HLA-DPA1*02:01~B1*01:01 is a risk haplotype for primary sclerosing cholangitis mediating activation of NKp44+ NK cells

OBJECTIVE

Primary sclerosing cholangitis (PSC) is characterised by bile duct strictures and progressive liver disease, eventually requiring liver transplantation. Although the pathogenesis of PSC remains incompletely understood, strong associations with HLA-class II haplotypes have been described. As specific HLA-DP molecules can bind the activating NK-cell receptor NKp44, we investigated the role of HLA-DP/NKp44-interactions in PSC.

DESIGN

Liver tissue, intrahepatic and peripheral blood lymphocytes of individuals with PSC and control individuals were characterised using flow cytometry, immunohistochemical and immunofluorescence analyses. HLA-DPA1 and HLA-DPB1 imputation and association analyses were performed in 3408 individuals with PSC and 34 213 controls. NK cell activation on NKp44/HLA-DP interactions was assessed in vitro using plate-bound HLA-DP molecules and HLA-DPB wildtype versus knock-out human cholangiocyte organoids.

RESULTS

NKp44+NK cells were enriched in livers, and intrahepatic bile ducts of individuals with PSC showed higher expression of HLA-DP. HLA-DP haplotype analysis revealed a highly elevated PSC risk for HLA-DPA1*02:01~B1*01:01 (OR 1.99, p=6.7×10-50). Primary NKp44+NK cells exhibited significantly higher degranulation in response to plate-bound HLA-DPA1*02:01-DPB1*01:01 compared with control HLA-DP molecules, which were inhibited by anti-NKp44-blocking. Human cholangiocyte organoids expressing HLA-DPA1*02:01-DPB1*01:01 after IFN-γ-exposure demonstrated significantly increased binding to NKp44-Fc constructs compared with unstimulated controls. Importantly, HLA-DPA1*02:01-DPB1*01:01-expressing organoids increased degranulation of NKp44+NK cells compared with HLA-DPB1-KO organoids.

CONCLUSION

Our studies identify a novel PSC risk haplotype HLA-DP A1*02:01~DPB1*01:01 and provide clinical and functional data implicating NKp44+NK cells that recognise HLA-DPA1*02:01-DPB1*01:01 expressed on cholangiocytes in PSC pathogenesis.

The co-inhibitory receptor TIGIT regulates NK cell function and is upregulated in human intrahepatic CD56bright NK cells

The crosstalk between NK cells and their surrounding environment is enabled through activating and inhibitory receptors, which tightly control NK cell activity. The co-inhibitory receptor TIGIT decreases NK cell cytotoxicity and is involved in NK cell exhaustion, but has also been associated with liver regeneration, highlighting that the contribution of human intrahepatic CD56bright NK cells in regulating tissue homeostasis remains incompletely understood. A targeted single-cell mRNA analysis revealed distinct transcriptional differences between matched human peripheral blood and intrahepatic CD56bright NK cells. Multiparameter flow cytometry identified a cluster of intrahepatic NK cells with overlapping high expression of CD56, CD69, CXCR6, TIGIT and CD96. Intrahepatic CD56bright NK cells also expressed significantly higher protein surface levels of TIGIT, and significantly lower levels of DNAM-1 compared to matched peripheral blood CD56bright NK cells. TIGIT+ CD56bright NK cells showed diminished degranulation and TNF-α production following stimulation. Co-incubation of peripheral blood CD56bright NK cells with human hepatoma cells or primary human hepatocyte organoids resulted in migration of NK cells into hepatocyte organoids and upregulation of TIGIT and downregulation of DNAM-1 expression, in line with the phenotype of intrahepatic CD56bright NK cells. Intrahepatic CD56bright NK cells represent a transcriptionally, phenotypically, and functionally distinct population of NK cells that expresses higher levels of TIGIT and lower levels of DNAM-1 than matched peripheral blood CD56bright NK cells. Increased expression of inhibitory receptors by NK cells within the liver environment can contribute to tissue homeostasis and reduction of liver inflammation.

Single-cell atlas of hepatic T cells reveals expansion of liver-resident naive-like CD4+ T cells in primary sclerosing cholangitis

BACKGROUND & AIMS

Little is known about the composition of intrahepatic immune cells and their contribution to the pathogenesis of primary sclerosing cholangitis (PSC). Herein, we aimed to create an atlas of intrahepatic T cells and thereby perform an in-depth characterization of T cells in inflamed human liver.

METHODS

Different single-cell RNA sequencing methods were combined with in silico analyses on intrahepatic and peripheral T cells from patients with PSC (n = 11) and healthy donors (HDs, n = 4). Multi-parameter flow cytometry and functional in vitro experiments were conducted on samples from patients with PSC (n = 24), controls with other liver diseases and HDs.

RESULTS

We identified a population of intrahepatic naive-like CD4⁺ T cells, which was present in all liver diseases tested, but particularly expanded in PSC. This population had a transcriptome and T cell receptor repertoire similar to circulating naive T cells but expressed a set of genes associated with tissue residency. Their periductal location supported the concept of tissue-resident naive-like T cells in livers of patients with PSC. Trajectory inference suggested that these cells had the developmental propensity to acquire a T helper 17 (T_H17) polarization state. Functional and chromatin accessibility experiments revealed that circulating naive T cells in patients with PSC were predisposed to polarize towards T_H17 cells.

CONCLUSION

We report the first atlas of intrahepatic T cells in PSC, which led to the identification of a previously unrecognized population of tissue-resident naive-like T cells in the inflamed human liver and to the finding that naive CD4⁺ T cells in PSC harbour the propensity to develop into T_H17 cells.

LAY SUMMARY

The composition of intrahepatic immune cells in primary sclerosing cholangitis (PSC) and their contribution to disease pathogenesis is widely unknown. We analysed intrahepatic T cells and identified a previously uncharacterized population of liver-resident CD4⁺ T cells which are expanded in the livers of patients with PSC compared to healthy liver tissue and other liver diseases. These cells are likely to contribute to the pathogenesis of PSC and could be targeted in novel therapeutic approaches.

IL-17A/F enable cholangiocytes to restrict T cell-driven experimental cholangitis by upregulating PD-L1 expression

BACKGROUND & AIMS

IL-17A-producing T cells are present in autoimmune cholestatic liver diseases; however, little is known about the contribution of IL-17 to periductal immune responses. Herein, we investigated the role of IL-17 produced by antigen-specific CD8⁺ T cells in a mouse model of cholangitis and in vitro in human cholangiocyte organoids.

METHODS

K14-OVAp mice express a major histocompatibility complex I-restricted ovalbumin (OVA) peptide sequence (SIINFEKL) on cholangiocytes. Cholangitis was induced by the adoptive transfer of transgenic OVA-specific ovalbumin transgene (OT)-1 CD8⁺ T cells that either had OT-1^wt or lacked IL-17A/F (OT-1^IL17ko). The response of mouse and human cholangiocytes/organoids to IL-17A was assessed in vitro.

RESULTS

Transfer of OVA-specific OT-1^IL17ko cells significantly aggravated periductal inflammation in K14-OVAp recipient mice compared with transfer of OT-1^wt T cells. OT-1^IL17ko T cells were highly activated in the liver and displayed increased cytotoxicity and proliferation. IL-17A/F produced by transferred OT-1^wt CD8⁺ T cells induced upregulation of the inhibitory molecule programmed cell death ligand 1 (PD-L1) on cholangiocytes, restricting cholangitis by limiting cytotoxicity and proliferation of transferred cells. In contrast, OT-1^IL17ko T cells failed to induce PD-L1 on cholangiocytes, resulting in uncontrolled expansion of cytotoxic CD8⁺ T cells and aggravated cholangitis. Blockade of PD-L1 after transfer of OT-1^wt T cells with anti-PD-L1 antibody also resulted in aggravated cholangitis. Using human cholangiocyte organoids, we were able to confirm that IL-17A induces PD-L1 expression in cholangiocytes.

CONCLUSIONS

We demonstrate that by upregulating PD-L1 on cholangiocytes, IL-17 has an important role in restricting cholangitis and protecting against CD8⁺ T cell-mediated inflammatory bile duct injury. Caution should be exercised when targeting IL-17 for the treatment of cholangitis.

LAY SUMMARY

IL-17 is assumed to be a driver of inflammation in several autoimmune diseases, such as psoriasis. IL-17 is also present in inflammatory diseases of the bile duct, but its role in these conditions is not clear, as the effects of IL-17 depend on the context of its expression. Herein, we investigated the role of IL-17 in an experimental autoimmune cholangitis mouse model, and we identified an important protective effect of IL-17 on cholangiocytes, enabling them to downregulate bile duct inflammation via checkpoint inhibitor PD-L1.

Failure of thymic deletion and instability of autoreactive Tregs drive autoimmunity in immune-privileged liver

The liver is an immune-privileged organ that can deactivate autoreactive T cells. Yet in autoimmune hepatitis (AIH), autoreactive T cells can defy hepatic control and attack the liver. To elucidate how tolerance to self-antigens is lost during AIH pathogenesis, we generated a spontaneous mouse model of AIH, based on recognition of an MHC class II–restricted model peptide in hepatocytes by autoreactive CD4⁺ T cells. We found that the hepatic peptide was not expressed in the thymus, leading to deficient thymic deletion and resulting in peripheral abundance of autoreactive CD4⁺ T cells. In the liver, autoreactive CD4⁺ effector T cells accumulated within portal ectopic lymphoid structures and maturated toward pathogenic IFN-γ and TNF coproducing cells. Expansion and pathogenic maturation of autoreactive effector T cells was enabled by a selective increase of plasticity and instability of autoantigen-specific Tregs but not of nonspecific Tregs. Indeed, antigen-specific Tregs were reduced in frequency and manifested increased IL-17 production, reduced epigenetic demethylation, and reduced expression of Foxp3. As a consequence, autoantigen-specific Tregs had a reduced suppressive capacity, as compared with that of nonspecific Tregs. In conclusion, loss of tolerance and the pathogenesis of AIH were enabled by combined failure of thymic deletion and peripheral regulation.

Monocytes as Potential Mediators of Pathogen-Induced T-Helper 17 Differentiation in Patients With Primary Sclerosing Cholangitis (PSC)

BACKGROUND AND AIMS

T cells from patients with primary sclerosing cholangitis (PSC) show a prominent interleukin (IL)-17 response upon stimulation with bacteria or fungi, yet the reasons for this dominant T-helper 17 (Th17) response in PSC are not clear. Here, we analyzed the potential role of monocytes in microbial recognition and in skewing the T-cell response toward Th17.

APPROACH AND RESULTS

Monocytes and T cells from blood and livers of PSC patients and controls were analyzed ex vivo and in vitro using transwell experiments with cholangiocytes. Cytokine production was measured using flow cytometry, enzyme-linked immunosorbent assay, RNA in situ hybridization, and quantitative real-time PCR. Genetic polymorphisms were obtained from ImmunoChip analysis. Following ex vivo stimulation with phorbol myristate acetate/ionomycin, PSC patients showed significantly increased numbers of IL-17A-producing peripheral blood CD4⁺ T cells compared to PBC patients and healthy controls, indicating increased Th17 differentiation in vivo. Upon stimulation with microbes, monocytes from PSC patients produced significantly more IL-1β and IL-6, cytokines known to drive Th17 cell differentiation. Moreover, microbe-activated monocytes induced the secretion of Th17 and monocyte-recruiting chemokines chemokine (C-C motif) ligand (CCL)-20 and CCL-2 in human primary cholangiocytes. In livers of patients with PSC cirrhosis, CD14^hiCD16^int and CD14^loCD16^hi monocytes/macrophages were increased compared to alcoholic cirrhosis, and monocytes were found to be located around bile ducts.

CONCLUSIONS

PSC patients show increased Th17 differentiation already in vivo. Microbe-stimulated monocytes drive Th17 differentiation in vitro and induce cholangiocytes to produce chemokines mediating recruitment of Th17 cells and more monocytes into portal tracts. Taken together, these results point to a pathogenic role of monocytes in patients with PSC.

The Transcription Factor Promyelocytic Leukemia Zinc Finger Protein Is Associated With Expression of Liver-Homing Receptors on Human Blood CD56bright Natural Killer Cells

The transcription factor promyelocytic leukemia zinc finger protein (PLZF) is involved in the development of natural killer (NK) cells and innate lymphoid cells, including liver-resident NK cells in mice. In human NK cells, the role of PLZF in liver residency is still unknown. Expression of PLZF in matched human peripheral blood- and liver-derived NK cells and the association of PLZF expression with surface molecules and transcription factors relevant for tissue residency were investigated using multiparameter flow cytometry and assessing single-cell messenger RNA (mRNA) levels. Intrahepatic cluster of differentiation (CD)56^bright NK cells expressed significantly higher levels of PLZF than peripheral blood CD56^bright NK cells, which were predominantly PLZF^lo. Expression of PLZF was highest within C-X-C motif chemokine receptor 6 (CXCR6)⁺CD69⁺ liver-resident NK cells among intrahepatic CD56^bright NK cell populations. Association of PLZF with liver-residency markers was also reflected at mRNA levels. A small PLZF^hiCD56^bright NK cell population was identified in peripheral blood that also expressed the liver-residency markers CXCR6 and CD69 and shared functional characteristics with liver-resident NK cells. Conclusion: PLZF is implicated as part of a transcriptional network that promotes liver residency of human NK cells. Expression of liver-homing markers on peripheral blood PLZF^hiCD56^bright NK cells identifies an intermediate population potentially contributing to the maintenance of liver-resident NK cells.

Interferon-γ-dependent immune responses contribute to the pathogenesis of sclerosing cholangitis in mice

BACKGROUND AND AIMS

Primary sclerosing cholangitis (PSC) is an idiopathic, chronic cholestatic liver disorder characterized by biliary inflammation and fibrosis. Increased numbers of intrahepatic interferon-γ- (IFNγ) producing lymphocytes have been documented in patients with PSC, yet their functional role remains to be determined.

METHODS

Liver tissue samples were collected from patients with PSC. The contribution of lymphocytes to liver pathology was assessed in Mdr2-/- x Rag1-/- mice, which lack T and B cells, and following depletion of CD90.2+ or natural killer (NK)p46+ cells in Mdr2-/- mice. Liver pathology was also determined in Mdr2-/- x Ifng-/- mice and following anti-IFNγ antibody treatment of Mdr2-/- mice. Immune cell composition was analysed by multi-colour flow cytometry. Liver injury and fibrosis were determined by standard assays.

RESULTS

Patients with PSC showed increased IFNγ serum levels and elevated numbers of hepatic CD56bright NK cells. In Mdr2-/- mice, hepatic CD8+ T cells and NK cells were the primary source of IFNγ. Depletion of CD90.2+ cells reduced hepatic Ifng expression, NK cell cytotoxicity and liver injury similar to Mdr2-/- x Rag1-/- mice. Depletion of NK cells resulted in reduced CD8+ T cell cytotoxicity and liver fibrosis. The complete absence of IFNγ in Mdr2-/-x Ifng-/- mice reduced NK cell and CD8+ T cell frequencies expressing the cytotoxic effector molecules granzyme B and TRAIL and prevented liver fibrosis. The antifibrotic effect of IFNγ was also observed upon antibody-dependent neutralisation in Mdr2-/- mice.

CONCLUSION

IFNγ changed the phenotype of hepatic CD8+ T cells and NK cells towards increased cytotoxicity and its absence attenuated liver fibrosis in chronic sclerosing cholangitis. Therefore, unravelling the immunopathogenesis of PSC with a particular focus on IFNγ might help to develop novel treatment options.

LAY SUMMARY

Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease characterized by biliary inflammation and fibrosis, whose current medical treatment is hardly effective. We observed an increased interferon (IFN)-γ response in patients with PSC and in a mouse model of sclerosing cholangitis. IFNγ changed the phenotype of hepatic CD8+ T lymphocytes and NK cells towards increased cytotoxicity, and its absence decreased liver cell death, reduced frequencies of inflammatory macrophages in the liver and attenuated liver fibrosis. Therefore, IFNγ-dependent immune responses may disclose checkpoints for future therapeutic intervention strategies in sclerosing cholangitis.

CD49a Expression Identifies a Subset of Intrahepatic Macrophages in Humans

Macrophages play central roles in inflammatory reactions and initiation of immune responses during infections. More than 80% of total tissue macrophages are described to be located in the liver as liver-resident macrophages, also named Kupffer cells (KCs). While studies in mice have established a central role of liver-resident KCs in regulating liver inflammation, their phenotype and function are not well-characterized in humans. Comparing paired human liver and peripheral blood samples, we observed significant differences in the distribution of macrophage (Mφ) subsets, with lower frequencies of CD14^hiCD16^lo and higher frequencies of CD14^int−hiCD16^int Mφ in human livers. Intrahepatic Mφ consisted of diverse subsets with differential expression of CD49a, a liver-residency marker previously described for human and mice NK cells, and VSIG4 and/or MARCO, two recently described human tissue Mφ markers. Furthermore, intrahepatic CD49a⁺ Mφ expressed significantly higher levels of maturation and activation markers, exhibited higher baseline levels of TNF-α, IL-12, and IL-10 production, but responded less to additional in vitro TLR stimulation. In contrast, intrahepatic CD49a⁻ Mφ were highly responsive to stimulation with TLR ligands, similar to what was observed for CD49a⁻ monocytes (MOs) in peripheral blood. Taken together, these studies identified populations of CD49a⁺, VSIG4⁺, and/or MARCO⁺ Mφ in human livers, and demonstrated that intrahepatic CD49a⁺ Mφ differed in phenotype and function from intrahepatic CD49a⁻ Mφ as well as from peripheral blood-derived monocytes.

CCL21-expression and accumulation of CCR7+ NK cells in livers of patients with primary sclerosing cholangitis

The pathogenesis of primary sclerosing cholangitis (PSC), an autoimmune liver disease, remains unknown. The aim of this study was to characterize peripheral blood and intrahepatic NK cells from patients with PSC. Peripheral blood samples from patients with PSC, other autoimmune liver diseases, and from healthy control individuals were used, as well as liver tissues from PSC patients undergoing liver transplantation. Multiparameter flow cytometry showed that peripheral blood NK cells from PSC patients were significantly enriched for CCR7⁺ and CXCR3⁺ cells, and CCR7⁺ but not CXCR3⁺ cells were also significantly increased within intrahepatic NK cells. PSC patients undergoing liver transplantation furthermore had significantly higher plasma levels of the CCR7-ligand CCL21, and the CXCR3-ligands CXCL10 and CXCL11, and significantly higher levels of CCL21, but not CXCL10, were detected in liver tissues. CCR7⁺ and CXCR3⁺ NK cells from PSC patients exhibited significantly higher functional capacity in peripheral blood, but not liver tissues, consistent with chronic activation of these NK cells in the inflamed liver. These data show that PSC is characterized by intrahepatic CCL21 expression and accumulation of CCR7⁺ NK cells in the inflamed liver tissue.

Human liver-derived CXCR6+ NK cells are predominantly educated through NKG2A and show reduced cytokine production

NK cells have been implicated to affect the outcome of numerous liver diseases. In particular, members of the killer-cell Ig-like receptor (KIR) family, predominantly expressed by NK cells, have been associated with the outcome of hepatitis C virus infection and clearance of hepatocellular carcinoma. Inhibitory KIRs tune NK cell function through interaction with HLA class I, a process termed education. Nevertheless, the impact of the hepatic environment on NK cell education is incompletely understood. Therefore, we investigated the composition and function of hepatic KIR-expressing NK cells. Matched PBMC and hepatic lymphocytes were isolated from 20 individuals undergoing liver surgery and subsequently phenotypically analyzed for expression of KIRs and markers for tissue residency using flow cytometry. NK cell function was determined by co-culturing NK cells with the target cell line 721.221 and subsequent assessment of CD107a, IFN-γ, and TNF-α expression. Liver-resident CXCR6⁺ /CD56^Bright NK cells lacked KIRs and were predominantly educated through NKG2A, while CXCR6^- /CD16⁺ NK cells expressed KIRs and resembled peripheral blood NK cells. Hepatic NK cells showed lower response rates compared to peripheral blood NK cells; in particular, CXCR6⁺ NK cells were hyporesponsive to stimulation with target cells. The high proportion of educated NK cells in both subsets indicates the importance of self-inhibitory receptors for the balance between maintenance of self-tolerance and functional readiness. However, the reduced functionality of hepatic NK cells may reflect the impact of the tolerogenic hepatic environment on NK cells irrespective of NK cell education.

Interactions Between KIR3DS1 and HLA-F Activate Natural Killer Cells to Control HCV Replication in Cell Culture

Killer-cell immunoglobulin-like receptors (KIRs) are transmembrane glycoproteins expressed by natural killer (NK) cells. Binding of KIR3DS1 to its recently discovered ligand, HLA-F, activates NK cells and has been associated with resolution of hepatitis C virus (HCV) infection. We investigated the mechanisms by which KIR3DS1 contributes to the antiviral immune response. Using cell culture systems, mice with humanized livers, and primary liver tissue from HCV-infected individuals, we found that the KIR3DS1 ligand HLA-F is up-regulated on HCV-infected cells, and that interactions between KIR3DS1 and HLA-F contribute to NK cell-mediated control of HCV. Strategies to promote interaction between KIR3DS1 and HLA-F might be developed for treatment of infectious diseases and cancer.

Tissue-resident NK cells differ in their expression profile of the nutrient transporters Glut1, CD98 and CD71

Metabolism is a critical basis for immune cell functionality. It was recently shown that NK cell subsets from peripheral blood modulate their expression of nutrient receptors following cytokine stimulation, demonstrating that NK cells can adjust to changes in metabolic requirements. As nutrient availability in blood and tissues can significantly differ, we examined NK cells isolated from paired blood-liver and blood-spleen samples and compared expression of the nutrient transporters Glut1, CD98 and CD71. CD56^bright tissue-resident (CXCR6⁺) NK cells derived from livers and spleens expressed lower levels of Glut1 but higher levels of the amino acid transporter CD98 following stimulation than CD56^bright NK cells from peripheral blood. In line with that, CD56^dim NK cells, which constitute the main NK cell population in the peripheral blood, expressed higher levels of Glut1 and lower levels of CD98 and CD71 compared to liver CD56^bright NK cells. Our results show that NK cells from peripheral blood differ from liver- and spleen-resident NK cells in the expression profile of nutrient transporters, consistent with a cell-adaptation to the different nutritional environment in these compartments.

Mechanistic peculiarities of activation-induced mobilization of cytotoxic effector proteins in human T cells

It is widely accepted that cytotoxic T and NK cells store effector proteins including granzymes, perforin and Fas ligand (FasL) in intracellular granules, often referred to as secretory lysosomes. Upon target cell encounter, these organelles are transported to the cytotoxic immunological synapse, where they fuse with the plasma membrane to release the soluble effector molecules and to expose transmembrane proteins including FasL on the cell surface. We previously described two distinct species of secretory vesicles in T and NK cells that differ in size, morphology and protein loading, most strikingly regarding FasL and granzyme B. We now show that the signal requirements for the mobilization of one or the other granule also differ substantially. We report that prestored FasL can be mobilized independent of extracellular Ca2+, whereas the surface exposure of lysosome-associated membrane proteins (Lamps; CD107a and CD63) and the release of granzyme B are calcium-dependent. The use of selective inhibitors of actin dynamics unequivocally points to different transport mechanisms for individual vesicles. While inhibitors of actin polymerization/dynamics inhibit the surface appearance of prestored FasL, they increase the activation-induced mobilization of CD107a, CD63 and granzyme B. In contrast, inhibition of the actin-based motor protein myosin 2a facilitates FasL-, but impairs CD107a-, CD63- and granzyme B mobilization. From our data, we conclude that distinct cytotoxic effector granules are differentially regulated with respect to signaling requirements and transport mechanisms. We suggest that a T cell might 'sense' which effector proteins it needs to mobilize in a given context, thereby increasing efficacy while minimizing collateral damage.

Proliferative capacity exhibited by human liver-resident CD49a+CD25+ NK cells

The recruitment and retention of Natural Killer (NK) cells in the liver are thought to play an important role during hepatotropic infections and liver cirrhosis. The aims of this study were to determine differences between liver-derived and peripheral blood-derived NK cells in the context of liver inflammation and cirrhosis. We conducted a prospective dual-center cross-sectional study in patients undergoing liver transplantation or tumor-free liver resections, in which both liver tissue and peripheral blood samples were obtained from each consenting study participants. Intrahepatic lymphocytes and PBMCs were stained, fixed and analyzed by flow cytometry. Our results showed that, within cirrhotic liver samples, intrahepatic NK cells were particularly enriched for CD49a+ NK cells when compared to tumor-free liver resection samples. CD49a+ liver-derived NK cells included populations of cells expressing CD25, CD34 and CXCR3. Moreover, CD49a+CD25+ liver-derived NK cells exhibited high proliferative capacity in vitro in response to low doses of IL-2. Our study identified a specific subset of CD49a+CD25+ NK cells in cirrhotic livers bearing functional features of proliferation.

[Pseudoaneurysm of the hepatic artery presenting with hemobilia--a complication of laparoscopic cholecystectomy]

INTRODUCTION

Hemobilia, defined as a bleeding into the bile duct, is a rare disease. One of its infrequent causes is a hepatic artery pseudoaneurysm, usually developed after arterial iatrogenic leasion.

MATERIAL AND METHODS

A case review, presenting right hepatic artery pseudoaneurysm with a biliovascular fistula as a consequence of hepatic artery and bile duct injuries during "uncomplicated" laparoscopic cholecystectomy.

DISCUSSION

Bile duct injury is one of the most serious complication after laparoscopic cholecystectomy. Hepatic artery may be injured simultaneously, resulting in the pseudoaneurysm and/or biliovascular fistula, presenting with hemobilia. Time interval from the injury to symptoms widely varies from few hours to weeks or even several months.

CONCLUSION

Melena or hematemesis after recent laparoscopic cholecystectomy should be always suspicious from hepatic artery and/or bile duct injuries, manifesting with hemobilia.

[Infliximab in the treatment of Wegener's granulomatosis: case report]

PURPOSE

to evaluate the efficacy of monoclonal anti-tumor necrosis factor alpha antibody infliximab in treatment of refractory Wegene's granulomatosis. Clinical manifestations of Wegener's granulomatosis at the time of infliximab initiation were: proptosis of both eyes due to progressive retrobulbar granulomas, visual impairment, optic disc edema, progressive diplopia, sinus and renal involvement. The disease was refractory to a treatment with various immunosuppressants, including intravenous cyclophosphamide or high doses of mycophenolate mofetil in combination with corticosteroids.

METHODS

Observational case report.

RESULTS

the patient received six infusions of infliximab (3 mg/kg) in addition to low doses of oral cyclophosphamide and corticosteroids. The interval between the first two infusions was 1 week. The interval between the second and third infusions was 4 weeks, thereafter 8, 12 and 34 weeks. Following the third infusion of infliximab the remission of Wegener's granulomatosis was seen. After the regression of retrobulbar granulomas visual acuity increased, ocular motility improved, diplopia and optic disc edema decreased. Remission has been maintained for 17 months. Infliximab was well tolerated during the short-term follow-up.

CONCLUSION

Infliximab successfully induced remission in case of sight-threatening Wegener's granulomatosis in our patient. It seems that infliximab provides more effective therapeutic option in treatment of Wegener's granulomatosis refractory to standard immunosuppression and offers better perspectives for patients with previously poor prognosis. Furthermore, it enables reducing the exposure to immunosuppressive drugs.

[The chemiluminescence test in the laboratory evaluation of effects of immunostimulatory therapy]

BACKGROUND

Number of patients treated by general practitioners with various immunomodulatory drugs has recently increased. Effects of such medication on the immune system were not usually monitored. The aim of our work was to evaluate effect of selected immunomodulatory drugs on the phagocytic and metabolic activities of the phagocytes.

METHODS AND RESULTS

51 patients (18 males and 33 females) of the average age 36 years with repeating respiratory, mycotic and herpetic infections were investigated. Immunomodulatory treatment included: Decaris (Lavamizolum), Isoprinosine (Methisoprinolum), Imudon (Lysatum bacteriale mixtum), Biostim (Klebsiella pneumoniae), and Immodin (Leukocyti dialysati lyophylysatum). Before and after treatment all patients underwent basic immunological examination IgG, IgA, IgM, C3, C4 complement components, PEG, CD3, CD4, CD8 and CD19). Phagocytotic activity was estimated by means of FAGO MSHP test with HEMA particles and by chemiluminiscence test. Chemiluminiscence was measured using ML 3000 Microtiter Plate Luminometer (Dynex), 26 healthy individuals of the corresponding age were the controls. Results were statistically evaluated by Student's t-test. Significant increase of the cellular metabolic activity was found in Decaris and Immodin treated patients (P < 0.001).

CONCLUSIONS

Chemiluminiscence test, which evaluates the metabolic activity of phagocytes, can be used for the accurate laboratory monitoring of the effects of some immunomodulatory drugs on the natural immunity of patients.

[CD5-positive B lymphocytes and antinuclear antibodies]

BACKGROUND

The production of natural autoantibodies incl. antinuclear antibodies (ANA) is ascribed to lymphocytes which have a CD5 molecule on their surface. The role of CD5 positive B lymphocytes in the induction of autoimmunity is obscure so far. The authors focused their attention on the incidence of antinuclear antibodies (AA) in subjects with different diseases and sought a relationship with the ratio of CD5 positive B lymphocytes in the peripheral blood stream.

METHODS AND RESULTS

CD5 positive lymphocytes were assessed on a flow cytometer using monoclonal anti CD5 and anti CD19 antibodies. Antinuclear antibodies are detected by indirect fluorescence on a substrate of human leucocytes and HEP-2 cells. In a group of 134 subjects the authors did not provide evidence of a direct relationship between the relative number of CD5 positive B lymphocytes in the peripheral blood stream and the presence of ANA (IgG, IgA, IgM), not even in 33 patients with autoimmune diseases. In 86 patients the authors revealed that antinuclear antibodies type IgM predominate in patients with repeated respiratory infections. In systemic diseases the isotype IgG predominates (p = 0.01). After immunosuppressive treatment with a favourable clinical effect the ANA isotype IgG disappears and isotype IgM is found more frequently. The incidence of the ANA isotype IgM is significantly higher in healthy subjects aged over 60 years than in younger subjects (12.5%/6.1%, p = 0.06), and more frequent in women (p = 0.05).

CONCLUSIONS

The presence of antinuclear antibodies is not associated with the amount of CD5 positive B lymphocyte in the peripheral blood stream.

[Behcet's disease]

The author evaluates diagnostic and therapeutic results in nine patients with Behcet's disease investigated at the uveological ambulance of the First Ophthalmological Clinic, Medical Faculty Charles University in Prague during 1987-1996. Anterior uveitis with hypopyon was recorded twice as frequently as retinal vasculitis. Chronic CME, secondary glaucoma and occlusive vasculitis were the most serious complications of ophthalmological manifestations of BD. Ulcerations of connective tissue and skin manifestations of BD were found most frequently in the authors patients. In two thirds of the patients also the risk phenotype HLA B5 was recorded.

[Diagnosis and therapy of Wegener's granulomatosis based on ocular changes]

The authors draw attention to the different ophthalmological manifestations of Wegener's granulomatosis in two patients examined at the First Ophthalmological Clinic of the First Medical Faculty, Charles University, Prague. The patients complaints led later to establishment of the diagnosis of WG or its relapse. Combined immunosuppressive treatment with steroids and cyclophosphamide relieved the ocular as well as general manifestations of WG.

[Acute anterior uveitis, systemic diseases and HLA-B27]

The author investigated the rate of phenotype HLA-B27 and systemic diseases in patients with acute anterior uveitis (AAU) in our geographical area. The evaluated clinical differences of AAU manifestations in HLA-B27 positive and HLA-B27 negative patients in a group of 104 subjects followed up for a 10-year period. The patients were under 40 years of age. Men were affected twice as frequently as women. HLA B27 positive AAU is manifested above all by serofibrous exsudation into the anterior chamber and by more frequent relapses. In patients with early treatment there were fewer complications and the prognosis was favourable. AAU in HLA-B27 positive patients is associated in 65% with rheumatic disease. In our population it is above all ankylosing spondylitis and Reiter's disease. In 71% rheumatic diseases were manifested in men. Despite the different clinical course of AAU HLA-B27 positive and negative patients, during long-term follow up the visual acuity is not markedly altered in any of the investigated groups.

[Diagnosis of uveitis with laboratory tests and specialized examinations]

The authors evaluated the importance of a large scale of laboratory examinations and specialized examinations in a group of 174 patients with endogenous uveitis examined at the uveological ambulance of the First Ophthalmological Clinic of the First Faculty, Charles University Prague. Laboratory examinations which are part of screening examinations are of little value for the diagnosis of uveitis. Alone they are unable to assess its type or prognosis. They cannot be recommended for routine work in the field. Only the incidence of phenotype HLA B27 in patients with anterior uveitis is, as compared with the healthy population, statistically significant (p < 0.005). Aimed collaboration with specialists from other disciplines is more important. The latter can on the basis of aimed examinations confirm or rule out systemic disease of a patient with uveitis suspected by the ophthalmologist.

[Treatment of herpes simplex keratouveitis with systemic and local administration of acyclovir]

Sixteen patients with relapsing or chronic HSV keratouveitis were treated during a new attack by acyclovir 15 mg/kg/day by the i.v. route for 5 days with local combination of acyclovir 3% ung. and steroids. In all 16 patients improvement of signs of keratouveitis occurred on the fourth day of therapy, in 10 patients with improvement of visual acuity. In 5 patients perforating keratoplasty was performed on account of turbidity of the cornea. The authors observed four relapses of the disease in the course of 12 months after termination of treatment.

[Cataract surgery in patients with endogenous uveitis]

The authors present an account of surgery of complicated cataract in 20 patients with anterior and intermediate uveitis. During a one-year follow-up period they evaluate the difference of postoperative development and visual acuity in extracapsular extraction without or with implantation of an intraocular lens. In 10 patients (5x m. Fuchs, 3x anterior uveitis, 2x intermediate uveitis) they performed only ECCE. In 10 patients with the same diagnosis an intraocular lens was implemented. The authors did not find marked differences between the ECCE operation and ECCE operation with an intraocular lens in patients with uveitis. The visual acuity improved in all 20 patients, a marked inflammatory reaction in the anterior chamber was observed in both groups only during the first days after surgery. The two groups did not differ markedly as regards late complications. From the investigation ensues that implantation of an intraocular lens is well tolerated in patients with anterior and intermediate uveitis assuming a minimum 12-week remission of the disease.

[The spectrum of diseases associated with antineutrophil cytoplasmic antibodies]

BACKGROUND

Antineutrophil cytoplasmic antibodies (ANCA) are considered as a diagnostic marker of systemic vasculitis and rapidly progressing glomerulonephritis. They are frequently associated with other pathological conditions. The author's objective was to analyze a group of patients examined at the Department of Clinical Immunology of the First Medical Faculty Charles University in the course of one year and evaluation of the diagnostic asset of the ANCA examination.

METHODS AND RESULTS

ANCA was assessed in serum using the method of indirect immunofluorescence. In cases of p-ANCA the ELISA test was used to assess antimyeloperoxidase antibodies. Clinical data were evaluated on the basis of analysis of a questionnaire sent to doctors of patients where ANCA was detected. In 1992 1010 specimens were examined and in 115 ANCA was detected. This was the case in a group of 65 patients with the following diagnoses: systemic vasculitis 26x, systemic immunopathological diseases 12x, renal diseases 9x, inflammatory bowel diseases 7x, inflammatory eye diseases 6x, monoclonal paraproteinaemia 2x, other 4x. The patients had renal affections (45%), affections of the joints (20%), skin (18%), eyes (14%), lungs (12%), GIT (11%), ENT (9%), and nerves (9%). Type c in titres above 1:160 was always associated with the diagnosis of Wegener's granulomotosis, in other instances c- or x-types titres of 1:20 were involved. Antibodies against myeloperoxidase were detected in four instances.

CONCLUSIONS

The authors confirmed that c-ANCA in high concentrations are specific for the predominantly active form of Wegener's granulomatosis. The group of patients with p-ANCA is too small to generalize the diagnostic impact. Low ANCA concentrations are found in many other diseases. The importance of ANCA can be evaluated only in a clinical context and the importance of their presence must not be overestimated.

[Initial experience with therapy of endogenous uveitis with Consupren--the Czech cyclosporin A]

The authors treated as part of a controlled trial, five patients with Consupren, Galen a Co, i.e. the Czech preparation of cyclosporin A. All patients suffered from endogenous uveitis which was refractory to treatment with a combination of prednisone and cyclophosphamide or prednisone and azathioprin. Mitigation of the disease was achieved already during the first three weeks of treatment. In two patients during treatment a slight relapse of the inflammation was observed. As to side effects of this treatment, the authors observed only once readily controllable hypertension and a rise of some indicators of liver metabolism which returned to normal already during treatment. Side-effect in conjunction with renal affection were not observed in any of the patients. Based on these preliminary results the authors assume that Consupren is in the given indication, and when the described pattern of administration is used, effective and justifies the authors to continue with their investigation.

[Endogenous uveitis]

In a brief historical review of views on inflammatory affections of the uveal tissue the authors focused attention also on distinguished personalities in Czech ophthalmology who worked at the Czech Ophthalmological Clinic and participated in the development of uveology. Based on their own observations, they give an account on of their experience with the diagnosis of endogenous uveitis. Consistent with the world literature, they were able to reveal in a group of 174 patients with endogenous uveitis that the condition was associated with a systemic disease in 30%, in 9% they found an infectious aetiology and the remaining 61% were described as idiopathic endogenous uveitis. From the group of idiopathic uveitis they separated clinical entities diagnosed in 29%.

[Personal experience with immunosuppressive therapy of endogenous uveitis]

The authors investigated 43 patients with the original diagnosis of endogenous idiopathic uveitis for a period of one year. Comprehensive ophthalmological, immunological and rheumatological examination revealed that in all investigated cases either systemic disease was involved or diseases associated with impaired immunity or endogenous idiopathic uveitis. The patients were treated by immunosuppressive therapy either by Prednisone alone or by a combination of Prednisone and Cyclophosphamide. In all instances remission was achieved, contrary to previous therapy employed in these patients. In the majority of patients/21 of 23 and 12 of 18 resp./remission persisted for at least one year. The authors discuss indications and pitfalls of immunosuppressive therapy based on recommendations found in the literature.

[Immunologic mechanisms and the effect of immunosuppressive therapy in ophthalmology]

The authors mention some immunopathological mechanisms which participate in the beginning and maintenance of activity in so-called idiopathic endogenous uveitis. They draw attention to the possibility to influence these mechanisms by immunosuppressive treatment, mention its advantages and the feasibility of risk of undesirable side-effects. The authors assume that it is useful to use corticoids and cytotoxic substances as well as the more aimed action on immunity exerted by Cyclosporine A.

[Ocular involvement in Lyme disease]

Lyme disease is a tick-born multisystemic disease, caused by the Spirochete Borrelia burgdorferi. We examined and treated a 60-year-old woman, who 6 months after a tick bite had developed bilateral uveitis, with the involvement of the anterior segment, vitreous opacities and retinal vasculitis. The ocular involvement was, besides the skin lesion in the first stage of the disease, the only systemic manifestation of the infection.

[Diagnostic problems in uveitis]

The authors examined and followed up for two years 102 subjects who were referred to the First Ophthalmological Clinic of the First Medical Faculty, Charles University, Prague on account of idiopathic uveitis. They used a wide range of examination methods by means of which they were able to differentiate idiopathic uveitis from anterior uveitis with the presence of HLA B27, Fuchs disease and Eales disease. A quarter of the patients suffered from general disease, internal or neurological, where uveitis can be one of the symptoms. This disease was not diagnosed at the time of exacerbation of uveitis. The authors describe a series of examination methods and their contribution to the assessment of the correct diagnosis. They discuss the development of views regarding the diagnosis of idiopathic uveitis and views on the treatment of this disease.

[Immunologic profile in patients with acute anterior uveitis]

The authors investigated 52 patients (22 men and 30 women) with acute anterior uveitis where they ruled out systemic autoimmune disease, metabolic disease and focal or chronic infection. At the time of the infection the patients had not been treated for several months by any immunosuppressive treatment. The authors investigated in these patients serum concentrations of immunoglobulins G, A and M, the concentration of the C3 component of complement and the concentration of circulating immune complexes. Before the onset of therapy they investigated the response to antigens of the Immunoskin test. They assessed also the ratio of transplantation antigens class I by the microlymphocytotoxic test. They compared furthermore immunological indicators in subjects with a first attack and relapse of the disease and in groups, classified by the severity of the inflammatory symptoms. The authors detected significantly more frequently (p = 0.0005) the incidence of HLA-B27 antigen. Those where it was present were more frequently affected with a severe inflammation, as compared with subjects who did not have this phenotype (p less than 0.04). The relapse of the disease was more frequent in women (p = 0.1). The immunological laboratory findings did not differ in the first attacks and relapses of the disease, differences were, however, found in groups which differed as to the severity of inflammatory symptoms. In these groups the response rate to tests of skin sensitivity differed also. Based on these findings the authors assume that the ratio of immune processes in the development of acute idiopathic anterior uveitis cannot be ruled out.

Common variable immunodeficiency and malignancy: a report of two cases and possible explanation for the association

Two patients with common variable immunodeficiency (CVID) and malignant tumours are reported. The first patient developed myelogenous leukaemia soon after the myelodysplastic syndrome has been diagnosed. The undifferentiated gastric lymphoma found in the second patient suggests that an increased risk of gastrointestinal malignancies in CVID could partly be due to lymphomas. We hypothesize that the tissue- or site-specific risk of lymphomas and gastrointestinal cancer can be explained by an increased chromosomal or genomic instability with a higher mutation rate and genomic disorganization, and that this instability could be related to viral carcinogenesis. The primary immunodeficiency per se may not be responsible for the cancer susceptibility in CVID patients.

[Administration of Decaris (levamisole) patients with complicationsp6n surgical wound healing]

The authors report on their experience with the administration of Decaris (Levamisol) to patients with complication in the surgical wound after surgery. Decaris was administered on average 20.2 days after unsuccessful common local and general treatment. In patients with an anamnestic suspicion of immunodeficiency this drug was administered already before operation. After Decaris administration in 77% of the patients the wounds healed within 24 days. For patients with complications in surgical wounds Decaris treatment may be one of the possible conservative approaches to their condition.

Peroxidase and pseudoperoxidase reactions in relation to sudanophilia

A selective staining of hemoglobin in erythroid cell series was achieved by use of Sudan Black B (modified method of Sheehan and Storey) if optimal amount of hydrogen peroxide was added to the staining mixture. The effect of some inhibitory agents (KCN, wet heat, pH) on this staining as well as on the Lepehne's pseudoperoxidase reaction for hemoglobin was similar. Both reactions were more resistant to these factors than the peroxidase reactions and sudanophilia in granulocytes in which both could be blocked by the pretreatment with absolute methanol. Moreover the effect of some extraction procedures for lipids on both myeloperoxidase reactions and sudanophilia was investigated. The results support the view that the sudanophilia in granulocytes is due to their peroxidase activity and for the staining of hemoglobin by use of Sudan Black B with H2O2 its pseudoperoxidase activity is responsible. In addition the effect of the substitution of phenolphosphate by dihydroxybenzenes on granulocyte sudanophilia is reported.

Phagocytic activity of leukaemic blasts

Phagocytic activity of leukaemic blasts in 20 adults and 16 children suffering from acute leukaemia was studied in vitro by the use of ferrioxidsaccharate. Most frequently phagocytosing blasts were encountered in myelomonocytic leukaemias. The morphological character of positive blasts resembled often that of monocytoid cells. In lymphoblastic and reticular leukaemias phagocytic ability of blasts was an exceptional finding.