Elevations in IFN-gamma, IL-5, and IL-10 in patients with the autoimmune disease primary biliary cirrhosis: association with autoantibodies and soluble CD30

HSCs-derived exosomes regulate the levels of inflammatory cytokines in HIBECs through miR-122-5p mediated p38 MAPK signaling pathway

PBC is an autoimmune-mediated liver disease, and intrahepatic biliary epithelial cells (IBECs) are the target cells of early damage. Previous studies found that miRNAs and inflammation is closely related to PBC. In this study, we extracted exosomes from serum and human IBECs supernatant, and RNA-sequence analyzed the expression profiles of miRNAs. Elisa measured the levels of inflammatory cytokines. RT- qPCR and western blot detected the levels of miR-122-5p, p38 and p-p38. The results showed that 263 differentially expressed (DE) miRNAs were identified in serum exosomes of PBC patients. The levels of IL-1β, IL-6, IL-12, IL-17 A, IFN-γ, TNF-α and TGF-β1 in peripheral blood of PBC patients were higher than those of normal controls. According to the validation results and previous literature, exosomal miR-122-5p was finally selected as the study object, and correlated with inflammatory factors. In vitro experiments further found that exosomal miR-122-5p may derive from hepatic stellate cells (HSCs), and can be HIBECs intake, and influence HIBECs inflammatory factor levels though p38 MAPK signaling pathways. This may provide a new strategy for the treatment of PBC.

Interleukin-30 Suppresses Not Only CD4+ T Cells but Also Regulatory T Cells in Murine Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is a chronic liver autoimmune disease with augmented T helper (Th) 1 and corresponding cytokine IFN-γ immune responses. Using 2-octynoic acid (2-OA) coupled to OVA (2-OA-OVA)-induced mouse models of autoimmune cholangitis (inducible chemical xenobiotic models of PBC), our previous study demonstrated that overexpression of IFN-γ in the model mice enhanced liver inflammation upon disease initiation, but subsequently led to the suppression of chronic inflammation with an increase in interleukin-30 (IL-30) levels. In this study, we investigated whether IL-30 had an immunosuppressive function and whether it could be part of an immune therapeutic regimen for PBC, by treating model mice with murine IL-30-expressing recombinant adeno-associated virus (AAV-mIL-30). We first defined the effects of AAV-mIL-30 in vivo by administering it to a well-known concanavalin A (ConA)-induced hepatitis model of mice and found that AAV-mIL-30 reduced the numbers of activated CD25⁺CD4⁺ T cells and the levels of serum IFN-γ and IL-12. In autoimmune cholangitis, decreased numbers of activated CD4⁺ T cells and Foxp3⁺ regulatory T cells were noted in the mice treated with AAV-mIL-30 at 3 weeks after the 2-OA-OVA immunization. Treatment with IL-30 did not change the features of autoimmune cholangitis including autoantibodies, cell infiltration, and collagen deposition in the liver at 11 weeks of examination. However, increased levels of cytokines and chemokines were observed. These results suggest that IL-30 suppresses not only CD4⁺ T cells but also regulatory T cells. Additionally, the administration of IL-30 did not suppress liver inflammation in the murine model of PBC.

Signaling through the interleukin-4 and interleukin-13 receptor complexes regulates cholangiocyte TMEM16A expression and biliary secretion

TMEM16A is a Ca²⁺-activated Cl^- channel in the apical membrane of biliary epithelial cells, known as cholangiocytes, which contributes importantly to ductular bile formation. Whereas cholangiocyte TMEM16A activity is regulated by extracellular ATP-binding membrane purinergic receptors, channel expression is regulated by interleukin-4 (IL-4) through an unknown mechanism. Therefore, the aim of the present study was to identify the signaling pathways involved in TMEM16A expression and cholangiocyte secretion. Studies were performed in polarized normal rat cholangiocyte monolayers, human Mz-Cha-1 biliary cells, and cholangiocytes isolated from murine liver tissue. The results demonstrate that all the biliary models expressed the IL-4Rα/IL-13Rα1 receptor complex. Incubation of cholangiocytes with either IL-13 or IL-4 increased the expression of TMEM16A protein, which was associated with an increase in the magnitude of Ca²⁺-activated Cl^- currents in response to ATP in single cells and the short-circuit current response in polarized monolayers. The IL-4- and IL-13-mediated increase in TMEM16A expression was also associated with an increase in STAT6 phosphorylation. Specific inhibition of JAK-3 inhibited the increase in TMEM16A expression and the IL-4-mediated increase in ATP-stimulated currents, whereas inhibition of STAT6 inhibited both IL-4- and IL-13-mediated increases in TMEM16A expression and ATP-stimulated secretion. These studies demonstrate that the cytokines IL-13 and IL-4 regulate the expression and function of biliary TMEM16A channels through a signaling pathway involving STAT6. Identification of this regulatory pathway provides new insight into biliary secretion and suggests new targets to enhance bile formation in the treatment of cholestatic liver disorders.NEW & NOTEWORTHY The Ca²⁺-activated Cl^- channel transmembrane member 16A (TMEM16A) has emerged as an important regulator of biliary secretion and hence, ductular bile formation. The present studies represent the initial description of the regulation of TMEM16A expression in biliary epithelium. Identification of this regulatory pathway involving the IL-4 and IL-13 receptor complex and JAK-3 and STAT-6 signaling provides new insight into biliary secretion and suggests new therapeutic targets to enhance bile formation in the treatment of cholestatic liver disorders.

The Contribution of B Cells in Autoimmune Liver Diseases

Autoreactive B cells can promote autoimmunity through antigen presentation to autoreactive T cells, production of autoantibodies, generation of cytokines promoting T cell activation and differentiation, and inhibition of regulatory T cells and B cells. Here, the authors highlight studies pertaining to B cell mechanisms associated with disease pathogenesis and outcomes in autoimmune hepatitis and the immune-mediated cholangiopathies (primary biliary cholangitis, primary sclerosing cholangitis, and biliary atresia). The vast majority of investigations focus on autoantibodies and future research endeavors should include deciphering the role of the B cell in T cell activation (through antigen presentation, cytokine/chemokine production, and inhibition of regulation). Targeting B cell mechanisms in the treatment of autoimmune liver diseases is also highlighted.

Endogenous IL-10 maintains immune tolerance but IL-10 gene transfer exacerbates autoimmune cholangitis

The immunomodulatory effect of IL-10 as an immunosuppressive and anti-inflammatory cytokine is well known. Taking advantage of our established mouse model of autoimmune cholangitis using 2-octynoic acid conjugated ovalbumin (2-OA-OVA) induction, we compared liver pathology, immune cell populations and antimitochondrial antibodies between IL-10 knockout and wild type mice immunized with 2-OA-OVA. At 10 weeks post immunization, portal inflammation and fibrosis were more severe in 2-OA-OVA immunized IL-10 knockout mice than in wild type mice. This was accompanied by significant higher levels of collagen I and III expression, T, NK and NKT subsets in liver and IgG anti-mitochondrial autoantibodies (AMAs) compared to 2-OA-OVA immunized wild type mice, suggesting that endogenous IL-10 is necessary for the maintenance of immune tolerance in primary biliary cholangitis (PBC). Further, we investigated whether administration of exogenous IL-10 could prevent PBC by administration of IL-10 expressing recombinant adeno-associated virus (AAV-IL-10) either 3 days before or 3 weeks after the establishment of liver pathology. Interestingly, administration of AAV-IL-10 resulted in increased liver inflammation and fibrosis, accompanied by increases in IFN-γ in liver CD4⁺ T cell, granzyme B, FasL, and CD107a in liver CD8⁺ T and NKT cells, and granzyme B and FasL in liver NK cells of AAV-IL-10 administered mice compared with control mice. Furthermore, administration of AAV-IL-10 significantly increased levels of proinflammatory cytokines and chemokines (IFN-γ, TNF-α, CXCL9 and CXCL10) and collagen I and III production in naïve mice, together with increase in immune cell infiltration and collagen deposition in the liver, suggesting a role of IL-10 in fibrosis. In conclusion, our data demonstrate that endogenous IL-10 is critical in the maintenance of immune tolerance but exogenous administration of IL-10 exacerbates liver inflammation and fibrosis. Furthermore, the distinctive presence of inflammatory immune cell populations and collagen expression in AAV-IL-10 treated naïve mice cautions against the clinical use of exogenous IL-10 in patients with autoimmune cholangitis.

Dual Roles of IFN-γ and IL-4 in the Natural History of Murine Autoimmune Cholangitis: IL-30 and Implications for Precision Medicine

Primary biliary cirrhosis (PBC) is a progressive autoimmune liver disease with a long natural history. The pathogenesis of PBC is thought to be orchestrated by Th1 and/or Th17. In this study, we investigated the role of CD4⁺ helper T subsets and their cytokines on PBC using our previous established murine model of 2-OA-OVA immunization. We prepared adeno-associated virus (AAV)-IFN-γ and AAV-IL-4 and studied their individual influences on the natural history of autoimmune cholangitis in this model. Administration of IFN-γ significantly promotes recruitment and lymphocyte activation in the earliest phases of autoimmune cholangitis but subsequently leads to downregulation of chronic inflammation through induction of the immunosuppressive molecule IL-30. In contrast, the administration of IL-4 does not alter the initiation of autoimmune cholangitis, but does contribute to the exacerbation of chronic liver inflammation and fibrosis. Thus Th1 cells and IFN-γ are the dominant contributors in the initiation phase of this model but clearly may have different effects as the disease progress. In conclusion, better understanding of the mechanisms by which helper T cells function in the natural history of cholangitis is essential and illustrates that precision medicine may be needed for patients with PBC at various stages of their disease process.

Ustekinumab for patients with primary biliary cholangitis who have an inadequate response to ursodeoxycholic acid: A proof-of-concept study

The interleukin (IL)-12 signaling cascade has been associated with primary biliary cholangitis (PBC). This multicenter, open-label, proof-of-concept study evaluated the anti-IL12/23 monoclonal antibody, ustekinumab (90 mg subcutaneous at weeks 0 and 4, then every 8 weeks through week 20), in adults with PBC and an inadequate response to ursodeoxycholic acid therapy (i.e., alkaline phosphatase [ALP] >1.67× upper limit of normal [ULN] after ≥6 months). ALP response was defined as a >40% decrease from baseline and ALP remission as ALP normalization (if baseline ALP 1.67×-2.8× ULN) or <1.67× ULN (if baseline ALP >2.8× ULN). Changes in Enhanced Liver Fibrosis (ELF) scores and serum bile acids were also assessed. At baseline, patients had median disease duration of 3.2 years, median ELF score of 9.8, and highly elevated total bile acid concentration (median, 43.3 μmol/L); 13 of 20 (65%) patients had baseline ALP >3× ULN. Although steady-state serum ustekinumab concentrations were reached by week 12, no patient achieved ALP response or remission. Median percent ALP reduction from baseline to week 28 was 12.1%. ELF score decreased slightly from baseline to week 28 (median reduction: 0.173), and total serum bile acid concentrations decreased from baseline to week 28 (median reduction: 8.8 μmol/L). No serious infections or discontinuations resulting from adverse events were reported through week 28. One patient had a serious upper gastrointestinal hemorrhage considered unrelated to test agent by the investigator.

CONCLUSION

Open-label ustekinumab therapy, though associated with a modest decrease in ALP after 28 weeks of therapy, did not otherwise appreciably change ALP and overt proof-of-concept was not established as per prespecified primary endpoint of proposed efficacy. No new ustekinumab safety signals were observed. (Hepatology 2016;64:189-199).

The coexistence of Sjögren's syndrome and primary biliary cirrhosis: a comprehensive review

Organ-specific and systemic autoimmune diseases share numerous features and often coexist in the same patient. Autoimmune cholangitis/primary biliary cirrhosis and Sjogren syndrome represent paradigmatic examples of the common grounds of different autoimmunity phenotypes based on similarities in clinical manifestations and immunopathogenesis. In fact, primary biliary cirrhosis and Sjogren's syndrome have both been coined as an autoimmune epithelitis in which apoptosis may be in both cases the key element to explain the organ-specific immune-mediated injury against the biliary and exocrine gland epithelia, respectively. Further, growing evidence supports in both diseases the view that B cells, T cytotoxic cells, and T helper cells are involved in chronic inflammation, likely via the altered expression of pro-inflammatory cytokines. The presence of estrogen receptors on the biliary and exocrine gland epithelia has been advocated as a key to the female predominance encountered in primary biliary cirrhosis and Sjogren's syndrome. Sadly, despite available data, therapeutic approaches remain largely unsatisfactory and recent studies with mechanistic approaches (as in the case of B cell depletion with rituximab) have been of partial benefit only. Future studies should focus on new molecular tools (single-cell transcriptomics, microRNA, epigenetics) to provide unique insights into common mechanisms.

Innate immunity drives the initiation of a murine model of primary biliary cirrhosis

Invariant natural killer T (iNKT) cells play complex roles in bridging innate and adaptive immunity by engaging with glycolipid antigens presented by CD1d. Our earlier work suggested that iNKT cells were involved in the initiation of the original loss of tolerance in primary biliary cirrhosis (PBC). To address this issue in more detail and, in particular, to focus on whether iNKT cells activated by a Th2-biasing agonist (2s,3s,4r)-1-O-(α-_D-galactopyranosyl)-N-tetracosanoyl-2-amino-1,3,4-nonanetriol (OCH), can influence the development of PBC in a xenobiotic-induced PBC murine model. Groups of mice were treated with either OCH or, as a control, α-galactosylceramide (α-GalCer) and thence serially followed for cytokine production, markers of T cell activation, liver histopathology and anti-mitochondrial antibody responses. Further, additional groups of CD1d deleted mice were similarly studied. Our data indicate that administration of OCH has a dramatic influence with exacerbation of portal inflammation and hepatic fibrosis similar to mice treated with α-GalCer. Further, iNKT cell deficient CD1d knockout mice have decreased inflammatory portal cell infiltrates and reduced anti-mitochondrial antibody responses. We submit that activation of iNKT cells can occur via overlapping and/or promiscuous pathways and highlight the critical role of innate immunity in the natural history of autoimmune cholangitis. These data have implications for humans with PBC and emphasize that therapeutic strategies must focus not only on suppressing adaptive responses, but also innate immunity.

Innate immunity drives xenobiotic-induced murine autoimmune cholangitis

Although primary biliary cirrhosis (PBC) is considered a model autoimmune disease, it has not responded therapeutically to traditional immunosuppressive agents. In addition, PBC may recur following liver transplantation, despite the absence of major histocompatibility complex (MHC) matching, in sharp contrast to the well-known paradigm of MHC restriction. We have suggested previously that invariant natural killer T (iNK T) cells are critical to the initiation of PBC. In this study we have taken advantage of our ability to induce autoimmune cholangitis with 2-octynoic acid, a common component of cosmetics, conjugated to bovine serum albumin (2-OA-BSA), and studied the natural history of pathology in mice genetically deleted for CD4 or CD8 following immunization with 2-OA-BSA in the presence or absence of α-galactosylceramide (α-GalCer). In particular, we address whether autoimmune cholangitis can be induced in the absence of traditional CD4 and CD8 responses. We report herein that CD4 and CD8 knock-out mice immunized with 2-OA-BSA/PBS or 2-OA-BSA/α-GalCer develop anti-mitochondrial antibodies (AMAs), portal infiltrates and fibrosis. Indeed, our data suggest that the innate immunity is critical for immunopathology and that the pathology is exacerbated in the presence of α-GalCer. In conclusion, these data provide not only an explanation for the recurrence of PBC following liver transplantation in the absence of MHC compatibility, but also suggest that effective therapies for PBC must include blocking of both innate and adaptive pathways.

Significance of correlation between interferon-γ and soluble intercellular adhesion molecule-1 and interleukin-17 in hepatitis B virus-related cirrhosis

BACKGROUND AND OBJECTIVE

Hepatitis B virus (HBV)-related cirrhosis is known to be associated with chronic hepatic inflammation. The present study aimed to examine the correlation between inflammatory mediators INF-γ, IL-17, and sICAM-1 in HBV cirrhotic patients.

METHODS

The levels of sICAM-1, interleukin-17, and IFN-γ were measured with enzyme-linked immunosorbent assays in 120 cirrhotic patients with HBV and 270 sex- and age-matched healthy controls. Total bilirubin (TB) was measured and the association between TB and IFN-γ, sICAM-1, interleukin-17 were analyzed. The levels of these cytokines in serum and the association between IFN-γ and sICAM-1 as well as interleukin-17 were investigated. Relationships between these cytokines and Child-Pugh classes were analyzed in patients.

RESULTS

Age and sex were similar, but TB values were significantly different between the two groups (P<0.001). Serum levels of sICAM-1, interleukin-17, and IFN-γ were significantly higher in cirrhotic patients with HBV than in controls (P<0.001 for both). TB levels were positively correlated with IFN-γ, interleukin-17 and sICAM-1 levels. Significantly positive correlations were also found between IFN-γ and interleukin-17 as well as sICAM-1 (r=0.817 and r=0.561, respectively, P<0.01). There were significant differences between the studied cytokines (sICAM-1, interleukin-17, and IFN-γ) and Child-Pugh classes (P<0.01).

CONCLUSIONS

The increased IFN-γ level was correlated with both IL-17 and sICAM-1, and it may primarily play a role as cytokines trigger in liver injury. Both IL-17 and sICAM-1 may synergistically contribute to liver damage.

Serum and CSF soluble CD26 and CD30 concentrations in healthy pediatric surgical outpatients

Activated T-helper type 1 (Th1) lymphocytes induce a cellular type immune response, and Th2 lymphocytes, a humoral or antibody-mediated type immune response. Soluble CD26 (sCD26) and soluble CD30 (sCD30) are regarded as markers of Th1 and Th2 lymphocyte activation, respectively. Serum from 112 generally healthy pediatric surgical patients and cerebrospinal fluid (CSF) from 39, aged 1-17 years were measured for sCD26 and sCD30 using an enzyme-linked immunosorbent assay method. The detection limit for sCD26 was 6.8 ng/ml and for sCD30, 1.9 IU/ml. For serum sCD26 and sCD30, 2.5% and 97.5% percentiles constituted the reference limits, and the 95% credible intervals for the percentiles were calculated using regression models with a Bayesian approach. A significant between-gender difference was observed (P = 0.015) in serum sCD26 concentration, of which the lower limits ranged between 273 and 716 ng/ml for girls and 235 and 797 ng/ml for boys. The upper limits ranged between 1456 and 1898 ng/ml for girls and between 1419 and 1981 ng/ml for boys. Moreover, the concentrations of sCD26 increased in infants and children up to 10 years in girls and 12 years in boys. After this however, the values decreased. The serum sCD30 concentration was highest among the youngest infants aged 1 year (80-193 IU/ml), after which a consistent age-related decrease was found. The lowest values were found at the age of 17 years (10-89 IU/ml). A significant between-gender difference in sCD30 concentration was observed (P = 0.019). sCD26 and sCD30 concentrations were low in the CSF samples analyzed: 13.3 ng/ml (median); range 8.3-51.5 ng/ml and 7.6 IU/ml; 2.1-18.5 IU/ml, respectively. Reference limits for serum sCD26 in children aged 1-17 years were established as being 235-1800 ng/ml in toddlers and 400-1800 ng/ml in female adolescents and 700-2000 ng/ml in male adolescents. For sCD30; reference limits of 80-190 IU/ml were established in the youngest age group and 10-90 IU/ml in adolescents.

Fine phenotypic and functional characterization of effector cluster of differentiation 8 positive T cells in human patients with primary biliary cirrhosis

In primary biliary cirrhosis (PBC), patients develop a multilineage response to a highly restricted peptide of the E2 component of pyruvate dehydrogenase (PDC-E2) involving autoantibody and autoreactive cluster of differentiation (CD)4(+) and CD8(+) T-cell responses. Recent data from murine models have suggested that liver-infiltrating CD8(+) cells play a critical role in biliary destruction in PBC. We hypothesized that chronic antigen stimulation of CD8(+) T cells alters effector memory T cell (T(EM) ) frequency and function similar to that seen with chronic viral infections, including failure to terminally differentiate and relative resistance to apoptosis. We have rigorously phenotyped CD8(+) T-cell subpopulations from 132 subjects, including 76 patients with PBC and 56 controls, and report a higher frequency of T(EM) cells characterized as CD45RO(high) CD57(+) CD8(high), but expressing the gut homing integrin, α4β7, in peripheral blood mononuclear cells of PBC. These CD8(high) T(EM) cells have reduced expression of Annexin V after TCR stimulation. Consistent with a T(EM) phenotype, CD45RO(high) CD57(+) CD8(high) T cells express higher levels of granzyme A, granzyme B, perforin, CCR5 and α4β7, and lower levels of CCR7 and CD28 than other CD8(high) T cells. Furthermore, interleukin (IL)-5 produced by CD8(+) CD57(+) T lymphocytes upon in vitro T-cell receptor stimulation are increased in PBC. Histologically, CD8(+) CD57(+) T cells accumulate around the portal area in PBC. Moreover, CD8(+) CD57(+) T cells respond specifically to the major histocompatibility class I epitope of PDC-E2.

CONCLUSION

In conclusion, our data demonstrate that CD45RO(high) CD57(+) CD8(high) T cells are a subset of terminally differentiated cytotoxic T(EM) cells, which could play a critical role in the progressive destruction of biliary epithelial cells.

Hepatic IL-17 responses in human and murine primary biliary cirrhosis

The emergence of new regulatory and pro-inflammatory immune cell subsets and cytokines dictates the need to re-examine the role of these subsets in various diseases involving the immune system. IL-17 has been recently identified as a key cytokine involved in numerous autoimmune processes. However, its role in liver autoimmune diseases remains unclear. Primary biliary cirrhosis (PBC) is characterized histologically by autoreactive CD4 and CD8 T cells surrounding damaged bile ducts. CD4(+) T cells are a major source of IL-17, which compose a distinct T helper subset (Th17). Thus we set out to determine the role of IL-17 in both human and a murine model of PBC in a liver-targeted manner. Our data demonstrate an increase in the frequency of IL-17(+) lymphocytic infiltration in liver tissues from PBC patients and those with other liver dysfunctions as compared to healthy livers. IL-2 receptor alpha knockout mice, a recently identified murine model of human PBC, also demonstrate marked aggregations of IL-17-positive cells within portal tracts and increased frequencies of Th17 cells in the liver compared to the periphery. Interestingly, CD4(+) T cells from livers of normal C57BL/6J mice also secreted higher levels of IL-17 relative to those from spleens, indicating a preferential induction of Th17 cells in liver tissues. Importantly, C57BL/6J cocultures of splenic CD4(+) T cells and liver non-parenchymal cells increased IL-17 production approximately 10-fold compared to T cells alone, suggesting a role of the liver microenvironment in Th17 induction in cases of liver autoimmunity and other liver inflammatory diseases.

High serum soluble CD30 does not predict acute rejection in liver transplant patients

Increased pre- and posttransplantation values of soluble CD30 (sCD30) have been shown to be associated with acute kidney transplant rejection. We sought to study whether high sCD30 could predict rejection early after liver transplantation. The study population included 54 consecutive liver transplant patients, whose samples were collected before liver transplantation and at discharge, which was at a mean time of 3 weeks after transplantation. During the first 6 months posttransplantation, 22 patients experienced an acute rejection episode. Serum sCD30 concentrations were measured by an enzyme-linked immunoassay; changes in serum sCD30 levels posttransplantation were also expressed as relative values compared with pretransplantation results. Liver patients before transplantation displayed higher serum sCD30 values compared with healthy controls: mean values +/- SD were 93 +/- 58 IU/mL vs 17 +/- 8 IU/mL, respectively. At 3 weeks after transplantation the mean sCD30 concentration in liver transplant patients decreased to 59 +/- 42 IU/mL (P = .005). The mean pretransplantation serum sCD30 value was slightly lower among rejecting vs nonrejecting patients: 78 +/- 43 IU/mL vs 104 +/- 65 IU/mL (P = NS). Posttransplantation values in both groups decreased significantly: 47 +/- 34 IU/mL in patients with rejection (P = .014) vs 69 +/- 45 IU/mL in patients without rejection (P = .012). The relative value at 3 weeks posttransplantation decreased slightly more among patients with vs without rejection (70% vs 88%; NS). No correlation was found between serum sCD30 and anti-HLA class I antibodies or crossmatch positivity. In conclusion, neither pre- nor posttransplantation sCD30 levels were associated with acute rejection in liver transplant patients.

Self-reactivities to the non-erythroid alpha spectrin correlate with cerebral malaria in Gabonese children

BACKGROUND

Hypergammaglobulinemia and polyclonal B-cell activation commonly occur in Plasmodium sp. infections. Some of the antibodies produced recognize self-components and are correlated with disease severity in P. falciparum malaria. However, it is not known whether some self-reactive antibodies produced during P. falciparum infection contribute to the events leading to cerebral malaria (CM). We show here a correlation between self-antibody responses to a human brain protein and high levels of circulating TNF alpha (TNFalpha), with the manifestation of CM in Gabonese children.

METHODOLOGY

To study the role of self-reactive antibodies associated to the development of P. falciparum cerebral malaria, we used a combination of quantitative immunoblotting and multivariate analysis to analyse correlation between the reactivity of circulating IgG with a human brain protein extract and TNFalpha concentrations in cohorts of uninfected controls (UI) and P. falciparum-infected Gabonese children developing uncomplicated malaria (UM), severe non-cerebral malaria (SNCM), or CM.

RESULTS/CONCLUSION

The repertoire of brain antigens recognized by plasma IgGs was more diverse in infected than in UI individuals. Anti-brain reactivity was significantly higher in the CM group than in the UM and SNCM groups. IgG self-reactivity to brain antigens was also correlated with plasma IgG levels and age. We found that 90% of CM patients displayed reactivity to a high-molecular mass band containing the spectrin non-erythroid alpha chain. Reactivity with this band was correlated with high TNFalpha concentrations in CM patients. These results strongly suggest that an antibody response to brain antigens induced by P. falciparum infection may be associated with pathogenic mechanisms in patients developing CM.

Are immunological mechanisms involved in colon cancer and are they possible markers for biotherapy improvement?

This paper focuses on our data on colon cancer patients. Our overall results lead us to believe that the suppressive effect of specific cytokines in colon cancer patients alters the functionality of TH1 and TH2 subsets of CD4+ T-cells, with an expansion of TH2 cells and a malfunctioning of TH1 cells. This immunological disregulation appears to increase with stage progression, suggesting a direct role in the mechanisms that allow the tumour to locate and expand within the host. It is also clear that in order to identify disease markers and generate an in vivo immune response that corrects the imbalance between TH1 and TH2 cells, we need to understand how tumour mechanisms cause this imbalance to begin with.

Primary biliary cirrhosis: what we know and what we want to know about human PBC and spontaneous PBC mouse models

Human autoimmune cholangiopathy comprises several intractable liver diseases that ultimately lead to hepatic failure. Primary biliary cirrhosis (PBC), allograft rejection, graft versus host diseases, and, possibly, primary sclerosing cholangitis are representative of immune-mediated cholangiopathies. Among them, PBC is the best-investigated human autoimmune cholangiopathy. The immunological approach to PBC has provided much critical information regarding its pathogenesis. The breakdown of self-tolerance in both B cells and T cells toward E2 components of the pyruvate dehydrogenase complex is evident. However, a number of questions regarding its etiology are unclear, in particular, the mechanisms involved in the selectivity of cholangiocyte destruction. In this brief review, we discuss what we know and we do not know regarding the pathogenesis of PBC.

Increased Levels of Interleukin-10 in Serum from Patients with Hepatocellular Carcinoma Correlate with Profound Numerical Deficiencies and Immature Phenotype of Circulating Dendritic Cell Subsets

Increased levels of interleukin (IL)-10 have been described as a negative prognostic indicator for survival in patients with various types of cancer. IL-10 exerts tolerogenic and immunosuppressive effects on dendritic cells, which are crucial for the induction of an antitumor immune response. Blood dendritic cell antigen (BDCA)-2 and BDCA-4 are specifically expressed by CD123(bright) CD11c- plasmacytoid dendritic cells; whereas BDCA-1 and BDCA-3 define 2 distinct subsets of CD11c+ myeloid dendritic cells. In this study, the T-helper cell (Th)1/Th2 cytokine serum profile of 65 hepatocellular carcinoma patients was assessed. We found that serum levels of IL-10 were substantially increased in hepatocellular carcinoma patients as compared with controls. Peripheral blood mononuclear cells from healthy volunteers were exposed to recombinant human (rh)IL-10 in vitro to additionally characterize its impact on distinct blood dendritic cell subsets. A dramatic decrease of all myeloid dendritic cell (MDC) and plasmacytoid dendritic cell (PDC) subsets was detectable after 24 hours of continuous rhIL-10 exposure. Moreover, the expression of HLA-DR, CD80 and CD86, was significantly reduced on rhIL-10-treated dendritic cell subsets. Direct ex vivo flow cytometric analysis of various dendritic cell subpopulations in peripheral blood from hepatocellular carcinoma patients revealed an immature phenotype and a substantial reduction of circulating dendritic cells that was associated with increased IL-10 concentrations in serum and with tumor progression. These findings confirm a predominantly immunosuppressive role of IL-10 for circulating dendritic cells in patients with hepatocellular carcinoma and, thus, may indicate novel aspects of tumor immune evasion.

Critical role of interleukin 5 and eosinophils in concanavalin A-induced hepatitis in mice

BACKGROUND & AIMS

Eosinophils are observed in several liver diseases, but their contribution in the pathogenesis of these disorders remains poorly investigated. Concanavalin A (Con A)-induced hepatitis is an experimental model of immune-mediated liver injury in which natural killer T (NKT) cells play a critical role through the production of interleukin (IL)-4 and the expression of Fas ligand (FasL). Because activated NKT cells also produce IL-5, a critical cytokine for eosinophil maturation and function, the role of IL-5 was investigated in this model.

METHODS

IL-5-deficient mice, eosinophil depletion in wild-type (WT) mice, and NKT cell transfer from WT- or IL-5-deficient mice into NKT cell-deficient mice were used to assess the role of IL-5 and eosinophils.

RESULTS

Liver eosinophil infiltrate and IL-5 production were observed after Con A challenge. Liver injury was dramatically reduced in IL-5-deficient or eosinophil-depleted mice. In addition, residual hepatitis observed in Fas-deficient mice was abolished after IL-5 neutralization. Finally, we showed that NKT cells constituted a critical source of IL-5. Indeed, transfer of WT NKT cells to mice lacking NKT cells restored liver injury, whereas transfer of IL-5-deficient NKT cells did not.

CONCLUSIONS

These observations highlight the pathologic role of IL-5 and eosinophils in experimental immune-mediated hepatitis.

Interleukin-5 inhibition of biliary cell chloride currents and bile flow

Recent studies have detected significant elevations of interleukin (IL)-5 mRNA in the liver parenchyma of patients with both primary biliary cirrhosis and acute rejection after liver transplantation. In both of these disorders, intrahepatic biliary epithelial cells (BECs) are the targets of injury. We hypothesized that BECs may themselves express IL-5 receptors that may modulate key biliary functions. RNAs coding for IL-5alpha and -beta receptors were amplified by RT/PCR from a biliary cell line derived from a human cholangiocarcinoma (Mz-ChA-1) and verified by DNA sequencing. IL-5 receptor distribution was detected immunocytochemically on Mz-ChA-1 cells, immortalized murine BEC, bile duct-ligated rat liver, and isolated cholangiocytes. Patch-clamp studies on Mz-ChA-1 cells showed that IL-5 inhibits 5'-N-ethylcarboxamidoadenosine-stimulated chloride currents. Additional functional studies showed that IL-5 inhibits secretin-induced bile flow. We conclude that BECs express IL-5 receptors and that IL-5 modulates BEC chloride currents and fluid secretion. Since IL-5 has previously been associated with cholestatic liver disease, we speculate that IL-5 may contribute to liver injury through its effects on biliary secretion.

Role of CD30+ T cells in rheumatoid arthritis: a counter-regulatory paradigm for Th1-driven diseases

CD30 has been proposed to identify Th0/2-type clones. However, the in vivo relevance of this finding is still a matter of debate, as high serum levels of soluble CD30 have been found in both Th1- and Th2- dominated disorders. Among these, rheumatoid arthritis represents a condition where the Th1 predominance is combined with the presence of CD30(+) T-cell activity, particularly in specific stages of the disease. This article discusses the hypothesis that CD30(+) T cells might play a counter-regulatory role at sites of inflammation in Th1-mediated conditions, such as rheumatoid arthritis.

Ex vivo modulation of RANTES and sCD30 by proinflammatory stimuli in HIV-seropositive and -negative individuals

RANTES and sCD30 were measured in ex vivo culture supernatants of unstimulated or stimulated PBMC in order to investigate their potential role as markers of acute immune activation. Patients in an advanced stage of HIV infection (AIDS A) were compared to AIDS patients who were evaluated for pneumonia at the time of blood withdrawal (AIDS B); HIV(+) individuals with nonprogressive infection (LTNP) and healthy donors (N) served as controls. Constitutive levels of RANTES were significantly elevated in AIDS B patients (P 0.0001), whereas spontaneous release of sCD30 was strongly correlated with the presence of both pneumonia (P 0.002) and HIV infection (P 0.004). LPS was a strong inducer of RANTES in all four categories; however, in AIDS B patients a negative and positive correlation between constitutive and induced levels was observed with LPS (P 0.0004) and IFN-gamma (P 0.006), respectively. We clearly showed that IFN-gamma reached a fourfold superinduction of sCD30 release in both HIV-positive and -negative individuals, whereas IL-6-driven production of both sCD30 and RANTES occurred only in healthy donors. Ex vivo RANTES levels may also be monitored as an index of acute immune activation under conditions of chronic activation of the immune system, whereas sCD30 release may be equally indicative of both acute and chronic processes of T cell activation. Proinflammatory stimuli differentially affected RANTES and sCD30 secretion in ex vivo PBMC cultures, suggesting complex pathways in the in vivo regulation of these two molecules.

The restricted expression pattern of the Hodgkin's lymphoma-associated cytokine receptor CD30 is regulated by a minimal promoter

One of the most peculiar immunohistological characteristics of the tumour cells of Hodgkin's lymphoma, anaplastic large cell lymphoma (ALCL), and embryonal carcinoma of the testis is the expression of the CD30 antigen. Physiologically, CD30 expression is restricted to a few activated lymphocytes in normal lymphoid tissue and a small population of decidual cells. To clarify the reasons behind this highly restricted expression pattern and to learn about the combination of transcription factors involved in this regulation in Hodgkin's lymphoma and other CD30(+) malignancies, the 5'-flanking regulatory region of the cd30 gene was analysed. The major transcription start site was determined to be 270 bases upstream of the translational start codon in the Hodgkin's lymphoma-derived cell lines L591 and L428. Reporter gene assays revealed that the CD30 promoter (-413 to 84) induces a 50- to 1000-fold higher luciferase expression in CD30(+) human lymphoid cell lines (Co, Jurkat, and the Hodgkin's lymphoma-derived cell line L540) than in CD30(-) human lymphoid cell lines (DG75, SUP-T1, and U698M), CD30(-) human carcinoma cell lines (HeLa and MCF-7), or COS1 cells. Deletion analysis defined a TATA-less, minimal promoter sequence from -164 to 84. The transcription factor Sp1 and members of the Ets family induce CD30 expression, whereas the transcription factor Sp3 diminishes its induction. These data suggest that a high Sp1/Sp3 expression ratio and a peculiar expression pattern of the Ets transcription factors are involved in the overexpression of CD30 and might contribute to the transformation of CD30(+) tumour cells.

Chronic cholestatic diseases

Chronic cholestatic diseases, whether occurring in infancy, childhood or adulthood, are characterized by defective bile acid transport from the liver to the intestine, which is caused by primary damage to the biliary epithelium in most cases. In this article, approaches to diagnosis and management of the main specific disorders are provided and some of the recent developments in this field are discussed. Major advances in the understanding of the cellular and molecular physiology of bile secretion have led to identification of genetic defects responsible for the different types of progressive familial intrahepatic cholestasis (PFIC). The potential role of the genes involved in PFIC in some adult cholestatic disorders remains to be determined. The majority of adult patients with chronic cholestasis have primary biliary cirrhosis (PBC) or primary sclerosing cholangitis (PSC). Recently, variant forms of PBC have been described. The term autoimmune cholangitis is used to describe patients having chronic non-suppurative cholangitis with negative antimitochondrial antibodies (AMA) but positive antinuclear and/or antismooth muscle antibodies. Autoimmune cholangitis and AMA-positive PBC are quite similar in terms of clinical presentation, survival and response to ursodeoxycholic acid (UDCA) therapy. In contrast, autoimmune cholangitis must be distinguished from PBC-autoimmune hepatitis (AIH) overlap syndrome in which biochemical and histological characteristics of both PBC and AIH coexist. Combination of UDCA and corticosteroids is required in most patients with overlap syndrome to obtain a complete clinical and biochemical response. Long-term UDCA treatment improves survival without liver transplantation in PBC patients. Among the putative mechanisms of the beneficial effects of UDCA, description of anti-apoptotic properties and effect on endotoxin disposal in biliary cells have provided new insights. In patients with incomplete response to UDCA, combination of UDCA with antiinflammatory or immunosuppressive drugs is under evaluation. Variant forms of PSC have also been described, including PSC-AIH overlap syndrome, especially in children or young adults, and small-duct PSC, which is characterized by normal cholangiogram in patients having chronic cholestasis, histologic features compatible with PSC and inflammatory bowel disease. Development of cholangiocarcinoma (CC) is a major feature of PSC, occurring in 10-15% of patients. Early diagnosis of CC is a difficult challenge, although positron emission tomography seems a promising tool. Unlike PBC, effective medical therapy is not yet available in PSC, reflecting the lack of knowledge about the exact pathogenesis of the disease. Currently, liver transplantation is the only effective therapy for patients with advanced disease, although recurrence of PSC in the graft may occur.

Cytokine profile of liver-infiltrating CD4+ T cells separated from murine primary biliary cirrhosis-like hepatic lesions induced by graft-versus-host reaction

BACKGROUND AND METHODS

We have previously reported that CD4+ T cells induced primary biliary cirrhosis (PBC)-like hepatic lesions in mice with graft-versus-host reaction due to major histocompatibility complex class II disparity. To clarify the relationship between the cytokine profile produced by CD4+ T cells and the formation of hepatic lesions, we sorted CD4+ T cells from the liver by using flow cytometry and examined their cytokine mRNA expression at various times after GVHR induction. We also examined the associated changes in the serum levels of antimitochondrial antibodies (AMA).

RESULTS

Histologically, the infiltration of CD4+ T cells around the bile ducts was observed from day 5, and the lesions deteriorated gradually until day 14. On day 14, CD8+, B220+ and Mac-1+ cells, as well as CD4+ T cells were seen around the bile ducts. In the liver-infiltrating CD4+ T cells, the expression level of interferon-gamma (IFN-gamma) mRNA was observed to increase at an early phase (day 3), whereas that of interleukin (IL)-10 mRNA was elevated at a later phase (day 14). The elevation of IFN-gamma mRNA expression at an early phase before the appearance of non-suppurative destructive cholangitis suggests that IFN-gamma may be related to the pathogenesis of PBC in this model. Serum levels of AMA on day 14 were significantly higher than those on day 5. Interleukin-10 was considered to stimulate antibody production, to show an inhibitory effect upon the function of T helper 1 cells, and to inhibit fibrosis.

CONCLUSIONS

Interferon-gamma may play an important role in the pathogenesis of this model. Moreover, delayed expression of IL-10 mRNA may control PBC-like hepatic lesions.

Influence of long term silicone implantation on type II collagen induced arthritis in mice

OBJECTIVES

The use of silicone implants in cosmetic and reconstructive surgery has been implicated in the development of autoimmune connective tissue diseases. Previous investigation of the influence of short-term silicone implantation using an experimental model of rheumatoid arthritis revealed no adverse influence upon disease despite the generation of autoantibodies against silicone bound proteins. This study was designed to examine the influence of long term implantation of different forms of silicone in collagen induced arthritis.

METHODS

DBA/1 mice were surgically implanted with silicone elastomers, gel or oil nine months before immunisation with type II collagen emulsified in Freund's incomplete adjuvant. The incidence and severity of arthritis, antibodies to type II collagen, and serum cytokines were assessed and compared with sham implanted mice. Silicone implants were recovered, and autoantibodies to silicone bound proteins evaluated in arthritic and non-arthritic mice.

RESULTS

Immunisation with CII/FIA resulted in a 30% arthritis incidence in sham implanted DBA/1 mice. Long term silicone implantation resulted in an increased incidence of arthritis, with a significant increase of 90% arthritis in animals implanted with silicone elastomers. Animals implanted with silicone elastomer also developed foreign body sarcomas during the study. Serum concentrations of interleukin 10 were increased in mice implanted with elastomers and immunised with CII/FIA, while interleukin 5 concentrations were significantly diminished in these mice. The production of autoantibodies to autologous silicone bound proteins, including anti-type I collagen antibody, was also attributed to the implantation of either silicone gel or silicone elastomer in type II collagen immunised animals.

CONCLUSIONS

These data suggest that long term silicone implantation results in both the production of autoantibodies to connective tissue antigens and increased susceptibility to an experimental model of autoimmune disease.

Ursodeoxycholic acid inhibits eosinophil degranulation in patients with primary biliary cirrhosis

Eosinophilia is a distinctive feature of primary biliary cirrhosis (PBC), especially in its early stages. Intriguingly, treatment with ursodeoxycholic acid (UDCA) ameliorates eosinophilia as well as liver tests in patients with PBC. It remains unknown, however, whether eosinophils in PBC patients are functionally activated and whether UDCA inhibits eosinophil activation. In the present study, we systematically examined eosinophil dynamics in the blood and liver in patients with stage I to II PBC before and after UDCA treatment. We determined serum concentrations of eosinophil granule proteins (major basic protein [MBP] and eosinophil-derived neurotoxin [EDN]) by radioimmunoassay and quantitated eosinophil degranulation using computer-assisted morphometry after MBP immunohistochemistry. Before UDCA treatment, patients with PBC (n = 25) showed significantly higher circulating eosinophil counts (P <. 05) and serum concentrations of MBP (P <.0005) and EDN (P <.02) compared with patients with chronic viral hepatitis (n = 22), autoimmune hepatitis (n = 10), and obstructive jaundice (n = 12). Four-week UDCA treatment significantly reduced blood eosinophil counts (P <.0001) and serum MBP (P <.0001) and EDN (P <.0001) levels in PBC patients. MBP immunohistochemistry and computer-assisted quantitative morphometry showed infiltration and degranulation of eosinophils in the portal tract in patients with PBC and significant reductions in the number of sites and the area occupied by extracellular MBP deposits after UDCA treatment for 2 years (P <.02) but not in placebo-treated patients. Our results suggest that eosinophils in patients with PBC are not only increased in number, but also release granule proteins, and that UDCA treatment inhibits this eosinophil activation/degranulation.

Soluble cytokine receptor CD30 in atopic disorders: a case-control study

BACKGROUND

The cytokine receptor CD30 is an activation marker of T cells which preferentially associates with the production of the TH2 cytokine IL-4. Therefore, it may potentially be a candidate marker for atopic disorders and a target molecule for new therapeutic approaches.

OBJECTIVE

To test the hypothesis that elevated levels of soluble CD30 (sCD30) are significantly associated with atopic disorders after adjustment for other predictors of atopy.

METHODS

The presence of elevated sCD30 (> or = 20 U/mL) in atopic disorders was evaluated in a nested case-control study. Cases (n = 60) were blood donors with specific IgE antibodies, total serum levels of IgE > or = 100kU/L and presence or history of allergic symptoms. Controls (n = 59) were blood donors without presence or history of allergic symptoms and serum levels of IgE < 50 kU/L. sCD30 was determined from serum samples by an enzyme-linked immunosorbent assay. Odds ratios (OR) and confidence intervals (CI) were calculated from logistic regression coefficients.

RESULTS

Mean sCD30 levels for cases were 75 U/mL (SD 110U/mL) as compared with 35 U/mL (SD 59 U/mL) for controls. Serum levels of sCD30 were elevated in 65% of cases and 32% of controls (OR 3.9, 95% CI 1.8-8.4). The odds ratio for elevated sCD30 as a predictor of atopic disorders slightly decreased to 3.7 after controlling for smoking, age and gender. Blood eosinophilia which was a strong predictor of atopy (OR 11.7) was a weak confounder of the association between sCD30 levels and atopic disorders. Family history of allergy, another strong predictor of atopy (OR 8.6), did not confound the association.

CONCLUSIONS

The results are consistent with the hypothesis that CD30 is involved in the pathogenesis of atopic disorders independent of eosinophilia and family history of allergy.

Expression and cytokine regulation of immune recognition elements by normal human biliary epithelial and established liver cell lines in vitro

BACKGROUND/AIMS

Biliary epithelial cells are targets of immune-mediated attack in conditions such as primary biliary cirrhosis and allograft rejection. This has been attributed to the ability of biliary epithelial cells to express ligands for T cell receptors. We aimed to investigate the expression of immune recognition elements and the effects of pro-inflammatory and anti-inflammatory cytokines on cell surface phenotypes of normal human biliary epithelial cells and established human liver-derived (PLC/PRF/5, HepG2, Hep3B and CC-SW) lines.

METHODS

Cells were cultured in the presence or absence of cytokines for 72 h, and expression of cell surface molecules was assessed by flow cytometry and immunofluorescence.

RESULTS

All cell lines expressed MHC class I, ICAM-1 (CD54), LFA-3 (CD58) and EGF receptor, and all but Hep3B expressed Fas/Apo-1 (CD95). Unlike hepatocyte-derived cell lines, biliary epithelial cells and CC-SW expressed CD40 and CD44. As expected, IFNgamma and TNFalpha upregulated expression of ICAM-1, MHC class I and MHC class II, particularly in biliary epithelial cells. TGFbeta downregulated these molecules and downregulated CD95 on biliary epithelial cells, but upregulated LFA-3. The Th2 cytokines had little effect, although IL-4 upregulated CD95 expression on biliary epithelial cells. IFNgamma upregulated CD40 expression on biliary epithelial cells, CC-SW and HepG2.

CONCLUSIONS

These findings imply that biliary epithelial cells may be capable of interacting with activated T lymphocytes via CD40 and LFA-3, which are thought to be important T cell accessory ligands for T cell activation in a B7-independent manner. Sensitivity to pro-inflammatory cytokines and expression of CD95 may explain why biliary epithelial cells are primary targets for autoimmune attack.

Pathogenesis of primary biliary cirrhosis, primary sclerosing cholangitis, and autoimmune cholangiopathy

Autoimmune liver diseases have much in common with each other, and there are clear associations with genetic haplotypes. Elegant studies have shown autoimmune liver disease induced by viruses and drugs. Although there is evidence for nonimmunological events precipitating immune disease, especially in primary sclerosing cholangitis, the precise pathways, what is bystander and what is essential, have not been determined. This article reviews some of the mechanisms involved in pathogenesis.

Allograft rejection after liver transplantation for autoimmune liver diseases

Autoimmune liver diseases (AILD) may progress to liver failure, requiring liver transplantation as definitive therapy, and these immune-mediated disorders may predispose the patient to more frequent graft rejection. The objective of this study was to determine the effect of preexisting AILD on the incidence of allograft rejection after liver transplantation. Sixty-three patients who underwent liver transplantation between March 1988 and December 1994 for AILDs that included autoimmune hepatitis (AIH; n = 33) and primary biliary cirrhosis (PBC; n = 30) were retrospectively compared with 47 patients who underwent liver transplantation for alcoholic cirrhosis during the same time period. There was a lower incidence of acute allograft rejection in patients with AILD who received tacrolimus-based compared with cyclosporine-based immunosuppression (50% v 85.5%; P = .02). However, patients with AILDs overall had a higher incidence of acute rejection than patients with alcoholic cirrhosis (81% v 46.8%; P < .001), regardless of the type of immunosuppression. In addition, steroid-resistant rejection occurred more frequently in patients with AILDs than in patients with alcoholic cirrhosis (38.1% v 12.8%; P = .003). There was also a trend toward a higher incidence of chronic rejection in patients with AILDs compared with patients with alcoholic cirrhosis (11.1% v 2.1%), but this difference did not reach statistical significance. Patient and graft survivals at 1 and 3 years were similar between patients with AILDs and alcoholic liver disease. Compared with alcoholic cirrhosis, preexisting AILDs are associated with a higher incidence of acute allograft rejection and a trend toward more frequent chronic rejection.