Ennia Dametto

Cytokines and chronic rejection: a study in kidney transplant long-term survivors.

Background. In part, the long-term survival of kidney transplants depends on the efforts to perform grafts with good human leukocyte antigen (HLA) compatibility, but there are other mechanisms that must induce some sort of tolerance and impair the anti-graft immune reaction. Because cytokines are one of the main components of immune response, we evaluated single nucleotide polymorphisms (SNPs) of several cytokine genes that may influence the production of a given cytokine and therefore the features of immune reactions. Methods. A total of 416 first cadaveric kidney transplants were monitored for HLA matching. After 10 years, the graft was still functional in 171 of 416 patients; 102 of 171 patients were also typed for cytokine polymorphisms. Results. The mismatch distributions in patients who underwent transplantation were not statistically different from the entire group of patients who underwent transplantation during the same time period. Moreover, it seems that almost all of the HLA class I incompatible long-term survivors are homozygous for GG at the −1082 interleukin (IL)-10 or CC at the −33IL4. Conclusions. We observed that a match for class I and class II HLA antigens apparently does not favor the long-term survival of transplanted kidneys. In fact, matched grafts are lost before 10 years in the same proportion as the mismatched grafts. We also demonstrated (1) that patients who are homozygous for GG at the SNP −1082IL10 (high IL-10 producers) and HLA class I mismatched (but matched for class II) are protected from chronic rejection, and (2) that patients who are homozygous for CC at the SNP −33IL4 (low IL-4 producers) and HLA class I mismatched (regardless of matching for class II) are protected from chronic rejection.

Specific polymorphisms of cytokine genes are associated with different risks to develop single-system or multi-system childhood Langerhans cell histiocytosis.

Cytokines and chemokines determine mobilisation of Langerhans cells and their dysregulation is implicated in the pathogenesis of Langerhans cell histiocytosis (LCH). Twenty point mutations of 12 different cytokine genes were studied in 41 Italian children, 15 with single‐system (SS) and 26 with multi‐system disease. The allele and genotype distributions of interleukin‐4 (IL‐4) and interferon‐γ (IFNγ) were significantly different in patients vs. 140 controls (P = 0.007, and P = 0.018). Older children with single‐system disease shared the ‘anti‐inflammatory profile’ determined by the intermediate producer genotype IFNγ +874A/T (P = 0.029) and the high‐producer genotypes IL‐4 –590C/T and T/T (P = 0.029). Our findings suggest that specific cytokine gene variants affect susceptibility to LCH and its clinical heterogeneity.

Cytokine gene polymorphisms in hepatitis C virus‐related oral lichen planus

Abstract:  Cytokine polymorphisms may influence both the risk of developing oral lichen planus (OLP) and the outcome of hepatitis C virus (HCV)‐infected patients and OLP has been frequently associated with HCV infection. The aim of the present study was to analyse whether cytokine polymorphisms may influence the susceptibility to HCV‐related OLP. Thirty‐five patients with OLP and chronic HCV infection (OLP–HCV+ve) took part in the study. As controls, 44 patients with OLP but without HCV (OLP–HCV−ve) infection and 140 healthy donors were studied. Thirteen cytokine genes with 22 single nucleotide polymorphisms (SNP) were studied. IFN‐γ UTR 5644 genotype frequencies showed an increase in number of A/T heterozygote in OLP–HCV+ve patients compared with OLP–HCV−ve that approached the statistical significance [P = 0.03, P‐corrected (PC) = 0.66]. Contrarily, in OLP–HCV+ve patients, the frequency of genotype −308 G/A of the TNF‐α was decreased, whereas the genotype −308 G/G was increased compared with OLP–HCV−ve (P = 0.0005, PC = 0.011 and P = 0.0016, PC = 0.0352, respectively). OLP patients with and without HCV infection showed a different genetic cytokine background suggesting distinct pathogenetic mechanisms.

HLA-C/KIR GENOTYPES IN ORAL LICHEN PLANUS PATIENTS INFECTED OR NON INFECTED WITH HEPATITIS C VIRUS

OBJECTIVES Oral Lichen Planus (OLP) is associated with hepatitis C virus (HCV) infection and resembles graft-versus-host disease (GVHD) both clinically and histologically. The killer cell immunoglobulin-like receptor (KIR) genes encode a family of receptors expressed on NK and T cells and are supposed to play a significant role in GVHD and HCV infection. The aim of this study was to analyze the association among OLP, HCV infection and variants in KIR gene expression. METHODS A total of 81 patients with OLP (36 HCV+ve and 45 HCV-ve) and 217 healthy controls (HCV-ve) were typed for the presence of eight KIR genes and of HLA-Cw* alleles by polymerase chain reaction-sequence specific primer. RESULTS There were no significant differences in the frequency of the KIR genes and HLA-C1/C2 group alleles between cases and controls. We only found a significant difference in the frequency of the gene KIR2DL2 between HCV+ve and HCV-ve OLP patients. CONCLUSIONS The present data suggest that OLP is not associated with particular KIR genes or with HLA-Cw* alleles in patients without HCV infection. Contrarily, the role of the genes in OLP-HCV+ve patients remains unclear and might warrant further researches.

Association of HLA class I markers with multiple sclerosis in the Italian and UK population: evidence of two independent protective effects

Background The association of HLA A*02 with multiple sclerosis (MS) was recently confirmed by the authors, and it was observed that the combined presence of HLA Cw*05 significantly enhanced (threefold) the protective effect of HLA A*02. Objectives and methods Since A*02-Cw*05 is carried by two HLA extended haplotypes characterised by the B*4402 and B*1801 alleles, respectively, the association analysis was extended to HLA B*44 and B*18 in an Italian sample (1445 MS cases and 973 controls) and these associations were verified in a UK cohort (721 MS cases, 408 controls and 480 family trios). Results A strong protective effect, independent of DR15, of the A*02-Cw*05 combination carrying B*44 (OR 0.27, p=3.3×10-5) was seen in the Italian samples and confirmed in UK family trios (OR 0.33, p=5.5×10-4) and in a combined cohort of UK families and case–controls (OR 0.53, p=0.044). This protective effect was significantly stronger than that mediated by A*02 alone. Logistic regression showed that A*02-Cw*05 maintained a significant protection when adjusted for B alleles (Italy: OR 0.38, p=6.5×10-7; UK: OR 0.60, p=0.0029), indicating that it was not secondary to linkage disequilibrium with B*44. Different from A*02, the other HLA class I tested markers individually showed no significant (Cw*05, B*18) or a modest (B*44) protection when adjusted for the remaining markers. Conclusions This study identified at least two independent protective effects which are tagged by A*02–Cw*05 and A*02, respectively. Further studies are needed to elucidate whether this protective effect is due to the presence of an unanalysed factor characterising the HLA extended haplotype(s) carrying A*02 and Cw*05 or to a direct interaction between these alleles.

Human Liver Stem Cells Suppress T-Cell Proliferation, NK Activity, and Dendritic Cell Differentiation

Human liver stem cells (HLSCs) are a mesenchymal stromal cell-like population resident in the adult liver. Preclinical studies indicate that HLSCs could be a good candidate for cell therapy. The aim of the present study was to evaluate the immunogenicity and the immunomodulatory properties of HLSCs on T-lymphocytes, natural killer cells (NKs), and dendritic cells (DCs) in allogeneic experimental settings. We found that HLSCs inhibited T-cell proliferation by a mechanism independent of cell contact and dependent on the release of prostaglandin E2 (PGE2) and on indoleamine 2,3-dioxygenase activity. When compared with mesenchymal stromal cells (MSCs), HLSCs were more efficient in inhibiting T-cell proliferation. At variance with MSCs, HLSCs did not elicit NK degranulation. Moreover, HLSCs inhibited NK degranulation against K562, a NK-sensitive target, by a mechanism dependent on HLA-G release. When tested on DC generation from monocytes, HLSCs were found to impair DC differentiation and DCs ability to induce T-cell proliferation through PGE2. This study shows that HLSCs have immunomodulatory properties similar to MSCs, but, at variance with MSCs, they do not elicit a NK response.

Interleukin-4RA gene polymorphism is associated with oral mucous membrane pemphigoid.

OBJECTIVE The aim of this study was to analyse whether the polymorphisms of several pro- and anti-inflammatory cytokines may influence the susceptibility to predominantly oral Mucous membrane pemphigoid (MMP) in a Northern Italian population. MATERIAL AND METHODS DNA was obtained from 41 MMP patients (29 with exclusively oral pemphigoid [OP]) and 140 unrelated bone marrow donors. Thirteen cytokine genes with 22 single-nucleotide polymorphisms (SNP) were studied by a sequence-specific PCR assay. RESULTS There was no significant difference between the patients taken together and healthy controls for any cytokine gene polymorphism studied. However, the allele A of the IL-4 receptor A (IL-4RA) was significantly more frequent in OP than controls (P < 0.05), causing an increased frequency of genotype A/A in OP patients (89.7 vs. 67.9, odds ratio: 4.11, 95% confidence intervals 1.18-14.28, P = 0.023, Pc = 0.046). CONCLUSION IL-4RA-1902 A/A genotype has been associated with a reduced response to IL-4 and has been found in 90% OP patient. Giving the supposed importance of IL-4 in MMP fibrotic process, our results can partially explain the low likelihood of scarring in OP patients.

Early reduced liver graft survival in hepatitis C recipients identified by two combined genetic markers.

HLA and IL‐28B genes were independently associated with severity of HCV‐related liver disease. We investigated the effects of these combined genetic factors on post‐transplant survival in HCV‐infected recipients, aiming to provide new data to define the optimal timing of novel antiviral therapies in the transplant setting. HLA‐A/B/DRB1 alleles and IL‐28B rs12979860 (C > T) polymorphism frequencies were determined in 449 HCV viremic recipients and in their donors. Median follow‐up was 10 years; study outcome was graft survival. HLA‐DRB1*11 phenotype and IL‐28B C/C genotype were significantly less frequent in recipients than donors (27.8% vs. 45.9% and 27.4% vs. 44.9%, respectively, P < 0.00001). Ten‐year graft survival was better in patients with HLA‐DRB1*11 (P = 0.0183) or IL‐28B C/C (P = 0.0436). Conversely, concomitant absence of HLA‐DRB1*11 and IL‐28B C/C in 228 (50.8%) predicted worse survival (P = 0.0006), which was already evident at the first post‐transplant year (P = 0.0370). In multivariable Cox analysis, absence of both markers ranked second as risk factor for survival (HR = 1.74), following donor age ≥ 70 years (HR = 1.77). In the current era of direct‐acting antiviral agents, the negative effects of this common immunogenetic profile in HCV‐infected recipients could be most effectively neutralized by peri‐transplant treatment. This should be particularly relevant in countries where elderly donors represent an unavoidable resource.

Phosphorylated alpha-enolase induces autoantibodies in HLA-DR8 pancreatic cancer patients and triggers HLA-DR8 restricted T-cell activation.

Pancreatic ductal adenocarcinoma (PDAC) is the fourth cause of cancer-induced death in the Western World. In PDAC patients, alpha-enolase (ENOA), a glycolytic enzyme that also acts as plasminogen receptor, is up-regulated and elicits the production of autoantibodies. Our previous studies revealed that most PDAC patients specifically produce antibodies to Serine(419)phosphorylated ENOA (Ser(419)P-ENOA) isoforms (ENOA1,2), and that this humoral response correlates with a better clinical outcome. Since autoantibody production can be influenced by HLA polymorphisms, and the ENOA sequence presents multiple peptides predicted to preferentially bind HLA-DR molecules, including the peptide containing Ser(419), we hypothesized that the presence of autoantibodies against ENOA1,2 is associated with specific HLA-DRB1 alleles. Here, we demonstrate that the HLA-DRB1*08 allele is significantly more frequent in PDAC patients with autoantibodies to ENOA1,2 (ENOA1,2(+), 8%) compared to healthy controls (3%, p=0.0112). We observed that a Ser(419)P-ENOA peptide, bioinformatically predicted to bind with high affinity to the HLA-DR8 allele coded by HLA-DRB1*08:01 or *08:04 alleles, was able to activate specific CD4(+) T cell clones derived from a HLA-DRB1*08:01. Thus complexes of the Ser(419)P-ENOA peptide with the HLA that trigger T-cell signaling might be relevant for induction of anti-tumor immune response.

Evaluation of Alloreactivity in Responder-Stimulator Pairs by Determination of Gamma Interferon-Producing Cells and Cytotoxic-T-Lymphocyte Precursor Frequencies

ABSTRACT We used the enzyme-linked immunospot (ELISPOT) assay and the cytotoxic-T-lymphocyte precursor frequency assay to evaluate alloreactivity in responder-stimulator pairs. High frequencies of responder cells among cells from HLA-mismatched pairs and low frequencies among cells from pairs of siblings with identical HLA types were detected by both assays. The ELISPOT assay thus illustrated the helper and cytotoxic-T-cell response to allogeneic HLA antigens.