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The search for target antigens for CAR-T cell therapy against multiple myeloma defined the B-cell maturation antigen (BCMA) as an interesting candidate. Several studies with BCMA-directed CAR-T cell therapy showed promising results. Second-generation point-of-care BCMA.CAR-T cells were manufactured to be of a GMP (good manufacturing practice) standard using the CliniMACS Prodigy® device. Cytokine release in BCMA.CAR-T cells after stimulation with BCMA positive versus negative myeloma cell lines, U266/HL60, was assessed via intracellular staining and flow cytometry. The short-term cytotoxic potency of CAR-T cells was evaluated by chromium-51 release, while the long-term potency used co-culture (3 days/round) at effector/target cell ratios of 1:1 and 1:4. To evaluate the activation and exhaustion of CAR-T cells, exhaustion markers were assessed via flow cytometry. Stability was tested through a comparison of these evaluations at different timepoints: d0 as well as d + 14, d + 90 and d + 365 of cryopreservation. As results, (1) Killing efficiency of U266 cells correlated with the dose of CAR-T cells in a classical 4 h chromium-release assay. There was no significant difference after cryopreservation on different timepoints. (2) In terms of endurance of BCMA.CAR-T cell function, BCMA.CAR-T cells kept their ability to kill all tumor cells over six rounds of co-culture. (3) BCMA.CAR-T cells released high amounts of cytokines upon stimulation with tumor cells. There was no significant difference in cytokine release after cryopreservation. According to the results, BCMA.CAR-T cells manufactured under GMP conditions exerted robust and specific killing of target tumor cells with a high release of cytokines. Even after 1 year of cryopreservation, cytotoxic functions were maintained at the same level. This gives clinicians sufficient time to adjust the timepoint of BCMA.CAR-T cell application to the patient's course of the underlying disease. [ABSTRACT FROM AUTHOR]

Background: The administration of modified immune cells (MIC) before kidney transplantation led to specific immunosuppression against the allogeneic donor and a significant increase in regulatory B lymphocytes. We wondered how this approach affected the continued clinical course of these patients. Methods: Ten patients from a phase I clinical trial who had received MIC infusions prior to kidney transplantation were retrospectively compared to 15 matched standard-risk recipients. Follow-up was until year five after surgery. Results: The 10 MIC patients had an excellent clinical course with stable kidney graft function, no donor-specific human leukocyte antigen antibodies (DSA) or acute rejections, and no opportunistic infections. In comparison, a retrospectively matched control group receiving standard immunosuppressive therapy had a higher frequency of DSA (log rank P = 0.046) and more opportunistic infections (log rank P = 0.033). Importantly, MIC patients, and in particular the four patients who had received the highest cell number 7 days before surgery and received low immunosuppression during follow-up, continued to show a lack of anti-donor T lymphocyte reactivity in vitro and high CD19+CD24hiCD38hi transitional and CD19+CD24hiCD27+ memory B lymphocytes until year five after surgery. Conclusions: MIC infusions together with reduced conventional immunosuppression were associated with good graft function during five years of follow-up, no de novo DSA development and no opportunistic infections. In the future, MIC infusions might contribute to graft protection while reducing the side effects of immunosuppressive therapy. However, this approach needs further validation in direct comparison with prospective controls. [ABSTRACT FROM AUTHOR]

The transcription factor SOX11 is a tumor-associated antigen with low expression in normal cells, but overexpression in glioblastoma (GBM). So far, conventional surgery, chemotherapy, and radiotherapy have not substantially improved the dismal prognosis of relapsed/refractory GBM patients. Immunotherapy is considered a promising strategy against GBM, but there is a fervent need for better immunotargets in GBM. To this end, we performed an in silico prediction study on SOX11, which primarily yielded ten promising HLA-A*0201-restricted peptides derived from SOX11. We defined a novel peptide FMACSPVAL, which had the highest score according to in silico prediction (6.02 nM by NetMHC-4.0) and showed an exquisite binding affinity to the HLA-A*0201 molecule in the peptide-binding assays. In the IFN-γ ELISPOT assays, FMACSPVAL demonstrated a high efficiency for generating SOX11-specific CD8+ T cells. Nine out of thirty-two healthy donors showed a positive response to SOX11, as assessed by the ELISPOT assays. Therefore, this novel antigen peptide epitope seems to be promising as a target for T cell-based immunotherapy in GBM. The adoptive transfer of in vitro elicited SOX11-specific CD8+ T cells constitutes a potential approach for the treatment of GBM patients. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor T (CAR-T) cells targeting CD19 came into clinical practice for the treatment of B cell lymphoma in 2018. However, patients being treated for B cell lymphoma often suffer from comorbidities such as chronic pain, cardiovascular diseases and arthritis. Thus, these patients frequently receive concomitant medications that include nonsteroidal anti-inflammatory drugs (NSAIDs) like cyclooxygenase (COX) inhibitors. Celecoxib, a selective COX-2 inhibitor, and aspirin, a non-selective COX-1 and COX-2 inhibitor, are being used as anti-inflammatory, analgesic and anti-pyretic drugs. In addition, several studies have also focused on the anti-neoplastic properties of COX-inhibitors. As the influence of COX-inhibitors on CD19.CAR-T cells is still unknown, we investigated the effect of celecoxib and aspirin on the quantity and quality of CD19.CAR-T cells at different concentrations with special regard to cytotoxicity, activation, cytokine release, proliferation and exhaustion. A significant effect on CAR-T cells could be observed for 0.1 mmol/L of celecoxib and for 4 mmol/L of aspirin. At these concentrations, we found that both COX-inhibitors could induce intrinsic apoptosis of CD19.CAR-T cells showing a significant reduction in the ratio of JC-10 red to JC-10 green CAR-T cells from 6.46 ± 7.03 (mean ± SD) to 1.76 ± 0.67 by celecoxib and to 4.41 ± 0.32 by aspirin, respectively. Additionally, the ratios of JC-10 red to JC-10 green Daudi cells were also decreased from 3.41 ± 0.30 to 0.77 ± 0.06 by celecoxib and to 1.26 ± 0.04 by aspirin, respectively. Although the cytokine release by CD19.CAR-T cells upon activation was not hampered by both COX-inhibitors, activation and proliferation of CAR-T cells were significantly inhibited via diminishing the NF-ĸB signaling pathway by a significant down-regulation of expression of CD27 on CD4+ and CD8+ CAR-T cells, followed by a clear decrease of phosphorylated NF-ĸB p65 in both CD4+ and CD8+ CAR-T cells by a factor of 1.8. Of note, COX-inhibitors hampered expansion and induced exhaustion of CAR-T cells in an antigen stress assay. Collectively, our findings indicate that the use of COX-inhibitors is a double-edged sword that not only induces apoptosis in tumor cells but also impairs the quantity and quality of CAR-T cells. Therefore, COX-inhibitors should be used with caution in patients with B cell lymphoma under CAR-T cell therapy. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor T (CART) cells targeting CD19 have shown promising results in the treatment of chronic lymphocytic leukemia (CLL). However, efficacy seems to be inferior compared to diffuse large B‐cell lymphoma or acute lymphoblastic leukemia. Impaired T‐cell fitness of CLL patients may be involved in treatment failure. Less‐differentiated naïve‐like T cells play an important role in CART expansion and long‐term persistence in vivo. These cells are sparse in CLL patients. Therefore, optimization of CART cell production protocols enriching less differentiated T cell subsets may overcome treatment resistance. The B‐cell receptor inhibitor ibrutinib targeting Bruton's tyrosine kinase (BTK) is approved for the treatment of CLL. Besides BTK, ibrutinib additionally inhibits interleukin‐2‐inducible T‐cell kinase (ITK) which is involved in T‐cell differentiation. To evaluate the effect of ibrutinib on CART cell production, peripheral blood mononuclear cells from nine healthy donors and eight CLL patients were used to generate CART cells. T‐cell expansion and phenotype, expression of homing and exhaustion makers as well as functionality of CART cells were evaluated. CART cell generation in the presence of ibrutinib resulted in increased cell viability and expansion of CLL patient‐derived CART cells. Furthermore, ibrutinib enriched CART cells with less‐differentiated naïve‐like phenotype and decreased expression of exhaustion markers including PD‐1, TIM‐3 and LAG‐3. In addition, ibrutinib increased the cytokine release capacity of CLL patient‐derived CART cells. In summary, BTK/ITK inhibition with ibrutinib during CART cell culture can improve yield and function of CLL patient‐derived CART cell products. What's new? Chimeric antigen receptor T (CART) cells targeting CD19 have shown promising results in chronic lymphocytic leukemia (CLL). However, naïve‐like T cells play an important role in CART expansion and long‐term persistence in vivo, and these cells are sparse in CLL patients. Here, the authors show that BTK/ITK inhibition with Ibrutinib during CART cell generation may improve CLL patient‐derived CART cell products and enhance CART cell function. Supplementing CART cell production with ibrutinib increases CART cell yields and enriches CART cells with less‐differentiated phenotypes and lower expression of exhaustion markers, representing a potential avenue to improve the clinical outcome of patients. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T cell therapy has shown promising responses in patients with refractory or relapsed aggressive B-cell malignancies that are resistant to conventional chemotherapy or stem cell transplantation. A potentially combinatorial therapeutic strategy may be the inhibition of anti-apoptotic Bcl-2 family proteins, overexpressed in most cancer cells. In this study we investigated the combination of 3rd-generation CD19.CAR-T cells and the BH3 mimetics venetoclax, a Bcl-2 inhibitor, or S63845, a Mcl-1 inhibitor, under three different treatment conditions: pre-sensitization of cancer cells with BH3 mimetics followed by CAR-T cell treatment, simultaneous combination therapy, and the administration of BH3 mimetics after CAR-T cell treatment. Our results showed that administration of CAR-T cells and BH3 mimetics had a significant effect on the quantity and quality of CD19.CAR-T cells. The administration of BH3 mimetics prior to CAR-T cell therapy exerted an enhanced cytotoxic efficacy by upregulating the CD19 expression and pro-apoptotic proteins in highly sensitive tumor cells, and thereby improving both CD19.CAR-T cell cytotoxicity and persistence. In simultaneous and post-treatment approaches, however, the quantity of CAR-T cells was adversely affected. Our findings indicate pre-sensitization of highly sensitive tumor cells with BH3 mimetics could enhance the cytotoxic efficacy of CAR-T cell treatment. [ABSTRACT FROM AUTHOR]

Despite encouraging results with chimeric antigen receptor T (CART) cells, outcome can still be improved by optimization of the CART cell generation process. The proportion of less‐differentiated T cells within the transfused product is linked to enhanced in vivo CART cell expansion and long‐term persistence. The clinically approved PI3Kδ inhibitor idelalisib is well established in the treatment of B cell malignancies. Besides B cell receptor pathway inhibition, idelalisib can modulate T cell differentiation and function. Here, detailed longitudinal analysis of idelalisib‐induced effects on T cell phenotype and function was performed during CART cell production. A third generation CD19.CAR.CD28.CD137zeta CAR vector system was used. CART cells were generated from peripheral blood mononuclear cells of healthy donors (HDs) and chronic lymphocytic leukemia (CLL) patients. Idelalisib‐based CART cell generation resulted in an enrichment of less‐differentiated naïve‐like T cells (CD45RA+CCR7+), decreased expression of the exhaustion markers PD‐1 and Tim‐3, as well as upregulation of the lymph node homing marker CD62L. Idelalisib increased transduction efficiency, but did not impair viability and cell expansion. Strikingly, CD4:CD8 ratios that were altered in CART cells from CLL patients were approximated to ratios in HDs by idelalisib. Furthermore, in vivo efficacy of idelalisib‐treated CART cells was validated in a xenograft mouse model. Intracellular TNF‐α and IFN‐γ production decreased in presence of idelalisib. This effect was reversible after resting CART cells without idelalisib. In summary, PI3Kδ inhibition with idelalisib can improve CART cell products, particularly when derived from CLL patients. Further studies with idelalisib‐based CART cell generation protocols are warranted. What's new? Despite encouraging results with anti‐CD19 chimeric antigen receptor T (CART) cell therapy for B cell malignancies, clinical outcome could still be improved by optimization of the CART cell generation process. Here, the authors show that ex vivo PI3Kδ inhibition by the B cell malignancy drug idelalisib during CART cell generation can increase the proportion of less‐differentiated T cells and lead to a less exhausted T cell phenotype. Idelalisib optimized the phenotype of CART cells derived from chronic lymphocytic leukemia (CLL) patients. This study thus provides important novel and potentially practice‐changing findings for CART cell generation and expansion, especially for CLL patients. [ABSTRACT FROM AUTHOR]

Introduction Chimeric antigen receptor (CAR) T cells spark hope for patients with CD19+ B cell neoplasia, including relapsed or refractory (r/r) acute lymphoblastic leukaemia (ALL) or r/r non-Hodgkin's lymphoma (NHL). Published studies have mostly used second-generation CARs with 4-1BB or CD28 as costimulatory domains. Preclinical results of third-generation CARs incorporating both elements have shown superiority concerning longevity and proliferation. The University Hospital of Heidelberg is the first institution to run an investigatorinitiated trial (IIT) CAR T cell trial (Heidelberg Chimeric Antigen Receptor T cell Trial number 1 [HD-CAR-1]) in Germany with third-generation CD19-directed CAR T cells. Methods and analysis Adult patients with r/r ALL (stratum I), r/r NHL including chronic lymphocytic leukaemia, diffuse large B-cell lymphoma, follicular lymphoma or mantle cell lymphoma (stratum II) as well as paediatric patients with r/r ALL (stratum III) will be treated with autologous T-lymphocytes transduced by third-generation RV-SFG.CD19.CD28.4-1BB zeta retroviral vector (CD19.CAR T cells). The main purpose of this study is to evaluate safety and feasibility of escalating CD19.CAR T cell doses (1-20×106 transduced cells/m²) after lymphodepletion with fludarabine (flu) and cyclophosphamide (cyc). Patients will be monitored for cytokine release syndrome (CRS), neurotoxicity, i.e. CART- cell-related encephalopathy syndrome (CRES) and/or other toxicities (primary objectives). Secondary objectives include evaluation of in vivo function and survival of CD19. CAR T cells and assessment of CD19.CAR T cell antitumour efficacy. HD-CAR-1 as a prospective, monocentric trial aims to make CAR T cell therapy accessible to patients in Europe. Currently, HD-CAR-1 is the first and only CAR T cell IIT in Germany. A third-generation Good Manufacturing Practice (GMP) grade retroviral vector, a broad spectrum of NHL, treatment of paediatric and adult ALL patients and inclusion of patients even after allogeneic stem cell transplantation (alloSCT) make this trial unique. Ethics and dissemination Ethical approval and approvals from the local and federal competent authorities were granted. Trial results will be reported via peer-reviewed journals and presented at conferences and scientific meetings. [ABSTRACT FROM AUTHOR]

CD56bri natural killer (NK) cells play an important role in the pathogenesis of graft-vs. -host disease (GVHD) and immune defense in the early period after allogeneic hematopoietic stem cell transplantation. Extracorporeal photopheresis (ECP) as an immunomodulating therapy has been widely used for GVHD treatment. However, the mechanism of action of ECP still remains to be elucidated, particularly the influence of ECP on NK cells. Thirty-four patients with steroid-refractory/resistant acute GVHD (aGVHD) ≥ °II and moderate to severe chronic GVHD (cGVHD) received ECP therapy. Patient samples obtained during intensive and long-term treatment were analyzed. Immunomonitoring with respect to cell phenotype and function was performed on rested peripheral blood mononuclear cells (PBMCs) using multiparametric flow cytometry. NK activity in terms of cytokine release was analyzed by intracellular cytokine staining after co-culture with K562 cells. Moreover, the proliferative capacity of NK cells, CD4+, and CD8+ T cells was determined by carboxyfluorescein succinimidyl ester (CFSE) staining. Clinically, 75% of aGVHD and 78% of cGVHD patients responded to ECP therapy. Moreover, our data show that aGVHD, cGVHD patients and healthy donors (HDs) present distinct NK patterns: aGVHD patients have a higher frequency of CD56bri NK subsets with stronger NKG2D and CD62L expression, while CD56−CD16+ NK cells with higher expression of CD57 and CD11b stand out as a signature population for cGVHD. ECP therapy could significantly decrease CD56briCD16− NK cells with shifting the quality from a cytotoxic to a regulatory pattern and additionally mature CD56dim NK cells via upregulation of CD57 in complete responding aGVHD patients. Moreover, ECP could keep the anti-viral and anti-leukemic effects intact via maintaining specialized anti-viral/leukemic CD57+NKG2C+CD56dim NK cells as well as remaining the quality and quantity of cytokine release by NK cells. The proliferative capacity of effector cells remained constant over ECP therapy. In conclusion, ECP represents an attractive option to treat GVHD without compromising anti-viral/leukemic effects. Shaping of CD56bri NK cell compartment by downregulating the cytotoxic subset while upregulating the regulatory subset contributes to the mechanisms of ECP therapy in aGVHD. [ABSTRACT FROM AUTHOR]

Graft-vs.-host disease (GvHD), a severe complication of allogeneic hematopoietic stem cell transplantation, significantly affects the post-transplant morbidity and mortality. Systemic steroids remain the gold standard for the initial management of GvHD. However, up to 60% of patients will not sufficiently respond to steroids. Extracorporeal photopheresis (ECP), a cell-based immunotherapy, has shown good clinical results in such steroid-refractory/resistant GvHD patients. Given its immunomodulatory, but not global immunosuppressive and steroid-sparing capacity, ECP constitutes an attractive option. In the case of GvHD, the balance of immune cells is destroyed: effector cells are not any longer efficiently controlled by regulatory cells. ECP therapy may restore this balance. However, the precise mechanism and the impact of ECP on anti-viral/anti-leukemic function remain unclear. In this study, 839 ECP treatments were performed on patients with acute GvHD (aGvHD) and chronic GvHD (cGvHD). A comprehensive analysis of effector and regulatory cells in patients under ECP therapy included multi-parametric flow cytometry and tetramer staining, LuminexTM-based cytokine, interferon-γ enzyme-linked immunospot, and chromium-51 release assays. Gene profiling of myeloid-derived suppressor cells (MDSCs) was performed by microarray analysis. Immunologically, modulations of effector and regulatory cells as well as proinflammatory cytokines were observed under ECP treatment: (1) GvHD-relevant cell subsets like CD62L+ NK cells and newly defined CD19hiCD20hi B cells were modulated, but (2) quantity and quality of anti-viral/anti-leukemic effector cells were preserved. (3) The development of MDSCs was promoted and switched from an inactivated subset (CD33−CD11b+) to an activated subset (CD33+CD11b+). (4) The frequency of Foxp3+CD4+ regulatory T cells (Tregs) and CD24+CD38hi regulatory B cells was considerably increased in aGvHD patients, and Foxp3+CD8+ Tregs in cGvHD patients. (5) Proinflammatory cytokines like IL-1β, IL-6, IL-8, and TNF-α were significantly reduced. In summary, ECP constitutes an effective immunomodulatory therapy for patients with steroid-refractory/resistant GvHD without impairment of anti-viral/leukemia effects. [ABSTRACT FROM AUTHOR]

Adoptive cell therapy with NY-ESO-1-specific T cells is a promising option for the treatment of soft tissue sarcoma (STS) but achieves only transient tumor control in the majority of cases. A strategy to optimize this cell therapeutic approach might be the modulation of the expression of the cancer-testis antigen NY-ESO-1 using histone deacetylase inhibitors (HDACis). In this study, the ex vivo effect of combining NY-ESO-1-specific T cells with the clinically approved pan HDACis panobinostat or vorionstat was investigated. Our data demonstrated that STS cells were sensitive to HDACis. Administration of HDACi prior to NY-ESO-1-specific T cells exerted enhanced lysis against the NY-ESO-1+ STS cell line SW982. This correlated with an increase in the NY-ESO-1 and HLA-ABC expression of SW982 cells, as well as increased CD25 expression on NY-ESO-1-specific T cells. Furthermore, the immune reactivity of NY-ESO-1-specific CD8+ T cells in terms of cytokine release was enhanced by HDACis. In summary, pretreatment with HDACis represents a potential means of enhancing the cytotoxic efficacy of NY-ESO-1-specific T cells against NY-ESO-1-positive STS. [ABSTRACT FROM AUTHOR]

After solid-organ transplantation, reactivation of the cytomegalovirus (CMV) is often observed in seronegative patients and associated with a high risk of disease and mortality. CMV-specific T cells can prevent CMV reactivation. In a phase 1 trial, CMV-seronegative patients with end-stage renal disease listed for kidney transplantation were subjected to CMV phosphoprotein 65 (CMVpp65) peptide vaccination and further investigated for T-cell responses. To this end, CMV-specific CD8+ T cells were characterized by bulk T-cell-receptor (TCR) repertoire sequencing and combined single-cell RNA and TCR sequencing. In patients mounting an immune response to the vaccine, a common SYE(N)E TCR motif known to bind CMVpp65 was detected. CMV-peptide-vaccination-responder patients had TCR features distinct from those of non-responders. In a non-responder patient, a monoclonal inflammatory T-cell response was detected upon CMV reactivation. The identification of vaccine-induced CMV-reactive TCRs motifs might facilitate the development of cellular therapies for patients wait-listed for kidney transplantation. [ABSTRACT FROM AUTHOR]

Chimeric-antigen-receptor (CAR)-T-cell therapy is already widely used to treat patients who are relapsed or refractory to chemotherapy, antibodies, or stem-cell transplantation. Multiple myeloma still constitutes an incurable disease. CAR-T-cell therapy that targets BCMA (B-cell maturation antigen) is currently revolutionizing the treatment of those patients. To monitor and improve treatment outcomes, methods to detect CAR-T cells in human peripheral blood are highly desirable. In this study, three different detection reagents for staining BCMA-CAR-T cells by flow cytometry were compared. Moreover, a quantitative polymerase chain reaction (qPCR) to detect BCMA-CAR-T cells was established. By applying a cell-titration experiment of BCMA-CAR-T cells, both methods were compared head-to-head. In flow-cytometric analysis, the detection reagents used in this study could all detect BCMA-CAR-T cells at a similar level. The results of false-positive background staining differed as follows (standard deviation): the BCMA-detection reagent used on the control revealed a background staining of 0.04% (±0.02%), for the PE-labeled human BCMA peptide it was 0.25% (±0.06%) and for the polyclonal anti-human IgG antibody it was 7.2% (±9.2%). The ability to detect BCMA-CAR-T cells down to a concentration of 0.4% was similar for qPCR and flow cytometry. The qPCR could detect even lower concentrations (0.02–0.01%). In summary, BCMA-CAR-T-cell monitoring can be reliably performed by both flow cytometry and qPCR. In flow cytometry, reagents with low background staining should be preferred. [ABSTRACT FROM AUTHOR]

Chimeric-antigen-receptor-T (CAR-T) cells are currently revolutionizing the field of cancer immunotherapy. Therefore, there is an urgent need for CAR-T cell monitoring by clinicians to assess cell expansion and persistence in patients. CAR-T cell manufacturers and researchers need to evaluate transduction efficiency and vector copy number for quality control. Here, CAR expression was analyzed in peripheral blood samples from patients and healthy donors by flow cytometry with four commercially available detection reagents and on the gene level by quantitative polymerase chain reaction (qPCR). Flow cytometric analysis of CAR expression showed higher mean CAR expression values for CD19 CAR detection reagent and the F(ab')2 antibody than Protein L and CD19 Protein. In addition, the CD19 CAR detection reagent showed a significantly lower median background staining of 0.02% (range 0.007–0.06%) when compared to the F(ab')2 antibody, CD19 protein and Protein L with 0.80% (range 0.47–1.58%), 0.65% (range 0.25–1.35%) and 0.73% (range 0.44–1.23%). Furthermore, flow cytometry-based CAR-T cell frequencies by CD19 CAR detection reagent showed a good correlation with qPCR results. In conclusion, quality control of CAR-T cell products can be performed by FACS and qPCR. For the monitoring of CAR-T cell frequencies by FACS in patients, CAR detection reagents with a low background staining are preferable. [ABSTRACT FROM AUTHOR]

Introduction: Cytomegalovirus (CMV) reactivation occurs in seronegative patients after solid organ transplantation (SOT) particularly from seropositive donors and can be lethal. Generation of CMV-specific T cells helps to prevent CMV reactivation. Therefore, we initiated a clinical phase I CMVpp65 peptide vaccination trial for seronegative end-stage renal disease patients waiting for kidney transplantation. Methods: The highly immunogenic nonamer peptide NLVPMVATV derived from CMV phosphoprotein 65(CMVpp65) in a water-in-oil emulsion (Montanide™) plus imiquimod (Aldara™) as an adjuvant was administered subcutaneously four times biweekly. Clinical course as well as immunological responses were monitored using IFN-γ ELISpot assays and flow cytometry for CMV-specific CD8+ T cells. Results: Peptide vaccination was well tolerated, and no drug-related serious adverse events were detected except for Grade I–II local skin reactions. Five of the 10 patients (50%) mounted any immune response (responders) and 40% of the patients presented CMV-specific CD8+ T cell responses elicited by these prophylactic vaccinations. No responders experienced CMV reactivation in the 18 months post-transplantation, while all non-responders reactivated. Conclusion: CMVpp65 peptide vaccination was safe, well tolerated, and clinically encouraging in seronegative end-stage renal disease patients waiting for kidney transplantation. Further studies with larger patient cohorts are planned. [ABSTRACT FROM AUTHOR]

NY-ESO-1-specific T cells have shown promising activity in the treatment of soft tissue sarcoma (STS). However, standardized protocols for their generation are limited. Particularly, cost-effectiveness considerations of cell production protocols are of importance for conducting clinical studies. In this study, two different NY-ESO-1-specific T cell production protocols were compared. Major differences between protocols 1 and 2 include culture medium, interleukin-2 and retronectin concentrations, T cell activation strategy, and the transduction process. NY-ESO-1-specific T cells generated according to the two protocols were investigated for differences in cell viability, transduction efficiency, T cell expansion, immunophenotype as well as functionality. NY-ESO-1-specific T cells showed similar viability and transduction efficiency between both protocols. Protocol 1 generated higher absolute numbers of NY-ESO-1-specific T cells. However, there was no difference in absolute numbers of NY-ESO-1-specific T cell subsets with less-differentiated phenotypes accounting for efficient in vivo expansion and engraftment. Furthermore, cells generated according to protocol 1 displayed higher capacity of TNF-α generation, but lower cytotoxic capacities. Overall, both protocols provided functional NY-ESO-1-specific T cells. However, compared to protocol 1, protocol 2 is advantageous in terms of cost-effectiveness. Cell production protocols should be designed diligently to achieve a cost-effective cellular product for further clinical evaluation. [ABSTRACT FROM AUTHOR]

Simple Summary: To monitor patients after CAR T cell treatment, measuring frequencies of chimeric antigen receptor (CAR) T cells is crucial. However, experimental assays to quantify CAR T cells are lacking. Here, we describe a quantitative single copy gene-based PCR approach to measure frequencies of CAR T cells based on the FMC63 single chain variable fragment (scFv) including commercially available CAR T cell products. Besides enabling to monitor development of CAR T cells after treatment and guide further therapeutic decisions, this quantification assay proved highly useful for diagnosis of CAR T cell associated neurotoxic side effects. Overall, this quantification approach contributes significantly to the better monitoring and safety of treatment of patients with CAR T cells. Chimeric antigen receptor (CAR) T cell (CART) therapy has been established as a treatment option for patients with CD19-positive lymphoid malignancies in both the refractory and the relapsed setting. Displaying significant responses in clinical trials, two second-generation CART products directed against CD19, axicabtagene ciloleucel (axi-cel) and tisagenlecleucel (tisa-cel), have been approved and integrated into the clinical routine. However, experimental assay for quantitative monitoring of both of these CART products in treated patients in the open domain are lacking. To address this issue, we established and validated a quantitative single copy gene (SCG)-based duplex (DP)-PCR assay (SCG-DP-PCR) to quantify CARTs based on the FMC63 single chain variable fragment (scFv), i.e., axi-cel and tisa-cel. This quantitative PCR (qPCR) approach operates without standard curves or calibrator samples, offers a tool to assess cellular kinetics of FMC63 CARTs and allows direct comparison of CART-copies in axi-cel versus tisa-cel patient samples. For treating physicians, SCG-DP-PCR is an important tool to monitor CARTs and guide clinical decisions regarding CART effects in respective patients. [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor T cell (CART) therapy is currently one of the most promising treatment approaches in cancer immunotherapy. However, the immunosuppressive nature of the tumor microenvironment, in particular increased reactive oxygen species (ROS) levels, provides considerable limitations. In this study, we aimed to exploit increased ROS levels in the tumor microenvironment with prodrugs of ROS accelerators, which are specifically activated in cancer cells. Upon activation, ROS accelerators induce further generation of ROS. This leads to an accumulation of ROS in tumor cells. We hypothesized that the latter cells will be more susceptible to CARTs. CD19-specific CARTs were generated with a CD19.CAR.CD28.CD137zeta third-generation retroviral vector. Cytotoxicity was determined by chromium-51 release assay. Influence of the ROS accelerators on viability and phenotype of CARTs was determined by flow cytometry. The combination of CARTs with the ROS accelerator PipFcB significantly increased their cytotoxicity in the Burkitt lymphoma cell lines Raji and Daudi, as well as primary chronic lymphocytic leukemia cells. Exposure of CARTs to PipFcB for 48 h did not influence T cell exhaustion, viability, or T cell subpopulations. In summary, the combination of CARTs with ROS accelerators may improve adoptive immunotherapy and help to overcome tumor microenvironment-mediated treatment resistance. [ABSTRACT FROM AUTHOR]

• ECP was able to increase Tfh cells to ameliorate GvHD. • Upregulation of Th22 cells was observed in aGvHD patients with CR. • Tim-3 expression was downregulated on effector T cells by ECP. • ECP shows immunomodulatory effects in GvHD setting. Extracorporeal photopheresis (ECP), a personalized cellular immunotherapy, constitutes a promising treatment for steroid-refractory/-resistant graft-versus-host disease (SR-GvHD), with encouraging clinical response rates. To further investigate its mechanism of action, ECP's effects on T helper (Th) cells as well as on expression of immune checkpoint (PD-1 and Tim-3) and apoptotic (Fas receptor [FasR]) molecules were investigated in 27 patients with SR-GvHD. Our data show that GvHD patients had significantly higher levels of Th2, Th17, Th22 and granulocyte-macrophage colony-stimulating factor (GM-CSF)-positive Th (ThG) cells and clearly lower levels of T follicular helper (Tfh) cells, including Th1- and Th2-like cells, compared with healthy donors. ECP therapy for GvHD was effective through the modulation of different Th subsets: increases of Th22 (1.52-fold) and Tfh cells (1.48-fold) in acute GvHD (aGvHD) and increases of Th2-like Tfh cells (1.74-fold) in chronic GvHD (cGvHD) patients were associated with clinical response. Expression of FasR was further upregulated in CD4+CD8+ T cells. Additionally, Tim-3–expressing effector T cells associated with the severity of GvHD were reduced. Taken together, these data show that ECP therapy exerts immunomodulatory effects by promoting a balanced immune reconstitution and inducing immune tolerance. Therefore it represents an attractive option for the treatment of GvHD. [ABSTRACT FROM AUTHOR]

BACKGROUNDPreclinical experiments have shown that donor blood cells, modified in vitro by an alkylating agent (modified immune cells [MICs]), induced long-term specific immunosuppression against the allogeneic donor.METHODSIn this phase I trial, patients received either 1.5 × 106 MICs per kg BW on day -2 (n = 3, group A), or 1.5 × 108 MICs per kg BW on day -2 (n = 3, group B) or day -7 (n = 4, group C) before living donor kidney transplantation in addition to post-transplantation immunosuppression. The primary outcome measure was the frequency of adverse events (AEs) until day 30 (study phase) with follow-up out to day 360.RESULTSMIC infusions were extremely well tolerated. During the study phase, 10 treated patients experienced a total of 69 AEs that were unlikely to be related or not related to MIC infusion. No donor-specific human leukocyte antigen Abs or rejection episodes were noted, even though the patients received up to 1.3 × 1010 donor mononuclear cells before transplantation. Group C patients with low immunosuppression during follow-up showed no in vitro reactivity against stimulatory donor blood cells on day 360, whereas reactivity against third-party cells was still preserved. Frequencies of CD19+CD24hiCD38hi transitional B lymphocytes (Bregs) increased from a median of 6% before MIC infusion to 20% on day 180, which was 19- and 68-fold higher, respectively, than in 2 independent cohorts of transplanted controls. The majority of Bregs produced the immunosuppressive cytokine IL-10. MIC-treated patients showed the Immune Tolerance Network operational tolerance signature.CONCLUSIONMIC administration was safe and could be a future tool for the targeted induction of tolerogenic Bregs.TRIAL REGISTRATIONEudraCT number: 2014-002086-30; ClinicalTrials.gov identifier: NCT02560220.FUNDINGFederal Ministry for Economic Affairs and Technology, Berlin, Germany, and TolerogenixX GmbH, Heidelberg, Germany. [ABSTRACT FROM AUTHOR]