Mechanisms of acute cellular allograft rejection followed liver transplantation employs the activation, proliferation and differentiation of CD4+CD154+ and CD8+CD154+ T cells into effector cells ...triggered by direct allorecognition pathway, which is performed by both but is dominated by CD4+ T cells, and indirect allorecognition pathway virtually restricted to CD8+ T cells·
Summary
Decreasing graft rejection and increasing graft and patient survival are great challenges facing liver transplantation (LT). Different T cell subsets participate in the acute cellular rejection (ACR) of the allograft. Cell‐mediated immunity markers of the recipient could help to understand the mechanisms underlying acute rejection. This study aimed to analyse different surface antigens on T cells in a cohort of adult liver patients undergoing LT to determine the influence on ACR using multi‐parametric flow cytometry functional assay. Thirty patients were monitored at baseline and during 1 year post‐transplant. Two groups were established, with (ACR) and without (NACR) acute cellular rejection. Leukocyte, total lymphocyte, percentages of CD4+CD154+ and CD8+CD154+ T cells, human leukocyte antigen (HLA) mismatch between recipient–donor and their relation with ACR as well as the acute rejection frequencies were analysed. T cells were stimulated with concanavalin A (Con‐A) and surface antigens were analysed by fluorescence activated cell sorter (FACS) analysis. A high percentage of CD4+CD154+ T cells (P = 0·001) and a low percentage of CD8+CD154+ T cells (P = 0·002) at baseline were statistically significant in ACR. A receiver operating characteristic analysis determined the cut‐off values capable to stratify patients at high risk of ACR with high sensitivity and specificity for CD4+CD154+ (P = 0·001) and CD8+CD154+ T cells (P = 0·002). In logistic regression analysis, CD4+CD154+, CD8+CD154+ and HLA mismatch were confirmed as independent risk factors to ACR. Post‐transplant percentages of both T cell subsets were significantly higher in ACR, despite variations compared to pretransplant. These findings support the selection of candidates for LT based on the pretransplant percentages of CD4+CD154+ and CD8+CD154+ T cells in parallel with other transplant factors.
Killer immunoglobulin-like receptors (KIRs) bind human leukocyte antigen (HLA) class-I (HLA-I) ligands and regulate functions of natural killer cells and subsets of T cells. KIR/HLA-I interactions ...allow predicting natural killer cell alloreactivity in hematopoietic stem cell transplantation and in HLA-compatible kidney transplants, but its meaning in liver transplantation remains controversial.
KIR and HLA genotypes were studied in 402 liver transplants, using sequence-specific oligonucleotides and primer methods. Recipients and donor KIRs, HLA-C genotypes, KIR gene mismatches (MMs) between recipient-donor pairs, and KIR/HLA-ligand combinations were analyzed in overall transplantations, in the acute rejection (AR; n=110) and non-AR (n=292) groups.
KIR gene MMs between recipients and donors, mainly in activating KIRs, and KIR2DL3 and KIR2DS1 of recipients in the presence of donor C2 ligands, significantly enhanced early AR rate (P<0.05), with KIR2DL3 and KIR2DS1 exhibiting a synergic effect in dependence of the donor C2 ligand number (χ2=7.662, P=0.022). KIR2DL3, KIR2DS1, and also KIR2DS4 significantly influenced short-term graft survival, with a benefit for transplantations combining KIR2DL3 recipients and donors having C1 ligands (log rank, P<0.019 at 1 year; hazards ratio HR, 0.321; 95% confidence interval CI, 0.107-0.962; P=0.042), whereas KIR2DS1 and KIR2DS4 recipients combined with donors lacking C1 ligands (C2/C2) exhibited a worse graft survival (log rank, P=0.035 at 6 months; HR, 7.713; 95% CI, 2.156-27.369; P=0.002 for KIR2DS1; and log rank, P=0.006 at 1 year; HR, 3.794; 95% CI, 1.267-11.365; P=0.017 for KIR2DS4).
This study shows that KIR gene-gene MMs increase AR and that KIRs/C ligands associated to AR and KIR2DS4/C ligands also influence short-term graft survival.
Abstract Background There is no consensus about the impact of thresholds of complement-fixing antibody assays. Recently, a C1q-SAB assay has been developed to identify complement-fixing HLA ...antibodies with high sensitivity and specificity. Our aim was to determine the correlation between IgG single antigens beads (SAB) and C1q-SAB assay results among patients on the renal waiting list. Patients and Methods Serum samples from immunized renal waiting list patients as well as negative and positive controls were valided by Luminex (LMX). These sera, which were positive for 166 antibody specificities, were tested for HLA class I in parallel by LMX-IgG and LMX-C1q. Results Comparison of antibody detection revealed no correlation based on median fluorescent intensity (MFI), levels between the IgG SAB and the C1qSAB assay ( P > .05). IgG-positive sera with MFIs as low as 700 were able to fix C1q, whereas other sera with MFIs as high 14,500 did not. Furthermore, there appeared to be disparities in the profiles of class I antigens able to fix C1q-SAB. In our series, only 34% class I IgG SAB antibodies were also C1qSAB+. In several patients, we detected C1qSAB+ against IgGSAB- that was surely due to IgM antibodies. So, the C1qSAB assay detected IgM antibodies that fix complement. Conclusion These data suggested that the C1q-SAB assay could be an important method to evaluate pretransplant virtual crossmatch and to define nonpermitted specificities (C1q-fixing) in kidney transplantation.
Summary
Anti‐inflammatory cytokines have an important role in disease, tumour and transplant processes. Alterations in the regulation of several cytokines have been implicated in a variety of ...inflammatory disorders, including IBD (inflammatory bowel disease) Crohn′s disease (CD) and ulcerative colitis (UC). Cytokine polymorphisms are also known to affect the level of gene expression. Thus, the aim of this study was to determine the relationship between cytokine polymorphisms and the IBD pathologies in a Spanish population. Polymorphisms analysis was performed using PCR‐SSOP using a microbeads luminex assay. The following polymorphisms were determined: TNFα −238G/A (rs361525) and −308G/A (rs1800629), IFNγ +874A/T (rs62559044), TGFβ +869C/T (rs1982073) and +915G/C (rs1800471), IL10 −1082A/A (rs1800896), −592A/C (rs1800872), −819C/T (rs1800871), IL6 −174C/G (rs1800795), IL12p40 3′UTR −1188A/C (rs3212227), IL1α −889C/T (rs1800587), IL1β −511C/T (rs1143634) and +3962C/T (rs1143633), IL1R Pst‐1 1970C/T and IL1RA Mspa‐1 11100C/T. No statistical differences in TNFα, IFNγ, TGFβ, IL10, IL6, IL1α, IL1β, IL1R and IL1Ra genotypes and allele distributions between the IBD groups and healthy controls were found. However, we observed significant differences in the 3′UTR −1188A/C polymorphism of IL12p40. So −1188A allele was increased in patients with UC and the −1188C allele (high IL12p40 production) was increased in patients with CD with respect to controls. These data are in concordance with the fact that CD has been shown to be associated with a Th1 T‐cell‐mediated inflammation model and high IL12/IFNγ production at histological affected sites. These data suggest that cytokine polymorphisms in TNFα, IFNγ, TGFβ, IL10, IL6 and IL1α, IL1β, IL1R and IL1Ra cytokine gene do not seem to be relevant in IBD susceptibility and IL12p40 3′UTR −1188A/C polymorphism seems to be associated with a differential IBD development.
Summary
Tumour necrosis factor alpha (TNF‐α) has an important role in inflammatory response. Alterations in the regulation of TNF‐α have been implicated in a variety of inflammatory disorders, ...including Inflammatory bowel disease (IBD). Indeed, a common treatment for IBD is the use of TNF‐α inhibitors. Polymorphisms in the TNF‐α promoter region are known to affect the level of gene expression. Our aim was to investigate the influence of these single nucleotide polymorphisms (SNPs) in TNF‐α promoter gene play in the risk of IBD in a Spanish population and their individual response to anti‐TNF‐α treatment. DNA samples from patients with IBD and controls were screened for TNF‐α −238G/A (rs361525) and −308G/A (rs1800629) SNPs by PCR‐SSOP using a microbeads luminex assay and compared with response to TNF‐α inhibitors. There were not statistical differences in −238G/A and −308G/A allele and genotype frequencies between patients. However, we found an increased frequency of −308A allele and −308GA genotype in these nonresponders patients to TNF‐α inhibitors with respect to responders patients (Pc < 0.05). This −308GA genotype has been classified as high producer of this cytokine. This fact could actually be interesting to explain the different response of patients with IBD with respect to TNF‐α inhibitors. TNF‐α promoter gene polymorphism does not seem to play a role in IBD susceptibility, but particular TNF‐α genotypes may be involved in the different responses to TNF‐α inhibitor treatment in Spanish patients with IBD.
Fully human leukocyte antigens (HLA)-mismatched liver grafts are well accepted, but the HLA influence on acceptance or rejection is unclear and much less so the impact of HLA-C, which may be ...conditioned by the fact that HLA-C-encode molecules are the major ligands for killer cell immunoglobulin-like receptors (KIR).
The HLA-C allele compatibility and the effect of donor and recipient HLA-C genotype on early liver graft acceptance and on CD8KIR T-cells recuperation were analyzed in a series of 431 primary liver transplants. Standard polymerase chain reaction PCR-SSO was used for HLA-C typing and flow cytometry to identify T cells KIR positives. Transplants were classified into two groups: acute rejection and nonacute rejection, and individual HLA-C genotypes as C1/C1, C2/C2, and C1/C2.
A favorable effect of HLA-C allelic compatibility on early liver graft acceptance was found because acute rejection significantly increased in transplants performed with 2 HLA-C allele mismatches (P=0.02). Considering the HLA-C groups, it was observed that C1/C2 heterozygous donors were best accepted in C1/C1 patients than in C2/C2 recipients, who experienced a high rate of acute rejection (P<0.004 and P<0.005, respectively). In addition, after transplantation CD3CD8KIR2D T-cells repertoires significantly increased in C1/C1 and C1/C2, but not in C2/C2 patients.
This study confirms the benefit of HLA-C allele matching on early liver transplant outcome and shows that donor HLA-C heterozygosis influences the alloresponse of C1 and C2 homozygous patients and the recuperation of CD3CD8KIR2D T cells, suggesting an involvement in liver graft tolerance.
Abstract Background Acute rejection (AR) remains a significant cause of graft loss. Better approaches to predict AR are being investigated. Surface CD28 protein is essential for T-cell proliferation ...and survival as well as cytokine production. Patients and Methods Pretransplant CD4+ CD28+ peripheral T cells were examined in 30 liver recipients (LRs) and 31 kidney recipients (KRs) by flow cytometry. Results Pretransplant CD4+ CD28+ T cells in LRs were significantly lower in rejectors than nonrejectors ( P = .002). Furthermore, the total number of CD28 molecules per cell in LRs ( P = .02) as well as KRs ( P = .047) was significantly lower in rejectors than nonrejectors. The healthy group did not display differences when compared with patients with end-stage liver disease or renal failure; however, stratification analysis displayed higher levels of CD4+ CD28+ when compared with rejected LRs ( P = .04) but not KRs. CD28 levels <41.94% were able to discriminate LRs at high risk of AR ( P = .003). Similarly, a total number of CD28 molecules ≤8359 ( P = .031) in LRs and ≤7669 ( P = .046) in KRs correlated with high risk of AR. Conclusion The preliminary results presented herein exhibit a fast and noninvasive method that assists clinicians to prevent AR by monitoring CD4+ CD28+ peripheral T cells.
Complement component C6 deficiency is a genetic disease presenting as increased susceptibility to invasive Neisseria meningitidis infections. This disorder has rarely been diagnosed in the Spanish ...population. In this work we report the immunochemical and molecular characterization of complement C6 deficiency in a Spanish patient showing no detectable functional activity of either the classical or alternative complement pathways and reporting a history of several episodes of meningococcal meningitis. The levels of individual complement components C3, C4, C5, C7, C8 and C9 were within the normal range. However, C6 level was low in the patient's serum as measured by radial immunodiffusion. Exon-specific polymerase chain reaction and sequencing of the C6 gene revealed a previously described homozygous single base deletion in exon 6 (c.821delA), leading to a shift in the reading frame that caused the generation of a downstream stop codon, which, in turn, provoked the truncation of the C6 protein (p.Gln274fs). To our knowledge, this is the first report on the c.821delA mutation in the Spanish population, which has previously only been identified in individuals of African ancestry. Characterization of this mutation was thought interesting in order to elucidate its source and help understand the molecular basis of this uncommon deficiency in our population. Moreover, this report highlights the importance of complement screening in cases of repeated meningococcal infections in order to establish its involvement and to consider adequate clinical recommendations such as prophylactic antibiotics or meningococcal vaccines and, subsequently, for genetic counselling.
•We report a Spanish patient with complement component C6 deficiency.•Sequence analysis of the C6 gene revealed the homozygous mutation c.821delA.•This is the first report on the c.821delA mutation in the Spanish population.•C6 deficiency is associated with a restricted pattern of genetic defects.
The promyelocytic leukemia zinc finger (PLZF) gene, involved in rare cases of acute promyelocytic leukemia, encodes a Krüppeltype zinc finger transcription factor. It has been reported that PLZF ...affects myeloid cell growth, differentiation, and apoptosis. However, the function of PLZF in the lymphoid compartment, where PLZF is also expressed, remains largely unknown. To investigate a potential relationship between PLZF expression in lymphocytes and programmed cell death, an inducible model of stable clones of the lymphoid Jurkat cell line was created by using the tet-off system. Although induction of PLZF expression by itself did not produce changes in the basal levels of apoptosis, PLZF had a significant anti-apoptotic effect in Jurkat cells cultured in conditions of serum starvation, as measured by annexin V staining and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling. In addition, retarded loss of mitochondrial transmembrane potential was observed in the PLZF-expressing clones, suggesting that PLZF protects from cell death through a mitochondrial-dependent mechanism. To identify apoptosis-related targets of PLZF, a screen for differential expression identified BID, a proapoptotic member of the Bcl2 family, as significantly down-regulated by PLZF. Furthermore, a high-affinity PLZF-binding site element was identified upstream of the BID transcriptional start site, as assessed by electrophoretic mobility-shift assays. These results suggest that BID is a target of PLZF repression and a candidate gene to mediate the PLZF-induced resistance to apoptosis.
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