HLA-G Expressing Immune Cells in Immune Mediated Diseases.

HLA-G is a HLA class Ib antigen that possesses immunomodulatory properties. HLA-G-expressing CD4+ and CD8+ T lymphocytes, NK cells, monocytes, and dendritic cells with immunoregulatory functions are present in small percentages of patients with physiologic conditions. Quantitative and qualitative derangements of HLA-G+ immune cells have been detected in several conditions in which the immune system plays an important role, such as infectious, neoplastic, and autoimmune diseases as well as in complications from transplants and pregnancy. These observations strongly support the hypothesis that HLA-G+ immune cells may be implicated in the complex mechanisms underlying the pathogenesis of these disorders.

Evaluation of membrane-bound and soluble forms of human leucocyte antigen-G in systemic sclerosis.

Systemic sclerosis (SSc) is a complex disease characterized by immune dysregulation, extensive vascular damage and widespread fibrosis. Human leucocyte antigen-G (HLA-G) is a non-classic class I major histocompatibility complex (MHC) molecule characterized by complex immunomodulating properties. HLA-G is expressed on the membrane of different cell lineages in both physiological and pathological conditions. HLA-G is also detectable in soluble form (sHLA-G) deriving from the shedding of surface isoforms (sHLA-G1) or the secretion of soluble isoforms (HLA-G5). Several immunosuppressive functions have been attributed to both membrane-bound and soluble HLA-G molecules. The plasma levels of sHLA-G were higher in SSc patients (444·27 ± 304·84 U/ml) compared to controls (16·74 ± 20·58 U/ml) (P < 0·0001). The plasma levels of transforming growth factor (TGF)-ß were higher in SSc patients (18 937 ± 15 217 pg/ml) compared to controls (11 099 ± 6081 pg/ml; P = 0·003), and a significant correlation was found between TGF-ß and the plasma levels of total sHLA-G (r = 0·65; P < 0·01), sHLA-G1 (r = 0·60; P = 0·003) and HLA-G5 (r = 0·47; P = 0·02). The percentage of HLA-G-positive monocytes (0·98 ± 1·72), CD4+ (0·37 ± 0·68), CD8+ (2·05 ± 3·74) and CD4+ CD8+ double-positive cells (14·53 ± 16·88) was higher in SSc patients than in controls (0·11 ± 0·08, 0·01 ± 0·01, 0·01 ± 0·01 and 0·39 ± 0·40, respectively) (P < 0·0001). These data indicate that in SSc the secretion and/or shedding of soluble HLA-G molecules and the membrane expression of HLA-G by peripheral blood mononuclear cells (PBMC) is clearly elevated, suggesting an involvement of HLA-G molecules in the immune dysregulation of SSc.

OxLDL- and HSP-60 antigen-specific CD8(+) T lymphocytes are detectable in the peripheral blood of patients suffering from coronary artery disease.

Inflammatory and immunologic mechanisms are important for the initiation and the progression of atherosclerotic lesions. OxLDL and HSP-60 antigens are involved in the pathogenesis of atherosclerotic disease by triggering immune cells within the plaques. Through the MHC pentamer assays, we investigated the presence of OxLDL- and HSP-60-specific CD8(+) T lymphocytes in twenty HLA-A2-positive patients suffering from coronary artery disease (10 NSTEMI and 10 stable angina). Similarly, 10 age- and sex-matched healthy subjects were enrolled as controls. Biological samples were collected within 6 h of admission to hospital, at 30 days and at 180 days. OxLDL- and HSP-60-specific CD8(+) T lymphocytes were never detectable in the peripheral blood from all the healthy controls. On the contrary, at each scheduled time point, both of these specific cells could be detected in peripheral blood from all enrolled patients. More in detail, the flow cytometric analysis of MHC-1 pentamer OxLDL-specific CD8(+) T lymphocytes revealed a sharp and significant increase at the hospital admission, within 6 h from the chest pain onset, followed by an evident decline to lower levels at 30 days and at 180 days from the enrollment in the study. On the contrary, although MHC-1 pentamer HSP-60 CD8(+) T lymphocytes were detectable in enrolled patients, almost no variance could be detectable during the follow-up scheduled evaluations. On the whole, this finding indicates that HSP-60- and OxLDL-specific CD8(+) T lymphocytes could play a role in the maintenance or worsening of the atherosclerotic coronary disease.

Rare diffuse diseases of the lung. Pulmonary alveolar proteinosis, lymphangioleiomyomatosis, amyloidosis.

Pulmonary alveolar proteinosis (PAP), lymphangioleyomiomatosis (LAM) and amyloidosis are three unrelated diseases of rare occurrence, with characteristic histopathological features. A pattern of alveolar filling with granular pink material accumulation is characteristic of PAP. This material can be recognized in lung biopsies, but also in bronchial lavage fluid. PAP is clinically related to the abnormal clearance of alveolar surfactant, most commonly due to the disruption of the granulocyte macrophage-colony stimulating factor signalling pathway. Whole lung lavage is the treatment of choice. LAM is characterized by cystic lung degeneration and interstitial proliferation of LAM cells, which express both melanocyte and smooth muscle cell markers, has a typical cystic pattern on CT scan, can be associated clinically with abdominal angiomyolipomas and limphangioleiomyomas, and occurs in female patients, either in isolation or as a manifestation of tuberous sclerosis. Sex hormone manipulation is the therapy of choice in this otherwise progressive disease. Diffuse interstitial or perivascular amyloid deposits in the lung can form in the context of systemic amyloidosis, usually associated with myeloma or monoclonal gammopathy, and less often with chronic inflammatory diseases. Nodular amyloid deposits, in contrast, are not associated with systemic lung disease, and present instrumentally as a coin lesion or lung mass. Isolated tracheobronchial amyloidosis is another rare form that is not related to systemic disease. In all conditions, amyloid has a typical waxy, amorphous, slightly eosinophilic stain, stains red with Congo red and presents a characteristic apple-green birefringence under polarized light, which is essential for diagnosis.

Successful antiviral therapy determines a significant decrease in squamous cell carcinoma antigen-associated (SCCA) variants' serum levels in anti-HCV positive cirrhotic patients.

Aberrant squamous cell carcinoma antigen (SCCA) expression is an early event in hepatocarcinogenesis, and increasing serum levels of SCCA variants IgM immune complexes (SCCA-IgM IC) have been found in cirrhotic patients developing hepatocellular carcinoma (HCC). We longitudinally evaluated a cohort of cirrhotic patients with hepatitis C virus infection (HCV) who underwent pegylated interferon (PEG-IFN) and ribavirin treatment. SCCA-IgM IC levels were assessed in the sera of 33 cirrhotic patients with HCV (21 males, median age 57 years) before, at the end and at 6-month and 1-year follow-up after treatment with PEG-IFN and ribavirin. SCCA-IgM IC serum levels (arbitrary units/mL, AU/mL) were evaluated according to treatment outcome: sustained virological response (SVR) vs nonresponse (NR). Overall, 15 patients obtained a SVR to antiviral therapy (45%). There was no significant difference in baseline SCCA-IgM IC serum levels between SVR and NR patients. When compared to baseline (451.2 AU/mL), SVR patients showed a significant decrease in median SCCA-IgM IC serum levels at the end of treatment (186.8 AU/mL, P = 0.013) and at both 6-month (96.8 AU/mL, P < 0.001) and 1-year follow-up (52.4 AU/mL, P < 0.001), while no significant modification was observed in NR patients. In patients with HCV-related liver cirrhosis, successful antiviral therapy is associated with a dramatic and significant decrease in SCCA-IC serum levels. Because of the pathophysiological correlation between SCCA and liver carcinogenesis, it is hypothesized that in patients with liver cirrhosis, SVR may be accompanied by a decreased proliferative stimulation.

IGF-I induced rapid recruitment of integrin beta1 to lipid rafts is Caveolin-1 dependent.

Caveolin-1 (Cav-1) regulates both insulin like growth factor receptor (IGF-IR) and integrin beta1 function. However, the role of Cav-1 in IGF-IR/integrin beta1 cross talk remains to be established. In this study, we observed that IGF-I did not induce integrin beta1 internalization but its plasma membrane reorganization. In particular, we found a rapid and transient association between integrin beta1 and Cav-1 followed by the enrichment of integrin beta1 in lipid rafts. To determine the role of Cav-1 in this process, we transfected Hacat cells with small interfering RNA specific for Cav-1 (siRNA-Cav-1) and with a scrambled siRNA as control (siRNA-Ctr). Cav-1 down regulated Hacat cells were then stimulated with IGF-I and analyzed by immunofluorescence and flow cytometry. We found that Cav-1 silencing abolished the recruitment of integrin beta1 to lipid rafts in the presence of IGF-I. These data demonstrate that IGF-IR/integrin beta1 cross talk is followed by integrin beta1 lipid raft compartmentalization and that Cav-1 is required for this process.

Soluble HLA-G and HLA-A,-B,-C serum levels in patients with allergic rhinitis.

BACKGROUND: Allergic rhinitis (AR) is characterized by Th2-polarized immune response. Soluble HLA (sHLA) molecules play an immunomodulatory activity. So far, however, no study investigated them in AR. OBJECTIVE: The aim of this study was to evaluate sHLA-G and sHLA-A,-B,-C serum levels in AR patients with pollen allergy and in a group of healthy controls. METHODS: Forty-nine AR patients were enrolled. A group of healthy nonallergic subjects was considered as control. sHLA-G and sHLA-A,-B,-C serum levels were determined by immunoenzymatic method. The study was conducted during the winter, such as outside the pollen season. RESULTS: Allergic patients had significantly higher levels of both sHLA-G (P < 0.0001) and sHLA-A,-B,-C (P = 0.011) molecules than normal controls. Moreover, there was a significant relationship between these two soluble molecules (r = 0.69) in allergic patients. CONCLUSION: The present study provides the first evidence that both sHLA-G and sHLA-A,-B,-C serum levels are significantly increased in AR patients with pollen allergy.

Peripheral blood serum markers for apoptosis and liver fibrosis: are they trustworthy indicators of liver realness?

BACKGROUND/AIMS: No reliable serum markers for liver inflammation, apoptosis and fibrosis have been established yet, although a large number have been evaluated. Moreover, it is not clear if a molecule detected and quantified in peripheral vein blood is a really trustworthy marker of the liver condition. To answer to this question, we had the opportunity to study paired serum samples drawn simultaneously during haemodynamic study from the right hepatic vein and from a peripheral vein from patients with hepatitis C virus related cirrhosis. METHODS: The serum levels of transforming growth factor beta-1, tumour necrosis factor-alpha, hyaluronic acid, soluble (s)human leukocyte class I antigens, soluble FAS ligand, and stumour necrosis factor related ligand were assessed in a consecutive series of 15 patients with hepatitis C virus related cirrhosis. RESULTS: No statistically significant differences were found between hepatic vein and peripheral vein levels for the cytokines, substance or soluble molecules evaluated, excepted for shuman leukocyte class I antigens. Instead a strong correlation between hepatic vein and peripheral vein levels was present for: hepatic vein, shuman leukocyte class I antigens, tumour necrosis factor-alpha, soluble FAS ligand and stumour necrosis factor related ligand, but not for transforming growth factor beta-1. CONCLUSIONS: Our results show that peripheral vein measurements seem to reflect the liver compartment in a large majority of cases, but not for all molecules and probably for any liver diseases. Further studies on this line are warranted in particular for new molecules.

Soluble apoptosis molecules in primary biliary cirrhosis: analysis and commitment of the Fas and tumour necrosis factor-related apoptosis-inducing ligand systems in comparison with chronic hepatitis C.

Apoptosis in the liver is generated mainly by the Fas system. Tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) has been proposed recently as a new apoptotic inducer. In the liver environment hepatocytes and biliary epithelial cells express TRAIL receptors which are up-regulated by increased levels of bile acids and during viral hepatitis. As for FasL, a soluble form of TRAIL has been described. To explore the commitment and level of activation of these two apoptotic systems in patients affected by primary biliary cirrhosis (PBC) or chronic hepatitis C (CH-C), a comparative study was drawn. Thirty patients with PBC on ursodeoxycholic acid have been enrolled. This group was compared with 30 patients with CH-C and with 20 healthy subjects. Soluble Fas ligand (sFasL) and soluble TRAIL (sTRAIL) levels were evaluated by double determinant immune assay and enzyme-linked immunosorbent assay (ELISA), respectively. Soluble FasL molecules were higher in PBC compared to CH-C (P=0 x 009). Soluble FasL was not detected in controls. Soluble TRAIL was significantly higher in CH-C patients compared to PBC (P=0 x 0001). Soluble TRAIL levels were higher in PBC and in CH-C than in controls (P=0 x 015 and P<0 x 001, respectively). No correlation between sFasL and sTRAIL, stage of disease, liver histology in each disease and cytolysis was present. Our data show different levels of commitment of TRAIL and Fas apoptosis-inducing systems in CH-C and PBC. Thus a different prominent role of TRAIL and Fas systems in the pathogenesis of these two conditions can be speculated: the former by inducing the death of infected hepatocytes, the latter by mediating the disappearance of bile duct.

In vivo apoptosis of CD8(+) lymphocytes in acute myeloid leukemia patients: involvement of soluble HLA-I and Fas ligand.

In this study, we show that high serum levels of soluble human leukocyte antigens (HLA) class I molecules (sHLA-I, range: 0.7-1.7 micro g/ml) and soluble Fas ligand (FasL, range: 0.4-1.9 ng/ml) are detected in patients with acute myeloid leukemia (AML) at diagnosis, compared with healthy donors (HD) (sHLA-I, range: 0.1-0.6 micro g/ml; sFasL, range: 0.1-0.4 ng/ml). Patients' sera were able to induce transcription and secretion of FasL in CD8(+) T cells, followed by apoptosis in vitro; this apoptosis was inhibited by anti-HLA-I-specific monoclonal antibodies, suggesting that sHLA-I is responsible for cell death. These findings closely relate to the in vivo upregulation of FasL transcription observed in peripheral blood (PB) lymphocytes from AML patients; in the same cells, mRNA for the antiapoptotic proteins Bcl-2 and Bcl-x(L) was downregulated. Interestingly, caspase-8 and caspase-3, both downstream mediators of death receptor-induced apoptosis, were activated in CD8(+) cells of AML patients; one-third of these cells were already apoptotic in vivo, at variance with lymphocytes of HD. These data strongly suggest that in AML, increased levels of sHLA-I molecules may contribute to the elimination of potentially anti-tumor effector cells through a FasL/Fas interaction.

Increased levels of interleukin-10 in saliva of Sjögren's syndrome patients. Correlation with disease activity.

The aim of the study was to determine the levels of interleukin (IL)-10, IL-2, IL-4, and interferon-gamma in the saliva of patients with Sjögren's syndrome and to correlate them with laboratory and clinical parameters of disease activity. The levels of IL-2, IL-4, IL-10, and interferon-gamma were measured in salivary samples, obtained directly from the Stenone duct of 14 Sjögren's syndrome patients and 26 healthy controls by ELISA. A significant elevation of IL-10 was found in salivary fluids of Sjögren's syndrome patients compared with healthy controls (P=0.007). Elevated interferon-gamma levels were found in some patients. IL-2 and IL-4 were undetectable in all saliva samples. In patients, IL-10 levels significantly correlated with the degree of xerophthalmia and xerostomia (P=0.02 and P=0.01, respectively) and with the erythrocyte sedimentation rate (P=0.006). Our data suggest that elevated IL-10 levels are detectable in the saliva of Sjögren's syndrome patients and correlate with the severity of the disease.

Involvement of reactive oxygen species in the bactericidal activity of activated carbon fibre supporting silver; Bactericidal activity of ACF(Ag) mediated by ROS.

An activated carbon fibre supporting silver (ACF(Ag)) was tested for its antibacterial capacity against Escherichia coli (E. coli). Water that has passed through ACF(Ag) demonstrated strong bactericidal ability. This activity decreased over the time suggesting that generated bactericidal species were short lifespan. Since formation of reactive oxygen species (ROS) might be catalysed by silver impregnated and/or ACF itself, implication of ROS and silver was evaluated by the use of ROS scavengers and a silver ions neutralizing agent. The role of ROS in the E. coli mortality was confirmed by the use of a molecular approach which revealed a strong expression of oxidative stress genes.

A self-restricted CD38-connexin 43 cross-talk affects NAD+ and cyclic ADP-ribose metabolism and regulates intracellular calcium in 3T3 fibroblasts.

Connexin 43 (Cx43) hexameric hemichannels, recently demonstrated to mediate NAD(+) transport, functionally interact in the plasma membrane of several cells with the ectoenzyme CD38 that converts NAD(+) to the universal calcium mobilizer cyclic ADP-ribose (cADPR). Here we demonstrate that functional uncoupling between CD38 and Cx43 in CD38-transfected 3T3 murine fibroblasts is paralleled by decreased [Ca(2+)](i) levels as a result of reduced intracellular conversion of NAD(+) to cADPR. A sharp inverse correlation emerged between [Ca(2+)](i) levels and NAD(+) transport (measured as influx into cells and as efflux therefrom), both in the CD38(+) cells (high [Ca(2+)](i), low transport) and in the CD38(-) fibroblasts (low [Ca(2+)](i), high transport). These differences were correlated with distinctive extents of Cx43 phosphorylation in the two cell populations, a lower phosphorylation with high NAD(+) transport (CD38(-) cells) and vice versa (CD38(+) cells). Conversion of NAD(+)-permeable Cx43 to the phosphorylated, NAD(+)-impermeable form occurs via Ca(2+)-stimulated protein kinase C (PKC). Thus, a self-regulatory loop emerged in CD38(+) fibroblasts whereby high [Ca(2+)](i) restricts further Ca(2+) mobilization by cADPR via PKC-mediated disruption of the Cx43-CD38 cross-talk. This mechanism may avoid: (i) leakage of NAD(+) from cells; (ii) depletion of intracellular NAD(+) by CD38; (iii) overproduction of intracellular cADPR resulting in potentially cytotoxic [Ca(2+)](i).

In vitro immunosuppressive activity of soluble HLA class I and Fas ligand molecules: do they play a role in autologous blood transfusion?

BACKGROUND: The immunomodulatory effects of allogeneic blood transfusion may contribute to a poor prognosis in patients with cancer who are undergoing surgery, and clinical trials have been carried out to investigate whether these patients would benefit from autologous blood donation. As the immunomodulatory effects of allogeneic blood transfusion have been related to soluble molecules released from residual WBCs during storage, the in vitro immunomodulatory activity of soluble molecules detected in supernatants from stored autologous blood was evaluated. STUDY DESIGN AND METHODS: Blood was donated by four healthy volunteers. Packed WBC-reduced RBCs were obtained and stored for 30 days, and supernatants were collected. FFP and serum were also obtained. The concentration of soluble molecules was determined by immunoenzymatic assays. The in vitro immunomodulatory activity of undiluted blood component supernatant was assessed by antigen-specific cytotoxic T-cell activity and mixed lymphocyte reactions in autologous combinations and by apoptosis induction in Fas+ cells. RESULTS: The concentrations of soluble Fas-ligand and HLA class I molecules were higher in packed RBCs than in WBC-reduced RBCs, FFP, and serum. Undiluted supernatants of packed RBCs strongly inhibited functional assays and induced apoptosis in Fas+ cells. The immunomodulatory effects were correlated with the amount of soluble Fas ligand and HLA class I molecules. CONCLUSION: The results of the present study are comparable with those already reported in allogeneic blood components, and they indicate that undiluted supernatants of autologous blood components may exert immunosuppressive effects in vitro.

Impairment of CD8+ T suppressor cell function in patients with active systemic lupus erythematosus.

Alteration of T cell suppression function has been recognized in patients with systemic lupus erythematosus (SLE). Recently, CD8(+) T suppressor lymphocytes (CD8(+) Ts) have been generated in vitro by incubating purified CD8(+) T cells with IL-2 and GM-CSF. Using this method, we generated CD8(+) Ts from patients affected by SLE. No major differences were found in the CD8(+) Ts phenotype between SLE patients and healthy subjects. CD8(+) Ts from SLE patients with active disease did not inhibit the anti-CD3 mAb-induced proliferation of autologous PBMC, whereas CD8(+) Ts from SLE patients in remission exerted an inhibitory activity comparable to normal subjects. The inhibitory effect of CD8(+) Ts cells was neither mediated by cytotoxic activity nor by apoptosis induction. Two cytokines, IFN-gamma and IL-6, were found to be responsible for the function of CD8(+) TS: In fact, counteraction of CD8(+) Ts suppression activity was obtained by blocking IFN-gamma with a specific Ab or by inhibiting CD8(+) Ts-mediated IL-6 secretion by an antisense oligonucleotide. Interestingly, CD8(+) Ts from SLE patients showed a peculiar cytokine pattern characterized by an impaired secretion of IL-6 and an increased secretion of IL-12. Thus, it appears that an altered balance between inhibitory (IL-6) and stimulatory (IL-12) cytokines might be responsible for the functional impairment of CD8(+) Ts in SLE patients.

Soluble HLA class I and Fas ligand molecules in blood components and their role in the immunomodulatory effects of blood transfusions.

It has been known for many years that blood transfusions may have immunomodulatory effects, however an ultimate explanation of this phenomenon is lacking. In the present paper we report that the concentrations of soluble HLA class I (sHLA-I) and soluble Fas ligand (sFasL) molecules in supernatants of blood components which contain elevated numbers of residual donor leukocytes, like red blood cells and random-donor platelets, are significantly higher than in other blood components. Elevated amounts of sFasL molecules are also found in some commercial immunoglobulin preparations. sHLA-I and sFasL molecules in blood components and in immunoglobulin preparations are biologically active in vitro as they inhibit mixed lymphocyte responses and cytotoxic T cell activity in allogeneic and autologous combinations and induce apoptosis in Fas-positive cells. If these results are paralleled in vivo the amount of sHLA-I and sFasL molecules should be taken into account in clinical practice in order to select the blood component and the immunoglobulin preparation which could induce the desired immunomodulatory effect in the recipient.

[The immunomodulatory effect of blood transfusions and intravenous immunoglobulins: the role of the soluble molecules of the Class-I major histocompatibility complex and of the Fas ligand]. / Effetto immunomodulatorio delle emotrasfusioni e delle immunoglobuline per via endovenosa: ruolo delle molecole del complesso maggiore di istocompatibilità di classe I e Fas-ligando solubili.

Allogeneic blood transfusions may have immunomodulatory effects including improved allograft acceptance and increased risk for cancer recurrence or post-operative bacterial infections. These effects are associated with the presence of leukocytes in transfused blood and are reduced by pre-storage leuko-reduction. However, the precise mechanism of this effect has not yet been elucidated. We report that the concentrations of soluble major histocompatibility complex class I and soluble Fas-ligand molecules are significantly higher in supernatants of blood components containing elevated numbers of residual donor leukocytes, such as red blood cells and random-donor platelets, than in other blood components. Elevated amounts of soluble Fas-ligand molecules are also found in some intravenous immunoglobulin preparations. Soluble molecules detected in blood components and in immunoglobulin preparations are biologically active in vitro. In fact, they inhibit mixed lymphocyte responses and cytotoxic T cell activity in allogeneic and autologous combinations and induce apoptosis in Fas-positive cells. These results should be taken into account in clinical practice to select the blood component or the immunoglobulin preparation in order to induce or prevent an immunosuppressive effect in the recipient.