Vaccines against SARS-CoV-2 have shown high efficacy in clinical trials, yet a full immunologic characterization of these vaccines, particularly within the human upper respiratory tract, is less well ...known. Here, we enumerate and phenotype T cells in nasal mucosa and blood using flow cytometry before and after vaccination with the Pfizer-BioNTech COVID-19 vaccine (n = 21). Tissue-resident memory (Trm) CD8
T cells expressing CD69
CD103
increase in number ~12 days following the first and second doses, by 0.31 and 0.43 log
cells per swab respectively (p = 0.058 and p = 0.009 in adjusted linear mixed models). CD69
CD103
CD8
T cells in the blood decrease post-vaccination. Similar increases in nasal CD8
CD69
CD103
T cells are observed, particularly following the second dose. CD4
cells co-expressing CCR6 and CD161 are also increased in abundance following both doses. Stimulation of nasal CD8
T cells with SARS-CoV-2 spike peptides elevates expression of CD107a at 2- and 6-months (p = 0.0096) post second vaccine dose, with a subset of donors also expressing increased cytokines. These data suggest that nasal T cells may be induced and contribute to the protective immunity afforded by this vaccine.
The coronavirus disease 2019 (Covid-19) pandemic, caused by SARS-CoV-2, has resulted in a global testing supply shortage. In response, pooled testing has emerged as a promising strategy that can ...immediately increase testing capacity. In pooled sample testing, multiple samples are combined (or pooled) together and tested as a single unit. If the pool is positive, the individual samples can then be individually tested to identify the positive case(s). Here, we provide support for the adoption of sample pooling with the point-of-care Cepheid Xpert® Xpress SARS-CoV-2 molecular assay. Corroborating previous findings, the limit of detection of this assay was comparable to laboratory-developed reverse-transcription quantitative PCR SARS-CoV-2 tests, with observed detection below 100 copies/mL. The Xpert® Xpress assay detected SARS-CoV-2 after samples with minimum viral loads of 461 copies/mL were pooled in groups of six. Based on these data, we recommend the adoption of pooled testing with the Xpert® Xpress SARS-CoV-2 assay where warranted based on public health needs. The suggested number of samples per pool, or the pooling depth, is unique for each point-of-care testing site and can be determined by the positive test rates. To statistically determine appropriate pooling depth, we have calculated the pooling efficiency for numerous combinations of pool sizes and test rates. This information is included as a supplemental dataset that we encourage public health authorities to use as a guide to make recommendations that will maximize testing capacity and resource conservation.
Abstract
Participation in an EQA program is critical to the quality assurance process. Reliable and precise CD4 T-cells enumeration are essential to improve the clinical management of patients by ...evaluating the disease progression and by monitoring the effectiveness of ART in HIV-patients. The CIRCB, CD4 reference laboratory, in collaboration with the Canadian QASI-program, recruited sites, distributed and analyzed CD4-panels in 61 sites across Cameroon. A trend and performance analysis in the pre-analytical, analytical and post-analytical phases was performed. Continuous training and corrective actions carried out from 2014 to 2018 increased the number of participating sites from 15 to 61 sites, the number of unacceptable results decreased from 50 to 10%. Specific challenges included errors in pre analytic (17.5%), analytic (77.0%) and post-analytic (5.5%) phases. This EQA requires the application of good laboratory practices, fluidic communication between all the stakeholders, continuous training, application of specific on-site corrective measures, and timely equipment maintenance in order to avoid repetitive errors and to increase laboratory performance. It could be extended to other HIV-1 testing like viral load and EID point-of-care. Partnership with QASI serve as a model for implementation of a successful EQA model for resource limited countries wanting to implement EQA for HIV testing and monitoring in alignment with 90–90–90 targets.
Patients with end-stage renal disease (ESRD) are at elevated risk of acquiring infectious diseases, including tuberculosis (TB). Inflammation and uremia negatively impact immune function in this ...population, but specific pathways involved in TB immunity have not been identified. Although γδ T cells are known to contribute to protection from TB, their phenotype and function in patients with ESRD is relatively unknown. To determine this we recruited 20 patients with and 20 without ESRD (controls), with or without latent TB infection to assess γδ T cell frequency, surface phenotype, and cytokine production by flow cytometry in response to stimulation. γδ T cells derived from patients with ESRD exhibited significantly lower expression of CCR5, CXCR3, and CD26 compared to controls. Furthermore, patients with ESRD, particularly the group with latent TB infection, exhibited poor IFNγ, TNFα, and GMCSF responses to stimulation with either phosphoantigen HMB-PP, IL-12/IL-18, E. coli, or phorbol myristate acetate and ionomycin. Similar dysfunctional responses were observed in patients with active TB. Surprisingly, neither the γδ phenotype nor its function was associated with plasma markers of inflammation or microbial translocation. Thus, there is significant perturbation of the γδ T-cell population in patients with ESRD, particularly in those with latent TB infection.
End-stage renal disease (ESRD) is associated with an increased susceptibility to infectious diseases, including infection with
. Mucosal-associated invariant T (MAIT) cells recognize vitamin B ...metabolites produced by many bacterial species, including Mtb, and may play an important role in providing protective immunity against tuberculosis infection in the lung. To date, little is known about MAIT cell frequency, phenotype, or function in ESRD patients.
MAIT cells, identified by surface marker expression or MR1 tetramer binding, were characterized in 20 ESRD and 20 healthy control participants by multicolor flow cytometry.
MAIT cell phenotype and cytokine production following PMA/ionomycin, IL-12/IL-18, or
stimulation were determined. Monocyte phenotype and plasma C-reactive protein/inflammatory cytokine levels were quantified by flow cytometry, ELISA, and multiplex bead array.
Peripheral blood MAIT cells were significantly depleted among ESRD patients compared to controls by both phenotypic and tetramer analysis and exhibited a loss of CXCR3 expression coupled to increased expression of CCR6 and CXCR6. ESRD was also associated with a shift in MAIT PMA-induced cytokine production away from IFNγ production and toward granulocyte macrophage-colony stimulating factor (GM-CSF) secretion, and a loss of
-stimulated tumor necrosis factor α expression. Loss of IFNγ expression was associated with a combination of age, alterations in Tbet and Eomes expression, and inflammatory plasma cytokine levels.
The loss of peripheral blood MAIT cells and associated shifts in tissue homing receptor expression and GM-CSF production may contribute to an immune environment that is permissive to bacterial replication, particularly in the lungs.
Although chronic immune activation correlates with CD4+ T cell loss in HIV infection, an understanding of the factors mediating T cell depletion remains incomplete. We propose that reduced expression ...of CD127 (IL-7 receptor α chain, IL-7Rα), induced by immune activation, contributes to CD4+ T cell loss in HIV infection. In particular, loss of CD127 on central memory CD4+ T cells (TCM ) severely restrains the regenerative capacity of the memory component of the immune system, resulting in a limited ability to control T cell homeostasis. Studies from both pathogenic and controlled HIV infection indicate that the containment of immune activation and preservation of CD127 expression are critical to the stability of CD4+ T cells in infection. A better understanding of the factors regulating CD127 expression in HIV disease, particularly on TCM cells, might unveil new approaches exploiting the IL-7/IL-7R receptor pathway to restore T cell homeostasis and promote immune reconstitution in HIV infection.
Objectives
Tuberculosis comorbidity with chronic diseases including diabetes, HIV and chronic kidney disease is of rising concern. In particular, latent tuberculosis infection (LTBI) comorbidity with ...end‐stage kidney disease (ESKD) is associated with up to 52.5‐fold increased risk of TB reactivation to active tuberculosis infection (ATBI). The immunological mechanisms driving this significant rise in TB reactivation are poorly understood. To contribute to this understanding, we performed a comprehensive assessment of soluble and cellular immune features amongst a unique cohort of patients comorbid with ESKD and LTBI.
Methods
We assessed the plasma and cellular immune profiles from patients with and without ESKD and/or LTBI (N = 40). We characterised antibody glycosylation, serum complement and cytokine levels. We also assessed classical and non‐classical monocytes and T cells with flow cytometry. Using a systems‐based approach, we identified key immunological features that discriminate between the different disease states.
Results
Individuals with ESKD exhibited a highly inflammatory plasma profile and an activated cellular state compared with those without ESKD, including higher levels of inflammatory antibody Fc glycosylation structures and activated CX3CR1+ monocytes that correlate with increased inflammatory plasma cytokines. Similar elevated inflammatory signatures were also observed in ESKD+/LTBI+ compared with ESKD−/LTBI+, suggesting that ESKD induces an overwhelming inflammatory immune state. In contrast, no significant inflammatory differences were observed when comparing LTBI+ and LTBI− individuals.
Conclusion
Our study highlights the highly inflammatory state induced by ESKD. We hypothesise that this inflammatory state could contribute to the increased risk of TB reactivation in ESKD patients.
End‐stage kidney disease (ESKD), regardless of aetiology, shares a common, highly inflammatory course promoting monocyte activation, leukocyte chemoattraction, and generalised inflammation. With substantial rates of TB reactivation in this patient group and mechanistic uncertainty, our study assesses plasma and cellular immune profiles from ESKD patients with and without latent tuberculosis infection (LTBI). We learn how ESKD+/LTBI+ co‐infection remains a highly inflammatory state compared to ESKD−/LTBI+ and find unique inflammatory signatures driven by the presence of ESKD.
Abstract End-stage renal disease (ESRD) patients exhibit elevated risk of tuberculosis (TB) reactivation, but current diagnostics, including the interferon gamma release assay (IGRA), exhibit poor ...sensitivity in ESRD. We tested 80 ESRD patients and found an 18.75% prevalence of IGRA positivity. A subset of patients was assessed for Mtb-specific expression of 44 cytokines/chemokines, and CD4 + T cell phenotype and function. Similar to non-ESRD IGRA + individuals, Mtb-specific IFNγ, IL-1RA, IP-10, MCP-3 and IL-2 responses were identified in the ESRD IGRA + group. 27% of the ESRD IGRA- group exhibited MCP-3 or IL-2 Mtb-specific responses, which may identify cases of latent TB infection in ESRD. Stimulation of PBMC with PPD demonstrated similar CD4 + T cell production of IFNγ, TNFα and GM-CSF by ESRD patients. The reported low sensitivity of the IGRA in ESRD cohorts is therefore unlikely to be due to poor T cell cytokine secretion, and may instead reflect defects in antigen presentation.
Outcome of Mycobacterium tuberculosis (Mtb) infection is affected by virulence of the infecting strain of Mtb, host environment, co-morbidities, and the genetic composition of the host, specifically ...the presence or absence of genes involved in immune responses/regulation. It is hypothesized that specific killer immunoglobulin-like receptor (KIR) genes may be associated with Mtb infection and clinical outcome. This cross-sectional study examined the KIR gene frequencies, profiles, and haplotypes of individuals with active tuberculosis, latent tuberculosis infection, compared to TB and HIV negative healthy controls.
Analysis of KIR gene frequencies revealed differences among disease status groups, suggesting that enrichment or depletion of specific KIR genes may direct the disease outcome. Mtb infected individuals were more likely to have a centromeric-AA haplotype compared to controls.
The differences in KIR gene frequencies and haplotypes may result in differential cytokine expression, contributing to different disease outcomes, and suggest a genetic influence on Mtb susceptibility and pathogenesis.
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