Cigarette smoking induces human CCR6+Th17 lymphocytes senescence and VEGF-A secretion.

Chronic exposure to environmental pollutants is often associated with systemic inflammation. As such, cigarette smoking contributes to inflammation and lung diseases by inducing senescence of pulmonary cells such as pneumocytes, fibroblasts, and endothelial cells. Yet, how smoking worsens evolution of chronic inflammatory disorders associated with Th17 lymphocytes, such as rheumatoid arthritis, psoriasis, Crohn's disease, and multiple sclerosis, is largely unknown. Results from human studies show an increase in inflammatory CD4+ Th17 lymphocytes at blood- and pulmonary level in smokers. The aim of the study was to evaluate the sensitivity of CD4+ Th17 lymphocytes to cigarette smoke-induced senescence. Mucosa-homing CCR6+ Th17- were compared to CCR6neg -and regulatory T peripheral lymphocytes after exposure to cigarette smoke extract (CSE). Senescence sensitivity of CSE-exposed cells was assessed by determination of various senescence biomarkers (ß-galactosidase activity, p16Ink4a- and p21 expression) and cytokines production. CCR6+ Th17 cells showed a higher sensitivity to CSE-induced senescence compared to controls, which is associated to oxidative stress and higher VEGFα secretion. Pharmacological targeting of ROS- and ERK1/2 signalling pathways prevented CSE-induced senescence of CCR6+Th17 lymphocytes as well as VEGFα secretion. Altogether, these results identify mechanisms by which pro-oxidant environmental pollutants contribute to pro-angiogenic and pathogenic CCR6+Th17 cells, therefore potential targets for therapeutic purposes.

Human CCR6+ Th17 Lymphocytes Are Highly Sensitive to Radiation-Induced Senescence and Are a Potential Target for Prevention of Radiation-Induced Toxicity.

PURPOSE: This study addresses the sensitivity of different peripheral CD4+ T-lymphocyte subsets to irradiation (IR) and identifies potential targets for the prevention or treatment of radiation-induced toxicity. METHODS: This study was performed on peripheral blood mononuclear cells or sorted peripheral memory lymphocytes of CCR6+ mucosa-homing Th17/CCR6negTh and regulatory T subtypes of healthy volunteers. Cells were irradiated with a 2 Gy with or without pharmacologic inhibitors of different signaling pathways. Senescence of irradiated cells was assessed by resistance to apoptosis and determination of various senescence-associated biomarkers (senescence associated b-galactosidase activity, p16Ink4a-, p21Cdkn1a-, gH2A.X-, H2A.J expression). Cytokine production was measured in supernatants of irradiated cells by Luminex technology. RESULTS: Not all CD4+ memory T lymphocyte subsets were equally radiosensitive. High sensitivity of CCR6+Th17 lymphocytes to IR-induced senescence was shown by expression of the histone variant H2A.J, higher SA-b-Gal activity, and upregulation of p16Ink4a and p21Cdkn1a expression. Lower Annexin V staining and cleaved caspase-3, and higher expression of antiapoptotic genes Bcl-2 and Bcl-xL LF, showed that CCR6+Th17 lymphocytes were more resistant to IR-induced apoptosis than CCR6neg memory Th and regulatory T lymphocytes. After a 2 Gy IR, both CCR6+Th17 and CCR6neg cells acquired a moderate senescence-associated secretory phenotype, but only CCR6+Th17 cells secreted interleukin 8 (IL-8) and vascular endothelial growth factor-A (VEGF-A). Pharmacologic targeting of reactive oxygen species (ROS), mitogen-activated protein kinases (MAPKs), and mammalian target of rapamycin (mTOR) signaling pathways prevented the expression of senescent markers and IL-8 and VEGF-A expression by CCR6+Th17 cells after IR. CONCLUSIONS: This study suggests that IR induces senescence of CCR6+Th17 lymphocytes associated with secretion of IL-8 and VEGF-A that may be detrimental to the irradiated tissue. ROS-MAPKs signaling pathways are candidate targets to prevent this CCR6+Th17-dependent radiation-induced potential toxicity. Finally, the ratio of circulating H2A.J+ senescent CCR6+ Th17/CD4+ T lymphocytes may be a candidate marker of individual intrinsic radiosensitivity.

Ionizing radiation-induced cellular senescence promotes tissue fibrosis after radiotherapy. A review.

Ionizing radiation-exposure induces a variety of cellular reactions, such as senescence and apoptosis. Senescence is a permanent arrest state of the cell division, which can be beneficial or detrimental for normal tissue via an inflammatory response and senescence-associated secretion phenotype. Damage to healthy cells and their microenvironment is considered as an important source of early and late complications with an increased risk of morbidity in patients after radiotherapy (RT). In addition, the benefit/risk ratio may depend on the radiation technique/dose used for cancer eradication and the irradiated volume of healthy tissues. For radiation-induced fibrosis risk, the knowledge of mechanisms and potential prevention has become a crucial point to determining radiation parameters and patients' intrinsic radiosensitivity. This review summarizes our understanding of ionizing radiation-induced senescent cell in fibrogenesis. This mechanism may provide new insights for therapeutic modalities for better risk/benefit ratios after RT in the new era of personalized treatments.

Interleukin-15 Is Associated with Severity and Mortality in Stevens-Johnson Syndrome/Toxic Epidermal Necrolysis.

Early diagnosis and prognosis monitoring for Stevens-Johnson syndrome/toxic epidermal necrolysis (TEN) still remain a challenge. This study aims to explore any cytokine/chemokine with prognostic potential in Stevens-Johnson syndrome/TEN. Through screening a panel of 28 serological factors, IL-6, IL-8, IL-15, tumor necrosis factor-α, and granulysin were upregulated in patients with Stevens-Johnson syndrome/TEN and selected for the further validation in total 155 patients with Stevens-Johnson syndrome/TEN, including 77 from Taiwan and 78 from the Registry of Severe Cutaneous Adverse Reactions. Among these factors evaluated, the levels of IL-15 (r = 0.401; P < 0.001) and granulysin (r = 0.223; P = 0.026) were significantly correlated with the disease severity in 112 samples after excluding patients with insufficient data to calculate the score of TEN. In addition, IL-15 was also associated with mortality (P = 0.002; odds ratio, 1.09; 95% confidence interval, 1.03-1.14; P = 0.001; adjusted odds ratio, 1.10; 95% confidence interval, 1.04-1.16). Consistent results were obtained after the exclusion of Taiwanese patients with sepsis to rule out possible confounders. Moreover, IL-15 was shown to enhance cytotoxicity of cultured natural killer cells and blister cells from patients with TEN. Our findings highlight a usefulness of IL-15 in prognosis monitoring and therapeutic intervention of this devastating condition.

Lack of Transcription Factor p53 Exacerbates Elastase-Induced Emphysema in Mice.

The transcription factor p53 is overexpressed in the lung of patients with emphysema, but it remains unclear if it has a deleterious or protective effect in disease progression. We investigated the role of p53 in the elastase-induced emphysema model and the molecular underlining mechanisms. Wild-type (WT) and p53(-/-) mice were instilled with pancreatic porcine elastase. We quantified emphysema (morphometric analysis), chemokine (C-C motif) ligand 2 (CCL2), and TNF-α in bronchoalveolar lavage (BAL) (ELISA), oxidative stress markers [heme oxygenase 1 (HO1), NAD(P)H dehydrogenase quinone 1 (NQO1), and quantitative RT-PCR], matrix metalloproteinase 12 (MMP12) expression, and macrophage apoptosis (cleaved caspase-3, immunofluorescence). p53 gene expression was up-regulated in the lung of elastase-instilled mice. p53 deletion aggravated elastase-induced emphysema severity, pulmonary inflammation (macrophage and neutrophil numbers and CCL2 and TNF-α levels in BAL), and lung oxidative stress. These findings, except for the increase in CCL2, were reproduced in WT mice transplanted with p53(-/-) bone marrow cells. The increased number of macrophages in p53(-/-) mice was not a consequence of reduced apoptosis or an excess of chemotaxis toward CCL2. Macrophage expression of MMP12 was higher in p53(-/-) mice compared with WT mice after elastase instillation. These findings provide evidence that p53(-/-) mice and WT mice grafted with p53(-/-) bone marrow cells are more prone to developing elastase-induced emphysema, supporting a protective role of p53, and more precisely p53 expressed in macrophages, against emphysema development. The pivotal role played by macrophages in this phenomenon may involve the MMP12-TNF-α pathway.

Lung fibroblasts share mesenchymal stem cell features which are altered in chronic obstructive pulmonary disease via the overactivation of the Hedgehog signaling pathway.

BACKGROUND: Alteration of functional regenerative properties of parenchymal lung fibroblasts is widely proposed as a pathogenic mechanism for chronic obstructive pulmonary disease (COPD). However, what these functions are and how they are impaired in COPD remain poorly understood. Apart from the role of fibroblasts in producing extracellular matrix, recent studies in organs different from the lung suggest that such cells might contribute to repair processes by acting like mesenchymal stem cells. In addition, several reports sustain that the Hedgehog pathway is altered in COPD patients thus aggravating the disease. Nevertheless, whether this pathway is dysregulated in COPD fibroblasts remains unknown. OBJECTIVES AND METHODS: We investigated the stem cell features and the expression of Hedgehog components in human lung fibroblasts isolated from histologically-normal parenchymal tissue from 25 patients--8 non-smokers/non-COPD, 8 smokers-non COPD and 9 smokers with COPD--who were undergoing surgery for lung tumor resection. RESULTS: We found that lung fibroblasts resemble mesenchymal stem cells in terms of cell surface marker expression, differentiation ability and immunosuppressive potential and that these properties were altered in lung fibroblasts from smokers and even more in COPD patients. Furthermore, we showed that some of these phenotypic changes can be explained by an over activation of the Hedgehog signaling in smoker and COPD fibroblasts. CONCLUSIONS: Our study reveals that lung fibroblasts possess mesenchymal stem cell-features which are impaired in COPD via the contribution of an abnormal Hedgehog signaling. These processes should constitute a novel pathomechanism accounting for disease occurrence and progression.

The immunosuppressive enzyme IL4I1 promotes FoxP3(+) regulatory T lymphocyte differentiation.

IL4I1 (interleukin-4-induced gene 1) is a phenylalanine oxidase produced mainly by APCs of myeloid origin, and converts phenylalanine (Phe) to phenylpyruvate, hydrogen peroxide, and ammonia. We have previously shown that IL4I1 is highly expressed by tumor-associated macrophages from various human cancers and facilitates immune evasion from the cytotoxic response in a murine tumor model. Indeed, IL4I1 inhibits T-cell proliferation via hydrogen peroxide toxicity on effector/memory T cells. Here, we explored the effect of IL4I1 on naïve CD4(+) T-cell differentiation. We show that IL4I1 stimulates the generation of Foxp3(+) regulatory T (Treg) cells in vitro from human and mouse T cells. This effect was observed with IL4I1 from different sources, including the naturally produced enzyme. Conversely, IL4I1 limits Th1 and Th2 polarization while modifying the Th17 phenotype, in particular, by inducing its own production. Analysis of Treg-cell induction under conditions of Phe deprivation and hydrogen peroxide addition suggests that Phe consumption by the enzyme participates in Treg-cell enrichment. In line with this hypothesis, IL4I1 inhibits mTORC1 signaling shortly after T-cell activation. Thus, the IL4I1 enzyme may act on T cells both by direct inhibition of effector cell proliferation and by indirect immunoregulation mediated by Treg-cell induction.

Primary cutaneous aggressive epidermotropic CD8+ T-cell lymphoma with KIR3DL2 and NKp46 expression in a human immunodeficiency virus carrier.

Primary cutaneous aggressive epidermotropic T-cell lymphoma (PCAETCL) is a very rare lymphoma characterized by rapidly growing necrotic cutaneous lesions with an epidermotropic CD8+ T-cell neoplastic infiltrate observed histopathologically. It is associated with a very poor outcome, despite aggressive multi-agent chemotherapy. We report a 49-year-old human immunodeficiency virus (HIV)-infected patient who developed PCAETCL with associated marked vascular injury leading to diffuse purpuric and necrotic lesions complicated by recalcitrant hemophagocytic activation syndrome. The lymphoma strongly and diffusely expressed CD158k/KIR3DL2 at the protein and transcript level and NKp46 transcripts, in addition to CD8 and cytotoxic proteins. We observed a diffuse CD158k/KIR3DL2 protein expression in another case of PAETCL, not associated with immunodeficiency, which was used as a positive control. PCAETCL can develop in HIV-infected patients and may present in vasculitis-like fashion. The possible role of immunosuppression and/or HIV in oncogenesis can be postulated, as patients infected with HIV may develop anti-HIV cytotoxic CD8+ lymphoproliferations. The frequency of CD158k/KIR3DL2 and NKp46 expression in PCAECL remains to be studied in a series of cases, and may represent interesting targets for future treatments.

COMMD1 modulates noxious inflammation in cystic fibrosis.

Cystic fibrosis (CF) is an autosomal recessive disease caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene, which encodes an epithelial anion channel. Morbidity is mainly due to lung disease, which is characterized by chronic neutrophilic inflammation. Deregulation of inflammatory pathways is observed in the airways of CF patients, as evidenced by exaggerated NF-κB activity, causing an increase in the local release of pro-inflammatory cytokines such as IL-8. COMMD1, a pleiotropic protein, was recently shown to interact with CFTR and to promote CFTR cell surface expression. The effect of COMMD1 on the NF-κB pathway was assessed in CF and non-CF bronchial epithelial cells by knockdown and overexpression experiments. Results showed that (i) COMMD1 knockdown induced NF-κB-dependent transcription, (ii) COMMD1 overexpression inhibited NF-κB activity and was associated with a decrease in IL-8 transcript level and protein secretion. These data demonstrate the anti-inflammatory properties of COMMD1 in bronchial epithelial cells and open new therapeutic avenues in CF.

The cyclooxygenase-2-prostaglandin E2 pathway maintains senescence of chronic obstructive pulmonary disease fibroblasts.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is associated with lung fibroblast senescence, a process characterized by the irreversible loss of replicative capacity associated with the secretion of inflammatory mediators. However, the mechanisms of this phenomenon remain poorly defined. OBJECTIVES: The aim of this study was to analyze the role of prostaglandin E2 (PGE2), a prostaglandin known to be increased in COPD lung fibroblasts, in inducing senescence and related inflammation in vitro in lung fibroblasts and in vivo in mice. METHODS: Fibroblasts were isolated from patients with COPD and from smoker and nonsmoker control subjects. Senescence markers and inflammatory mediators were investigated in fibroblasts and in mice. MEASUREMENTS AND MAIN RESULTS: Lung fibroblasts from patients with COPD exhibited higher expression of PGE2 receptors EP2 and EP4 as compared with nonsmoker and smoker control subjects. Compared with both nonsmoker and smoker control subjects, during long-term culture, COPD fibroblasts displayed increased senescent markers (increased senescence associated-ß galactosidase activity, p16, and p53 expression and lower proliferative capacity), and an increased PGE2, IL-6, IL-8, growth-regulated oncogene (GRO), CX3CL1, and matrix metalloproteinase-2 protein and cyclooxygenase-2 and mPGES-1 mRNA expression. Using in vitro pharmacologic approaches and in vivo experiments in wild-type and p53(-/-) mice we demonstrated that PGE2 produced by senescent COPD fibroblasts is responsible for the increased senescence and related inflammation. PGE2 acts either in a paracrine or autocrine fashion by a pathway involving EP2 and EP4 prostaglandin receptors, cyclooxygenase-2-dependent reactive oxygen species production and signaling, and consecutive p53 activation. CONCLUSIONS: PGE2 is a critical component of an amplifying and self-perpetuating circle inducing senescence and inflammation in COPD fibroblasts. Modulating the described PGE2 signaling pathway could provide a new basis to dampen senescence and senescence-associated inflammation in COPD.

Titanium dioxide nanoparticles induce matrix metalloprotease 1 in human pulmonary fibroblasts partly via an interleukin-1ß-dependent mechanism.

Exposure to titanium dioxide (TiO2) nanoparticles (NPs) is associated with lung remodeling, but the underlying mechanisms are unknown. Matrix metalloprotease (MMP)-1 is an important actor in matrix homeostasis and could therefore participate in TiO2 NP effects. Our aim was to evaluate the effects of TiO2 NPs on MMP-1 expression and activity in lung pulmonary fibroblasts and to understand the underlying mechanisms and assess the importance of the physicochemical characteristics of the particles in these effects. Human pulmonary fibroblasts (MRC-5 cell line and primary cells) were exposed to 10 or 100 µg/cm(2) TiO2 (two anatases, two anatase/rutile mix, one rutile NP, and one micrometric) and carbon black (CB) NPs for 6 to 48 hours. We examined cell viability, MMP-1 expression and activity, and the implication of oxidative stress, transforming growth factor (TGF)-ß, extracellular MMP inducer, and IL-1ß in MMP-1 expression. All TiO2 NPs induced MMP-1 (mRNA and protein expression), repression of procollagen-1, and α-actin expression, but only the two anatase/rutile mix induced MMP-1 activity. Micrometric TiO2 had smaller effects than TiO2 NPs, and CB NPs did not induce MMP-1. MMP-1 induction by TiO2 NPs was not related to TGF-ß, oxidative stress, or EMPRIN expression but was related to IL-1ß expression, which partly drives MMP-1 induction by two TiO2 NPs (one anatase/rutile mix and the rutile one). Taken together, our results show that TiO2 NPs are potent inducers and regulators of MMP-1 expression and activity, partly via an IL-1ß-dependent mechanism. This may explain TiO2 lung remodeling effects.

CD158k/KIR3DL2 and NKp46 are frequently expressed in transformed mycosis fungoides.

Malignant Sezary cells express the natural killer (NK) receptors KIR3DL2 (CD158k) and Nkp46 and may co-express activating killer immunoglobulin-like receptors (KIR) that may participate to neoplastic T-cell activation through the JNK pathway. Little is known regarding NK receptor expression in other cutaneous T-cell lymphomas. We studied the expression of KIR and natural cytotoxicity receptor (NCR) transcripts, and KIR3DL1/2 at the protein level, in 16 skin biopsies from 10 patients with transformed mycosis fungoides (tMF). Some KIR and NCR transcripts were found in all cases, with various repertoires. Two to nine different KIR receptors were expressed in a single biopsy. Among them, KIR3DL2 was the most frequent, with the highest level of expression in quantitative analyses and correlated with in situ protein expression, while phosphorylated JNK was never detected. Among NCR, NKp46 was expressed in all investigated cases. The role of KIR3DL2 and NKp46 in tMF oncogenesis remains to be studied.

Telomere dysfunction causes sustained inflammation in chronic obstructive pulmonary disease.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is associated with chronic inflammation of unknown pathogenesis. OBJECTIVES: To investigate whether telomere dysfunction and senescence of pulmonary vascular endothelial cells (P-ECs) induce inflammation in COPD. METHODS: Prospective comparison of patients with COPD and age- and sex-matched control smokers. Investigation of mice null for telomerase reverse transcriptase (Tert) or telomerase RNA component (Terc) genes. MEASUREMENTS AND MAIN RESULTS: In situ lung specimen studies showed a higher percentage of senescent P-ECs stained for p16 and p21 in patients with COPD than in control subjects. Cultured P-ECs from patients with COPD exhibited early replicative senescence, with decreased cell-population doublings, a higher percentage of ß-galactosidase-positive cells, reduced telomerase activity, shorter telomeres, and higher p16 and p21 mRNA levels at an early cell passage compared with control subjects. Senescent P-ECs released cytokines and mediators: the levels of IL-6, IL-8, monocyte chemotactic protein (MCP)-1, Hu-GRO, and soluble intercellular adhesion molecule (sICAM)-1 were elevated in the media of P-ECs from patients compared with control subjects at an early cell passage, in proportion to the senescent P-EC increase and telomere shortening. Up-regulation of MCP-1 and sICAM-1 led to increased monocyte adherence and migration. The elevated MCP-1, IL-8, Hu-GROα, and ICAM-1 levels measured in lungs from patients compared with control subjects correlated with P-EC senescence criteria and telomere length. In Tert(-/-) and/or Terc(-/-) mouse lungs, levels of the corresponding cytokines (MCP-1, IL-8, Hu-GROα, and ICAM-1) were also altered, despite the absence of external stimuli and in proportion to telomere dysfunction. CONCLUSIONS: Telomere dysfunction and premature P-EC senescence are major processes perpetuating lung inflammation in COPD.

Involvement of the leptin receptor in the immune response in intestinal cancer.

The incidence of colorectal cancers (CRC) may be influenced by environmental factors, including nutrition. The role of peptides regulating food intake in controlling the growth and recurrence of human tumors is controversial. Leptin, a cytokine-like peptide, regulates food intake. We investigated the expression of leptin and its receptor in 171 consecutive patients (78 female and 93 male; 71 years) with CRC. Leptin concentrations in the serum (ELISA) were determined before tumor removal. ObRb was characterized in tumors and normal homologous tissues and culture cells (HT29, HCT116, and HCT116 with a transferred chromosome 3) by using immunocytochemistry, immunohistochemistry, reverse transcription-PCR (RT-PCR), and Western blotting. Microsatellite instability (MSI) phenotype was characterized by immunohistochemistry and pentaplex PCR. mRNAs of cytokines and chemokines were quantified in tumors and in normal homologous tissues (RT-PCR) in 43 patients. Adequate statistical tests, including multivariate analysis adjusted for pathologic tumor-node-metastasis (pTNM), MSI-H, and ObRb phenotypes, were used. Higher expression of ObRb in tumors compared with the homologous normal mucosa, pTNM staging but not leptin serum level, was associated with patients' progression-free survival (PFS). Tumor ObRb phenotype and pTNM were independent predictive factors of PFS. ObRb was more strongly expressed in HCT116 cells than in HCT116-Ch3 cells as well as in MSI-H tumors than in microsatellite stability and potentially associated with efficient cytotoxic antitumoral response as assessed by immunohistochemistry and RT-PCR measurements. We suggest that leptin receptor expression in tumors is involved in adaptive immune response in sporadic colon and rectal tumors likely via MSI-H phenotype orientation.

Leptin receptor-related immune response in colorectal tumors: the role of colonocytes and interleukin-8.

We have shown that ObRb, the leptin receptor, is overexpressed in colorectal cancer cells, and that this may influence the patients' outcome. We investigated colonocytes as leptin targets and characterized their pivotal role in antitumor immune response. Cytokine and chemokine mRNAs in HT29 cells were measured by targeted arrays. In vitro, normal colonocytes and human colon cancer cells (HT29, Caco-2, SW480, and HCT116) were used to investigate ObRb transduction system and cytokine releases. Animal colonocytes and CD8 splenocytes and human HT29, HCT116, and CD8(+) cells from blood donors were used to investigate the lymphocyte response to the colonocytes when stimulated by leptin. Leptin-induced cytokine releases in the normal colonic mucosa and tumor growth and cytokine releases within tumors in vivo were measured in male rats and nude mice, respectively. Statistical analysis was done by Fisher's exact and Mann-Whitney U tests. Various cytokines and their receptors were produced in normal and tumoral colonocytes in response to leptin by increasing nuclear factor-kappaB activation. Interleukin-8 (IL-8) was the main cytokine produced in vitro. The levels of IL-8 and its receptor, CXCR1, were higher in tumors than in homologous normal mucosa. Systemic leptin enhanced the proinflammatory cytokines in normal colonocytes and in HT29 xenografted tumor colonocytes. Colonocyte-derived products after leptin treatment stimulated perforin and granzyme B expressions in normal CD8(+) T cells in vitro. Leptin triggers an inflammatory response in tumor tissue by directly stimulating colonocytes, which can recruit T cytotoxic cells in the tumor microenvironment.

CD158K/KIR3DL2 transcript detection in lesional skin of patients with erythroderma is a tool for the diagnosis of Sézary syndrome.

The distinction between Sézary syndrome (SS) and benign erythrodermic inflammatory diseases (EID) is difficult to make both clinically and on skin biopsies, since histomorphology can provide nonspecific results. New markers of circulating malignant Sézary cells have been recently described, especially CD158k/KIR3DL2 and T-plastin, but it has not been yet determined whether they could help in the diagnosis of erythroderma in skin samples. In this study, 13 frozen skin specimens from 10 SS patients and 26 from EID were analyzed for CD158k/KIR3DL2 expression using immunohistochemistry with AZ158 mAb, which also recognizes the monomeric CD158e/KIR3DL1 receptor. Although positive in all SS samples, immunohistochemistry appeared to not reliably discriminate between SS and EID. Therefore in all samples disclosing a significant staining with AZ158 mAb, CD158k/KIR3DL2, CD158e/KIR3DL1 and T-plastin mRNA expression were analyzed on the same skin specimen using conventional and/or quantitative real-time reverse transcription (RT)-PCR. Interestingly, only CD158k/KIR3DL2 transcripts were found to be significantly overexpressed in skin biopsies from patients with SS (P<0.0001), including when normalization to CD3 expression was achieved (P=0.0003). In light of these findings, CD158k/KIR3DL2 transcripts appear to be a unique molecular marker of SS in skin samples, allowing differential diagnosis with benign EID in routine practice.

Evaluation of the potential role of cytokines in toxic epidermal necrolysis.

Toxic epidermal necrolysis is a rare disease observed as a consequence of adverse reactions to drugs. It results in the widespread apoptosis of epidermal cells and has a high mortality rate. The mechanisms leading to this apoptosis are not yet elucidated. We investigated whether the cytokines present in the blister fluid, which accumulates under necrotic epidermis, originated from T lymphocytes and may play a role in the propagation of keratinocyte apoptosis. Interferon gamma (IFN-gamma), soluble tumor necrosis factor alpha (TNF-alpha), soluble Fas ligand (sFas-L) were present in much higher concentration in the blister fluids of 13 toxic epidermal necrolysis (TEN) patients than in control fluids from burns. The results of RT-PCR studies, however, indicated that only IFN-gamma and to a lesser extent interleukin (IL)-18 were produced by mononuclear cells present in the fluid. That suggests that the other cytokines also present (TNF-alpha, sFas-L, IL-10) rather originated from activated keratinocytes. Fas-L was indeed overexpressed on the membranes of keratinocytes in lesional skin in situ. The Th1 profile of T lymphocyte activation found in the blister fluid of patients with TEN is consistent with a key role for drug-specific cytotoxic T lymphocytes (CTL) as previously reported, the activation of keratinocytes by IFN-gamma making them sensitive to cell-mediated cytolysis. We propose the hypothesis that the production of Fas-L, TNF-alpha, and IL-10 by keratinocytes could be a defense mechanism against CTL rather than a way of propagating apoptosis among epidermal cells.

Molecular diagnosis of renal-allograft rejection: correlation with histopathologic evaluation and antirejection-therapy resistance.

BACKGROUND: Because histopathologic criteria cannot always predict the pathogenesis and response to curative antirejection therapy, new hope derives from the molecular analysis of intragraft immunologic markers. We studied whether the cutoff of intragraft expression level of T-cell activation markers may define subgroups of acute rejection differing either in type of rejection or clinical outcome. METHODS: Forty-three human renal-allograft biopsies were quantified for mRNA expression of granzyme B, Fas ligand, interferon (IFN)gamma, interleukin (IL)-4, and IL-6 with a reverse-transcriptase real-time quantitative polymerase chain reaction (RT-PCR) method. Expression levels were correlated with the histopathologic rejection type according to the Banff 1997 classification criteria, and with the sensitivity to the antirejection immunosuppressive therapy, by means of receiver operating-characteristic (ROC) curves. RESULTS: Granzyme B and Fas ligand mRNA expression up-regulation correlated with all allograft rejection types (P<0.01 for all). Moreover, granzyme B showed the highest sensitivity (90%) and specificity (78%) for the potential detection of histologic borderline changes that will require immunosuppressive therapy (area under the curve [AUC]=0.856, P<0.01). Curative antirejection-therapy resistance of overt, acute-rejection episode was significantly associated with higher Fas ligand gene expression (AUC=0.764, P<0.01, sensitivity [71%], specificity [99.5%]). CONCLUSIONS: Real-time RT-PCR quantification of the over-expression of the granzyme B gene in kidney-graft biopsies has proved to be as reliable in detecting acute rejection as histologic assessment. Furthermore, we demonstrate that the simultaneous measurement of the mRNA up-regulation of Fas ligand might represent an efficient new tool for the prediction of pejorative outcome of acute rejection.