Activation of lymphocytes in vitro for immunotherapy of patients with melanoma

This article describes a method for activating lymphocytes isolated from the peripheral blood of melanoma patients and cultured in a medium supplemented with IL‑2 and IL‑15. It was shown that in these terms, lymphocytes have an increased proliferative and activation potential. The combination of cytokines has a positive effect on cytotoxicity, viability and the expression of activation markers (CD38, CD69, CD25, HLA-DR and NKG2D) on NK- and T-lymphocyte, and may be recommended for the culture of lymphocytes in melanoma patients for the purpose of adoptive immunotherapy.

Modeling and simulation of the “IL-36 cytokine” and CAR-T cells interplay in cancer onset

Background: CAR-T cells are chimeric antigen receptor (CAR)-T cells; they are target-specific engineered cells on tumor cells and produce T cell-mediated antitumor responses. CAR-T cell therapy is the “first-line” therapy in immunotherapy for the treatment of highly clonal neoplasms such as lymphoma and leukemia. This adoptive therapy is currently being studied and tested even in the case of solid tumors such as osteosarcoma since, precisely for this type of tumor, the use of immune checkpoint inhibitors remained disappointing. Although CAR-T is a promising therapeutic technique, there are therapeutic limits linked to the persistence of these cells and to the tumor’s immune escape. CAR-T cell engineering techniques are allowed to express interleukin IL-36, and seem to be much more efficient in antitumoral action. IL-36 is involved in the long-term antitumor action, allowing CAR-T cells to be more efficient in their antitumor action due to a “cross-talk” action between the “IL-36/dendritic cells” axis and the adaptive immunity. Methods: This analysis makes the model useful for evaluating cell dynamics in the case of tumor relapses or specific understanding of the action of CAR-T cells in certain types of tumor. The model proposed here seeks to quantify the action and interaction between the three fundamental elements of this antitumor activity induced by this type of adoptive immunotherapy: IL-36, “armored” CAR-T cells (i.e., engineered to produce IL-36) and the tumor cell population, focusing exclusively on the action of this interleukin and on the antitumor consequences of the so modified CAR-T cells. Mathematical model was developed and numerical simulations were carried out during this research. The development of the model with stability analysis by conditions of Routh–Hurwitz shows how IL-36 makes CAR-T cells more efficient and persistent over time and more effective in the antitumoral treatment, making therapy more effective against the “solid tumor”. Findings: Primary malignant bone tumors are quite rare (about 3% of all tumors) and the vast majority consist of osteosarcomas and Ewing’s sarcoma and, approximately, the 20% of patients undergo metastasis situations that is the most likely cause of death. Interpretation: In bone tumor like osteosarcoma, there is a variation of the cellular mechanical characteristics that can influence the efficacy of chemotherapy and increase the metastatic capacity; an approach related to adoptive immunotherapy with CAR-T cells may be a possible solution because this type of therapy is not influenced by the biomechanics of cancer cells which show peculiar characteristics.

Acute GvHD after HLA-Haploidentical Hematopoietic Cell Transplantation with Regulatory and Conventional T Cell Immunotherapy Does Not Adversely Affect Transplantation Outcomes

Introduction Adoptive immunotherapy with CD4+CD25+FOXP3+ regulatory T cells (Tregs) and conventional T cells (Tcons) has been employed after allogeneic hematopoietic stem cell transplantation (HSCT) to prevent Graft-versus-Host Disease (GvHD) while mantaining Graft-versus-Leukemia effect in the absence of any further immune suppressive GvHD prophylaxis (Di Ianni, Blood 2011; Martelli, Blood 2014). A recent study of age-adapted haploidentical HSCT with Treg/Tcon adoptive immunotherapy (Treg/Tcon haplo-HSCT) resulted in an unprecedented 75% chronic GvHD (cGvHD)/leukemia-free survival (CRFS) in acute myeloid leukemia patients. Acute GvHD (aGvHD) occured in 33% of patients and was the most frequent complication of the procedure (Pierini, Blood Advances 2021). Here, we analyzed clinical and histological characteristics of aGvHD and evaluated its impact on outcomes in patients who received Treg/Tcon haplo-HSCT. Methods We retrieved data of patients who underwent Treg/Tcon haplo-HSCT at Perugia University Hospital and who were evaluable for aGvHD from January 2015 until June 2021 (clinicaltrials.gov: NCT03977103). Histological features and lymphoid infiltration by immunohistochemistry were analyzed in gut samples of patients who received diagnostic colonscopy and biopsy for gastrointestinal symptoms. Results A total of 105 patients engrafted after Treg/Tcon haplo-HSCT. Mean age at transplant was 48 years (range 18-70). Acute leukemia was the most frequent diagnosis (78/105 myeloid, 23/105 lymphoblastic), 4 patients had myelodisplastic syndrome and 2 multiple myeloma. Twenty-seven (26%) patients had active disease at the time of HSCT. Fourteen (13%) patients received Treg/Tcon haplo-HSCT as a second HSCT procedure. Thirty-one (29%) patients developed grade II-IV aGvHD. Four patients had grade II aGvHD, 23 grade III, and 4 grade IV. Almost all patients (90%) presented gut involvement, while skin was involved in 64% of them and liver in 35%. To explain why gut symptoms such as diarrhea and abdominal pain were more frequently present than symptoms of skin or liver involvement, we evaluated 40 histological samples from 34 patients who received colonoscopy for suspected aGvHD. Twenty-two of them (65%) received a clinical diagnosis of aGvHD and pharmacological immune suppression was promptly started. Clinical diagnosis did not always match histological findings: biopsies were suggestive of aGvHD in 20/22 patients who required treatment, but also in 8/12 patients who did not. We found no difference in median CD3+ cell infiltration among patients who did not need immune suppressive treatments and patients with aGvHD (460 cells/mmq vs 446 cells/mmq). However, FOXP3+ Tregs preferentially infiltrated gut mucosa of patients who resolved clinical symptoms with no need of immune suppressive treatments (120 cells/mmq vs 59 cells/mmq, p = 0.008; FOXP3/CD3 ratio: 0.27 vs 0.18, p = 0.004). This observation suggested Treg defective homing to gut mucosa of aGvHD patients. Indeed, we found infused Tregs expressed lower levels of gut homing receptor α4β7 in comparison with Tcons (p< .001). Despite severe presentation at diagnosis, aGvHD resolved in the majority of patients (71%), and immune suppressive therapy could be completely withdrawn after a relatively short-course (median: 98 days, range 48-404). Sixteen/31 patients (52%) were steroid refractory and required further treatments after first-line (e.g. Ruxolitinib). Only two of them developed moderate/severe cGvHD and one is alive and off-therapy. Indeed, aGvHD diagnosis did not result in higher incidence of non-relapse mortality (cumulative incidence of 29% in aGvHD patients vs 27% in controls; p=non significant, ns, Fig.1A), relapse (13% vs 20%; p=ns, Fig.1B), or cGvHD (6.5% vs 3%; p=ns, Fig.1C). In fact, CRFS of aGvHD patients was similar to CRFS of patients that did not develop aGvHD (Fig. 1D, p=ns, median follow up of live patients: 1246 days). Conclusions Treg/Tcon haplo-HSCT is followed by low rates of relapse and cGvHD and results in good CRFS in high risk leukemia patients. aGvHD after Treg/Tcon haplo-HSCT preferentially involves the gut where Treg homing is defective. Strategies that enhance Treg homing in the gut (e.g. low-dose IL-2) may help reduce aGvHD after Treg/Tcon haplo-HSCT. In conclusion, despite aGvHD occurred in 29% of patients, it was responsive to treatments and it did not result in disease relapse or cGvHD. Figure 1 Figure 1. Disclosures No relevant conflicts of interest to declare.

TAMI-78. STEM CELL IMMUNOTHERAPY MODULATES IMMUNOREGULATORY PATHWAYS IN THE TUMOR MICROENVIRONMENT

INTRODUCTION A major obstacle in efficacious therapeutics against high-grade gliomas has been an inability to overcome powerful regulatory mechanisms within the TME that hamper immune activation. Fortunately, immunotherapy has enabled the enhancement of immune activation within the TME through adoptive immunotherapy and checkpoint inhibition. We found that co-transfer of hematopoietic stem cells (HSCs) with either adoptive immunotherapy or PD-1 blockade significantly improves therapeutic outcomes by manipulating the cellular components that make up the TME in high-grade gliomas. HSC co-transfer with immunotherapy leads to increased in situ downregulation of multiple immune regulatory pathways, activation of tumor-reactive T cells, and significant reduction in the frequency of MDCs and TAMs within the TME. METHODS C57BL/6 mice with orthotopic KR158B-gliomas received either adoptive immunotherapy using activated tumor-reactive T cells or αPD-1, either with or without HSC co-transfer. After treatment of late-stage tumors, brains were sectioned and digital spatial profiling (NanoString GeoMx) of the TME was conducted in situ. Briefly, tumor-bearing brain sections were stained for nuclei, CD3, CD45, and GFP (HSC-derived cells); regions of interest (ROIs) containing 200 nuclei were selected and processed for whole genome sequencing. Areas rich in immune cells within the TME were chosen as ROIs and compared between groups. Results were corroborated with flowcytometry and PCR. RESULTS Mice that received HSCs with either adoptive cellular therapy or αPD-1 had reductions in expression of multiple regulatory markers in the TME including iNOS, TGFβ, and PD-L1. This was accompanied by reductions in the frequencies of MDSCs and TAMs. An increased relative abundance of activated CD8+ T cells within the TME was also observed. Interestingly, we found that HSC-derived cells provided rich amounts of dendritic cells at the TME when co-transferred with immunotherapy. Host-derived myeloid cells were significantly displaced from the TME in mice receiving HSC plus adoptive cellular therapy or αPD-1.

Adoptive T-cell Therapy for Hodgkin Lymphoma

While CAR T-cell therapy is FDA-approved for B-cell non-Hodgkin lymphomas, the development of adoptive immunotherapy for the treatment of classic Hodgkin lymphoma (cHL) has not accelerated at a similar pace. Adoptive T-cell therapy with EBV-specific cytotoxic T lymphocytes and CD30 CAR T cells have demonstrated significant clinical responses in early clinical trials of patients with cHL. Additionally, CD19 and CD123 CAR T cells that target the immunosuppressive tumor microenvironment in cHL have also been investigated. Here we discuss the landscape of clinical trials of adoptive immunotherapy for patients with cHL with a view towards current challenges and novel strategies to improve the development of CAR T-cell therapy for cHL.