Marco W. Schreurs

The CXCR3 targeting chemokine CXCL11 has potent antitumor activity in vivo involving attraction of CD8+ T lymphocytes but not inhibition of angiogenesis.

The IFN-γ-inducible and CXCR3-targeting human CXC chemokines CXCL9 (Mig) and CXCL10 (IP10) have potent antitumor activity through attraction of cytotoxic T lymphocytes and inhibition of angiogenesis. The more recently identified CXCR3-targeting chemokine CXCL11 (I-TAC/IP9) proved to be a more potent chemokine than CXCL9 and CXCL10 in vitro, both in chemotaxis assays with CXCR3+ T lymphocytes and in calcium mobilization experiments. However, its antitumor activity in vivo has not been shown so far. To investigate this, mice were challenged with EL4 T-cell lymphoma cells, genetically modified to produce murine CXCL11. Tumor growth curves showed complete rejection of CXCL11-producing tumors but not of control tumors. Tumor infiltrate analysis by flow cytometry showed a clear correlation between rejection of CXCL11-producing tumors and an increase of tumor-infiltrating CD8+CXCR3+ as well as CD8+CXCR3- T lymphocytes. In vivo CD8 T-cell depletion completely abrogated the antitumor effect. No difference in angiogenesis between control and CXCL11-producing tumors was observed. In survivors, rechallenge experiments with wild-type tumor cells suggested development of protective antitumor immunity involving tumor-specific IFN-γ production by CD8+ T lymphocytes. These experiments show, for the first time, antitumor activity of CXCL11 in vivo, which warrants exploration for its potential role in anticancer immunotherapy.

Consumption of gluten with gluten-degrading enzyme by celiac patients: a pilot-study.

AIM To assesses the safety and efficacy of Aspergillus niger prolyl endoprotease (AN-PEP) to mitigate the immunogenic effects of gluten in celiac patients. METHODS Patients with initial diagnosis of celiac disease as confirmed by positive serology with subtotal or total villous atrophy on duodenal biopsies who adhere to a strict gluten-free diet (GFD) resulting in normalised antibodies and mucosal healing classified as Marsh 0 or I were included. In a randomised double-blind placebo-controlled pilot study, patients consumed toast (approximately 7 g/d gluten) with AN-PEP for 2 wk (safety phase). After a 2-wk washout period with adherence of the usual GFD, 14 patients were randomised to gluten intake with either AN-PEP or placebo for 2 wk (efficacy phase). Measurements at baseline included complaints, quality-of-life, serum antibodies, immunophenotyping of T-cells and duodenal mucosa immunohistology. Furthermore, serum and quality of life questionnaires were collected during and after the safety, washout and efficacy phase. Duodenal biopsies were collected after the safety phase and after the efficacy phase. A change in histological evaluation according to the modified Marsh classification was the primary endpoint. RESULTS In total, 16 adults were enrolled in the study. No serious adverse events occurred during the trial and no patients withdrew during the trial. The mean score for the gastrointestinal subcategory of the celiac disease quality (CDQ) was relatively high throughout the study, indicating that AN-PEP was well tolerated. In the efficacy phase, the CDQ scores of patients consuming gluten with placebo or gluten with AN-PEP did not significantly deteriorate and moreover no differences between the groups were observed. During the efficacy phase, neither the placebo nor the AN-PEP group developed significant antibody titers. The IgA-EM concentrations remained negative in both groups. Two patients were excluded from entering the efficacy phase as their mucosa showed an increase of two Marsh steps after the safety phase, yet with undetectable serum antibodies, while 14 patients were considered histologically stable on gluten with AN-PEP. Also after the efficacy phase, no significant deterioration was observed regarding immunohistological and flow cytometric evaluation in the group consuming placebo compared to the group receiving AN-PEP. Furthermore, IgA-tTG deposit staining increased after 2 wk of gluten compared to baseline in four out of seven patients on placebo. In the seven patients receiving AN-PEP, one patient showed increased and one showed decreased IgA-tTG deposits. CONCLUSION AN-PEP appears to be well tolerated. However, the primary endpoint was not met due to lack of clinical deterioration upon placebo, impeding an effect of AN-PEP.

In Vitro Generation and Life Span Extension of Human Papillomavirus Type 16-Specific, Healthy Donor-Derived CTL Clones

Human papillomavirus (HPV) type 16 infection is strongly associated with the development of cervical carcinoma (CxCa) in women. The HPV16-derived oncoproteins E6 and E7, responsible for both onset and maintenance of malignant transformation, are expressed constitutively in CxCa cells and represent tumor-associated Ags. As a result, E6 and E7 constitute potential targets for adoptive CTL-mediated immunotherapy of CxCa. However, the availability to date of well-characterized HPV16-specific, CxCa-reactive human CTLs is extremely limited. The current study describes the in vitro generation and isolation of HPV16 E7-specific, CxCa-reactive human CTL clones from low-frequency healthy donor-derived CD8β-positive precursors. For this purpose, an in vitro CTL induction protocol was used involving mature monocyte-derived dendritic cells as stimulator cells loaded with an HLA-A2.1-restricted, E711–20-derived high-affinity altered peptide ligand. A double tetramer-guided isolation procedure and subsequent limiting-dilution cloning resulted in Ag-specific CTL clones. Stringent CTL characterization clearly indicated Ag-specific, HLA-A2.1-restricted reactivity against different HPV16-transformed CxCa cell lines. To allow expansion of E711–20-specific CTL clones to numbers required for prolonged in vitro as well as in vivo application, their life span was significantly extended by ectopic expression of human telomerase reverse transcriptase. Collectively, our results show that optimized CTL induction and stringent CTL selection procedures, followed by human telomerase reverse transcriptase-mediated life span extension will allow continued availability of low-frequency HPV16-specific, CxCa-reactive human CTL clones. This may enhance the prospects of HPV16-specific adoptive CTL immunotherapy in CxCa patients.

Serum I-FABP as marker for enterocyte damage in coeliac disease and its relation to villous atrophy and circulating autoantibodies

Enterocyte damage is the hallmark of coeliac disease (CD) resulting in malabsorption. Little is known about the recovery of enterocyte damage and its clinical consequences. Serum intestinal fatty acid binding protein (I‐FABP) is a sensitive marker to study enterocyte damage.

Auto-SCT in refractory celiac disease type II patients unresponsive to cladribine therapy

Autologous hematopoietic SCT (auto-SCT) has been effective therapy for refractory disease, in both malignancies and severe autoimmune diseases. It seems feasible and safe for refractory celiac disease (RCD) type II, although long-term results have not been evaluated yet. With current therapies, progression into enteropathy-associated T-cell lymphoma (EATL) occurs in 60–80% patients, with a high mortality rate. Therefore, it is important to evaluate new treatment strategies. Between March 2004 and February 2010, 18 RCD II patients were evaluated for auto-SCT preceded by conditioning with fludarabine and melphalan, as a consequence of unresponsiveness to cladribine therapy. Adverse events, survival rate, EATL development and change in clinical, histological and immunological course were monitored. Thirteen patients were transplanted successfully and followed up for >2 years, 4-year survival rate was 66%. Only one patient died because of transplant-related complications. The majority of patients showed an impressive clinical improvement and five a complete histological remission. In five patients, auto-SCT could not be performed; they all died with a median survival of 5.5 months. EATL was observed in one transplanted patient, only after 4 years of follow-up. Auto-SCT after conditioning with high-dose chemotherapy in RCD II patients unresponsive to cladribine therapy is feasible and seems promising.

Evaluation of Cladribine treatment in refractory celiac disease type II

AIM To evaluate cladribine [2-chlorodeoxyadenosine (2-CdA)] therapy in refractory celiac disease (RCD) II. METHODS An open-label cohort-study of RCD II patients treated with 2-CdA was performed between 2000 and 2010. Survival rate, enteropathy associated T-cell lymphoma (EATL) occurrence, clinical course, and histological and immunological response rates were evaluated. RESULTS Overall, 32 patients were included with a median follow-up of 31 mo. Eighteen patients responded well to 2-CdA. Patients responsive to 2-CdA had a statistically significant increased survival compared to those who were unresponsive. The overall 3- and 5-year survival was 83% in the responder and 63% and 22% in the non-responder group, respectively. The overall 2-year clinical, histological and immunological response rates were 81%, 47% and 41%, respectively. Progression into EATL was reported in 16%, all of these patients died. CONCLUSION Treatment of RCD II with 2-CdA holds promise, showing excellent clinical and histological response rates, and probably less frequent transition into EATL.

Defective synthesis or association of T-cell receptor chains underlies loss of surface T-cell receptor–CD3 expression in enteropathy-associated T-cell lymphoma

Enteropathy-associated T-cell lymphoma, an often fatal complication of celiac disease, can result from expansion of aberrant intraepithelial lymphocytes in refractory celiac disease type II (RCD II). Aberrant intraepithelial lymphocytes and lymphoma cells are intracellularly CD3epsilon(+) but lack expression of the T-cell receptor (TCR)-CD3 complex on the cell surface. It is unknown what causes the loss of TCR-CD3 expression. We report the isolation of a cell line from an RCD II patient with the characteristic phenotype of enteropathy-associated T-cell lymphoma. We demonstrate that in this cell line the TCR-alpha and -beta chains as well as the CD3gamma, CD3delta, CD3epsilon, and zeta-chains are present intracellularly and that assembly of the CD3gammaepsilon, CD3deltaepsilon, and zetazeta-dimers is normal. However, dimerization of the TCR chains and proper assembly of the TCR-CD3 complex are defective. On introduction of exogenous TCR-beta chains, but not of TCR-alpha chains, assembly and functional cell surface expression of the TCR-CD3 complex were restored. Defective synthesis of both TCR chains was found to underlie loss of TCR expression in similar cell lines isolated from 2 additional patients. (Pre)malignant transformation in RCD II thus correlates with defective synthesis or defective association of the TCR chains, resulting in loss of surface TCR-CD3 expression.

Aberrant T-lymphocytes in refractory coeliac disease are not strictly confined to a small intestinal intraepithelial localization†

Refractory coeliac disease (RCD) is characterized by persisting mucosal pathology in spite of a strict gluten free diet (GFD). In RCD type II, phenotypically aberrant (CD7+CD3‐CD4/8‐cytoplasmicCD3+) T‐lymphocytes are present within the intraepitelial lymphocyte (IEL) population in the small intestine, and 50–60% of these patients develops an enteropathy associated T‐cell lymphoma (EATL).

Intestinal barrier gene variants may not explain the increased levels of antigliadin antibodies, suggesting other mechanisms than altered permeability

Various genes may influence intestinal barrier function, including MAGI2, MYO9B, and PARD3, which are associated with celiac disease. Because direct measurement of intestinal permeability is difficult, antibodies against gliadin (AGA) and Bakers yeast (anti-Saccharomyces cerevisiae antibodies [ASCA]) can be used as an indirect test. The objective of this study was to investigate whether intestinal permeability, represented by AGA, was correlated with MAGI2, MYO9B, and PARD3. Analyses were performed in patients with Down syndrome, a population with suspected increased intestinal permeability. Correlations between AGA and ASCA were investigated. Patients with Down syndrome (n = 126) were genotyped for six single-nucleotide polymorphisms in MAGI2 (rs1496770, rs6962966, rs9640699), MYO9B (rs1457092, rs2305764), and PARD3 (rs10763976). An allele dosage association of these risk genes and AGA levels was performed. The correlation between AGA and ASCA was studied. A strong correlation was found between AGA and ASCA (p < 0.01). The patient group with one or more risk genotypes had lower mean AGA levels (trend test p = 0.007) and consisted of a larger number of patients with normal AGA levels (p = 9.3 x 10(-5)). Celiac-associated risk genotypes are associated with lower AGA values instead of elevated ones. Thus, other immunologic phenomena play a role in the increased prevalence of elevated AGA in patients with Down syndrome, possibly involving altered induction and/or maintenance of tolerance.

Identification and Characterization of ErbB-3-Binding Protein-1 as a Target for Immunotherapy

Based on immune reactivity in response to a whole-cell colon tumor vaccine and using serological identification of Ags by recombinant cDNA expression cloning, we here describe the molecular and functional identification of a novel human tumor Ag. By screening a cDNA expression library derived from the coloncarcinoma cell line HT-29 with pooled colorectal cancer patients’ sera, 26 clones reactive with IgG Abs could be identified. Characterization of these cDNA clones by sequence analysis and alignment, and detailed serological analysis revealed cancer-related immunoreactivity for the ErbB-3-binding protein-1 (Ebp1). Immunohistochemical staining of colorectal tumors and neighboring normal colon tissue indicated the observed cancer-related immunogenicity of Ebp1 to be related to overexpression. Via reverse immunology, five potential HLA-A2-restricted T cell epitopes were identified, of which two (Ebp145–54 and Ebp159–67) bound HLA-A2 with intermediate and high affinity, respectively. Analysis of their immunogenicity in vitro indicated that only the high-affinity Ebp159 epitope gave rise to CD8+ T cells capable of recognizing both exogenously loaded Ebp1 peptide and endogenously expressed Ebp1 on target cells. In addition, in vivo CD8+ T cell responsiveness against the Ebp159 epitope could be detected in two of nine and three of six cancer patients PBMC and tumor draining lymph nodes, respectively, but not in nine of nine healthy donors tested. These data confirm that Ebp1 is an immunogenic protein, capable of eliciting CD8-mediated responses in vivo and in vitro, providing a rationale for further exploration of Ebp1 as a possible target for anticancer immunotherapy.