Multiple myeloma is a plasma cell cancer that progressively evolves to an aggressive, multi-drug resistant disease, which presents an unmet clinical need. In clinical trials, myeloma shows susceptibility to novel immunotherapeutic agents, particularly those targeting B-cell maturation antigen (BCMA). Among different classes of immunotherapies, T cell-based approaches have progressed the most due to their ability to induce durable responses in patients with advanced drug-resistant blood cancers. Most T cell engineering strategies rely on the use of chimeric antigen receptors (CARs), which although effective, can cause serious life-threatening toxicities. We created a new synthetic receptor, T cell antigen coupler (TAC), which recruits the endogenous T cell receptor and allows T cells to autoregulate their activity. Our experience in solid tumor models has shown that TAC-T cells are similarly efficacious and significantly less toxic than CAR-T cells. This thesis describes our optimization of BCMA-specific TAC-T cells and analysis of different anti-BCMA antigen-binding domains. TAC receptor functions by engaging endogenous TCR-CD3 complex and redirecting it to the target of interest. In Chapter 3, we characterize optimization and humanization of the CD3-recruitment domain in the TAC scaffold and provide evidence that TAC-T cells are effective against multiple myeloma, irrespective of receptor surface levels. In Chapter 4, we describe selection of the human BCMA-binding domain and the creation of a fully humanized TAC receptor against BCMA. Chapters 5 and 6 describe how a BCMA-targeting antigen-binding domain that cross-reacts with an unknown antigen in mice augments in vivo efficacy of TAC- and CAR-T cells, respectively. The work described in Chapters 3 and 4 presents an optimized, fully human BCMA-TAC that is being moved into clinical testing. The work in Chapters 5 and 6 improves our understanding of how antigen-targeting domains in synthetic receptors influence the functionality of engineered T cells. / Thesis / Doctor of Science (PhD) / Multiple myeloma is an incurable blood cancer that has a remarkable ability to develop resistance to different types of chemotherapy. In recent years, treatments redirecting immune cells against tumors have shown impressive clinical responses against different types of chemotherapy-resistant blood cancers, including multiple myeloma. Our lab has developed a new technology for redirecting T cells against tumors, called T cell antigen coupler (TAC) receptor. This thesis describes optimization of a fully human TAC receptor specific for a target on the surface of myeloma cells, known as BCMA. Durable remissions induced by TAC-engineered T cells in a preclinical mouse model of myeloma in the absence of toxicity warrant further testing of this therapeutic in a clinical trial.

Approximately 43.4% of medication errors occur at the time of administration despite the use of bar code medication administration (BCMA) System. This trend has prompted a national effort to mitigate this problem in the United States. Implementing BCMA in health care settings is one of those efforts. Studies focusing on the approaches employed by nurses when using this system are scant. The purpose of this qualitative case study was to investigate strategies nurses and their leaders use to ensure BCMA is implemented, maximized, and sustained. The technology acceptance model was used to guide the study. The 2 research questions addressed nurses' perceptions regarding the use and optimization of BCMA, and approaches of clinical nurses and their leaders to ensure that BCMA technology is properly used, optimized, and sustained in acute care units. Data collection included semistructured interviews with 8 participants. Thematic data analysis generated themes including ease of use, reduce errors, time saving, old technology, overreliance on technology, paper backups, and hope for future development. Common barriers to system effectiveness were system errors and inadequate training; intragroup and self-monitoring were important strategies to sustain use of the system. Study results may be used by health care leadership to reduce medication errors by adopting easy to use technology, change policies regarding training of BCMA end users in hospitals, increase the culture of patient safety among nurses, and prompt technology redesign within health care settings that meets the national patient safety goals.

The T cell function of a proliferation inducing ligand (APRIL or TNFSF13) remains unclear. By comparing APRIL-/- mice with wild type (WT) mice, we have investigated the roles of APRIL in Th1, Th2 and Th17 responses. With regard to APRIL in Th1 responses, cultured APRIL-/- CD4+ T cells showed increased IFN-gamma production under non-polarizing, but not under Th1 polarizing, conditions. No difference in antigen-specific IgG2a levels existed between APRIL-/- and WT mice immunized with ovalbumin (OVA) and complete Freund's adjuvant (CFA) which induces Th1 polarization. Our data indicate that APRIL represses Th1 responses only under non-polarizing conditions. As for APRIL in Th2 responses, cultured APRIL-/- CD4+ T cells exhibited enhanced Th2 cytokine production under non-polarizing conditions, and augmented IL-13 production under Th2 polarizing conditions. Upon immunization with OVA and aluminum potassium sulfate (alum) which induces Th2 polarization, APRIL-/- mice responded with an increased antigen-specific IgG1 response. In the OVA-induced allergic lung inflammation model which is mediated by Th2 responses, APRIL-/- mice had significantly aggravated allergic lung inflammation. Accordingly, a decoy receptor-Ig fusion protein, TACI-Ig, treatment to block APRIL in WT mice enhanced allergic lung inflammation. In agreement with the role of APRIL in CD4+ T cells, the transfer of APRIL sufficient, OVA-specific, TCR transgenic CD4+ T (OT-II) cells to APRIL-/- mice restored the suppressive effect of APRIL on allergic lung inflammation. Mechanistically, the expression of c-maf, the IL-4 gene transcription factor, was markedly enhanced in APRIL-/- CD4+ T cells under non-polarizing and Th2 polarizing conditions. Our data suggest that APRIL inhibits Th2 responses and allergic lung inflammation by suppressing IL-4 production in CD4+ T cells via diminished c-maf expression, and by suppressing IL-13 production in CD4+ T cells via an IL-4 independent, IL-13 specific pathway. Regarding APRIL in Th17 responses, the incidence of Th17-mediated collagen-induced arthritis (CIA) in APRIL-/- mice was reduced, in parallel with diminished levels of antigen-specific IgG2a autoantibody and IL-17 production. Our data indicate that APRIL promotes IL-17 production, and that APRIL-triggered signals contribute to arthritis. Our data clearly show that APRIL is important in T cell immunity, inhibitory in Th2 responses and costimulatory in Th17 responses.

INTRODUCTION: Multiple myeloma (MM) is a disease that results in the production of ineffective immunoglobulins and monoclonal proteins in the blood and urine, leading to insufficient organ function or death. Currently, there is a 5-year survival rate of 47% for patients diagnosed with MM, with a proportion of patients ultimately succumbing to the disease. The current standard of care for MM includes toxic combinations of chemotherapy. The evolution of chimeric antigen receptor (CAR) T-cell therapy for hematologic cancers such as lymphoma, leukemia, and now myeloma has provided another effective treatment option for patients who have relapsed after standard treatments for MM. Idecabtagene Vicleucel (ide-cel), was approved in March 2021 for patients with relapsed and refractory MM. While CAR T-cell treatment appears to be far less toxic than standard chemotherapy, this therapy comes with its own associated toxicities, mainly cytokine release syndrome (CRS) and neurotoxicity (NT). In clinical trials, ide-cel demonstrated to be an effective treatment in some patients, leading to the FDA approval for patients who have exhausted multiple other lines of therapy. Currently, it is unclear why patients respond differently to CAR T-cell treatment and why some patients present with more severe toxicity than others. Therefore, this study aims to examine patient factors such as demographics, age, and treatment history to determine if such characteristics may influence the CAR T-cell response; also, we assess the efficacy of ide-cel in a real-world experience outside of a clinical trial. METHODS: In this study, 14 patients’ medical records were reviewed after receiving commercial CAR T-cell therapy between August 2021 and January 2022. Eligible patients for the therapy were determined by strict inclusion criteria, including having a confirmed diagnosis of MM and exhausting at least four prior lines of therapy, as well as exclusion criteria, such as excluding individuals who have received CAR T-cells prior in a clinical trial setting. Approximately one month before preparation lymphodepletion chemotherapy, eligible patients underwent leukapheresis and had their blood sent to a laboratory to extract T-cells and genetically modify them to express the CAR for reinfusion. On 3 and 5 days prior to CAR T-cell infusion, patients underwent lymphodepletion using fludarabine and cyclophosphamide. Patients remained in the hospital for approximately one week following infusion, pending adverse reactions. After discharge, patients returned to the hospital for routine follow-ups. Data analysis was then performed on collected clinical readouts such as: prior treatments, bone marrow biopsies, response rates, laboratory values from blood samples, and pre- and post-infusion scans of various tissues within the body. RESULTS: At a median follow-up time of 15 weeks, six patients (43%) achieved a complete response (CR), three patients demonstrated a partial response (PR, 21%), and four patients showed disease progression (PD, 28%). Post-infusion scans were not available for one subject (7%) as they were still in the hospital. These results are similar to the phase I and phase II trials in which 45% and 33% of patients demonstrated a CR post-infusion, respectively. As for associated toxicities, 10 patients (71%) experienced CRS and one patient (7%) presented with ICANS. All patients that achieved a CR experienced ide-cel related toxicities, compared with only 38% of those with less favorable or unknown outcomes, which indicates that systemic immune system activation which causes CRS may be required to achieve a CR but CRS is not always linked with a CR outcome. There were 28 different chemotherapy regimens used as the standard of care treatment prior to ide-cel therapy. We assessed the most recent chemotherapeutic regimen in each patient to assess whether there is an association with most recent treatment and response. Of the six patients that achieved a CR to ide-cel, all were previously treated with RVD or CyBorD regimens, compared to the four patients who had disease progression who were mainly treated with salvage DCEP chemotherapy. Four patients (29%) received DCEP as their final chemotherapy regimen, and 3 of these 4 (75%) demonstrated progressive disease after ide-cel. Two patients received Belantamab-Mafodotin prior to ide-cel treatment, with one patient presenting with disease progression and the other patient achieving CR. 71% of patients experienced CRS following ide-cel infusion, which is resembles the phase II trial of ide-cel in which 84% of patients demonstrated CRS. In this study, only 7% of patients experienced neurological toxicity, which is comparable to the 18% of patients that demonstrated to have ICANS in the phase II study. CONCLUSIONS: We found similar performance of the ide-cel CAR-T therapy in the real world setting as in the clinical trial. Also, the complete responses were achieved by subjects with an array of characteristics, including varying recent chemotherapeutic treatments, IgG, IgA, and light-chain only subtypes of MM, and diverse demographics and other characteristics. The characteristic that demonstrated the most predictability and somewhat unique to subjects with CR was the associated toxicities from ide-cel. Development of these associated toxicities may attest that substantial immune activation, of CAR T-cells and other immune cells, leads to the efficacy of the product in eliminating cancer cells. Further analysis will need to be completed as more individuals enroll in this study to be able to determine if there are significant associations between demographics and prior lines of treatment with response to ide-cel CAR-T therapy. Lastly, future studies should assess the immune cell effector functions that are generated in CR patients that will help to specify the association between ide-cel activation, experienced associated toxicities, and its efficacy.

The idiopathic inflammatory myopathies (IIMs) are a heterogeneous group of chronic muscle diseases with frequent extramuscular organ involvement that contributes to serious prognosis. The presence of autoantibodies and composition of muscle infiltrates both support autoimmune nature of the disease and pathogenic role of B lymphocytes. Besides the traditional diagnostic subgroups, autoantibody characterised phenotype subsets have been identified with presumed similar pathogenic mechanisms. The best known is the antisynthetase syndrome which is characterised by presence of myositis, antisynthetase autoantibodies (with anti-Jo-1 being the most frequent), interstitial lung disease and other extramuscular manifestations. BAFF (B cell-Activating Factor of the TNF Family) is a key factor in B cell homeostasis modulation. In high levels, it allows survival of autoreactive B cell clones and thus participates in the pathogenesis of autoimmune diseases. Its expression is induced by type I interferons (IFN-1). The aim of the PhD thesis was to explore the role of BAFF in pathogenesis of IIMs by analysis of its serum levels, the receptors for BAFF in muscle tissue, their associations to IFN-1 and expression of BAFF gene mRNA transcription variants in peripheral blood cells. Further aspect was to study a possible...