Fine Analysis of Lymphocyte Subpopulations in SARS-CoV-2 Infected Patients: Differential Profiling of Patients With Severe Outcome.

COVID-19 is caused by the human pathogen severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and has resulted in widespread morbidity and mortality. CD4 T cells, CD8 T cells and neutralizing antibodies all contribute to control SARS-CoV-2 infection. However, heterogeneity is a major factor in disease severity and in immune innate and adaptive responses to SARS-CoV-2.

Complement Alternative and Mannose-Binding Lectin Pathway Activation Is Associated With COVID-19 Mortality.

Background: The SARS-CoV-2 infection triggers excessive immune response resulting in increased levels of pro-inflammatory cytokines, endothelial injury, and intravascular coagulopathy. The complement system (CS) activation participates to this hyperinflammatory response. However, it is still unclear which activation pathways (classical, alternative, or lectin pathway) pilots the effector mechanisms that contribute to critical illness.

[Performance criteria for the verification of IgE and tryptase assay methods: recommendations from the AllergoBioNet network].

Accreditation of an in vitro diagnostic assay according to the NF/EN/ISO 15189 standard requires to analyze its technical performance before implementation for routine use, and annually when reviewing effectiveness of quality controls. Performance is evaluated through repeatability, intermediate fidelity, accuracy and uncertainty of measurement. The coefficients of variation (CV) of the intra-assay and inter-assay precision tests must be compared with those of "peers" (results from laboratories employing the same method) and also with those obtained with "all methods", i.

Tumor microenvironment and clonal monocytes from chronic myelomonocytic leukemia induce a procoagulant climate.

Chronic myelomonocytic leukemia (CMML) is a myeloid hematological malignancy with overlapping features of myelodysplastic syndromes (MDSs) and myeloproliferative neoplasms (MPNs). The knowledge of the role of the tumor microenvironment (TME), particularly mesenchymal stromal cells (MSCs), in MDS pathogenesis is increasing. Generally, cancer is associated with a procoagulant state participating in tumor development.

Accurate quantification of fourteen normal bone marrow cell subsets in infants to the elderly by flow cytometry.

Background: Studies of normal bone marrow (BM) cell composition by flow cytometry are scarce. Presently, we aimed to quantify 14 cell subsets from infants to elderly patients.

Methods: Cell subsets in BM samples from 180 individuals without morphologically abnormal leukocytes were analyzed using a single combination of eight antibodies: CD3/CD10/CD38/CD19/CD36/CD16/CD34/CD45.

Novel Strategy for Phenotypic Characterization of Human B Lymphocytes from Precursors to Effector Cells by Flow Cytometry.

A precise identification and phenotypic characterization of human B-cell subsets is of crucial importance in both basic research and medicine. In the literature, flow cytometry studies for the phenotypic characterization of B-lymphocytes are mainly focused on the description of a particular cell stage, or of specific cell stages observed in a single type of sample. In the present work, we propose a backbone of 6 antibodies (CD38, CD27, CD10, CD19, CD5 and CD45) and an efficient gating strategy to identify, in a single analysis tube, a large number of B-cell subsets covering the whole B-cell differentiation from precursors to memory and plasma cells.

One tube with eight antibodies for 14-part bone marrow leukocyte differential using flow cytometry.

Background: Bone marrow analysis by flow cytometry is part of the routine diagnosis of hematological disorders in medical laboratories. Differential leukocyte count and identification of abnormal cell subsets is currently performed through morphological examination on bone marrow smears by skilled cytologists. In this work, we propose a single 8-color tube for providing equivalent information, using flow cytometry.

Accurate detection of the tumor clone in peripheral T-cell lymphoma biopsies by flow cytometric analysis of TCR-Vβ repertoire.

Multiparametric flow cytometry has proven to be a powerful method for detection and immunophenotypic characterization of clonal subsets, particularly in lymphoproliferative disorders of the B-cell lineage. Although in theory promising, this approach has not been comparably fulfilled in mature T-cell malignancies. Specifically, the T-cell receptor-Vβ repertoire analysis in blood can provide strong evidence of clonality, particularly when a single expanded Vß family is detected.

Usefulness of an in-vitro tuberculosis interferon-γ release assay (T-SPOT.TB) in the first-line check-up of uveitis patients.

Objectives: The main objective of this 1.5-year prospective study was to evaluate the value of T-SPOT®.TB as compared to the tuberculin skin test (TST) for the first-line assessment of uveitis.

Characterization and role of intra-hepatic regulatory T cells in chronic hepatitis C pathogenesis.

Background & Aims: In chronic hepatitis C (CHC), HCV-specific T-cell responses are often dysfunctionnal. In vitro data point out that regulatory T cells (Treg) are able to suppress HCV-specific lymphocyte proliferation and cytokine secretion but their implication in this pathology is still debated.

Methods: Three complementary approaches were performed to investigate phenotype, frequency or localization of intra-hepatic Treg in treatment naïve CHC patients.

Immunomonitoring of graft-versus-host minor histocompatibility antigen correlates with graft-versus-host disease and absence of relapse after graft.

Background: After HLA-identical hematopoietic stem cell transplantation, minor histocompatibility (mH) antigen alloreactivity plays a dominant role in the development of graft-versus-host disease (GVHD) and graft versus leukemia (GVL).

Study Design And Methods: We have analyzed the mH alloreactivity (enzyme-linked immunospot [ELISpot] for interferon-gamma[IFN-gamma] assay) from 24 donor/recipient pairs over a period of 2 years of follow-up and correlated such alloreactivity with the development of GVHD or absence of relapse. Circulating specific T cells anti-mH with multimer HLA-peptides were also studied.

Fine characterization of intrahepatic NK cells expressing natural killer receptors in chronic hepatitis B and C.

Background/aims: The fate of intrahepatic NK cell subsets in the course of HCV and HBV infections is not clearly understood.

Methods: Blood and intrahepatic CD56(+) NK cell subsets (expressing NKG2A, CD158a,h or CD158b,j receptors) from HCV or HBV patients were quantified by flow cytometry and localized by immunohistochemistry in liver biopsies.

Results: A significant reduction in NK cell frequency and a quantitative imbalance between CD56(bright) and CD56(dim) subsets were observed in chronic HCV patients as compared to HBV patients, underlining that the inflammatory environment is not the only cause of these phenomena.

Human C3 deficiency associated with impairments in dendritic cell differentiation, memory B cells, and regulatory T cells.

Primary C3 deficiency, a rare autosomal inherited disease (OMIM 120700), was identified in a 2-year-old male suffering from recurrent pyogenic infections from early infancy with undetectable total complement hemolytic activity (CH50) and C3 values. The nonconsanguineous parents and the two patients' two siblings had 50% normal serum C3 concentration. The molecular abnormality associated a paternal allele coding C3 with the missense mutation p.

Features and distribution of CD8 T cells with human leukocyte antigen class I-specific receptor expression in chronic hepatitis C.

Unlabelled: CD8(+) T cells represent a sizable component of the liver inflammatory infiltrate in chronic hepatitis C and are thought to contribute to immune-mediated tissue injury. Because chronic stimulation may promote the expression by CD8(+) T cells of distinct human leukocyte antigen class I-specific natural killer cell receptors (NKRs) susceptible to both inhibiting effector functions and promoting cell survival, we examined the distribution and characteristics of CD8(+) T cells with such receptors in chronic hepatitis C patients. NKR CD8(+) T cells were detectable in liver and peripheral blood from hepatitis C virus (HCV)-infected patients but were not major subsets.

Phenotypic and functional characterization of intrahepatic T lymphocytes during chronic hepatitis C.

The pathogenesis of liver cell injury during chronic hepatitis C (CHC) is poorly understood. The cellular immune response is thought to play a key role in both inhibition of viral replication and liver pathology. However, little is currently known about which lymphocyte populations and which immune effectors contribute to or control liver damage.

T lymphocytes infiltrating the liver during chronic hepatitis C infection express a broad range of T-cell receptor beta chain diversity.

Background/aims: During viral chronic hepatitis C (CHC), the intra-hepatic lymphocyte infiltrate is mainly composed of T lymphocytes expressing alphabeta T-cell receptors (TCR). Since little is known about the TCRalphabeta diversity of intra-hepatic T lymphocytes (IHL), we evaluated the IHL repertoire from CHC patients (n=8) as compared to healthy subjects (n=4), total peripheral blood mononuclear cells, and purified peripheral and intra-hepatic CD8(+) cells (n=2).

Methods: The diversity of TCRalphabeta receptors was evaluated by determining the size and the sequence of the TCRbeta chain complementarity determining region 3 (CDR3).

Quality control for the validation of extracorporeal photopheresis process using the Vilbert-Lourmat UV-A irradiation's system.

In agreement with good practices for therapeutic use of human cells, quality control has to be performed to valid the process of extracorporeal photopheresis (ECP) with the Vilbert-Lourmat system. Since no protocol exists, we evaluated a technique based on the measurement of the inhibition of mitogen (PHA, Con-A, OKT3)-induced proliferation, in 164 procedures from 16 patients. Whatever the pathology, we observed a high proliferation rate in most samples, and we obtained over 90% ECP-induced inhibition in as many as 94% of the cases.