Indoor particulate matter concentrations and air cleaner intervention association with biomarkers in former smokers with COPD.

BACKGROUND: Indoor pollutants have been associated with worse clinical outcomes in chronic obstructive pulmonary disease (COPD). Elevated biomarkers are associated with ambient pollution exposure, however the association with indoor pollution remains unclear. METHODS: Former smokers with spirometry-confirmed COPD were randomized to portable air cleaner or placebo. Indoor particulate matter (PM2.5, PM10, and ultrafine particles [UFP; PM<0.1]) and biomarkers were measured longitudinally at pre-specified intervals and course PM fraction (PM10-2.5) was calculated. Biomarkers were categorized based on associations with biologic mechanisms: inflammation (white blood cell count, interleukin [IL]-6, IL-8, IL-1ß, tumor necrosis factor-α, interferon-γ, serum amyloid A), platelet activation (P-selectin, CD40 ligand [CD40L], 11-dehdydro-thromboxane-B2 [11dTxB2]), endothelial dysfunction (Vascular Cell Adhesion Molecule [VCAM]-1, Intercellular Adhesion Molecule [ICAM]-1), and oxidative stress (thiobarbituric acid reactive substances [TBARS], 8-hydroxydeoxyguanosine, 8-isoprostane). Associations between PM concentrations and each biomarker were analyzed using multivariable linear mixed models. An intention-to-treat analysis was performed to evaluate the air cleaner intervention on the biomarker levels longitudinally. RESULTS: Fifty-eight participants were randomized to each group. Finer PM was more strongly associated with higher IL-8 (mean difference per doubling: UFP 13.9% [p = 0.02], PM2.5 6.8% [p = 0.002], PM10-2.5 5.0% [p = 0.02]) while interferon-γ was associated with UFP and IL-1ß with PM10-2.5. UFP and PM2.5 were associated with elevated levels of the oxidative stress biomarkers TBARS and 8-isoprostane respectively. For platelet activation markers, UFP was associated with higher 11dTxB2 while PM2.5 was associated with higher P-selectin and CD40L. Pollutants were not associated with biomarkers of endothelial dysfunction. In intention-to-treat analysis there was no association of the air cleaner intervention with any of the biomarkers. DISCUSSION: Among former smokers with COPD, elevated levels of indoor air pollutants, particularly ultrafine particles (PM<0.1), were associated with elevated biomarkers of inflammation, platelet activation, and oxidative stress. However, an air cleaner intervention that reduced PM did not significantly reduce biomarker levels.

The potential role of follicular helper T cells and helper T cells type 1 in Warthin tumour.

Warthin tumour (WT) is a benign tumour of the salivary gland that proliferates in both glandular epithelial and lymphoid tissue components, and rarely exhibits cystic changes. T follicular helper cells (Tfh) are involved in the formation and maintenance of germinal centres, the differentiation of B cells into plasma cells, and the maintenance of helper T cell type 2 (Th2)-dominant humoral immune responses. T-bet induces differentiation into helper T cell type 1 (Th1) by suppressing differentiation into Tfh and enhances cellular immune responses. The objective of this study was to enhance our understanding of the immune responses and relationship between Tfh and Th1 cells in patients with WTs. In this study, we classified WTs (n = 64) into solid-type (n = 25) and cyst-type (n = 39). We also performed immunostaining of the Tfh markers CXCR5 and CD40 L, and the Th1 marker T-bet for statistical analysis. The cyst-type exhibited significant atrophy of the germinal centre area (P = 0.0019), significantly fewer Tfh-positive lymphocytes in germinal centres (P < 0.0001), and significantly more T-bet-positive lymphocytes in the epithelium (P = 0.0017). We observed that Tfh were involved in the formation and maintenance of lymphoid follicles in WTs. In the cyst-type, Th2-dominant humoral immune responses were suppressed, and Th1-dominant cellular immune responses may have caused damage to tumour tissue.

Detection of alloreactive T cells from cryopreserved human peripheral blood mononuclear cells.

Precise analyses of alloreactive T cell phenotype and function can inform both the nature and intensity of adaptive responses to transplant antigens. However, alloreactive T cells are sparse and difficult to detect, particularly in cryopreserved peripheral blood mononuclear cells (PBMCs) and from hypo-responsive individuals. An assay to identify and phenotype alloreactive cells would be particularly valuable, especially for multi-center clinical trials that often store frozen samples for batch analysis. Herein we demonstrate consistent and reproducible alloreactive T cell detection in cryopreserved PBMC following a short-term mixed lymphocyte reaction (MLR). The inherent background expression levels of activation markers on responder T cells were minimized by including a resting period prior to the assay. Stimulator cells were activated before inclusion in the MLR by addition of CD40L and IL-4. The time frame and markers to identify and phenotype alloreactive T cells following stimulation were optimized using short term co-cultures. We defined subsets of CD4+ and CD8+ T cells co-expressing CD69 and either CD154 or CD137 following allostimulation as alloreactive, and further phenotyped these cells with a variety of surface markers such as PD-1, LAG-3, and TIM-3. This assay may allow for the monitoring of donor-specific T cells in transplant recipients with longitudinally collected and cryopreserved PBMCs and provide a useful tool to identify biomarkers associated with tolerance. These biomarkers may add to mechanistic insights in immune recognition of transplanted tissues and/or cells.

CD154 inhibits death of T cells via a Cis interaction with the α5ß1 integrin.

CD154 plays a major role in the pathogenesis of several autoimmune and inflammatory diseases. In addition to CD40, soluble CD154 (sCD154) binds to other receptors namely αIIbß3, αMß2, α5ß1 and αvß3 integrins. We have previously reported that binding of sCD154 to α5ß1 integrin expressed on several human T cell lines is capable of inhibiting Fas-induced cell death. In the current study, we show that such effect of the sCD154/α5ß1 interaction is not restricted to the cell death response induced by Fas but could also be exhibited toward other death signals such as TRAIL and TNF- α. We also demonstrate that sCD154 is capable of inhibiting Fas-mediated death of human activated T cells, more importantly of CD4+ than CD8+ T ones. Our data also show that membrane-bound CD154 and α5ß1 integrin expressed on the surface of distinct cells failed to influence cell death responses. However, when membrane-bound CD154 and α5ß1 are expressed on the surface of same cell, their interaction was capable of down regulating cell death. CD154 was shown to co-localize with the α5ß1 integrin on the surface of these cells. These data strongly suggest a cis-type of interaction between CD154 and α5ß1 when both are expressed on the same cell surface, rather than a trans-interaction which usually implicates the ligand and its receptor each expressed on the surface of a distinct cell. Taken together, these findings add to the list of roles through which CD154 is contributing to the pathogenesis of autoimmune-inflammatory diseases, i.e. by protecting T cells from death and enhancing their survival.

Different roles of soluble CD40 ligand in central nervous system damage.

Backgroud and purpose: Soluble CD40 ligand (sCD40L) plays an important role in inflammation and autoimmune disorders. There is still a controversy regarding sCD40L in neuromyelitis optica spectrum disorders (NMOSD) and multiple sclerosis (MS). Herein the aims of this study were to evaluate the levels of sCD40L in patients with NMOSD, MS, and other noninflammatory neurological diseases; to investigate its potential relationship with laboratory parameters, glial fibrillary acidic protein (GFAP), thrombopoietin (TPO) and IL-6; and to address whether serum sCD40L levels in acute attacks of NMOSD patients were decreased after treatment with immunoglobulins, plasma exchange, or methylprednisolone.Materials and methods: We enrolled 13 patients with NMOSD, 9 patients with MS, and 9 patients with other noninflammatory neurological diseases. The levels of sCD40L, IL-6 were measured by cytokine multiplex assay. GFAP levels were measured by ELISA.Results: Both serum and cerebrospinal fluid (CSF) sCD40L levels were increased in NMOSD and MS. No differences were found in serum and CSF sCD40L levels between NMOSD and MS. The CSF sCD40L levels were positively correlated with the CSF cell counts in NMOSD, whereas serum sCD40L levels were positively correlated with the albumin index in MS. Furthermore, the levels of CSF sCD40L were positively correlated with CSF GFAP levels in NMOSD. Serum sCD40L levels were correlated with serum TPO levels in MS. No correlation was found between levels of sCD40L and IL-6 in NMOSD and MS. No statistically meaningful difference between NMOSD patients with or without immunotherapy. Conclusions: Our study suggests that sCD40L can contribute to the destruction of the blood-brain barrier in MS, whereas it may contribute to CNS inflammation in NMOSD. The serum sCD40L concentrations were not changed after treatment with immunoglobulins, plasma exchange, or methylprednisolone in acute attacks of NMOSD.

Composition and structure of synaptic ectosomes exporting antigen receptor linked to functional CD40 ligand from helper T cells.

Planar supported lipid bilayers (PSLB) presenting T cell receptor (TCR) ligands and ICAM-1 induce budding of extracellular microvesicles enriched in functional TCR, defined here as synaptic ectosomes (SE), from helper T cells. SE bind peptide-MHC directly exporting TCR into the synaptic cleft, but incorporation of other effectors is unknown. Here, we utilized bead supported lipid bilayers (BSLB) to capture SE from single immunological synapses (IS), determined SE composition by immunofluorescence flow cytometry and enriched SE for proteomic analysis by particle sorting. We demonstrate selective enrichment of CD40L and ICOS in SE in response to addition of CD40 and ICOSL, respectively, to SLB presenting TCR ligands and ICAM-1. SE are enriched in tetraspanins, BST-2, TCR signaling and ESCRT proteins. Super-resolution microscopy demonstrated that CD40L is present in microclusters within CD81 defined SE that are spatially segregated from TCR/ICOS/BST-2. CD40L+ SE retain the capacity to induce dendritic cell maturation and cytokine production.

Association between the No-Reflow Phenomenon and Soluble CD40 Ligand Level in Patients with Acute ST-Segment Elevation Myocardial Infarction.

Background and objectives: No-reflow (NR) phenomenon is defined as insufficient myocardial perfusion in coronary circulation in the absence of angiographic evidence of mechanical obstruction. The primary mechanisms of the NR occurrence are thought to be high platelet activity and thrombus burden. Soluble CD40 ligand (sCD40L), which is released into the plasma following platelet activation, accelerates the inflammatory process and causes further platelet activation. The aim of our study is to investigate the relationship between the NR phenomenon and sCD40L level in patients with ST-elevation myocardial infarction (STEMI). Methods: A total of 81 acute STEMI patients undergoing primary percutaneous coronary intervention and 40 healthy participants were included in this study. Acute STEMI patients were classified into two groups: 41 patients with the NR phenomenon (NR group) and 40 patients without the NR phenomenon (non-NR group). The serum sCD40L level was measured for all groups. Results: The serum sCD40L level was significantly higher in the NR group than in non-NR and control groups (379 ± 20 pg/mL, 200 ± 15 pg/mL and 108 ± 6.53 pg/mL, respectively; p < 0.001). Univariate regression analysis demonstrated that male sex, age, Gensini score and sCD40L level were the possible factors affecting the occurrence of the NR phenomenon. In multivariate regression analysis, age (odds ratio [OR], 1.091; 95% confidence interval [CI], 1.023-1.163; p < 0.008) and serum sCD40L (OR, 1.016; 95% CI, 1.008-1.024; p < 0.001) remained the independent predictor of the presence of NR. Conclusions: Our study showed that serum sCD40L level was an independent predictor of the NR phenomenon occurrence.

Mould-reactive T cells for the diagnosis of invasive mould infection-A prospective study.

Invasive mould infections (IMI) in immunocompromised patients are difficult to diagnose. Early and targeted treatment is paramount, but minimally invasive tests reliably identifying pathogens are lacking. We previously showed that monitoring pathogen-specific CD4+T cells in peripheral blood using upregulation of induced CD154 positive lymphocytes can be used to diagnose acute IMI. Here, we validate our findings in an independent patient cohort. We stimulated peripheral blood cells from at-risk patients with Aspergillus spp. and Mucorales lysates and quantitated mould-reactive CD4/CD69/CD154 positive lymphocytes via flow cytometry. Mould-reactive lymphocytes were quantitated in 115 at-risk patients. In 38 (33%) patients, the test was not evaluable, mainly due to low T cell counts or non-reactive positive control. Test results were evaluable in 77 (67%) patients. Of these, four patients (5%) had proven IMI and elevated mould-reactive T cell signals. Of 73 (95%) patients without proven IMI, 59 (81%) had mould-reactive T cell signals within normal range. Fourteen (19%) patients without confirmed IMI showed elevated T cell signals and 11 of those received antifungal treatment. The mould-reactive lymphocyte assay identified presence of IMI with a sensitivity of 100% and specificity of 81%. The mould-reactive lymphocyte assay correctly identified all patients with proven IMI. Assay applicability is limited by low T cell counts during bone marrow suppression. The assay has the potential to support diagnosis of invasive mould infection to facilitate tailored treatment even when biopsies are contraindicated or cultures remain negative.

Post Cardiovascular Surgery Atrial Fibrillation. Biomarkers Determining Prognosis.

BACKGROUND: New onset of atrial fibrillation (AF) after cardiovascular surgery is associated with increased risk of complications and length of hospital stay. Identification of patients at high risk of post-operative AF (POAF) may help to act with preventive strategies having clinical and economic relevance. OBJECTIVE: The focus of this review is to summarize findings on biomarkers of myocardial fibrosis (PICP and PIIINP), profibrotic mediators (TGF-beta1), extracellular matrix remodeling (MMP-9), myocardial stretch (BNP and NTpro-BNP), inflammation (interleukins, C-reactive protein and sCD40L), and myocardial necrosis (high-sensitivity troponin T), biomarkers, that can be used in clinical practice to stratify patients at risk for POAF. METHOD: We searched English-language studies on MEDLINE and PubMed. Evidence synthesis was based on cohort studies, clinical trials and meta-analysis data. International clinical practice guidelines were reviewed, as well. RESULTS: Factors such as cardiac remodelling, atrial pressure, surgery trauma, inflammation, oxidative stress, and sympathetic/parasympathetic activation have been implicated in the development of POAF. On the basis of multifactorial mechanism underlying the onset of POAF, several studies have investigated the predictive value of some serum biomarkers. To date, there are promising preliminary data on the clinical utility of PICP, PIINP, TGF-ß1 and sCD40L, whereas data on NT-proBNP, BNP, CRP, IL- 6, and hs-cTnT are controversial. CONCLUSION: Although some studies have shown promising results, there is a need for future larger studies with longer follow-up, before applying biomarkers as tools for POAF risk-stratification into clinical practice.

Quantification and functional evaluation of CD40L production from the adenovirus vector ONCOS-401.

Adaptive immunity involves activation of T cells via antigen presentation by antigen presenting cells (APCs) along with the action of co-stimulatory molecules and pattern recognition receptors. Cluster of differentiation 40 (CD40) is one such costimulatory molecule that is expressed on APCs that binds to CD40 ligand (CD40L) on T helper cells and activates a signaling cascade, subsequently resulting in a wide range of immune and inflammatory responses. Considering its important role in regulation of immune response, CD40/40 L has been used for developing antitumor vaccines. In this study, we developed methods for evaluating and quantifying the activity of CD40L expressed from an adenovirus vector ONCOS-401. Our results show that the ONCOS-401 vector produces functional CD40L, which can bind and activate a NF-κB-dependent signaling cascade, leading to secreted embryonic alkaline phosphatase reporter production in HEK293-BLUE cells. In addition, quantification of CD40L production using enzyme-linked immunosorbent assay and HEK-293 BLUE reporter cells showed reproducibly higher recovery of CD40L from ONCOS-401 than from the negative control vector or uninfected cells with consistent inter and intra-assay precision. Thus, a rapid and easy method for quantifying and assessing CD40L production and activity from adenovirus vectors would support the assessment of efficacy of the vector for gene therapy - this was the objective of our study.

PTPN22 1858C>T polymorphism is associated with increased CD154 expression and higher CD4+ T cells percentage in rheumatoid arthritis patients.

BACKGROUND: CD40 is a costimulatory molecule for B cells, and CD154 is a marker of CD4+ T cells activation. CD40-CD154 interaction promotes pro-inflammatory cytokines secretion and autoantibodies production. PTPN22 gene encodes LYP protein, an inhibitor of T- and B-cell activation. PTPN22 1858C>T polymorphism confers rheumatoid arthritis (RA) susceptibility. Hence, we evaluate the relationship between 1858C>T polymorphism with CD40 and CD154 expression and IFN-γ secretion in RA patients. METHODS: PTPN22 1858C>T polymorphism was genotyped in 315 RA patients and 315 control subjects (CS) using PCR-RFLP method. Later, we selected only ten anti-CCP-positive RA patients, naïve to disease-modifying antirheumatic drugs and ten CS, all with known 1858C>T PTPN22 genotype. The CD40 and CD154 membrane expressions were determined by flow cytometry in peripheral B and T cells, correspondingly. RESULTS: The B cells percentage and mCD40 expression were similar between RA and CS (P > 0.05) and we did not find an association between these variables and the 1858C>T polymorphism. The CD4+ T cells percentage was higher in RA patients than CS (P = 0.003), and in the RA group, the CD4+ T cells percentage and mCD154 expression were higher in the 1858 T allele carriers (P = 0.008 and P = 0.032, respectively). The IFN-γ levels were lower in RA patients carrying the PTPN22 risk allele (P = 0.032). CONCLUSION: The PTPN22 1858 T risk allele is associated with increased CD4+ T cells percentage and high mCD154 expression in RA patients, which could favor the pro-inflammatory cytokine release and the establishment of the inflammatory response at the seropositive RA.

Assessment of soluble platelet CD40L and CD62P during the preparation process and the storage of apheresis platelet concentrates: Absence of factors related to donors and donations.

Platelet transfusions may be associated with certain adverse effects in recipients, potentially caused by the presence of biological response modifiers contained in the platelet concentrates. The aim of this study is to identify the parameters that reflect platelet activation during both the preparation process and the storage of platelet concentrates. A total of 3,949apheresis platelet concentrate samples were studied with regard to parameters related to the donor as well as to the preparation process and their storage. Key glycoproteins characteristic of platelet activation, i.e. soluble CD40L and CD62P, were quantified in platelet concentrate supernatants on completion of their processing and during storage, using Luminex technology. We observed an increase in soluble factors over time. However, the different parameters studied in connection either with the donors or with the donations, such as (i) donor gender, (ii) donor blood group, (iii) time of collection and (iv) type of apheresis separator, do not seem to have any effect on platelet activation or the release of soluble CD40L and CD62P.

Immature platelets and antiplatelet therapy response to aspirin in Kawasaki disease.

INTRODUCTION: Kawasaki disease is a kind of systemic vasculitis that mainly damages moderate and small-sized blood vessels, and is a leading cause of coronary artery lesions (CAL). Antiplatelet therapy is a routine component of Kawasaki disease treatment strategies. So it is important to evaluate the antiplatelet effect of aspirin because of the individual biological variability of antiplatelet effect of aspirin. The immature platelet fraction (IPF) has attracted particular attention as it may influence the antiplatelet effect of aspirin. This study investigated the prognostic factors for evaluating the degree of vasculitis and the effect of antiplatelet therapy in children with Kawasaki disease. MATERIALS AND METHODS: Blood samples were collected from 44 patients with Kawasaki disease before aspirin treatment and 7 to 10 days after treatment. The IPF counts, percentage of the IPF, and highly fluorescent IPF were detected by a Sysmex XE-5000 instrument. The levels of 11-dehydrothromboxane B2 (11-DH-TXB2), soluble CD40 ligand (sCD40L), and soluble P-selectin (sP-selectin) were measured by ELISA. The correlation between the measured factors and the degree of coronary artery damage in Kawasaki disease was analyzed. RESULTS: We found that 11-DH-TXB2, sP-selectin, and sCD40L levels were much more elevated in the CAL group than in the non-coronary artery lesions (NCAL) group before aspirin treatment. The concentrations of 11-DH-TXB2, sCD40L, sP-selectin, and IPF were reduced after aspirin treatment in the NCAL group but not the CAL group. This is related to the degree of coronary artery damage in Kawasaki disease patients. Additionally, 11-DH-TXB2, sCD40L, sP-selectin, and IPF were positively correlated with the degree of coronary artery damage in Kawasaki disease patients. CONCLUSION: The current study suggests that the presence of high plasma concentrations of 11-DH-TXB2, sCD40L, sP-selectin, and IPF can be considered a risk factor and experimental biomarker for CAL in Kawasaki disease patients.

Candida-reactive T cells for the diagnosis of invasive Candida infection of the lumbar vertebral spine.

Invasive Candida infection is the fourth most common bloodstream infection. Blood cultures are the current gold standard diagnostic method, however, false negatives remain a clinical challenge. We developed a new technique measuring Candida-reactive T cells as diagnostic read-out for invasive Candida infection. In a pilot study, we followed the treatment course of a patient with an invasive Candida infection of the lumbar vertebral spine. We present the case of a 56-year-old patient with HIV-associated Burkitt lymphoma who developed septic shock during chemotherapy-induced neutropenia. For the first time, we provide flow cytometry-based diagnostics with Candida-reactive T cells for invasive candidiasis with comprehensive MRI imaging. The Candida-reactive T cell assay has potential to complement current diagnostic assays for invasive Candida infection and thus to support targeted treatment.

Transcriptome Analysis of Mycobacteria-Specific CD4+ T Cells Identified by Activation-Induced Expression of CD154.

Analysis of Ag-specific CD4+ T cells in mycobacterial infections at the transcriptome level is informative but technically challenging. Although several methods exist for identifying Ag-specific T cells, including intracellular cytokine staining, cell surface cytokine-capture assays, and staining with peptide:MHC class II multimers, all of these have significant technical constraints that limit their usefulness. Measurement of activation-induced expression of CD154 has been reported to detect live Ag-specific CD4+ T cells, but this approach remains underexplored and, to our knowledge, has not previously been applied in mycobacteria-infected animals. In this article, we show that CD154 expression identifies adoptively transferred or endogenous Ag-specific CD4+ T cells induced by Mycobacterium bovis bacillus Calmette-Guérin vaccination. We confirmed that Ag-specific cytokine production was positively correlated with CD154 expression by CD4+ T cells from bacillus Calmette-Guérin-vaccinated mice and show that high-quality microarrays can be performed from RNA isolated from CD154+ cells purified by cell sorting. Analysis of microarray data demonstrated that the transcriptome of CD4+ CD154+ cells was distinct from that of CD154- cells and showed major enrichment of transcripts encoding multiple cytokines and pathways of cellular activation. One notable finding was the identification of a previously unrecognized subset of mycobacteria-specific CD4+ T cells that is characterized by the production of IL-3. Our results support the use of CD154 expression as a practical and reliable method to isolate live Ag-specific CD4+ T cells for transcriptomic analysis and potentially for a range of other studies in infected or previously immunized hosts.

Analysis of Mycobacterium ulcerans-specific T-cell cytokines for diagnosis of Buruli ulcer disease and as potential indicator for disease progression.

BACKGROUND: Buruli ulcer disease (BUD), caused by Mycobacterium (M.) ulcerans, is the third most common mycobacterial disease after tuberculosis and leprosy. BUD causes necrotic skin lesions and is a significant problem for health care in the affected countries. As for other mycobacterial infections, T cell mediated immune responses are important for protection and recovery during treatment, but detailed studies investigating these immune responses in BUD patients are scarce. In this study, we aimed to characterise M. ulcerans-specific CD4+ T cell responses in BUD patients and to analyse specific cytokine-producing T cells in the context of disease severity and progression. METHODOLOGY/PRINCIPAL FINDINGS: For this case-control study, whole blood samples of BUD patients (N = 36, 1.5-17 years of age) and healthy contacts (N = 22, 3-15 years of age) were stimulated with antigen prepared from M. ulcerans and CD4+ T cells were analysed for the expression of TNFα, IFNγ and CD40L by flow cytometry. The proportions and profile of cytokine producing CD4+ T cells was compared between the two study groups and correlated with disease progression and severity. Proportions of cytokine double-positive IFNγ+TNFα+, TNFα+CD40L+, IFNγ+CD40L+ (p = 0.014, p = 0.010, p = 0.002, respectively) and triple positive IFNγ+TNFα+CD40L+ (p = 0.010) producing CD4+ T cell subsets were increased in BUD patients. In addition, TNFα+CD40L-IFNγ- CD4+ T cells differed between patients and controls (p = 0.034). TNFα+CD40L-IFNγ- CD4+ T cells were correlated with lesion size (p = 0.010) and proportion were higher in 'slow' healers compared to 'fast healers' (p = 0.030). CONCLUSIONS: We were able to identify M. ulcerans-specific CD4+ T cell subsets with specific cytokine profiles. In particular a CD4+ T cell subset, producing TNFα but not IFNγ and CD40L, showed association with lesion size and healing progress. Further studies are required to investigate, if the identified CD4+ T cell subset has the potential to be used as biomarker for diagnosis, severity and/or progression of disease.

Predicting Cellular Rejection With a Cell-Based Assay: Preclinical Evaluation in Children.

BACKGROUND: Allospecific CD154+T-cytotoxic memory cells (CD154+TcM) predict acute cellular rejection after liver transplantation (LTx) or intestine transplantation (ITx) in small cohorts of children and can enhance immunosuppression management, but await validation and clinical implementation. METHODS: To establish safety and probable benefit, CD154+TcM were measured in cryopreserved samples from 214 children younger than 21 years (National Clinical Trial 1163578). Training set samples (n = 158) were tested with research-grade reagents and 122 independent validation set samples were tested with current good manufacturing practices-manufactured reagents after assay standardization and reproducibility testing. Recipient CD154+TcM induced by stimulation with donor cells were expressed as a fraction of those induced by HLA nonidentical cells in parallel cultures. The resulting immunoreactivity index (IR) if greater than 1 implies increased rejection-risk. RESULTS: Training and validation set subjects were demographically similar. Mean coefficient of test variation was less than 10% under several conditions. Logistic regression incorporating several confounding variables identified separate pretransplant and posttransplant IR thresholds for prediction of rejection in the respective training set samples. An IR of 1.1 or greater in posttransplant training samples and IR of 1.23 or greater in pretransplant training samples predicted LTx or ITx rejection in corresponding validation set samples in the 60-day postsampling period with sensitivity, specificity, positive, and negative predictive values of 84%, 80%, 64%, and 92%, respectively (area under the receiver operator characteristic curve, 0.792), and 57%, 89%, 78%, and 74%, respectively (area under the receiver operator characteristic curve, 0.848). No adverse events were encountered due to phlebotomy. CONCLUSIONS: Allospecific CD154+T-cytotoxic memory cells predict acute cellular rejection after LTx or ITx in children. Adjunctive use can enhance clinical outcomes.

Chronic HIV-1 Infection Impairs Superantigen-Induced Activation of Peripheral CD4+CXCR5+PD-1+ Cells, With Relative Preservation of Recall Antigen-Specific Responses.

Peripheral CD4+CXCR5+PD-1+ T cells are a putative circulating counterpart to germinal center T follicular helper (TFH) cells. They show both phenotypic and functional similarities to TFH cells, which provide necessary help for the differentiation of B cells to antibody-secreting plasmablasts. In this study, we evaluated the frequency, phenotypes, and responses of peripheral TFH-like (pTFH) cells to superantigen and recall antigen stimulation in 10 healthy and 34 chronically infected treatment-naive HIV-1+ individuals. There was no difference in the frequency of pTFH cells between HIV+ and HIV- individuals. Surface expression of ICOS, but not CD40L, was higher on pTFH cells at baseline in HIV+ individuals. Compared with HIV- individuals, pTFH cells from HIV+ individuals had decreased maximal expression of ICOS and CD40L in response to in vitro superantigen stimulation. This decreased response did not correlate with viral control, CD4 T-cell count, duration of infection, or the degree of neutralizing antibody breadth. Despite a decreased maximal response, pTFH responses to HIV Gag and tetanus toxoid recall antigens were preserved.

Quantification of A. fumigatus-specific CD154+ T-cells-preanalytic considerations.

Fungal specific CD154+ T-cells have been described as a biomarker in invasive aspergillosis. The influence of sample storage on the detection of these cells was assessed. Six-hour delay prior to PBMC isolation is associated with an 18% decrease of cell viability and alterations of the cellular composition of the sample. This results in 87% reduction of CD154+ A. fumigatus specific cells due to reduced assay sensitivity and increased background values in unstimulated samples. If prompt cell measurement is not feasible, isolated PBMCs can be frozen (at -20°C and -80°C) and processed later with comparable assay reliability (mean value fresh vs. thawing: 0.126, 0.133; Pearson-Coefficient: 0.962).

B cells from African American lupus patients exhibit an activated phenotype.

Systemic lupus erythematosus (SLE) is a complex systemic autoimmune disease driven by both innate and adaptive immune cells. African Americans tend to present with more severe disease at an earlier age compared with patients of European ancestry. In order to better understand the immunological differences between African American and European American patients, we analyzed the frequencies of B cell subsets and the expression of B cell activation markers from a total of 68 SLE patients and 69 normal healthy volunteers. We found that B cells expressing the activation markers CD86, CD80, PD1, and CD40L, as well as CD19+CD27-IgD- double-negative B cells, were enriched in African American patients vs. patients of European ancestry. In addition to increased expression of CD40L, surface levels of CD40 on B cells were lower, suggesting the engagement of the CD40 pathway. In vitro experiments confirmed that CD40L expressed by B cells could lead to CD40 activation and internalization on adjacent B cells. To conclude, these results indicate that, compared with European American patients, African American SLE patients present with a particularly active B cell component, possibly via the activation of the CD40/CD40L pathway. These data may help guide the development of novel therapies.