Explore the vast range of titles available.

SARS-CoV-2 messenger RNA vaccination in healthy individuals generates immune protection against COVID-19. However, little is known about SARS-CoV-2 mRNA vaccine-induced responses in immunosuppressed patients. We investigated induction of antigen-specific antibody, B cell and T cell responses longitudinally in patients with multiple sclerosis (MS) on anti-CD20 antibody monotherapy ( n  = 20) compared with healthy controls ( n  = 10) after BNT162b2 or mRNA-1273 mRNA vaccination. Treatment with anti-CD20 monoclonal antibody (aCD20) significantly reduced spike-specific and receptor-binding domain (RBD)-specific antibody and memory B cell responses in most patients, an effect ameliorated with longer duration from last aCD20 treatment and extent of B cell reconstitution. By contrast, all patients with MS treated with aCD20 generated antigen-specific CD4 and CD8 T cell responses after vaccination. Treatment with aCD20 skewed responses, compromising circulating follicular helper T (T FH ) cell responses and augmenting CD8 T cell induction, while preserving type 1 helper T (T H 1) cell priming. Patients with MS treated with aCD20 lacking anti-RBD IgG had the most severe defect in circulating T FH responses and more robust CD8 T cell responses. These data define the nature of the SARS-CoV-2 vaccine-induced immune landscape in aCD20-treated patients and provide insights into coordinated mRNA vaccine-induced immune responses in humans. Our findings have implications for clinical decision-making and public health policy for immunosuppressed patients including those treated with aCD20. SARS-CoV-2-specific antibodies and memory B cells are significantly reduced, but CD4 + and CD8 + T cells are robustly activated, in patients with multiple sclerosis on anti-CD20 monotherapy versus healthy controls after BNT162b2 or mRNA-1273 mRNA vaccination.

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS). Neither the antigenic target(s) nor the cell population(s) responsible for CNS tissue destruction in MS have been fully defined. The objective of this study was to simultaneously determine the antigen (Ag)-specificity and phenotype of un-manipulated intrathecal CD4+ and CD8+ T cells of patients with relapsing-remitting and progressive MS compared to subjects with other inflammatory neurological diseases. We applied a novel Ag-recognition assay based on co-cultures of freshly obtained cerebrospinal fluid T cells and autologous dendritic cells pre-loaded with complex candidate Ag's. We observed comparably low T cell responses to complex auto-Ag's including human myelin, brain homogenate, and cell lysates of apoptotically modified oligodendroglial and neuronal cells in all cohorts and both compartments. Conversely, we detected a strong intrathecal enrichment of Epstein-Barr virus- and human herpes virus 6-specific (but not cytomegalovirus-specific) reactivities of the Th1-phenotype throughout all patients. Qualitatively, the intrathecal enrichment of herpes virus reactivities was more pronounced in MS patients. This enrichment was completely reversed by long-term treatment with the IL-2 modulating antibody daclizumab, which strongly inhibits MS disease activity. Finally, we observed a striking discrepancy between diminished intrathecal T cell proliferation and enhanced cytokine production of herpes virus-specific T cells among progressive MS patients, consistent with the phenotype of terminally differentiated cells. The data suggest that intrathecal administration of novel therapeutic agents targeting immune cells outside of the proliferation cycle may be necessary to effectively eliminate intrathecal inflammation in progressive MS.

A small proportion of multiple sclerosis (MS) patients develop new disease activity soon after starting anti-CD20 therapy. This activity does not recur with further dosing, possibly reflecting deeper depletion of CD20-expressing cells with repeat infusions. We assessed cellular immune profiles and their association with transient disease activity following anti-CD20 initiation as a window into relapsing disease biology. Peripheral blood mononuclear cells from independent discovery and validation cohorts of MS patients initiating ocrelizumab were assessed for phenotypic and functional profiles using multiparametric flow cytometry. Pretreatment CD20-expressing T cells, especially CD20dimCD8⁺ T cells with a highly inflammatory and central nervous system (CNS)-homing phenotype, were significantly inversely correlated with pretreatment MRI gadolinium-lesion counts, and also predictive of early disease activity observed after anti-CD20 initiation. Direct removal of pretreatment proinflammatory CD20dimCD8⁺ T cells had a greater contribution to treatment-associated changes in the CD8⁺ T cell pool than was the case for CD4⁺ T cells. Early disease activity following anti-CD20 initiation was not associated with reconstituting CD20dimCD8⁺ T cells, which were less proinflammatory compared with pretreatment. Similarly, this disease activity did not correlate with early reconstituting B cells, which were predominantly transitional CD19+CD24highCD38high with a more anti-inflammatory profile. We provide insights into the mode-of-action of anti-CD20 and highlight a potential role for CD20dimCD8⁺ T cells in MS relapse biology; their strong inverse correlation with both pretreatment and early posttreatment disease activity suggests that CD20-expressing CD8⁺ T cells leaving the circulation (possibly to the CNS) play a particularly early role in the immune cascades involved in relapse development.

Multiple Sclerosis (MS) is an inflammatory disease of the central nervous system (CNS), which leads to accumulating neurological disability. Available therapies can ease symptoms and may decrease new episodes of injury, but they broadly target the immune system and can lead to adverse effects. Although T cells are implicated in MS, the particular subsets and their antigenic targets remain largely unknown. Elucidating these could guide development of more selective and safer treatments. In this dissertation, we focus on pediatric-onset MS, which offers us a window of opportunity into the earliest biological events of this disease. We use a range of cell-based assays including cell culture, flow cytometry and single-cell level proteogenomic analyses to assess the phenotype and functional profiles of circulating immune cells within high quality cryopreserved peripheral blood mononuclear cells isolated from well-characterized children with MS and compare them to samples isolated from other CNS inflammatory disease controls, as well as healthy children. The research presented in this dissertation provides novel insights into early MS disease-implicated T cells and explores mechanisms by which both previously implicated, as well as newly identified cell populations may contribute to disease pathogenesis. In Chapter 2, we identify an imbalance between effector T cells and regulatory T cells as a distinguishing characteristic in children with MS and implicate a particular pro-inflammatory memory T cell subset that co-expresses the ‘CNS-homing’ CCR2 and CCR5 chemokine receptors, which is present at a higher frequency in children with MS and exhibits exaggerated pro-inflammatory responses. In Chapter 3, we evaluate spontaneous activation and antigen-specificities of T cells (including the implicated CD4 T cells) to CNS (myelin) and Epstein-Barr Virus antigens, as well as determine how these abnormal T-cell responses are impacted in patients undergoing treatment with an effective MS therapy. In Chapter 4, we explore the single cell proteogenomic profile of T cells (with a focus on the implicated CCR2+CCR5+ CD4 T cells and memory T cells more generally) and discuss the potential implication of differential expression profiles detected in cells of children with MS, as well as the more recently recognized inflammatory demyelinating condition defined by presence of circulating anti-myelin oligodendrocyte glycoprotein (MOG) antibodies (MOG-associated disease; MOGAD). Collectively, the data in this dissertation broadens our understanding of T cell profiles and responses in these unique patient cohorts, as well as provides insights into the potential interactions with other cell types and their targets involved in early MS pathogenesis. We hope that this work will help develop better biological measures of disease state and could ultimately lead to the development of potentially novel biomarkers and therapeutic targets.

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS). Neither the antigenic target(s) nor the cell population(s) responsible for CNS tissue destruction in MS have been fully defined. The objective of this study was to simultaneously determine the antigen (Ag)-specificity and phenotype of un-manipulated intrathecal CD4+ and CD8+ T cells of patients with relapsing-remitting and progressive MS compared to subjects with other inflammatory neurological diseases. We applied a novel Ag-recognition assay based on co-cultures of freshly obtained cerebrospinal fluid T cells and autologous dendritic cells pre-loaded with complex candidate Ag's. We observed comparably low T cell responses to complex auto-Ag's including human myelin, brain homogenate, and cell lysates of apoptotically modified oligodendroglial and neuronal cells in all cohorts and both compartments. Conversely, we detected a strong intrathecal enrichment of Epstein-Barr virus- and human herpes virus 6-specific (but not cytomegalovirus-specific) reactivities of the Th1-phenotype throughout all patients. Qualitatively, the intrathecal enrichment of herpes virus reactivities was more pronounced in MS patients. This enrichment was completely reversed by long-term treatment with the IL-2 modulating antibody daclizumab, which strongly inhibits MS disease activity. Finally, we observed a striking discrepancy between diminished intrathecal T cell proliferation and enhanced cytokine production of herpes virus-specific T cells among progressive MS patients, consistent with the phenotype of terminally differentiated cells. The data suggest that intrathecal administration of novel therapeutic agents targeting immune cells outside of the proliferation cycle may be necessary to effectively eliminate intrathecal inflammation in progressive MS.

The cerebrospinal fluid (CSF) provides a unique glimpse into the central nervous system (CNS) compartment and offers insights into immune processes associated with both healthy immune surveillance as well as inflammatory disorders of the CNS. The latter include demyelinating disorders, such as multiple sclerosis (MS) and myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD), that warrant different therapeutic approaches yet are not always straightforward to distinguish on clinical and imaging grounds alone. Here, we establish a comprehensive phenotypic landscape of the pediatric CSF immune compartment across a range of non-inflammatory and inflammatory neurological disorders, with a focus on better elucidating CNS-associated immune mechanisms potentially involved in, and discriminating between, pediatric-onset MS (MS) and other pediatric-onset suspected neuroimmune disorders, including MOGAD. We find that CSF from pediatric patients with non-inflammatory neurological disorders is primarily composed of non-activated CD4+ T cells, with few if any B cells present. CSF from pediatric patients with acquired inflammatory demyelinating disorders is characterized by increased numbers of B cells compared to CSF of both patients with other inflammatory or non-inflammatory conditions. Certain features, including particular increased frequencies of antibody-secreting cells (ASCs) and decreased frequencies of CD14+ myeloid cells, distinguish MS from MOGAD and other acquired inflammatory demyelinating disorders.