The role of protein kinase C isoenzymes in the pathogenesis of human autoimmune diseases.

The physiological role of protein kinase C (PKC) enzymes in the immune system is presented briefly. From earlier publications of others data were collected how the defects of one/two isoenzymes of PKC system suggested their involvement in the pathogenesis of human autoimmune diseases. Our observations on the defects of seven PKC isoenzymes in the peripheral blood mononuclear cells (PBMC) demonstrate that these molecular impairments are not prerequisits of the pathogenesis of systemic lupus erythematosus (SLE), mixed connective tissue disease and Sjögren's syndrome. However, these defects can modulate the disease activity and symptoms especially in SLE by several pathways. The role of PKC system in other forms of autoimmune diseases is also very small. It was of note that we detected decreased expression of PKC isoenzymes in PBMC of a European white family with an X-linked genetic background showing seasonal undulations in the lupus patient and also in her healthy mother.

Altered Circulating Follicular T Helper Cell Subsets and Follicular T Regulatory Cells Are Indicators of a Derailed B Cell Response in Lupus, Which Could Be Modified by Targeting IL-21R.

Systemic lupus erythematosus (SLE) is characterized by the breakdown of self-tolerance, the production of high-affinity pathogenic autoantibodies and derailed B cell responses, which indicates the importance of central players, such as follicular T helper (TFH) subsets and follicular T regulatory (TFR) cells, in the pathomechanism of the disease. In this study, we aimed to analyze the distribution of the circulating counterparts of these cells and their association with disease characteristics and B cell disproportions in SLE. We found that the increased percentage of activated circulating TFH (cTFH) and cTFR cells was more pronounced in cutaneous lupus; however, among cTFH subsets, the frequency of cTFH17 cells was decreased in patients with lupus nephritis. Furthermore, the decreased proportion of cTFH17 cells was associated with low complement C4 levels and high disease activity scores. We also investigated whether the blocking of the IL-21 receptor (IL-21R) with an anti-IL-21R monoclonal antibody inhibits the B cell response, since IL-21 primarily produced by TFH cells potentially promotes humoral immunity. We observed that anti-IL-21R inhibited plasmablast generation and immunoglobulin production. Our study demonstrated that, besides cTFR/cTFH imbalance, cTFH17 cells play a crucial role in SLE pathogenesis, and modulating cTFH-B cell interaction through the IL-21/IL-21R pathway may be a promising therapeutic strategy to suppress the pathological B cell response.

Interactions between the NLRP3-Dependent IL-1ß and the Type I Interferon Pathways in Human Plasmacytoid Dendritic Cells.

Generally, a reciprocal antagonistic interaction exists between the antiviral type I interferon (IFN) and the antibacterial nucleotide-binding oligomerization domain (NOD)-like receptor pyrin domain containing 3 (NLRP3)-dependent IL-1ß pathways that can significantly shape immune responses. Plasmacytoid dendritic cells (pDCs), as professional type I IFN-producing cells, are the major coordinators of antiviral immunity; however, their NLRP3-dependent IL-1ß secretory pathway is poorly studied. Our aim was to determine the functional activity of the IL-1ß pathway and its possible interaction with the type I IFN pathway in pDCs. We found that potent nuclear factor-kappa B (NF-κB) inducers promote higher levels of pro-IL-1ß during priming compared to those activation signals, which mainly trigger interferon regulatory factor (IRF)-mediated type I IFN production. The generation of cleaved IL-1ß requires certain secondary signals in pDCs and IFN-α or type I IFN-inducing viruses inhibit IL-1ß production of pDCs, presumably by promoting the expression of various NLRP3 pathway inhibitors. In line with that, we detected significantly lower IL-1ß production in pDCs of psoriasis patients with elevated IFN-α levels. Collectively, our results show that the NLRP3-dependent IL-1ß secretory pathway is inducible in pDCs; however, it may only prevail under inflammatory conditions, in which the type I IFN pathway is not dominant.

High-density lipopoprotein antioxidant capacity, subpopulation distribution and paraoxonase-1 activity in patients with systemic lupus erythematosus.

BACKGROUND: The causes of increased cardiovascular risk in systemic lupus erythematosus (SLE) are not understood thoroughly, although presence of traditional cardiovascular risk factors and disease-specific agents were also proposed. In this study, we investigated the quantitative changes in the lipid profile, as well as qualitative characteristics of high-density lipoprotein (HDL) and markers of inflammation and disease activity in SLE patients. METHODS: Lipoprotein levels were determined in 51 SLE patients and 49 healthy controls, matched in age and gender. HDL antioxidant capacity was determined spectrophotometrically with a cell-free method of hemin-induced low-density lipoprotein (LDL) oxidation. Polyacrylamide gel-electrophoresis was used for HDL subfraction analysis. Human paraoxonase-1 (PON1) activity, apolipoprotein A1 (ApoA1) and oxidized LDL concentrations, as well as interleukin-6, high-sensitivity C-reactive protein, serum amyloid A and monocyte chemotactic protein-1 levels were determined. RESULTS: HDL-cholesterol and ApoA1 concentrations decreased significantly in SLE subjects. Also, PON1 arylesterase activity (125.65 ± 26.87 vs. 148.35 ± 39.34 U/L, p = 0.001) and total HDL antioxidant capacity (165.82 ± 58.28% vs. 217.71 ± 54.36%, p < 0.001) were significantly reduced in patients compared to controls. Additionally, all HDL subfraction concentrations were significantly decreased in patients, while the levels of the examined inflammatory markers were significantly elevated in SLE subjects. The latter correlated positively with disease activity, and negatively with HDL concentration and total HDL antioxidant capacity, respectively. PON1 arylesterase activity and erythrocyte sedimentation rate were independent predictors of total HDL antioxidant capacity. CONCLUSIONS: Induced by the systemic inflammation, altered composition and antioxidant activity may diminish the anti-atherogenic effect of HDL and therefore may contribute to the increased cardiovascular risk of SLE patients.

The in vitro treatment with vitamin D3 is ineffective on the expression of PKC isoenzymes, but decreases further the impaired production of IL-2 in the T lymphocytes of SLE patients.

The objective of the study was to investigate the possibility whether the in vitro treatment with vitamin D3 can restore the impaired expression of protein kinase C (PKC) isoenzymes and IL-2 production in the lymphocytes of patients with systemic lupus erythematosus (SLE). Purified T lymphocytes from 14 patients with SLE and 13 healthy controls were cultured for 48 h in the presence and absence of 1 and 100 nM doses of vitamin D3. The expressions of various PKC isoenzymes were tested by Western blot analysis, and the amounts of various cytokines were detected by ELISA in the culture supernatants. Neither the low (1 nM) nor the high (100 nM) doses of vitamin D3 (1α,-25-dihydroxyvitamin) applied in vitro for 48 h were able to restore the decreased expression of PKC isoenzymes in the T cells of SLE patients. However, 100 nM of vitamin D3 significantly increased the release of IL-10, but suppressed the production of IL-2, IL-6, interferon γ and TNF α in the culture supernatants of both groups. As the low production of IL-2 is one of the main pathologic features of SLE, we recommend to avoid the use of high doses of vitamin D3 for treatment of lupus patients with vitamin D3 deficiency.

Antiphospholipid Antibodies Are Major Risk Factors for Non-Thrombotic Cardiac Complications in Systemic Lupus Erythematosus.

In systemic lupus erythematosus (SLE), cardiovascular complications are among the leading causes of death. Cardiovascular risk in SLE is even higher in the presence of antiphospholipid antibodies or secondary antiphospholipid syndrome (APS). The aim of this retrospective, single-center study was to investigate the occurrence of antiphospholipid antibodies and non-thrombotic cardiac manifestations in 369 SLE patients. We also assessed the clinical and laboratory characteristics of the patients to reveal the risk factors for cardiac manifestations. Patients were divided into two groups based on the presence of antiphospholipid antibodies (APA); 258 (69.9%) patients were APA positive, and 111 (30.1%) patients were APA negative. Mitral and tricuspid insufficiency, aortic stenosis and pulmonary arterial hypertension were more common in APA-positive patients. Anticardiolipin IgG showed the strongest correlation with any non-thrombotic cardiac manifestations. Based on our results, the adjusted global antiphospholipid syndrome score (aGAPSS) above 8.5 is predictive of valvulopathies and ischemic heart disease, while aGAPSS above 9.5 is predictive of cardiomyopathies. The presence of antiphospholipid antibodies may affect the development of cardiac manifestations in SLE. Periodic cardiological and echocardiographic screening of patients without cardiac complaints, as well as regular monitoring of antiphospholipid antibodies, have great importance during the treatment of SLE patients.

A novel way to evaluate autoantibody interference in samples with mixed antinuclear antibody patterns in the HEp-2 cell based indirect immunofluorescence assay and comparison of conventional microscopic and computer-aided pattern recognition.

BACKGROUND: A major challenge of the HEp-2 cell-based indirect immunofluorescence (IIF) assays is the correct identification of the individual anti-nuclear antibodies (ANAs) if more than one is present in a sample. We created artificial mixes by pooling two different samples with a single autoantibody in different titers. Comparison of the expected and observed patterns and titers clarifies the interference between the two tested ANAs. METHODS: Serum samples with a single homogeneous or speckled ANA pattern were serially diluted and mixed in 16 combinations, providing end-point titers of 1:5,120 to 1:80 for both patterns. These mixes were tested by a HEp-2 IIF assay and were evaluated by conventional evaluation, the EUROPattern (EPa) system and on-screen analysis. RESULTS: Homogeneous pattern can alter the identification of the speckled pattern much more than vice versa, but both has an interfering effect on the other. The effect of the interfering on the tested pattern was higher if the titer of the former one was higher. The pattern recognition efficacy of conventional and the on-screen evaluation was similar and superior compared to the EPa analysis. CONCLUSIONS: The application of artificial mixed samples can help the evaluation of the efficacy of manual and computer-aided ANA HEp-2 pattern recognition.

Changes in Clinical Manifestations and Course of Systemic Lupus Erythematosus and Secondary Antiphospholipid Syndrome over Three Decades.

Systemic lupus erythematosus (SLE) is often associated with antiphospholipid syndrome (APS), which potentially results in a more severe disease course and reduced life expectancy. Since the therapeutic guidelines have been refined in the last 15 years, we assumed that the diseases course has become more favorable. In order to shed light on these achievements, we compared the data of SLE patients diagnosed before and since 2004. In our retrospective study, we assessed a wide spectrum of clinical and laboratory data of 554 SLE patients who received regular follow-up care and therapy at our autoimmune center. Among these patients, 247 had antiphospholipid antibodies (APAs) without clinical signs of APS, and 113 had definitive APS. In the APS group, among patients diagnosed since 2004, deep vein thrombosis (p = 0.049) and lupus anticoagulant positivity (p = 0.045) were more frequent, while acute myocardial infarction was less frequent (p = 0.021) compared with patients diagnosed before 2004. Among the APA positive patients without definitive APS, anti-cardiolipin antibody positivity (p = 0.024) and development of chronic renal failure (p = 0.005) decreased in patients diagnosed since 2004. Our study demonstrates that the disease course has changed in recent years; however, in the presence of APS, we have to expect repeated thrombotic events despite adequate anticoagulant therapy.

Psoriatic arthritis and its special features predispose not only for osteoporosis but also for fractures and falls.

Limited data are available on the predisposing factors to fractures and falls of patients with psoriatic arthritis (PsA). Our study intended to explore the differences between PsA patients and controls, concerning bone mineral density (BMD), the 10-year fracture risk, the number of prevalent fractures, the frequency of falls and to investigate the association of the same factors with PsA disease characteristics within the PsA group. Medical reports of 61 PsA patients and 69 consecutive, age-matched controls were analyzed, physical examination and bone mineral density (BMD, and T-score) were performed, and the 10-year fracture risk was calculated. The results were subjected to statistical analysis. Femoral neck BMD, as well as vertebral and femoral neck T-scores were lower, the odds ratio (OR) for low BMD and the 10-year risk of hip fracture was higher (p = 0.0029; 0.0002, p < 0.0001, OR = 21,9, p = 0.014) in the PsA group. The PsA patients were more predisposed to prevalent fractures, including peripheral fractures, and vertebral fractures as well as falls (OR 3.42; 2.26; 13.33; 3.95, respectively), compared to controls. Within the PsA group (beyond the age) scalp psoriasis and late-onset psoriasis, were significantly associated with a greater number of prevalent fractures (p = 0.0049; 0.029), while the number of falls per year correlated with late-onset psoriasis and the flexural psoriasis (p = 0.007; 0.023). Our results suggest that PsA is an independent risk factor for reduced bone density and falls hence to related bone fractures. Patients with late-onset psoriasis are more likely to suffer falls and related fractures, especially if their disease is characterized by the involvement of the hairy scalp and body folds.

Role of Altered Metabolism of Triglyceride-Rich Lipoprotein Particles in the Development of Vascular Dysfunction in Systemic Lupus Erythematosus.

BACKGROUND: Impaired lipid metabolism contributes to accelerated inflammatory responses in addition to promoting the formation of atherosclerosis in systemic lupus erythematosus (SLE). We aimed to evaluate the lipid profile, inflammatory markers, and vascular diagnostic tests in active SLE patients to clarify the association between dyslipidemia and early vascular damage. PATIENTS AND METHODS: 51 clinically active SLE patients and 41 age- and gender-matched control subjects were enrolled in the study. Lipoprotein subfractions were detected by Lipoprint. Brachial artery flow-mediated dilation and common carotid intima-media thickness were detected by ultrasonography. Arterial stiffness indicated by augmentation index (Aix) and pulse wave velocity was measured by arteriography. RESULTS: We found significantly higher Aix, higher VLDL ratio, plasma triglyceride, ApoB100, and small HDL, as well as lower HDL-C, large HDL, and ApoA1 in patients with SLE. There was a significant positive correlation of Aix with triglyceride, VLDL, IDL-C, IDL-B, and LDL1. A backward stepwise multiple regression analysis showed IDL-C subfraction to be the best predictor of Aix. CONCLUSIONS: Our results indicate that in young patients with SLE, triglyceride-rich lipoproteins influence vascular function detected by Aix. These parameters may be assessed and integrated into the management plan for screening cardiovascular risk in patients with SLE.

[Successful completed pregnancies in patients with systemic lupus erythematosus]. / Sikeresen kiviselt terhességek jellemzése szisztémás lupus erythematosusban.

UNLABELLED: Systemic lupus erythematosus is a chronic autoimmune disorder which affects women with child bearing potential. AIM: The aim of this study was to investigate the successful pregnancies in patients with lupus in the past 10 years. Women were followed up at the 3rd Department of Internal Medicine, University of Debrecen. RESULTS: During this investigated period, 26 patients became pregnant. Seven patients had a positive history for lupus before the pregnancy. A total of 29 children were born. The mean gestational age was 35 weeks. The average birth weight was 2415 grams. Toxemic pregnancy was the most common complication found in 9 patients. Lupus nephritis activity occurred in 2 patients, and 1 of them had it for the first time during the course of her disease. CONCLUSIONS: In the past years, the number of pregnancies in patients with lupus has been increasing. Due to proper patient care and education, the outcome is more favourable.

A Comprehensive Investigation into the Distribution of Circulating B Cell Subsets in the Third Trimester of Pregnancy.

Maternal B cells play a crucial role in the development and maintenance of pregnancy, due to their humoral activities and regulatory functions. In the study, we investigated the alterations in the distributions of naïve and memory B cell subsets, as well as regulatory B (Breg) cells, in the third trimester of pregnancy. Peripheral blood from 14 healthy pregnant women in the third trimester and 7 healthy non-pregnant women was collected and examined for the frequencies of B cell subsets, including IgD+CD27- naïve, IgD+CD27+ un-switched memory, IgD-CD27+ switched memory, CD38intCD24int mature-naïve, CD38-CD24hi primarily memory and CD38hiCD24hi transitional B cells by flow cytometry. Breg cell subsets were also characterized based on the expression of CD5, CD1d and IL-10. In pregnant women, the proportions of un-switched memory and transitional B cells were significantly decreased. Additionally, the frequencies of both CD5+CD1d+ Breg and IL-10-producing B10 cells were decreased in pregnancy. Changes in the distribution of transitional B cells as well as Breg cells may be crucial contributors for the development of altered maternal immune responses and tolerance needed for the maintenance of normal pregnancy in the third trimester.

The Effect of Aerobic Exercise and Low-Impact Pilates Workout on the Adaptive Immune System.

Growing evidence indicates the pronounced effects of physical activity on immune functions, which may largely depend on the type of exercise, intensity, and duration. However, limited information is available regarding the effects of low-impact exercises, especially on the level of adaptive immune system. Our study aimed to investigate and compare the changes in a broad spectrum of lymphocyte subtypes after 14 weeks of aerobic-type total-body-shaping workouts (TBSW) and Pilates workouts (PW) among healthy individuals. We determined the percentages of peripheral natural killer cells and different T and B lymphocyte subtypes with flow cytometry. At the end of the exercise program, significant changes in naïve and memory lymphocyte ratios were observed in TBSW group. Percentages of naïve cytotoxic T (Tc) cells elevated, frequencies of memory Tc and T-helper cell subsets decreased, and distribution of naïve and memory B cells rearranged. Proportions of activated T cells also showed significant changes. Nonetheless, percentages of anti-inflammatory interleukin (IL)-10-producing regulatory type 1 cells and immunosuppressive CD4+CD127lo/-CD25bright T regulative cells decreased not only after TBSW but also after PW. Although weekly performed aerobic workouts may have a more pronounced impact on the adaptive immune system than low-impact exercises, both still affect immune regulation in healthy individuals.

Anti-ß2-glycoprotein I autoantibodies influence thrombin generation parameters via various mechanisms.

INTRODUCTION: Antiphospholipid syndrome (APS) is a systemic autoimmune disease characterised by recurrent thrombotic events, pregnancy loss and thrombocytopenia and the presence of antiphospholipid antibodies (APL). The exact pathomechanism of APS is still unknown, thus we investigated the effect of anti-ß2-glycoprotein I (anti-ß2GPI) on thrombin generation in different plasma samples. METHODS: For the separation of anti-ß2GPI IgG, overall 12 APS patients were selected. The criteria were the existence of lupus anticoagulant, and the presence of anti-CL and anti-ß2GPI, the latter exceeding at least 25 times the upper reference limit. We purified anti-ß2GPI IgG antibodies from APS patients by affinity chromatography and added the antibodies to normal pooled, and heterozygous forms of inherited thrombophilia plasma samples (prothrombin G20210A, factor V Leiden). To further specify the mechanism of the effect, we also used factor deficient plasmas in the thrombin generation assay. RESULTS: In normal pooled plasma, the anti-ß2GPI significantly prolonged Lag Time according to the lupus anticoagulant effect, in contrast, it also elevated Peak Thrombin significantly, which suggests a procoagulant effect. The antibody was also able to exert this multi-faceted effect both in FVLeiden heterozygous plasma and prothrombin G20210A heterozygous polymorphism, however, the prolonging effect was more remarkable in the latter. By using factor deficient plasmas, it was found that FVII is required for the prolongation, while intrinsic factors are needed for the elevation of the Peak Thrombin. CONCLUSION: The anti-ß2GPI autoantibodies exert their effect in both normal and thrombophilic plasmas via various mechanisms.

The Imbalance of Circulating Follicular T Helper Cell Subsets in Primary Sjögren's Syndrome Associates With Serological Alterations and Abnormal B-Cell Distribution.

Since B-cell hyperactivity and pathologic antibody response are key features in the immunopathogenesis of primary Sjögren's syndrome (pSS), the role of follicular T helper (TFH) cells as efficient helpers in the survival and differentiation of B cells has emerged. Our aim was to investigate whether a change in the balance of circulating (c)TFH subsets and follicular regulatory T (TFR) cells could affect the distribution of B cells in pSS. Peripheral blood of 38 pSS patients and 27 healthy controls was assessed for the frequencies of cTFH cell subsets, TFR cells, and certain B cell subpopulations by multicolor flow cytometry. Serological parameters, including anti-SSA, anti-SSB autoantibodies, immunoglobulin, and immune complex titers were determined as part of the routine diagnostic evaluation. Patients with pSS showed a significant increase in activated cTFH cell proportions, which was associated with serological results. Frequencies of cTFH subsets were unchanged in pSS patients compared to healthy controls. The percentages and number of cTFR cells exhibited a significant increase in autoantibody positive patients compared to patients with seronegative pSS. The proportions of transitional and naïve B cells were significantly increased, whereas subsets of memory B cells were significantly decreased and correlated with autoantibody production. Functional analysis revealed that the simultaneous blockade of cTFH and B cell interaction with anti-IL-21 and anti-CD40 antibodies decreased the production of IgM and IgG. Imbalance in TFH subsets and TFR cells indicates an ongoing over-activated humoral immune response, which contributes to the characteristic serological manifestations and the pathogenesis of pSS.

Interleukin-23 receptor gene variants in Hungarian systemic lupus erythematosus patients.

OBJECTIVE: We investigated the association between systemic lupus erythematosus (SLE) and polymorphisms of interleukin-23 receptor (IL23R) gene, which was recently found to be associated with autoimmune diseases, including Crohn's disease, rheumatoid arthritis, psoriasis and ankylosing spondylitis. SUBJECTS: We analysed 383 SLE patients and 253 controls for rs11805303, rs10889677, rs1004819, rs2201841, rs11209032, 11209026, rs10489629, rs7517847 and rs7530511 variants. METHODS: The analysis was carried out using PCR-RFLP methods. Logistic regression analysis was used to compare the genotype distributions of the polymorphisms and haplotypes between the SLE patients and healthy controls. RESULTS: We observed no significant difference of the examined variants between the patient and control groups. CONCLUSIONS: Our results suggest that neither single nucleotide variants nor haplotypes of IL23R indicate susceptibility to developing SLE in the Hungarian population.

Antiphospholipid syndrome and the risk of myocardial infarction: current evidence and uncertainties.

Antiphospholipid syndrome (APS) encompasses a wide spectrum of disease manifestations that may prevail in the form of venous or arterial thrombosis or lead to pregnancy complications in the presence of persisting antiphospholipid antibodies (aPL). Unlike in the case of congenital thrombophilias, in which venous thromboses are more likely to occur as compared with arterial events, aPL may cause thrombosis in both types of vascular systems. Arterial thrombosis in APS is fairly common and often involve coronary or cerebral arteries leading to myocardial infarction (MI) or stroke. In this review, we summarize the complex pathomechanisms leading to aPL­associated thrombosis and list challenges during the laboratory detection of these antibodies. Specific features of MI in patients with APS are summarized based on a comprehensive literature search of available case reports. Preventive and treatment strategies are discussed based on the current recommendations and most recent evidence. We conclude that the risk of MI in patients with APS is considerable and MI may be the first manifestation of the disease. MI in APS shows specific clinical features including relatively young age at presentation, no sex dominance, often normal coronaries without the sign of atherosclerosis, high risk of recurrent thrombotic events. Treatment of acute MI in patients with APS is often challenging and adverse events, including stent thrombosis, are more frequent as compared with patients without APS. Preventive strategies in APS should be personalized and include strict management of additional cardiovascular risk factors and long­term anticoagulation with vitamin K antagonists. Current evidence does not support the use of direct oral anticoagulants in the management of patients with APS with arterial thrombosis due to the high risk of recurrent events.

Regulation of RLR-Mediated Antiviral Responses of Human Dendritic Cells by mTOR.

To detect replicating viruses, dendritic cells (DCs) utilize cytoplasmic retinoic acid inducible gene-(RIG) I-like receptors (RLRs), which play an essential role in the subsequent activation of antiviral immune responses. In this study, we aimed to explore the role of the mammalian target of rapamycin (mTOR) in the regulation of RLR-triggered effector functions of human monocyte-derived DCs (moDCs) and plasmacytoid DCs (pDCs). Our results show that RLR stimulation increased the phosphorylation of the mTOR complex (mTORC) 1 and mTORC2 downstream targets p70S6 kinase and Akt, respectively, and this process was prevented by the mTORC1 inhibitor rapamycin as well as the dual mTORC1/C2 kinase inhibitor AZD8055 in both DC subtypes. Furthermore, inhibition of mTOR in moDCs impaired the RLR stimulation-triggered glycolytic switch, which was reflected by the inhibition of lactate production and downregulation of key glycolytic genes. Blockade of mTOR diminished the ability of RLR-stimulated moDCs and pDCs to secret type I interferons (IFNs) and pro-inflammatory cytokines, while it did not affect the phenotype of DCs. We also found that mTOR blockade decreased the phosphorylation of Tank-binding kinase 1 (TBK1), which mediates RLR-driven cytokine production. In addition, rapamycin abrogated the ability of both DC subtypes to promote the proliferation and differentiation of IFN-y and Granzyme B producing CD8 + T cells. Interestingly, AZD8055 was much weaker in its ability to decrease the T cell proliferation capacity of DCs and was unable to inhibit the DC-triggered production of IFN-y and Granyzme B by CD8 + T cells. Here we demonstrated for the first time that mTOR positively regulates the RLR-mediated antiviral activity of human DCs. Further, we show that only selective inhibition of mTORC1 but not dual mTORC1/C2 blockade suppresses effectively the T cell stimulatory capacity of DCs that should be considered in the development of new generation mTOR inhibitors and in the improvement of DC-based vaccines.

Distinct and overlapping effects of ß2-glycoprotein I conformational variants in ligand interactions and functional assays.

One of the most abundant coagulation proteins is ß2-glycoprotein I (ß2GPI) that is present in humans at a concentration of around 200 mg/L. Its physiological role is only partially understood, but it adopts several different structural forms the majority of which are the open and closed forms. We isolated native (circular) ß2GPI and converted it into an open conformation. The effectiveness of these procedures was assessed by Western blot and negative-staining electron microscopy. We found that in coagulation assays the open form of ß2GPI had a significant prolonging effect on fibrin formation in a dilute prothrombin time test (p < 0.001). In the dilute activated partial thromboplastin time test, both conformations had a significant prolonging effect (p < 0.001) but the open conformation was more effective. In a fluorescent thrombin generation assay both conformations slightly delayed thrombin generation with no significant effect on the quantity of formed thrombin. By using surface plasmon resonance assays, the equilibrium dissociation constants of both the open and closed conformations of ß2GPI showed a similar and strong affinity to isolated anti-ß2GPI autoantibodies (Kd closed ß2GPI = 5.17 × 10-8 M, Kd open ß2GPI = 5.56 × 10-8 M) and the open form had one order of magnitude stronger affinity to heparin (Kd = 0.30 × 10-6 M) compared to the closed conformation (Kd = 3.50 × 10-6 M). The two different forms of ß2GPI have distinct effects in functional tests and in ligand binding, which may considerably affect the intravascular events related to this abundant plasma protein in health and disease.

Anti-neutrophil cytoplasmic antibody testing by indirect immunofluorescence: Computer-aided versus conventional microscopic evaluation of routine diagnostic samples from patients with vasculitis or other inflammatory diseases.

BACKGROUND: Detection of anti-neutrophil cytoplasmic antibodies (ANCA) by indirect immunofluorescence assays (IFA) is of diagnostic importance in vasculitides and some other inflammatory diseases. Automation of IFA may be beneficial in high-throughput clinical laboratories. An analytical appraisal of the EUROPattern (EPa) automated microscope and image analysis system has not been reported in a routine clinical laboratory setting testing samples from both vasculitis and non-vasculitis patients. METHODS: Results of EPa and on-screen ANCA pattern recognition of 568 consecutive routine serum samples were compared to those of conventional visual evaluation. RESULTS: Agreement of discrimination between negative and non-negative samples was 86.1% comparing EPa and conventional reading, and it increased to 96.7% after on-screen user validation. Importantly, from the 334 samples classified as negative by EPa 328 (98.2%) were also negative by conventional evaluation. Pattern recognition showed 'moderate' agreement between classical microscopic and EPa analysis (κ = 0.446) and 'very good' agreement after user validation (κ = 0.900). Misclassification by EPa was dominantly due to the presence of anti-nuclear/cytoplasmic antibodies (incorrect pattern, 80/568) and the lower fluorescence cut-off of the automated microscope (false positives, 73/568). CONCLUSIONS: Automated ANCA testing by EPa is a reliable alternative of classical microscopic evaluation, though classification of sera needs correction by trained personnel during on-screen validation.