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Chimeric antigen receptor (CAR) T-cell therapies have increased the patients with relapsed/refractory multiple myeloma (RRMM) in whom standard electrophoretic techniques fail to detect the M-protein. Quantitative immunoprecipitation mass spectrometry (QIP-MS) can accurately measure serum M-protein with high sensitivity, and identify interferences caused by therapeutic monoclonal antibodies. Here, we investigate the outcome of QIP-MS in 33 patients treated with the academic BCMA-directed CAR T-cell ARI0002h (Cesnicabtagene Autoleucel). QIP-MS offered more detailed insights than serum immunofixation (sIFE), identifying glycosylated M-proteins and minor additional peaks. Moreover, the potential interferences owing to daratumumab or tocilizumab treatments were successfully detected. When analysing different assay platforms during patient's monitoring after ARI0002h administration, we observed that QIP-MS showed a high global concordance (78.8%) with sIFE, whereas it was only moderate (55.6%) with bone marrow (BM)-based next-generation flow cytometry (NGF). Furthermore, QIP-MS consistently demonstrated the lowest negativity rate across the different timepoints (27.3% vs. 60.0% in months 1 and 12, respectively). Patients with QIP-MS(+)/BM-based NGF(-) showed a non-significant shorter median progression free survival than those with QIP-MS(-)/BM-based NGF(-). In summary, we show the first experience to our knowledge demonstrating that QIP-MS could be particularly useful as a non-invasive technique when evaluating response after CAR T-cell treatment in MM., (© 2024 The Author(s). British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Varnimcabtagene autoleucel (var-cel) is an academic anti-CD19 chimeric antigen receptor (CAR) product used for the treatment of non-Hodgkin lymphoma (NHL) in the CART19-BE-01 trial. Here we report updated outcomes of patients with NHL treated with var-cel. B-cell recovery was compared with patients with acute lymphoblastic leukaemia (ALL). Forty-five patients with NHL were treated. Cytokine release syndrome (any grade) occurred in 84% of patients (4% grade ≥3) and neurotoxicity in 7% (2% grade ≥3). The objective response rate was 73% at Day +100, and the 3-year duration of response was 56%. The 3-year progression-free and overall survival were 40% and 52% respectively. High lactate dehydrogenase was the only covariate with an impact on progression-free survival. The 3-year incidence of B-cell recovery was lower in patients with NHL compared to ALL (25% vs. 60%). In conclusion, in patients with NHL, the toxicity of var-cel was manageable, while B-cell recovery was significantly prolonged compared to ALL. This trial was registered as NCT03144583., (© 2023 The Authors. British Journal of Haematology published by British Society for Haematology and John Wiley & Sons Ltd.)

Background: Immune check-point blockade (ICB) has shown clinical benefit in mismatch repair-deficient/microsatellite instability high metastatic colorectal cancer (mCRC) but not in mismatch repair-proficient/microsatellite stable patients. Cancer vaccines with autologous dendritic cells (ADC) could be a complementary therapeutic approach to ICB as this combination has the potential to achieve synergistic effects., Methods: This was a Phase I/II multicentric study with translational sub-studies, to evaluate the safety, pharmacodynamics and anti-tumor effects of Avelumab plus ADC vaccine in heavily pre-treated MSS mCRC patients. Primary objective was to determine the maximum tolerated dose and the efficacy of the combination. The primary end-point was 40% progression-free survival at 6 months with a 2 Simon Stage., Results: A total of 28 patients were screened and 19 pts were included. Combined therapy was safe and well tolerated. An interim analysis (Simon design first-stage) recommended early termination because only 2/19 (11%) patients were disease free at 6 months. Median PFS was 3.1 months [2.1-5.3 months] and overall survival was 12.2 months [3.2-23.2 months]. Stimulation of immune system was observed in vitro but not clinically. The evaluation of basal RNA-seq noted significant changes between pre and post-therapy liver biopsies related to lipid metabolism and transport, inflammation and oxidative stress pathways., Conclusions: The combination of Avelumab plus ADC vaccine is safe and well tolerated but exhibited modest clinical activity. Our study describes, for the first-time, a de novo post-therapy metabolic rewiring, that could represent novel immunotherapy-induced tumor vulnerabilities., (© 2022. The Author(s).)

Encapsulation of water-soluble bioactive compounds for enabling specific accumulation in tumor locations, while avoiding premature clearance and/or degradation in the bloodstream, is one of the main hallmarks in nanomedicine, especially that of NIR fluorescent probes for cancer theragnosis. The herein reported technology furnishes water-dispersible double-walled polyurethane-polyurea hybrid nanocapsules (NCs) loaded with indocyanine green (ICG-NCs), using a versatile and highly efficient one-pot and industrially scalable synthetic process based on the use of two different prepolymers to set up the NCs walls. Flow cytometry and confocal microscopy confirmed that both ICG-loaded NCs internalized in monocyte-derived dendritic cells (moDCs). The in vivo analysis of xenograft A375 mouse melanoma model revealed that amphoteric functionalization of NCs' surface promotes the selective accumulation of ICG-NCs in tumor tissues, making them promising agents for a less-invasive theragnosis of cancer.

Existing immune signatures and tumor mutational burden have only modest predictive capacity for the efficacy of immune check point inhibitors. In this study, we developed an immune-metabolic signature suitable for personalized ICI therapies. A classifier using an immune-metabolic signature (IMMETCOLS) was developed on a training set of 77 metastatic colorectal cancer (mCRC) samples and validated on 4,200 tumors from the TCGA database belonging to 11 types. Here, we reveal that the IMMETCOLS signature classifies tumors into three distinct immune-metabolic clusters. Cluster 1 displays markers of enhanced glycolisis, hexosamine byosinthesis and epithelial-to-mesenchymal transition. On multivariate analysis, cluster 1 tumors were enriched in pro-immune signature but not in immunophenoscore and were associated with the poorest median survival. Its predicted tumor metabolic features suggest an acidic-lactate-rich tumor microenvironment (TME) geared to an immunosuppressive setting, enriched in fibroblasts. Cluster 2 displays features of gluconeogenesis ability, which is needed for glucose-independent survival and preferential use of alternative carbon sources, including glutamine and lipid uptake/β-oxidation. Its metabolic features suggest a hypoxic and hypoglycemic TME, associated with poor tumor-associated antigen presentation. Finally, cluster 3 is highly glycolytic but also has a solid mitochondrial function, with concomitant upregulation of glutamine and essential amino acid transporters and the pentose phosphate pathway leading to glucose exhaustion in the TME and immunosuppression. Together, these findings suggest that the IMMETCOLS signature provides a classifier of tumors from diverse origins, yielding three clusters with distinct immune-metabolic profiles, representing a new predictive tool for patient selection for specific immune-metabolic therapeutic approaches., Competing Interests: JM received research grants from Merck, Roche, Amgen, NanoString, Incyte, and Biocartis and reports personal fees from Advance Medical, Cancer Expert Now, Fundación Clínica Universitaria, Sirtex, Pierre-Fabre, Shire, AstraZeneca, Bayer, Servier, Sanofi, and Roche. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Pedrosa, Foguet, Oliveres, Archilla, de Herreros, Rodríguez, Postigo, Benítez-Ribas, Camps, Cuatrecasas, Castells, Prat, Thomson, Maurel and Cascante.)

We evaluated outcomes of 18 patients with isolated extramedullary disease (iEMD) relapsed/refractory (R/R) B-cell acute lymphoblastic leukemia (B-ALL) treated with the CD19-directed CAR T cells ARI-0001 in two centers (adult and pediatric), including patients treated in the CART19-BE-01 trial and the consecutive compassionate use program. iEMD was detected by PET-CT in 78% (14/18), and/or by cerebrospinal fluid analysis in 28% (5/18). Patients received cyclophosphamide and fludarabine followed by 1 × 10 6 ARI-0001 cells/kg, initially as a single dose (first patient) and later split into three fractions (10%, 30%, and 60%). Cytokine release syndrome (CRS) occurred in 50% (9/18) of patients, with no cases of grade ≥3 CRS, and 1 case (6%) of grade 1 neurotoxicity. Tocilizumab was used in 6% of patients (1/18). Procedure-related mortality was 0% at 2 years. Objective responses were seen in 94% (95% confidence interval [CI]: 73%-99%) of patients, with complete responses (CR) seen in 78% (95% CI: 52%-94%) of them. Progression-free and overall survival were 49% (95% CI: 30%-79%) and 61% (95% CI: 40%-92%) at 2 years. In conclusion, the use of ARI-0001 cells in patients with R/R ALL and iEMD was associated with a safety and efficacy profile that is comparable with what is observed in patients with marrow involvement and in line with other CART19 products., (© 2022 Wiley Periodicals LLC.)

CART19 cells are emerging as an alternative therapy for patients with chronic lymphocytic leukemia (CLL). Here we report the outcome of nine consecutive patients with CLL treated with ARI-0001 CART19 cells, six of them with Richter's transformation (RT). One patient with RT never received therapy. The cytokine release syndrome rate was 87.5% (12.5% grade ≥3). Neurotoxicity was not observed in any patient. All patients experienced absolute B-cell aplasia, and seven (87.5%) responded to therapy. With a median follow-up of 5.6 months, two patients with RT experienced a CD19-negative relapse. In conclusion, ARI-0001 cell therapy was feasible, safe, and effective in patients with high-risk CLL or RT., Competing Interests: VO-M: Consultant or advisory role (Kite Gilead, Celgene, Novartis), travel grants (Kite Gilead, Celgene, Novartis, Roche, Takeda, Janssen), honoraria (Kite Gilead). EG: Consultant or advisory role (Kite Gilead, Janssen, Genmab), research funding (Kite Gilead, Janssen, Roche). AM-R: Consultant or advisory role (Bristol Myers Squibb, Abbvie), travel grants (Kite Gilead, Roche, Takeda, Janssen, Abbvie), honoraria (Abbvie). ML: Honoraria (Grifols, Fresenius Kabi), research funding (Terumo BCT, Maco-Pharma). JE: Consultant or advisory role (Abbvie, Novartis, Celgene, Astellas, Jazz, Daiichi Dankyo, Roche, Amgen, Pfizer), travel grants (Celgene, Roche, Astellas, Daiichi Dankyo), research funding (Novartis, Celgene). AL-G: Consultant or advisory role (Roche, Kite Gilead, Celgene/Bristol-Myers, Incyte), honoraria (Roche, Novartis, Takeda, Bayer, Sandoz, Kern), research grants (Roche, Kite Gilead, Celgene/Bristol-Myers, Novartis, Incyte, Janssen, Pfizer, Takeda). ÁU-I: Consultant or advisory role (Kite Gilead, Celgene, Miltenyi), travel grants (Kite Gilead, Celgene). MJ: Consultant or advisory role (Kite Gilead, Grifols), honoraria (Kite Gilead, Grifols). The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Ortiz-Maldonado, Frigola, Español-Rego, Balagué, Martínez-Cibrián, Magnano, Giné, Pascal, Correa, Martínez-Roca, Cid, Lozano, Villamor, Benítez-Ribas, Esteve, López-Guillermo, Campo, Urbano-Ispizua, Juan and Delgado.)

We evaluated the administration of ARI-0001 cells (chimeric antigen receptor T cells targeting CD19) in adult and pediatric patients with relapsed/refractory CD19 + malignancies. Patients received cyclophosphamide and fludarabine followed by ARI-0001 cells at a dose of 0.4-5 × 10 6 ARI-0001 cells/kg, initially as a single dose and later split into 3 fractions (10%, 30%, and 60%) with full administration depending on the absence of cytokine release syndrome (CRS). 58 patients were included, of which 47 received therapy: 38 with acute lymphoblastic leukemia (ALL), 8 with non-Hodgkin's lymphoma, and 1 with chronic lymphocytic leukemia. In patients with ALL, grade ≥3 CRS was observed in 13.2% (26.7% before versus 4.3% after the amendment), grade ≥3 neurotoxicity was observed in 2.6%, and the procedure-related mortality was 7.9% at day +100, with no procedure-related deaths after the amendment. The measurable residual disease-negative complete response rate was 71.1% at day +100. Progression-free survival was 47% (95% IC 27%-67%) at 1 year: 51.3% before versus 39.5% after the amendment. Overall survival was 68.6% (95% IC 49.2%-88%) at 1 year. In conclusion, the administration of ARI-0001 cells provided safety and efficacy results that are comparable with other academic or commercially available products. This trial was registered as ClinicalTrials.gov: NCT03144583., (Copyright © 2020 The American Society of Gene and Cell Therapy. Published by Elsevier Inc. All rights reserved.)

During the last 20 years, chemotherapy has improved survival rates of colorectal cancer (CRC). However, the majority of metastatic cases do not respond to or progress after first line conventional chemotherapy and contribute to the fatalities of patients with CRC. Insights into the immune contexture of the tumor microenvironment (TME) have enabled the development of new systemic treatments that boost the host immune system against the tumor-the immune checkpoint inhibitors (ICI). These promising drugs have already shown astonishing efficacies in other cancer types and have raised new hope for the treatment of metastatic CRC (mCRC). In this review, we will summarize the results of the clinical trials that led to their accelerated approval by the U.S. Food and Drug Administration (FDA) in 2017, as well as all relevant recent studies conducted since then-some of which are not published yet. We will focus on therapeutic efficacy, but also discuss the available data for drug safety and security, changes in quality of life indicators and predictive biomarkers for treatment response. The burgeoning evidence for a potential use of ICIs in other settings than mCRC will also be mentioned. For each trial, we have made a preliminary assessment of the quality of clinical trial design and of the "European Society of Medical Oncology (ESMO) magnitude of clinical benefit" (ESMO-MCBS) in order to provide the first evidence-based recommendation to the reader.

Development of semi-automated devices that can reduce the hands-on time and standardize the production of clinical-grade CAR T-cells, such as CliniMACS Prodigy from Miltenyi, is key to facilitate the development of CAR T-cell therapies, especially in academic institutions. However, the feasibility of manufacturing CAR T-cell products from heavily pre-treated patients with this system has not been demonstrated yet. Here we report and characterize the production of 28 CAR T-cell products in the context of a phase I clinical trial for CD19+ B-cell malignancies (NCT03144583). The system includes CD4-CD8 cell selection, lentiviral transduction and T-cell expansion using IL-7/IL-15. Twenty-seven out of 28 CAR T-cell products manufactured met the full list of specifications and were considered valid products. Ex vivo cell expansion lasted an average of 8.5 days and had a mean transduction rate of 30.6 ± 13.44%. All products obtained presented cytotoxic activity against CD19+ cells and were proficient in the secretion of pro-inflammatory cytokines. Expansion kinetics was slower in patient's cells compared to healthy donor's cells. However, product potency was comparable. CAR T-cell subset phenotype was highly variable among patients and largely determined by the initial product. T CM and T EM were the predominant T-cell phenotypes obtained. 38.7% of CAR T-cells obtained presented a T N or T CM phenotype, in average, which are the subsets capable of establishing a long-lasting T-cell memory in patients. An in-depth analysis to identify individual factors contributing to the optimal T-cell phenotype revealed that ex vivo cell expansion leads to reduced numbers of T N , T SCM , and T EFF cells, while T CM cells increase, both due to cell expansion and CAR-expression. Overall, our results show for the first time that clinical-grade production of CAR T-cells for heavily pre-treated patients using CliniMACS Prodigy system is feasible, and that the obtained products meet the current quality standards of the field. Reduced ex vivo expansion may yield CAR T-cell products with increased persistence in vivo ., (Copyright © 2020 Castella, Caballero-Baños, Ortiz-Maldonado, González-Navarro, Suñé, Antoñana-Vidósola, Boronat, Marzal, Millán, Martín-Antonio, Cid, Lozano, García, Tabera, Trias, Perpiña, Canals, Baumann, Benítez-Ribas, Campo, Yagüe, Urbano-Ispizua, Rives, Delgado and Juan.)

Androgen receptor (AR) signaling remains crucial in castration-resistant prostate cancer (CRPC). Since it is also essential in immune cells, we studied whether the expression of AR full-length (ARFL) and its splicing variant ARV7 in peripheral blood mononuclear cells (PBMC) predicts systemic treatment response in mCRPC in comparison with circulating-tumor cells (CTC). We measured ARFL and ARV7 mRNA in PBMC and CTC from patients prior to receiving abiraterone (AA), enzalutamide (E), or taxanes by a pre-amplification plus quantitative reverse-transcription PCR. They were also tested in LNCaP- ARV7 -transfected and in 22RV1 docetaxel-resistant (22RV1DR) cells. We studied 171 PBMC from 136 patients and from 24 non-cancer controls, and 47 CTC from 22 patients. High PBMC ARV7 levels correlated with worse AA/E and better taxane response. In taxane-treated patients high PBMC ARFL also correlated with longer progression-free survival (PFS). High ARV7 and ARFL expression were independently associated with better biochemical-PFS. Conversely, high CTC ARV7 and ARFL correlated with shorter radiological-PFS and overall survival, respectively. High ARV7 in 22RV1DR and LNCaP- ARV7 cells correlated with taxane resistance. In conclusion, ARFL and ARV7 at PBMC or CTC have a different predictive role in the taxane response, suggesting a potential influence of the AR pathway from PBMC in such response modulation., Competing Interests: The authors declare no conflict of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results.

Background and Aims: Recent studies have shown the efficacy of autologous haematopoietic stem cell transplantation [HSCT] in severely refractory Crohn's disease [CD] patients. HSCT is thought to eliminate auto-reactive cells; however, no specific studies of immune reconstitution in CD patients are available., Methods: We followed a group of CD patients [n = 18] receiving autologous HSCT, with 50% of them achieving endoscopic drug-free remission. To elucidate the mechanisms driving efficacy, we monitored changes after HSCT in blood and intestine immune-cell composition. CD patients [n = 22] receiving anti-tumour necrosis factor [TNF]-α were included for comparison., Results: Severe immune ablation followed by HSCT induced dramatic changes in both peripheral blood T and B cells in all patients regardless of the efficacy of the treatment. Endoscopic remission at week 52 following HSCT was associated with significant intestinal transcriptional changes. A comparison of the remission signature with that of anti-TNFα identified both common and unique genes in the HSCT-induced response. Based on deconvolution analysis of intestinal biopsy transcriptome data, we show that response to HSCT, but not to anti-TNFα, is associated with an expansion of naïve B-cells, as seen in blood, and a decrease in the memory resting T-cell content. As expected, endoscopic remission, in response to both HSCT and anti-TNFα, led to a significant reduction in intestinal neutrophil and M1 macrophage content., Conclusions: Peripheral blood immune remodelling after HSCT does not predict efficacy. In contrast, a profound intestinal T-cell depletion that is maintained long after transplant is associated with mucosal healing following HSCT, but not anti-TNFα., (© European Crohn’s and Colitis Organisation (ECCO) 2018.)

Dendritic cells (DCs) are APCs essential in regulating the immune response. PGE 2 , produced during inflammation, has a pivotal role in the maturation of DCs and, therefore, is vital for the immune response. The large variety of biologic functions governed by PGE 2 is mediated by its signaling through 4 distinct E-type prostanoid (EP) receptors. Immunogenic DCs express EP 2 and EP 4 , which mediate the PGE 2 signaling. However, the expression and function of EP receptors in human tolerogenic DCs (tol-DCs), which present an inhibitory phenotype, have not yet, to our knowledge, been assessed. To clarify the role of EP receptors in tol-DCs, we examined the expression of different EP receptors and their effect using selective agonists in human cells. We find that EP 2 and EP 3 expression are up-regulated in in vitro-generated tol-DCs compared with mature DCs (mDCs). Activation of EP 2 -EP 4 has a direct effect on the surface expression of costimulatory molecules and maturation receptors, such as CD80, CD83, and CD86 or MHCII and CCR7 in tol-DCs, the latter being exclusively modulated by PGE 2 -EP 4 signaling. Importantly, we find that EP 2 and EP 3 receptors are involved in tolerance induction through IL-10 production by tol-DCs. These results are in sharp contrast with the inflammatory role of EP 4 Moreover, we show that DCs generated in the presence of agonists for EP receptors, induce naive T cell differentiation toward polarized Th1/Th17 cells. Given the differential effects of EP receptors, our results suggest that EP receptor agonist/antagonists might become relevant novel drug templates to modulate immune response., (© Society for Leukocyte Biology.)

The design of innovative strategies to selectively target cells, such antigen-presenting cells and dendritic cells, in vivo to induce immune tolerance is gaining interest and relevance for the treatment of immune-mediated diseases. A novel loaded-nanosystem strategy to generate tolerogenic dendritic cells (tol-DCs) was evaluated. Hence budesonide (BDS) was encapsulated in multiwalled polyurethane-polyurea nanoparticles (PUUa NPs-BDS) based on self-stratified polymers by hydrophobic interactions at the oil-water interface. DCs treated with encapsulated BDS presented a prominent downregulation of costimulatory molecules (CD80, CD83 and MHCII) and upregulation of inhibitory receptors. Moreover, DCs treated with these PUUa NPs-BDS also secreted large amounts of IL-10, a crucial anti-inflammatory cytokine to induce tolerance, and inhibited T lymphocyte activation in a specific manner compared to those cells generated with free BDS. These results demonstrate that PUUa NPs-BDS are a highly specific and efficient system through which to induce DCs with a tolerogenic profile. Given the capacity of PUUa NPs-BDS, this delivery system has a clear advantage for translation to in vivo studies., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Background & Aims: Crohn's disease (CD) has been associated with an altered immune response to commensal microbiota, mostly based on increased seroreactivity to microbial proteins. Although T cells are believed to contribute to the development of CD, little is known about the antigens involved. We investigated the antigen-specificity of T cells isolated from patients with CD., Methods: We isolated peripheral blood mononuclear cells from 65 patients with CD and 45 healthy individuals (controls). We investigated T-cell reactivity to commensal microbial antigens using proliferation assays (based on thymidine incorporation and carboxyfluorescein succinimidyl ester dilution). Gene expression patterns were determined using microarray and real-time polymerase chain reaction analyses. Cytokines, chemokines, and antibodies were measured by enzyme-linked immunosorbent assay, flow cytometry, or multiplex cytokine assays. Intestinal crypts were obtained from surgical resection specimens of 7 individuals without inflammatory bowel disease. We examined the effects of commensal-specific CD4(+) T cells on primary intestinal epithelial cells from these samples., Results: The bacterial proteins FlaX, A4-fla2, and YidX increased proliferation of CD4(+) T cells isolated from peripheral blood of patients with CD compared with controls. In blood samples from controls, CD4(+) T cells specific for FlaX, A4-fla2, or YidX had a T-helper (Th)1 phenotype; a larger proportion of CD4(+) T cells specific for these proteins in patients with CD had a Th17 phenotype or produced Th1 and Th17 cytokines. When supernatants collected from commensal-specific CD4(+) T cells from patients with CD were applied to healthy intestinal epithelial cells, the epithelial cells increased the expression of the chemokine (C-X-C motif) ligand 1 (CXCL1), CXCL8 and the CC chemokine ligand 20 (CCL20)., Conclusions: A larger proportion of commensal-specific CD4(+) T cells from patients with CD have a Th17 phenotype or produce Th1 and Th17 cytokines, compared with T cells from controls; this might contribute to intestinal inflammation in patients with CD. These cells might be targeted for treatment of CD. The transcriptional data of commensal-specific CD4(+) T cells from healthy individuals and CD patients have been deposited in the Gene Expression Omnibus at the National Center for Biotechnology Information (accession no: GSE70469)., (Copyright © 2016 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Background and Aims: Ex vivo-generated autologous tolerogenic dendritic cells [tolDCs] can restore immune tolerance in experimental colitis. The aim of this study was to determine the safety and tolerability of administration of autologous tolDCs in refractory Crohn's disease [CD] patients., Methods: A phase-I, single-centre, sequential-cohorts, dose-range study was designed. Stable tolDCs were generated ex vivo from monocytes following a previously developed protocol, and administered by sonography-guided intraperitoneal injection. Six sequential refractory-CD cohorts were established: the first three cohorts received a single intraperitoneal injection of tolDCs at escalating doses [2 x 10(6)/5 x 10(6)/10 x 10(6)]; and the last three cohorts received three biweekly intraperitoneal injections at same escalating doses. Safety was sequentially evaluated. Patients were assessed from week 0 to 12 and followed up for 1-year period for safety., Results: Nine patients were included. No adverse effects were detected during tolDC injection or follow-up. Three patients withdrew from the study due to CD worsening. Crohn's Disease Activity Index [CDAI] decreased from 274 [60] {mean (standard deviation [SD])} to 222 [113] [p = 0.3]; one [11%] patient reached clinical remission [CDAI < 150] and two [22%] clinical response [CDAI decrease ≥ 100]. Crohn's Disease Endoscopic Index of Severity [CDEIS] decreased from 18 [5] to 13 [8] [p = 0.4]; lesions improved markedly in three patients [33%]. Quality of life (inflammatory bowel disease questionnaire [IBDQ]) changed from 125 [27] to 131 [38] [p = 0.7]; remission [IBDQ at Week 12 ≥ 170] was reached in one [11%] case and response [IBDQ score increase ≥ 16] in two [22%]., Conclusions: Intraperitoneal administration of autologous tolDCs appears safe and feasible in refractory CD patients. Further studies should be developed to test clinical benefit, determine the optimal administration route and dose, and monitor the immune responses; See [www.eudract.ema.europa.eu, EudraCT number 2007-003469-42; www.aemps.gob.es number PEI 08-049]., (Copyright © 2015 European Crohn’s and Colitis Organisation (ECCO). Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

The aim of this study was to test the hypothesis whether MERTK, which is up-regulated in human DCs treated with immunosuppressive agents, is directly involved in modulating T cell activation. MERTK is a member of the TAM family and contributes to regulating innate immune response to ACs by inhibiting DC activation in animal models. However, whether MERTK interacts directly with T cells has not been addressed. Here, we show that MERTK is highly expressed on dex-induced human tol-DCs and participates in their tolerogenic effect. Neutralization of MERTK in allogenic MLR, as well as autologous DC-T cell cultures, leads to increased T cell proliferation and IFN-γ production. Additionally, we identify a previously unrecognized noncell-autonomous regulatory function of MERTK expressed on DCs. Mer-Fc protein, used to mimic MERTK on DCs, suppresses naïve and antigen-specific memory T cell activation. This mechanism is mediated by the neutralization of the MERTK ligand PROS1. We find that MERTK and PROS1 are expressed in human T cells upon TCR activation and drive an autocrine proproliferative mechanism. Collectively, these results suggest that MERTK on DCs controls T cell activation and expansion through the competition for PROS1 interaction with MERTK in the T cells. In conclusion, this report identified MERTK as a potent suppressor of T cell response., (© Society for Leukocyte Biology.)

LFA-1 is a leukocyte specific β2 integrin that plays a major role in regulating adhesion and migration of different immune cells. Recent data suggest that LFA-1 on mature dendritic cells (mDCs) may function as a chemokine-inducible anchor during homing of DCs through the afferent lymphatics into the lymph nodes, by transiently switching its molecular conformational state. However, the role of LFA-1 mobility in this process is not yet known, despite that the importance of lateral organization and dynamics for LFA-1-mediated adhesion regulation is broadly recognized. Using single particle tracking approaches we here show that LFA-1 exhibits higher mobility on resting mDCs compared to monocytes. Lymphoid chemokine CCL21 stimulation of the LFA-1 high affinity state on mDCs, led to a significant reduction of mobility and an increase on the fraction of stationary receptors, consistent with re-activation of the receptor. Addition of soluble monomeric ICAM-1 in the presence of CCL21 did not alter the diffusion profile of LFA-1 while soluble ICAM-1 nano-aggregates in the presence of CCL21 further reduced LFA-1 mobility and readily bound to the receptor. Overall, our results emphasize the importance of LFA-1 lateral mobility across the membrane on the regulation of integrin activation and its function as adhesion receptor. Importantly, our data show that chemokines alone are not sufficient to trigger the high affinity state of the integrin based on the strict definition that affinity refers to the adhesion capacity of a single receptor to its ligand in solution. Instead our data indicate that nanoclustering of the receptor, induced by multi-ligand binding, is required to maintain stable cell adhesion once LFA-1 high affinity state is transiently triggered by inside-out signals.

The gut mucosa undergoes continuous antigenic exposure from food antigens, commensal flora derived ligands, and pathogens. This constant stimulation results in controlled inflammatory responses that are effectively suppressed by multiple factors. This tight regulation, necessary to maintain intestinal homeostasis, is affected during inflammatory bowel diseases (IBD) resulting in altered immune responses to harmless microorganisms. Dendritic cells (DCs) are sentinels of immunity, located in peripheral and lymphoid tissues, which are essential for homeostasis of T cell-dependent immune responses. The expression of a particular set of pathogen recognition receptors allows DCs to initiate immune responses. However, in the absence of danger signals, different DC subsets can induce active tolerance by inducing regulatory T cells (Treg), inhibiting inflammatory T helper cell responses, or both. Interestingly, several protocols to generate clinical grade tolerogenic DC (tol-DCs) in vitro have been described, opening the possibility to restore the intestinal homeostasis to bacterial flora by cellular therapy. In this review, we discuss different DC subsets and their role in IBD. Additionally, we will review preclinical studies performed in animal models while describing recent characterization of tol-DCs from Crohn's disease patients for clinical application.

Autoimmune diseases, or immune-mediated diseases, are characterized by loss of tolerance to autoantigens and immune system activation causing damage to one or multiple organs. The mechanisms through which this abnormal immune response is started and maintained are not fully established. The therapeutic approach to these diseases is generally based on corticosteroids, immunomodulators, and monoclonal antibodies. Given the exceptional capacity of dendritic cells to induce immunogenicity, early results in humans for the treatment of tumors (melanoma) or infections (HIV) with immunogenic dendritic cells have recently been obtained. Identification of dendritic cells with tolerogenic capacity and the results in experimental models of autoimmune diseases (autoimmune encephalomyelitis, diabetes mellitus, colitis) suggests that treatment with tolerogenic dendritic cells could be a beneficial therapeutic alternative in the treatment of autoimmune diseases or immune-mediated diseases such as Crohn's disease., (Copyright © 2010 Elsevier España, S.L. All rights reserved.)