CD16ahigh NK cell infiltration and spatial relationships with T cells and macrophages can predict improved progression-free survival in high grade ovarian cancer

Background: High grade serous cancer (HGSC) remains a highly fatal malignancy with less than 50% of patients surviving 5 years after diagnosis. Despite its high mutational burden, HGSC is relatively refractory to checkpoint immunotherapy, suggesting that additional features of the cancer and its interactions with the immune system remain to be understood. Natural killer (NK) cells may contribute to HGSC control, but the role(s) of this population or its subsets in this disease are poorly understood. Methods: We used a TMA containing duplicate treatment-naive tumors from 1145 patients with HGSC and a custom staining panel to simultaneously measure macrophages, T cells and NK cells, separating NK cells based on CD16a expression. Using pathologist-validated digital pathology, machine learning, computational analysis and Pearsons correlations, we quantitated infiltrating immune cell density, co-infiltration and co-localization with spatial resolution to tumor region. We compared the prognostic value of innate, general, and adaptive immune cell neighborhoods to define characteristics of HGSC tumors predictive for progression-free survival and used flow cytometry to define additional features of the CD16adim NK cell subset. Results: NK cells were observed in >95% of tumor cores. Intrastromal localization of CD16alow and CD16ahigh NK cells was associated with shorter and longer progression-free survival, respectively. CD16ahigh NK cells most frequently co-localized with T cells and macrophages; their proximity was termed an adaptive neighborhood. We find that tumors with more area represented by adaptive immune cell neighborhoods corresponded to superior progression free survival. In contrast, CD16alow NK cells did not co-infiltrate with other immune cell types, and expressed the ectonucleotidases, CD39 and CD73, which have been previously associated with poor prognosis in patients with HGSC. Conclusions: Progression-free survival for patients with HGSC may be predicted by the subset of NK cells within the tumor infiltrate (i.e. CD16ahigh vs. CD16alow). NK cell subtypes were associated predictable co-infiltrating and co-localizing leukocyte subsets, suggesting that their presence and activity may influence, or be influenced by the tumor microenvironment. Our data suggest that immunotherapeutic strategies for HGSC should consider the constitution of NK cell subsets and may benefit from mobilizing and activating CD16high NK cells.

Universally Available Innate and Adaptive Immune Cell Counts in Acute Ischemic Stroke (AIS) in the Context of Shared Pathobiology with COVID-19; Scoping Review

Stroke is one of the leading cause of adult disability and the second leading cause of death worldwide. The immune system actively participates in the pathobiological process of AIS, during the index event and during the repair process despite the limited attention drawn to this aspect in the existing stroke guidelines globally. The similar clinical course and similar circulating innate and adaptive immune cell counts in AIS and COVID-19 has created a renewed interest in these easily available biomarkers innate and adaptive immunological changes in AIS with potential diagnostic, prognostic, and therapeutic implications. The current scoping review aimed to assess the significance of circulating neutrophil and lymphocyte counts and their ratio (NLR) in AIS and explore their association with post-stroke recovery trajectory. The Arksey and O'Malley methodological framework was employed to review the published papers on the neutrophil-lymphocyte ratio (NLR) and AIS in late November 2020. Only studies published in English from 2000-2020 were included in this scoping review. Fifty-three published papers were reviewed. This review's key finding is that a canonical inflammatory response occurs in AIS just as in the case of COVID-19 and neurological involvements well described in the recent literature. An excessive circulating innate immune cells (neutrophils) and reduced circulating adaptive immune cells (lymphocytes ) are associated with poorer outcomes during the acute interventions ( reperfusion therapies) as well as the recovery trajectory. Main representatives of innate and adaptive immunity follow a canonical course in AIS and COVID-19. Exaggerated circulating innate ( elevated neutrophils and elevated NLR) and reduced adaptive immune response (lymphopenia) correlate with the worse outcome in AIS and COVID-19. This scoping review's findings make the strongest case for a systems biology-based approach to the standard operating procedures in stroke care urgently.

SAT0496 INTERROGATING THE CIRCULATORY IMMUNE ARCHITECTURE OF ENTHESITIS-RELATED ARTHRITIS

Background:Enthesitis-related arthritis (ERA) is one of the most common subtype of juvenile idiopathic arthritis (JIA) in Asia1. It carries a poor prognosis, but limited knowledge of its pathogenesis hampers clinical diagnosis and treatment.Objectives:We hypothesise multiple aberrations from the healthy immunome culminating in an imbalance between the immune effector and regulatory cell subsets as key for driving ERA pathogenesis. Thus, we employed a comprehensive high-dimensional interrogative strategy using mass cytometry to assess the ERA immune architecture2.Methods:We examined peripheral blood mononuclear cells from 30 ERA patients (15 with active sacroilitis, 15 without active sacroilitis) within the first two years of disease and 30 healthy paediatric controls with mass cytometry, using two extensive antibody panels encompassing key lineage and functional markers. Dimensional reduction and unsupervised clustering were performed to identify immune cell subsets differentially present in ERA patients. Manual gating was performed to further describe observed differences in subset frequencies. These subsets were statistically evaluated with reference to the healthy cohort and their association with disease activity determined.Results:We identified broad differences in the ERA circulatory immune architecture that involved both innate and adaptive immune cell populations, notably with the enrichment of naive CD4+ T cells as well as depletion of cytolytic NK cells (CD56dimCD16+). The chemotactic profiles of their subsets also differed in ERA patients, which underscores their migratory capacity and hence potential effector role in the ERA arthritic microenvironment. In addition, there were some dissimilarities in the circulatory immunome of ERA patients with active sacroiliitis as compared to those without, which alludes to a possible mechanistic basis behind the disease complication.Conclusion:This is the first study, via deep parameterisation afforded by mass cytometry, to demonstrate a concomitant dysregulation of both innate and adaptive immune cell subsets in ERA patients. Further mechanistic studies of these immune cell subsets and their functional networks will inform the development of diagnostic and prognostic markers that can reliably predict clinical fate in ERA, thereby complementing clinical assessment in the care of ERA patients.References:[1]Arkachaisri et al. Paediatric rheumatology clinic in Southeast Asia: are we different?Rheumatology (Oxford). 2017.[2]Tay et al. Immunomics in pediatric rheumatic diseases.Front Med (Lausanne). 2019.Disclosure of Interests:None declared

Analysis of adaptive immune cell populations and phenotypes in the patients infected by SARS-CoV-2

Coronavirus disease-2019 (COVID-19), caused by SARS-CoV-2, has rapidly spread to most of countries in the world, threatening the health and lives of many people. Unfortunately, information regarding the immunological characteristics in COVID-19 patients remains limited. Here we collected the blood samples from 18 healthy donors (HD) and 38 COVID-19 patients to analyze changes in the adaptive immune cell populations and phenotypes. In comparison to HD, the lymphocyte percentage was slightly decreased, the percentages of CD4 and CD8 T cells in lymphocytes are similar, whereas B cell percentage increased in COVID-19 patients. T cells, especially CD8 T cells, showed an enhanced expression of late activation marker CD25 and exhaustion marker PD-1. Importantly, SARS-CoV-2 induced an increased percentage of T follicular helpher (Tfh)- and germinal center B-like (GCB-like) cells in the blood. However, the parameters in COVD-19 patients remained unchanged across various age groups. Therefore, we demonstrated that the T and B cells can be activated normally and exhibit functional features. These data provide a clue that the adaptive immunity in most people could be primed to induce a significant immune response against SARS-CoV-2 infection upon receiving standard medical care.

Global skin gene expression analysis of early diffuse cutaneous systemic sclerosis shows a prominent innate and adaptive inflammatory profile

ObjectivesDetermine global skin transcriptome patterns of early diffuse systemic sclerosis (SSc) and how they differ from later disease.MethodsSkin biopsy RNA from 48 patients in the Prospective Registry for Early Systemic Sclerosis (PRESS) cohort (mean disease duration 1.3 years) and 33 matched healthy controls was examined by next-generation RNA sequencing. Data were analysed for cell type-specific signatures and compared with similarly obtained data from 55 previously biopsied patients in Genetics versus Environment in Scleroderma Outcomes Study cohort with longer disease duration (mean 7.4 years) and their matched controls. Correlations with histological features and clinical course were also evaluated.ResultsSSc patients in PRESS had a high prevalence of M2 (96%) and M1 (94%) macrophage and CD8 T cell (65%), CD4 T cell (60%) and B cell (69%) signatures. Immunohistochemical staining of immune cell markers correlated with the gene expression-based immune cell signatures. The prevalence of immune cell signatures in early diffuse SSc patients was higher than in patients with longer disease duration. In the multivariable model, adaptive immune cell signatures were significantly associated with shorter disease duration, while fibroblast and macrophage cell type signatures were associated with higher modified Rodnan Skin Score (mRSS). Immune cell signatures also correlated with skin thickness progression rate prior to biopsy, but did not predict subsequent mRSS progression.ConclusionsSkin in early diffuse SSc has prominent innate and adaptive immune cell signatures. As a prominently affected end organ, these signatures reflect the preceding rate of disease progression. These findings could have implications in understanding SSc pathogenesis and clinical trial design.