Macrophage expression and prognostic significance of the long pentraxin PTX3 in COVID-19.

Long pentraxin 3 (PTX3) is an essential component of humoral innate immunity, involved in resistance to selected pathogens and in the regulation of inflammation. The present study was designed to assess the presence and significance of PTX3 in Coronavirus Disease 2019 (COVID-19). RNA-sequencing analysis of peripheral blood mononuclear cells, single-cell bioinformatics analysis and immunohistochemistry of lung autopsy samples revealed that myelomonocytic cells and endothelial cells express high levels of PTX3 in patients with COVID-19.

Immunological history governs human stem cell memory CD4 heterogeneity via the Wnt signaling pathway.

The diversity of the naïve T cell repertoire drives the replenishment potential and capacity of memory T cells to respond to immune challenges. Attrition of the immune system is associated with an increased prevalence of pathologies in aged individuals, but whether stem cell memory T lymphocytes (T) contribute to such attrition is still unclear. Using single cells RNA sequencing and high-dimensional flow cytometry, we demonstrate that T heterogeneity results from differential engagement of Wnt signaling.

CXCR3 Identifies Human Naive CD8 T Cells with Enhanced Effector Differentiation Potential.

In mice, the ability of naive T (T) cells to mount an effector response correlates with TCR sensitivity for self-derived Ags, which can be quantified indirectly by measuring surface expression levels of CD5. Equivalent findings have not been reported previously in humans. We identified two discrete subsets of human CD8 T cells, defined by the absence or presence of the chemokine receptor CXCR3.

Background fluorescence and spreading error are major contributors of variability in high-dimensional flow cytometry data visualization by t-distributed stochastic neighboring embedding.

Multidimensional single-cell analysis requires approaches to visualize complex data in intuitive 2D graphs. In this regard, t-distributed stochastic neighboring embedding (tSNE) is the most popular algorithm for single-cell RNA sequencing and cytometry by time-of-flight (CyTOF), but its application to polychromatic flow cytometry, including the recently developed 30-parameter platform, is still under investigation. We identified differential distribution of background values between samples, generated by either background calculation or spreading error (SE), as a major source of variability in polychromatic flow cytometry data representation by tSNE, ultimately resulting in the identification of erroneous heterogeneity among cell populations.

The early expansion of anergic NKG2A/CD56/CD16 natural killer represents a therapeutic target in haploidentical hematopoietic stem cell transplantation.

Natural killer cells are the first lymphocyte population to reconstitute early after non-myeloablative and T cell-replete haploidentical hematopoietic stem cell transplantation with post-transplant infusion of cyclophosphamide. The study herein characterizes the transient and predominant expansion starting from the second week following haploidentical hematopoietic stem cell transplantation of a donor-derived unconventional subset of NKp46/CD56/CD16 natural killer cells expressing remarkably high levels of CD94/NKG2A. Both transcription and phenotypic profiles indicated that unconventional NKp46/CD56/CD16 cells are a distinct natural killer cell subpopulation with features of late stage differentiation, yet retaining proliferative capability and functional plasticity to generate conventional NKp46/CD56/CD16 cells in response to interleukin-15 plus interleukin-18.

Curtailed T-cell activation curbs effector differentiation and generates CD8 T cells with a naturally-occurring memory stem cell phenotype.

Human T memory stem (T ) cells with superior persistence capacity and effector functions are emerging as important players in the maintenance of long-lived T-cell memory and are thus considered an attractive population to be used in adoptive transfer-based immunotherapy of cancer. However, the molecular signals regulating their generation remain poorly defined. Here we show that curtailed T-cell receptor stimulation curbs human effector CD8 T-cell differentiation and allows the generation of CD45RO CD45RA CCR7 CD27 CD95 -phenotype cells from highly purified naïve T-cell precursors, resembling naturally-occurring human T .

Differentiation of Diverse Progenies of Memory T Cells from Naïve CD8 T Cell Precursors.

Following recognition of the cognate antigen, naïve T cells differentiate in a diverse progeny of memory T cells which differ at the phenotypic, gene expression and metabolic level. These molecular differences are at the basis of discrete functionality, migratory capacity and persistence in the long-term. Such a division of labor benefits adoptive T cell transfer immunotherapy approaches for cancer and viral infections, as increased persistence and effector functions in vivo result in better control of the disease.

FACS Analysis of Memory T Lymphocytes.

Flow cytometry is a powerful and robust technology for detecting and monitoring multiple markers at the level of single cells. Since its early development, flow cytometry has been used to assess heterogeneity in a cell suspension. Over the years, the increasing number of parameters that could be included in a single assay combined with physical separation by fluorescence-activated cell sorting (FACS) revealed that the T cell compartment is extremely heterogenous in terms of phenotypic diversity, functional capacity, and transcriptional regulation.

Role of naive-derived T memory stem cells in T-cell reconstitution following allogeneic transplantation.

Early T-cell reconstitution following allogeneic transplantation depends on the persistence and function of T cells that are adoptively transferred with the graft. Posttransplant cyclophosphamide (pt-Cy) effectively prevents alloreactive responses from unmanipulated grafts, but its effect on subsequent immune reconstitution remains undetermined. Here, we show that T memory stem cells (TSCM), which demonstrated superior reconstitution capacity in preclinical models, are the most abundant circulating T-cell population in the early days following haploidentical transplantation combined with pt-Cy and precede the expansion of effector cells.