulation. The LUD99-008 trial used the cancer testis antigen NY-ESO-1 formulated with ISCOMATRIX adjuvant injected into patients intramuscularly. It was shown that this vaccination strategy is a safe and highly potent activator of the humoral and cellular immune system. Using the RAYS technology, we analyzed in detail the humoral immune response in these patients before and after vaccination: during the course of repeated vaccinations with the adjuvant, antibody titers against NY-ESO-1 and cross-reactivity to LAGE 1A and B increased as an indicator of an enhanced immune response, whereas no antibody response could be detected after vaccination without the adjuvant. Analysis of single fragments of the NY-ESO-1 protein revealed that the humoral response was almost exclusively directed against the N-terminal fragments and the number of fragments and their length being recognized by the NY-ESO-1-specific antibodies increased during the course of vaccination. The humoral immune response mainly consisted of antibodies of the IgG1 and IgG3 subclass. We rarely found IgG2 and IgG4 subclass antibodies. Our results support the implication that target-specific antibodies raised after vaccination contribute to the stimulation of an effective T cell response against the target antigen.

Identification of antigenic targets of paraproteins by expression cloning does not support a causal role of chronic antigenic stimulation in the pathogenesis of multiple myeloma and MGUS

Antigenic targets of monoclonal gammopathy of undetermined significance (MGUS) and multiple myeloma (MM) paraproteins have been suggested to play an important role as growth stimulators in the pathogenesis of these neoplasms. To identify such targets, we screened cDNA libraries from human testis, lung and breast cancer, bovine and porcine muscle and wheat germ for reactivity with paraproteins in the sera from 115 patients with MGUS and MM. Of >6 x 10(8) paraprotein-antigen interactions screened, an IgA paraprotein from a female patient bound to sperm-specific cylicin-2, and 3 IgG paraproteins bound to tripeptidyl-peptidase-II (TPP-2), insulin-like growth-factor binding-protein-2 (IGFBP-2) and porcine kinesin. Specificity was confirmed by reverse Western blots using recombinant antigens. The broad spectrum of auto-, allo- and heteroantigens as targets of human paraproteins in patients without signs of chronic antigenic stimulation renders a causal role of the antigenic stimulus in the pathogenesis of MGUS and MM unlikely.

Cross-presentation of HLA class I epitopes from influenza matrix protein produced in Saccharomyces cerevisiae

Here we report that genetically engineered yeast of the strain Saccharomyces cerevisiae expressing full-length influenza matrix protein (IMP) attached to the yeast cell wall are a very versatile host for antigen delivery. Feeding of dendritic cells with either intact yeast expressing IMP protein or soluble IMP protein cleaved off the cell wall resulted in protein uptake, processing and cross-presentation of IMP-derived peptides. This process was analysed using previously established T-cell lines recognizing the immuno-dominant 58-66 peptide when presented by HLA-A2*0201 complexes. In addition, IMP(58-66)/HLA-A2*0201-specific antibodies were selected from a naive phage library which confirmed that peptide presentation was an active process of endocellular uptake and not just a result of external peptide loading. Moreover, MHC peptide antibodies could block the recognition of peptide-presenting dendritic cells by IMP(58-66)-specific T-cells in a dose dependent manner. There was no difference in T-cell recognition when either intact yeast or yeast cell extracts were used for DC feeding. Together, these data demonstrate that yeast derived proteins either in their soluble form or as part of a whole yeast vaccine are taken up, processed and presented by dendritic cells in HLA class I context.

Naturally occurring T-cell response against mutated p21 ras oncoprotein in pancreatic cancer

Mutated p21 ras proteins (muRas) are present in approximately 90% of pancreatic adenocarcinomas and express mutants which can function as cancer-specific antigens. To evaluate the frequency and magnitude of the natural T-cell response against muRas in 19 HLA-A2-positive patients with muRas-positive pancreatic carcinomas, antigen-experienced T lymphocytes in fresh peripheral blood mononuclear cells were shown by IFN-gamma enzyme-linked immunospot using muRas peptides (5-21) that encompass both HLA class I (HLA-A2)- and class II-restricted (HLA-DRB1) epitopes. Six of 19 patients (32%) were found to have a specific T-cell response against individual mutation-specific ras(5-21) but not against other ras mutations or wild-type ras. In contrast, none of 19 healthy subjects had T cells specifically secreting IFN-gamma (P = 0.004). The T-cell response consisted of both CD8(+) and CD4(+) T cells but was dominated by CD8 T cells in three of four patients. MuRas(5-14) and muRas(6-14) were shown to specifically induce CD8(+) T-cell mediated cytotoxicity against HLA-A2-positive, muRas-bearing pancreatic carcinoma cells. The T-cell response was not correlated with prognostic or clinical variables such as tumor-node-metastasis status, stage, or survival. In conclusion, a natural T-cell response against muRas proteins that could be exploited for immunostimulatory therapeutic approaches has been shown in a significant proportion of patients with pancreatic cancer.

Prospective study on the expression of cancer testis genes and antibody responses in 100 consecutive patients with primary breast cancer

To determine the expression of cancer testis (CT) genes and antibody responses in a nonselected population of patients with primary breast cancer, we investigated the composite expression of 11 CT genes by RT-PCR in fresh biopsies of 100 consecutive cases of primary breast carcinoma and by immunohistology in selected RT-PCR-positive cases. Antibody responses against 7 CT antigens were analyzed using recombinant antigen expression on yeast surface. In 98 evaluable cases, SCP-1 and SSX-4 were expressed most frequently (both 65%), followed by HOM-TES-85/CT-8 (47%), GAGE (26%), SSX-1 (20%), NY-ESO-1 (13%), MAGE-3 (11%), SSX-2 (8%), CT-10 (7%), MAGE-4 (4%) and CT-7 (1%). One CT gene was expressed by 90% of the cases; 79% expressed > or =2, 48% > or =3, 29% > or =4, 12% > or =5, 6% > or =6, 3% > or =7, 2% > or =8 and one case coexpressed 9 antigens. Of 100 serum samples screened for CT antigen-specific antibodies, antibodies against NY-ESO-1 were detected in 4 patients, against SCP-1 in 6 patients and against SSX-2 in 1 patient, while no antibodies were detected against MAGE-3, CT-7 and CT-10. Expression of CT genes or antibody responses was not correlated with clinical parameters (menopausal status, tumor size, nodal involvement, grading, histology and estrogen receptor status) or the demonstration of CT gene expression at the protein level, by immunohistology. Our results show that breast carcinomas are among the tumors with the most frequent expression of CT antigens, rendering many patients potential candidates for vaccine trials.

Serological immune response to cancer testis antigens in patients with pancreatic cancer

Serological screening approaches have allowed for the identification of a large number of potentially relevant tumor antigens in cancer patients. Within this group, cancer testis antigens represent promising targets for cancer immunotherapy, since they are widely expressed in a variety of human cancer entities. In pancreatic cancer, however, there are only few data available about the expression pattern and serological response to cancer testis antigens and other serological-defined tumor antigens. Therefore, we investigated the IgG antibody response against 11 cancer testis antigens (SCP-1, GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5) recombinantly expressed on yeast surface (RAYS) in patients with pancreatic cancer (n = 96), chronic pancreatitis (n = 18) and healthy donors (n = 48). We found in 14% of all patients antibody responses to SCP-1, but not to other cancer testis antigens (GAGE, LAGE-1a,-1b, CT-7, NY-ESO-1, SSX-1-5). Antibody response correlated with the expression of SCP-1 in the primary tumor of the respective patient as shown by RT-PCR, immunohistochemistry and Western blot. In contrast, no serological response to cancer testis antigens was observed in healthy donors. The humoral immune response against SCP-1 was associated with the size of tumor, but not with other clinico-pathological parameters such as histology, stage, presence of lymph node metastases, grading, age, gender or gemcitabine treatment. In conclusion, antibody response to cancer testis antigen SCP-1 is found in a proportion of pancreatic carcinoma patients. These results indicate that identification of additional tumor antigens by serological screening of tumor cDNA expression libraries by RAYS is a promising goal in pancreatic cancer.

Identification of an epitope derived from the cancer testis antigen HOM-TES-14/SCP1 and presented by dendritic cells to circulating CD4+ T cells

Because of their frequent expression in a wide spectrum of malignant tumors but not in normal tissue except testis, cancer testis antigens are promising targets. However, except for HOM-TES-14/SCP1, their expression in malignant lymphomas is rare. SCP1 (synaptonemal complex protein 1) has been shown to elicit antibody responses in the autologous host, but no T-cell responses against HOM-TES-14/SCP1 have been reported. Using the SYFPEITHI algorithm, we selected peptides with a high binding affinity to major histocompatibility complex class 2 (MHC 2) molecules. The pentadecamer epitope p635-649 induced specific CD4+ T-cell responses that were shown to be restricted by HLA-DRB1*1401. The responses could be blocked by preincubation of T cells with anti-CD4 and antigen-presenting cells with anti-HLA-DR, respectively, proving the HLA-DR-restricted presentation of p635-649 and a CD4+ T-cell-mediated effector response. Responding CD4+ cells did not secrete interleukin-5 (IL-5), indicating that they belong to the T(H)1 subtype. The natural processing and presentation of p635-649 were demonstrated by pulsing autologous and allogeneic dendritic cells with a protein fragment covering p635-649. Thus, p635-649 is the first HOM-TES-14/SCP1-derived epitope to fulfill all prerequisites for use as a peptide vaccine in patients with HOM-TES-14/SCP1-expressing tumors, which is the case in two thirds of peripheral T-cell lymphomas.

Serological identification of breast cancer-related antigens from aSaccharomyces cerevisiae surface display library

A yeast cell surface display technology was used for the isolation and characterization of tumor antigens recognised by autologous or allogeneic breast cancer serum. More than 100 clones recognized by patient serum were isolated using high-through-put fluorescence activated cell sorting. Combined serological and sequence analysis confirmed that a number of proteins known to be overexpressed in breast cancer tissue could be detected. A recently identified small breast epithelial mucin almost exclusively expressed in mammary gland tissue was isolated as a mutated protein variant. Subsequent serological analysis using the yeast expression system for the wild-type and mutant form showed a strong recognition by patient sera, whereas no significant recognition was observed for the respective prokaryotically expressed proteins. The small breast epithelial mucin is present to a large extent in a membrane bound format and might be used for tumor targeting strategies.

Identification of an HLA-DR-restricted peptide epitope with a promiscuous binding pattern derived from the cancer testis antigen HOM-MEL-40/SSX2

The SSX2 gene encodes the tumor-specific antigen HOM-MEL-40/SSX2 expressed in a broad spectrum of tumors of different origin, against which humoral and CD8+ T-cell-mediated MHC-I-restricted responses have been demonstrated. Searching for promiscuous MHC-II-restricted peptides that might be suitable as a CD4+ stimulating vaccine for many patients, we used the SYFPEITHI algorithm and identified a HOM-MEL-40/SSX2-derived pentadecamer epitope (p45-59) that induced specific CD4+ T-cell responses restricted by the HLA-DRB1 subtypes *0701, *1101 and *1302 that have a cumulative prevalence of approximately 25% in the Caucasian population. The CD4+-mediated response against p45-59 and its DR restriction was demonstrated by inhibition with anti-CD4 and HLA-DR antibodies, respectively, and by blocking experiments using HLA-specific antibodies. The natural processing and presentation of p45-59 was demonstrated by recognition of the SSX2+ melanoma cell line Me 275 as well as autologous and allogeneic dendritic cells pulsed with whole-protein SSX2 by T cells with specificity for p45-59. p45-59 was able to induce responses in 3/6 breast cancer patients and 1/5 healthy controls. No correlation was found between CD4+ T-cell responses against p45-59 reactivity and anti-SSX2 antibody titers in the serum of patients, suggesting that CD4+ and B-cell responses are regulated independently. p45-59 holds promise as a broadly applicable peptide vaccine for patients with SSX2-positive neoplasms.

Rapid identification of preformed alloreactive T cells for use in a clinical setting

BACKGROUND

In clinical practice, HLA matching is generally applied to minimize the incidence of graft rejection after transplantation. Recently, graft rejection has been directly associated with the presence of preformed alloreactive T cells before transplantation. Despite this knowledge, assays to rapidly quantify preformed alloreactivity are not available for use in a clinical setting. In this study, such an assay was developed and evaluated in a large cohort to correlate alloreactive T-cell reactivity with HLA matching.

METHODS

Stimulator peripheral blood mononuclear cells were prestained with CD45-fluorescein isothiocyanate antibody and mixed with responder peripheral blood mononuclear cells. Activation-induced cytokine secretion was blocked using brefeldin A. After 6 hr, functionally active alloreactive responder CD4 and CD8 T cells were quantified among fluorescein isothiocyanate-negative cells by their expression of interferon-gamma on flow cytometry.

RESULTS

Directly alloreactive CD4 and CD8 T cells among both stimulators and responders were easily distinguished after 6 hr of stimulation without being affected by bystander activation. Among 128 paired combinations, 23.4% of individuals had alloreactive CD8 T cells, 15.7% had alloreactive CD4 T cells, and 12.5% had alloreactivity in both T-cell subpopulations. Alloreactive T cells decreased from circulation within a few days after transplantation. In line with well-known clinical observations that associate HLA matching with graft outcome, the number of HLA-A and -B mismatches correlated with alloreactive CD8 T-cell frequencies in the whole study population, whereas it did not predict alloreactivity on an individual basis.

CONCLUSION

Alloreactive T cells may rapidly be quantified after 6 hr of stimulation. Thus, the flow cytometric approach may be applied in a clinical setting to facilitate the individualization of immunosuppressive therapy and studies on the identification of patients who are at increased risk to develop graft rejection.

Identification of an antigenic peptide derived from the cancer-testis antigen NY-ESO-1 binding to a broad range of HLA-DR subtypes

NY-ESO-1 is a SEREX-defined cancer-testis antigen of which several MHC I, but only few MHC II-restricted epitopes have been identified. Searching for highly promiscuous MHC II-restricted peptides that might be suitable as a CD4+ stimulating vaccine for many patients, we used the SYFPEITHI algorithm and identified an NY-ESO-1-derived pentadecamer epitope (p134-148) that induced specific CD4+ T-cell responses restricted to the HLA-DRB1 subtypes *0101, *0301, *0401, and *0701 that have a cumulative prevalence of 40% in the Caucasian population. The DR restriction of the p134-148 pentadecamer was demonstrated by inhibition with an HLA-DR antibody and a functional peptide displacement titration assay with the pan-DR-binding T-helper epitope PADRE as the competitor. The natural processing and presentation of this epitope was demonstrated by recognition of an NY-ESO-1+ melanoma cell line by T cells with specificity for p134-148. The pentadecamer p134-148 was able to induce CD4+ responses in 4/38 cancer patients tested. However, no strict correlation was found between CD4+ T-cell responses against p134-148 reactivity and anti-NY-ESO-1 antibody titers in the serum of patients, suggesting that CD4+ and B-cell responses are regulated independently. In conclusion, p134-148 holds promise as a broadly applicable peptide vaccine for patients with NY-ESO-1-positive neoplasms.

Expression of cancer testis antigens in pancreatic carcinoma cell lines, pancreatic adenocarcinoma and chronic pancreatitis

In order to define antigens that might be suitable as vaccines for pancreatic carcinoma, we investigated the composite expression of 10 cancer testis (CT) antigens (SCP-1, NY-ESO-1, SSX-1, SSX-2, SSX-4, GAGE, MAGE-3, MAGE-4, CT-7 and CT-8) by Reverse Transcriptase-PCR (RT-PCR) in fresh biopsies of human pancreatic adenocarcinoma, chronic pancreatitis and pancreatic carcinoma cell lines. While all CT genes were frequently expressed in cell lines derived from pancreatic cancer, no expression of MAGE-3, SSX-1, SSX-2, NY-ESO-1 and CT-7 was detected in fresh tumor biopsies, and MAGE-4 (1/52), SSX-4 (1/39) and CT-8 (2/41) were only rarely expressed. In contrast, HOM-TES-14/SCP-1 was expressed in 48% (29/61) and GAGE in 21% (13/61) of cases, respectively. One CT gene was expressed by 59% (75% in male, 46% in female patients; p = 0.05) and 2 or more CT genes by 15% of the samples. SCP-1 protein expression correlated well with mRNA expression. While SCP-1 and GAGE were absent in normal pancreas, they were found in 2/8 (SCP-1) and 1/8 (GAGE) samples of chronic pancreatitis, respectively, supporting the concept of chronic pancreatitis as a premalignant condition. SCP-1 and GAGE represent promising candidates for vaccine development in pancreatic carcinoma. Whether SCP-1 and GAGE expression identify cases of chronic pancreatitis with a high risk of malignant transformation remains to be shown.

p-[123I]iodo-L-phenylalanine for detection of pancreatic cancer: basic investigations of the uptake characteristics in primary human pancreatic tumour cells and evaluation in in vivo models of human pancreatic adenocarcinoma

Pancreatic cancer is associated with the worst 5-year survival rate of any human cancer. This high mortality is due, in part, to difficulties in establishing early and accurate diagnosis. Because most tumours share the ability to accumulate amino acids more effectively than normal tissues and any other pathology, assessment of amino acid transport in tumour cells using radiolabelled amino acids has become one of the most promising tools for tumour imaging. This study investigated the potential of p-[(123)I]iodo-L-phenylalanine (IPA) for detection of pancreatic cancer by single-photon emission tomography. IPA affinity for pancreatic tumour was investigated in human pancreatic adenocarcinoma PaCa44 and PanC1 cells, followed by analysis of the underlying mechanisms of tracer accumulation in neoplastic cells. Thereafter, IPA was evaluated for targeting of pancreatic tumours using SCID mice engrafted with primary human pancreatic adenocarcinoma cells, as well as in acute inflammation models in immunocompetent mice and rats. IPA accumulated intensively in human pancreatic tumour cells. Radioactivity accumulation in tumour cells following a 30-min incubation at 37 degrees C/pH 7.4 varied from 41% to 58% of the total loaded activity per 10(6) cells. The cellular uptake was temperature and pH dependent and predominantly mediated by specific carriers for neutral amino acids, namely the sodium-independent and L-leucine-preferring (L-system) transporter and the alanine-, serine- and cysteine-preferring (ASC-system) transporter. Protein incorporation was less than 8%. Biodistribution studies showed rapid localization of the tracer to tumours, reaching 10%+/-2.5% to 15%+/-3% of the injected dose per gram (I.D./g) in heterotopic tumours compared with 17%+/-3.5% to 22%+/-4.3% I.D./g in the orthotopic tumours, at 60 and 240 min post injection of IPA, respectively. In contrast, IPA uptake in the gastrointestinal tract and areas of inflammation remained moderate and decreased with time. Excellent tumour detection was obtained by gamma camera imaging. The specific and high-level targeting of IPA to tumour and the negligible uptake in the gastrointestinal tract and areas of inflammation indicate that p-[(123)I]iodo-L-phenylalanine is a promising tracer for differential diagnosis of pancreatic cancer.

Identification of an HLA-A*02 restricted immunogenic peptide derived from the cancer testis antigen HOM-MEL-40/SSX2

HOM-MEL-40/SSX2 is a SEREX-defined cancer testis antigen with frequent expression in various human neoplasms. To search for HLA-A*0201 restricted peptides that induce HOM-MEL-40/SSX2-specific CD8+ responses in breast cancer patients, we used the SYFPEITHI algorithm to identify three HOM-MEL-40/SSX2-derived nonamers with high binding affinity for HLA-A*0201, which has a prevalence of 40% in the Caucasian population. Of the three peptides, p41-49 and p103-111 but not p167-175 had been shown to be processed by the proteasome. Only stimulation with p103-111 induced HOM-MEL-40-specific CTLs in 5/7 patients with HOM-MEL-40/SSX2 positive breast cancers and in 6/11 healthy controls. HLA-A*0201 restriction of p103-111 was demonstrated by blocking with specific antibodies. The natural processing and presentation of p103-111 was demonstrated by the recognition of the HOM-MEL-40/SSX2 positive cell line SK-MEL-37 and of COS7/A2 cells transfected with HOM-MEL-40/SSX2 by p103-111 specific CD8+ cells. No correlation was found between CD8+ T-cell responses against p103-111 and anti-HOM-MEL-40/SSX2 antibody titers in the serum of patients, suggesting that CD8+ and B-cell responses against HOM-MEL-40/SSX2 are regulated independently. p103-111 holds promise as a broadly applicable peptide vaccine for patients with HOM-MEL-40/SSX2 positive neoplasms.

Expression of cancer-testis genes in human hepatocellular carcinomas

Cancer-testis (CT) genes are expressed in a variety of human cancers, but not in normal tissues except for testis, and represent promising targets for immunotherapy and gene therapy. We investigated the expression of 10 CT genes (MAGE-1, MAGE-3, MAGE-4, GAGE, NY-ESO-1, SSX-1, HOM-MEL-40/SSX-2, SSX-4, HOM-TES-14/SCP-1, and HOM-TES-85) in 21 hepatocellular carcinoma (HCC) biopsy specimens. The most frequently expressed CT genes were SSX-1 and GAGE, which were found in 8/21 (38%) HCC samples, followed by HOM-TES-14/SCP-1 (6/21 or 29%), MAGE-3 (5/21 or 24%), HOM-TES-85 and MAGE-1 (4/21 or 19% each), whereas SSX-4 and HOM-MEL-40/SSX-2 were only expressed in 2/21 cases each, MAGE-4 in one case, and NY-ESO-1 not at all. Of the 21 HCC cases investigated, only four did not express any of the CT genes tested, 17 (81%) expressed at least one, 9 (43%) coexpressed two, four (19%) coexpressed four, three (14%) coexpressed five and one coexpressed 8 of the 10 CT genes tested. We conclude that a majority of HCC cases might be amenable to specific immunotherapeutic interventions. However, the identification of additional tumor-specific antigens with a frequent expression in HCCs is warranted to develop widely applicable, polyvalent HCC vaccines.

Use of spontaneous Epstein-Barr virus-lymphoblastoid cell lines genetically modified to express tumor antigen as cancer vaccines: mutated p21 ras oncogene in pancreatic carcinoma as a model

Spontaneous Epstein-Barr virus (EBV)-transformed lymphoblastoid cell lines (SP-LCLs) can be easily obtained from latently EBV-infected cancer patients and used as a source of antigen-presenting cells (APCs) for immunotherapy. Using point-mutated (codon 12) p21(ras) (muRas) as a model tumor antigen, we evaluated the practicability of using genetically modified SP-LCLs as cancer vaccines for patients with pancreatic cancer expressing mutated Ras (muRas). The repeated stimulation of peripheral blood mononuclear cells (PBMCs) from patients with muRas-LCLs elicited a strong, muRas-specific T cell response. A significant cytotoxic activity against EBV virus proteins or components of the expression vector was not observed. The T cells were able to recognize naturally presented muRas, as shown by their cytotoxicity against muRas (Gly-12 to Val-12 or Asp-12)-expressing tumor cells. The T cell response was mainly MHC class I restricted, and peptides containing amino acids 5 to 14 of muRas-Val-12 and muRas-Asp-12 were identified as immunogenic peptides for HLA-A2. In contrast to the situation in patients with putatively muRas-primed T cells, muRas-LCLs were not able to prime naive T lymphocytes from healthy controls. Vaccination of a pancreatic cancer patient with muRas-LCL induced muRas-specific T cells in PBMCs after 4 weeks. We conclude that genetically modified muRas-LCLs can efficiently present tumor antigens to the immune system and induce antigen-specific cytotoxic T cell responses in vitro and in vivo.

Sustained high frequencies of specific CD4 T cells restricted to a single persistent virus

Replication of cytomegalovirus (CMV) is largely controlled by the cellular arm of the immune response. In this study the CMV-specific CD4 T-cell response was characterized in a cohort of apparently healthy individuals. In 11% of all individuals, extremely high frequencies, between 10 and 40%, were found. High-level frequencies of CMV-specific CD4 T cells persisted over several months and were not the result of an acute infection. Specific T cells were oligoclonal and were phenotypically and functionally characterized as mature effector cells, with both cytokine-secreting and proliferative potential. These high-level frequencies do not seem to compromise the immune response towards heterologous infections, and no signs of immunopathology were observed. Whereas a large temporary expansion of virus-specific T cells is well known to occur during acute infection, we now show that extremely high frequencies of virus-specific T cells may continuously exist in chronic CMV infection without overtly compromising the remaining protective immunity.

Analysis of the B cell repertoire against autoantigens in patients with giant cell arteritis and polymyalgia rheumatica

The analysis of the antibody repertoire of patients with giant cell arteritis (GCA) and polymyalgia rheumatica (PMR) might identify target antigens of the autoimmune response with potential relevance to our understanding of the pathogenesis of the disease and to the development of serodiagnostic tests. To detect such antigens, we screened a cDNA library derived from normal human testis for antigens reacting with IgG antibodies in the 1 : 250 diluted sera of three patients with untreated GCA using SEREX, the serological identification of antigens by recombinant cDNA expression cloning. Of 100 000 clones screened with each serum, six, 28 and six clones, respectively, were positive, representing a total of 33 different antigens. Most of the antigens reacted only with the serum used for identification and/or at a similar frequency with normal control sera. However, lamin C and the nuclear antigen of 14 kD reacted specifically with 32% of GCA/PMR, but with none of the control sera, while human cytokeratin 15, mitochondrial cytochrome oxidase subunit II, and a new gene product were detected preferentially, but not exclusively by sera from GCA/PMR patients. We conclude that patients with GCA/PMR develop antibodies against a broad spectrum of human autoantigens. Antibodies against human lamin C, the nuclear autoantigen of 14 kD as well as human cytokeratin 15, mitochondrial cytochrome oxidase subunit II and the product of a new gene should be investigated further to determine their value as tools for the diagnosis and/or the definition of clinical subgroups of patients with GCA/PMR.

Systematic search and molecular characterization of the antigenic targets of myeloma immunoglobulins: a monoclonal IgA from a female patient targeting sperm-specific cylicin II

The identification of the antigenic stimuli of B-cell neoplasms might be of considerable importance since a causal relationship between these neoplasms and antigenic stimulation has been suggested. To date the identification of such antigens has been erratic and accidental. For a systematic search and molecular characterization of human proteins that are antigenic target structures of myeloma-associated immunoglobulins, we applied SEREX (serological analysis of antigens by recombinant cDNA expression cloning) using a testis cDNA expression library and myeloma proteins from 42 patients. A monoclonal IgA from a female patient was shown to target sperm-specific cylicin II. The specificity of the reaction was confirmed by the characteristic staining of the equatorial belt of human sperm heads by the patient's myeloma protein. Serological analysis of recombinantly expressed cDNAs is a straightforward and high throughput approach for the molecular characterization of the targets of myeloma-associated immunoglobulins. The analysis of the antigenic spectrum of immunoglobulins associated with B-cell neoplasms will provide valuable information for the understanding of the pathogenesis of these diseases.

Clinical approaches to vaccination in oncology

Immunotherapy of cancer is still in the early stages of development although almost a century has passed since initial attempts were made to stimulate the immune system in order to destroy malignant cells. Historically, a variety of specific and non-specific immunostimulatory strategies have been administered with only modest clinical success. However, recent advances in tumour immunology, most notably the identification of new tumour antigens and the better understanding of antigen processing and presentation to avoid or break immune tolerance, have paved the way for the development of a variety of novel and specific vaccine approaches. The most important and widely used are whole-cell vaccines, dendritic-cell-based immunotherapy and peptide vaccines. The first wave of clinical trials has revealed that, in general, such vaccination strategies are safe. However, clear examples of clinical responses, especially in conjunction with vaccine-induced immune responses, are still rare. Most clinical trials are too small to allow for comments on the efficacy, and the cohort of patients studied is too heterogeneous with regard to immune status. Therefore, standardised techniques for the accurate assessment of the individual immune phenotype before and during the trial are needed to allow for the identification of the sub-group of patients who will respond favourably to treatment. The precise definition of immune parameters in these patients will then lead the way for optimised treatment procedures that might even be beneficial for a larger group of cancer patients.

Gene-modified spontaneous Epstein-Barr virus-transformed lymphoblastoid cell lines as autologous cancer vaccines: mutated p21 ras oncogene as a model

The transfer of genes coding for tumor antigens (Ags) into Ag-presenting cells is a promising strategy to develop cancer vaccines for patients not limited by major histocompatibility complex restriction. To test whether autologous lymphoblastoid cell lines (LCL) can be used as an alternative to dendritic cells for Ag presentation, we established LCL by spontaneous growth in cyclosporin-containing medium in vitro (SP-LCL). SP-LCL, which have an advantage over B95-8-transfected LCL in that they carry no risk of introducing a new infectious agent when used for vaccination, served as a permanent source for transfection with an episomal Epstein-Barr virus-based expression vector encoding the Ki-ras p21 oncogene carrying a point mutation at codon 12 (muRas) as a model tumor Ag. The ability of muRas-transfected SP-LCL (muRas-LCL) to induce immunoreactivity was determined in vitro. After electroporation with an optimized protocol, muRas-LCL expressed mutated ras peptides for a considerable period of time (at least 8 weeks) on the cell surface. The transfection procedure did not affect the expression of the costimulatory molecules B7.1, intercellular adhesion molecule-1, and leukocyte function associated Ag-3 by SP-LCL. muRas-LCL were able to induce muRas-specific cytotoxic T lymphocytes from three of three healthy donors and one of one patient with pancreatic carcinoma. Our results suggest that the gene transfer of muRas sequences to SP-LCL leads to an endogenous processing of this Ag in the major histocompatibility complex class I pathway and to functional presentation of antigenic peptides to CD8+ T lymphocytes. Autologous SP-LCL can serve as an unlimited renewable source for autologous cellular vaccines and appear to be good candidates as presenters for a wide range of human tumor Ags.

[Isolated tumor cells in bone marrow predicts reduced survival in lymph node-negative non-small-cell lung cancer]

BACKGROUND

It became recently evident that isolated tumor cells undetectable by conventional tumor staging are frequently present in bone marrow of patients with apparently localized non-small cell lung cancer (NSCLC). The clinical relevance of this minimal hematogenous tumor cell dissemination is under vigorous debate.

METHODS

For tumor cell detection in the bone marrow we used monoclonal antibody CK2 against the epithelial intermediate filament protein cytokeratin 18. The influence of a positive bone marrow finding on clinical outcome was studied in 139 patients with NSCLC postoperatively staged as pT1-4, pN0-2, M0, R0 after a median follow up of 66 months (48-74).

FINDINGS

Cytokeratin-18-positive cells in bone marrow were demonstrated in 83 (59.7%) patients at the time of primary surgery and in 6 of 12 representative patients analyzed twice 3-18 months after surgery. In patients without histopathological lymph node metastases (pN0; n = 66) the occurrence of > or = 2 tumor cells in bone marrow at primary surgery was a strong and independent predictor for overall survival (p = 0.007) in univariate analysis. The multivariate analysis showed a 2.8 times increased risk for shorter survival in patients with disseminated tumor cells versus patients without such cells. Four of the six patients with a positive CK status after surgery developed a tumor recurrence 11-44 months after the operation, while in none of the patients with a negative bone marrow at all times intervals showed a tumor relapse.

CONCLUSIONS

Minimal residual bone marrow involvement is an independent prognostic factor for overall survival in patients with node-negative NSCLC, which may help to identify patients in need of an adjuvant systemic therapy. The postoperative persistence or re-appearance of tumor cells in bone marrow indicates that these are not only shredded cells but rather represent true micrometastasis.

Isolated tumor cells in bone marrow predict reduced survival in node-negative non-small cell lung cancer

BACKGROUND

It recently became evident that isolated tumor cells undetectable by conventional tumor staging are frequently present in bone marrow of patients with apparently localized non-small cell lung cancer (NSCLC). The clinical relevance of this minimal hematogenous tumor cell dissemination is under vigorous debate.

METHODS

For tumor cell detection in the bone marrow, we used monoclonal antibody CK2 against the epithelial intermediate filament protein cytokeratin 18. The influence of a positive bone marrow finding on clinical outcome was studied in 139 patients with NSCLC postoperatively staged as pT1-4, pN0-2, M0, and R0 after a median follow-up of 66 months (range 48 to 74 months).

RESULTS

Cytokeratin-18-positive cells in bone marrow were demonstrated in 83 (59.7%) patients at the time of primary surgery and in 6 of 12 representative patients analyzed twice 3 to 18 months after surgery. In patients without histopathological lymph node metastases (pN0; n = 66), the occurrence of 2 or more tumor cells in bone marrow at primary surgery was a strong and independent predictor for overall survival (p = 0.007) in univariate analysis. The multivariate analysis showed a 2.8 times increased risk for shorter survival in patients with disseminated tumor cells versus patients without such cells. Four of the 6 patients with a positive cytokeratin status after surgery developed a tumor recurrence 11 to 44 months after the operation, while none of the patients with a negative bone marrow at all time intervals showed a tumor relapse.

CONCLUSIONS

Minimal residual bone marrow involvement is an independent prognostic factor for overall survival in patients with node-negative NSCLC, which may help to identify patients in need of an adjuvant systemic therapy. The postoperative persistence or reappearance of tumor cells in bone marrow indicates that these are not only shed cells but rather represent true micrometastasis.

Myasthenia gravis: selective enrichment of antiacetylcholine receptor antibody production in untransformed human B cell cultures

B cells producing antibodies against the acetylcholine receptor (AchR) play a central role in the pathogenesis of myasthenia gravis (MG). Although anti-AchR autoantibodies have been studied extensively, not much is known about autoimmune B cells and their antigen-driven activation. This has mainly been due to difficulties in establishing and maintaining untransformed antigen-specific B cells in vitro. In this study, we show that highly enriched B cells from peripheral blood and thymus of MG patients can be maintained in culture over a period of 4 weeks when grown on the AchR-expressing rhabdomyosarcoma cell line TE671 together with an anti-CD40 stimulus and lymphokines. Anti-AchR antibody secretion could be detected in the majority of B cell cultures on TE671 cells up to 4 weeks. In contrast, B cells cultured on CDw32-transfected L cells binding anti-CD40 antibodies (the CD40 system) produced only small amounts of anti-AchR antibodies at single time points, whereas the overall IgG production was higher than on TE671 cells. The expression of the relevant autoantigen on the adherent cell line in addition to other growth stimuli could account for this difference and may provide a useful tool for investigating antigen-dependent B cell activation in MG and other B cell-mediated autoimmune conditions.

Disseminated tumor cells in lymph nodes as a determinant for survival in surgically resected non-small-cell lung cancer

PURPOSE

In recent years, the detection of even a few tumor cells in lymph nodes of patients with surgically resected non-small-cell lung cancer (NSCLC) became possible with immunohistochemical staining procedures. Tumor cells in lymph nodes have been shown to be associated with an increased rate of early recurrence. However, the prognostic significance of this minimal tumor cell spread for overall survival remains unclear.

PATIENTS AND METHODS

We used the epithelium-specific monoclonal antibody Ber-EP4, which recognizes the 17-1A antigen (also called EGP40 or Ep-CAM), to discover small tumor cell deposits (< or = three cells) in 565 regional lymph nodes judged as tumor-free by conventional histopathology in patients with NSCLC staged as pT1-4, pN0-2, M0, R0. In a prospective analysis, we studied the influence of the detected tumor cells on the cancer recurrence rate and survival of 117 patients.

RESULTS

Ber-EP4-positive cells were found in 27 of 125 patients (21.6%). After an observation period of 64 months, patients with disseminated tumor cells had reduced disease-free survival (P < .0001) and overall survival (P = .0001) rates in univariate analyses (logrank test). Multivariate analysis (Cox model) showed a 2.7 times increased risk for tumor relapse and a 2.5 times increased risk for shorter survival in patients with disseminated tumor cells compared with patients without such cells. Patients without any evidence of histopathologic and immunohistochemical lymph node involvement had an overall survival rate of 78%.

CONCLUSION

The immunohistochemical detection of disseminated tumor cells in lymph nodes of patients with completely resected NSCLC is an independent prognostic factor for overall survival.

Synergistic immunomodulatory effects of interferon-beta1b and the phosphodiesterase inhibitor pentoxifylline in patients with relapsing-remitting multiple sclerosis

Subcutaneous application of interferon-beta1b (IFN-beta1b) is an established therapy for patients with relapsing-remitting multiple sclerosis (RRMS), but early side effects are still a major concern. In vitro studies with myelin basic protein (MBP)-specific T-cell lines revealed a synergistic suppressive effect of IFN-beta1b and the phosphodiesterase inhibitor pentoxifylline (PTX) on proliferation and the production of tumor necrosis factor-alpha (TNF-alpha), lymphotoxin (LT), and interferon-gamma (IFN-gamma). In an initial, open labeled prospective trial, the cytokine messenger RNA (mRNA) expression of blood mononuclear cells from MS patients, receiving either IFN-beta1b alone or in combination with oral PTX, was determined by semi-quantitative reverse transcriptase polymerase chain reaction (RT-PCR). Patients treated with IFN-beta1b alone reported more side effects during the first 3 months of treatment and had upregulated TNF-alpha as well as IFN-gamma mRNA expression during the first month, which was not detected in patients receiving both drugs. A synergistic effect of both drugs was observed on the upregulation of interleukin (IL)-10 mRNA, which was accompanied by an increase in IL-10 serum levels. Both in vitro and in vivo data suggest that co-treatment of IFN-beta1b with PTX is a promising approach to correct the disturbed cytokine balance in MS patients.

Serum levels of macrophage-derived protein MRP-8/14 are elevated in active multiple sclerosis

Serum concentrations of two macrophage-derived calcium-binding proteins, MRP-8 and MRP-8/14, were studied in 28 patients with relapsing multiple sclerosis (MS). Serum levels were determined with a commercially available sandwich ELISA and the one-tailed Mann-Whitney U test was used for statistical analysis. Median serum levels of MRP-8/14 were significantly higher in MS patients (5150 ng/ml) compared to 26 healthy controls (1482 ng/ml) and significantly higher in MS patients within an acute relapse (6690 ng/ml) compared to MS patients with stable disease (3050 ng/ml). MRP-8 levels were not elevated in MS patients. These results may indicate an early activation of macrophages in the formation of demyelinating MS plaques. In addition, increased serum levels of MRP-8/14 may prove to be a useful paraclinical disease activity parameter in MS patients.

[Simultaneous immunocytochemical detection of tumor cells in lymph nodes and in bone marrow of patients with resectable bronchial carcinomas]

Despite an apparently curative resection more than 50% of patients with non-small cell carcinomas (NSCLC) will relapse after surgery. Therefore, it has to be assumed that in a substantial number of patients a tumor cell dissemination has occurred already at the time of surgery. In a prospective study we analyzed the extend of an early regional tumor cell dissemination into lymph nodes and/or a systemic tumor cell dissemination into the bone marrow in 91 patients with completely resected NSCLC by using sensitive immunocytochemical techniques. A tumor cell dissemination limited to the regional lymph nodes was detected in 14 (15.4%) patients. A systemic dissemination of tumor cells into the bone marrow alone in 10 (11.1%) patients. In 6 patients (6.6%) both body compartments were involved by immunocytochemistry. The detection of a nodal and a systemic tumor cell dissemination was associated with a significantly shortened disease free survival (p = 0.002 and p = 0.05, respectively). A Cox regression analysis demonstrated that the detection of tumor cells by immunocytochemistry is an independent prognostic factor (p = 0.018). In conclusion the detection of disseminated tumor cells by immunocytochemistry is an useful prognostic parameter, which underlines the requirement of a multimodal therapeutic strategy in these patients.