HLA-B35 upregulates the production of endothelin-1 in HLA-transfected cells: a possible pathogenetic role in pulmonary hypertension

Controversies in the pathophysiology of leg ulcers in sickle cell disease

Patients with sickle cell disease (SCD) often experience painful vaso-occlusive crises and chronic haemolytic anaemia, as well as various acute and chronic complications, such as leg ulcers. Leg ulcers are characterized by their unpredictability, debilitating pain and prolonged healing process. The pathophysiology of SCD leg ulcers is not well defined. Known risk factors include male gender, poor social conditions, malnutrition and a lack of compression therapy when oedema occurs. Leg ulcers typically start with spontaneous pain, followed by induration, hyperpigmentation, blister formation and destruction of the epidermis. SCD is characterized by chronic haemolysis, increased oxidative stress and decreased nitric oxide bioavailability, which promote ischaemia and inflammation and consequently impair vascular function in the skin. This cutaneous vasculopathy, coupled with venostasis around the ankle, creates an ideal environment for local vaso-occlusive crises, which can result in the development of leg ulcers that resemble arterial ulcers. Following the development of the ulcer, healing is hindered as a result of factors commonly observed in venous ulceration, including venous insufficiency, oedema and impaired angiogenesis. All of these factors are modulated by genetic factors. However, our current understanding of these genetic factors remains limited and does not yet enable us to accurately predict ulceration susceptibility.

HLA class I associations with the severity of COVID-19 disease in the United Arab Emirates

SARS-CoV-2 appears to induce diverse innate and adaptive immune responses, resulting in different clinical manifestations of COVID-19. Due to their function in presenting viral peptides and initiating the adaptive immune response, certain Human Leucocyte Antigen (HLA) alleles may influence the susceptibility to severe SARS-CoV-2 infection. In this study, 92 COVID-19 patients from 15 different nationalities, with mild (n = 30), moderate (n = 35), and severe (n = 27) SARS-CoV-2 infection, living in the United Arab Emirates (UAE) were genotyped for the Class I HLA -A, -C, and -B alleles using next-generation sequencing (NGS) between the period of May 2020 to June 2020. Alleles and inferred haplotype frequencies in the hospitalized patient group (those with moderate to severe disease, n = 62) were compared to non-hospitalized patients (mild or asymptomatic, n = 30). An interesting trend was noted between the severity of COVID-19 and the HLA-C*04 (P = 0.0077) as well as HLA-B*35 (P = 0.0051) alleles. The class I haplotype HLA-C*04-B*35 was also significantly associated (P = 0.0049). The involvement of inflammation, HLA-C*04, and HLA-B*35 in COVID-19 severity highlights the potential roles of both the adaptive and innate immune responses against SARS-CoV-2. Both alleles have been linked to several respiratory diseases, including pulmonary arterial hypertension along with infections caused by the coronavirus and influenza. This study, therefore, supports the potential use of HLA testing in prioritizing public healthcare interventions for patients at risk of COVID-19 infection and disease progression, in addition to providing personalized immunotherapeutic targets.

Renal disorders in rheumatologic diseases: the spectrum is changing (Part 1: connective tissue diseases)

The kidney is frequently involved by autoimmune rheumatic diseases. The renal manifestations may be variable, ranging from asymptomatic proteinuria and microscopic haematuria to nephrotic syndrome and rapidly progressive glomerulonephritis or vasculitis. In a number of cases the kidney involvement is related to the treatment of the original disease and may represent a major cause of morbidity and mortality. Thus, it is important for nephrologists and rheumatologists to remember that dysfunction of the kidney may be part of the primary systemic disorder or consequence of its pharmacotherapy. In the first part of this review we will analyse the kidney involvement in four autoimmune connective tissue diseases: systemic lupus erythematosus, Sjögren syndrome, polymyositis/dermatomyositis, and systemic sclerosis. Renal disease is common in lupus and is a main cause of morbidity and mortality. About 10% of patients with Sjögren syndrome may present interstitial nephritis or, more rarely, glomerulonephritis. Myoglobinuria and acute kidney injury is a frequent complication of polymyositis. Renal disease is one of the most serious complications of systemic sclerosis and may present with a dramatic renal crisis, characterized by malignant hypertension, oligo-anuria, and microangiopathic thrombocytopenic anaemia.

HLA Allele and Haplotype Frequencies in Three Urban Mexican Populations: Genetic Diversity for the Approach of Genomic Medicine

Genetic variability defends us against pathogen-driven antigens; human leucocyte antigens (HLA) is the immunological system in charge of this work. The Mexican mestizo population arises mainly from the mixture of three founder populations; Amerindian, Spaniards, and a smaller proportion of the African population. We describe allele and haplotype frequencies of HLA class I (-A and -B) and class II (-DRB1 and -DQB1), which were analyzed by PCR-SSP in Mexican mestizo from three urban populations of Mexico: Chihuahua-Chihuahua City (n = 88), Mexico City-Tlalpan (n = 330), and Veracruz-Xalapa (n = 84). The variability of the allele HLA class I and class II among the three regions of Mexico are in four alleles: HLA-A*24:02 (36.39%), -B*35:01 (16.04%), -DRB1*04:07 (17.33%), and -DQB1*03:02 (31.47%), these alleles have been previously described in some indigenous populations. We identified 5 haplotypes with a frequency >1%: HLA-A*02:01-B*35:01-DRB1*08:02-DQB1*04:02, A*68:01-B*39:01-DRB1*08:02-DQB1*04:02, A*02:01-B*35:01-DRB1*04:07-DQB1*03:02, A*68:01-B*39:01-DRB1*04:07-DQB1*03:02, and A*01:01-B*08:01-DRB1*03:01-DQB1*02:01. Also, the haplotype A*02:01-B*35:01-DRB1*08:02-DQB1*04:02 was identified in Tlalpan and Xalapa regions. Haplotype A*01:01-B*08:01-DRB1*03:01-DQB1*02:01 was found only in Tlalpan and Chihuahua. In the Xalapa region, the most frequent haplotype was A*24:02-B*35:01-DRB1*04:07-DQB1*03:02. These alleles and haplotypes have been described in Amerindian populations. Our data are consistent with previous studies and contribute to the analysis of the variability in the Mexican population.

Gene expression profiling reveals novel protective effects of Aminaphtone on ECV304 endothelial cells

Aminaphtone, a drug used in the treatment of chronic venous insufficiency (CVI), showed a remarkable role in the modulation of several vasoactive factors, like endothelin-1 and adhesion molecules. We analysed in vitro the effects of Aminaphtone on whole-genome gene expression and production of different inflammatory proteins. ECV-304 endothelial cells were stimulated with IL-1β 100U/ml in the presence or absence of Aminaphtone 6μg/ml. Gene expression profiles were compared at 1, 3, and 6h after stimulation by microarray. Supernatants of ECV-304 cultures were analysed at 3, 6, 12, and 24h by multiplex ELISA for production of several cytokine and chemokines. Microarrays showed a significant down-regulation at all times of a wide range of inflammatory genes. Aminaphtone appeared also able to modulate the regulation of immune response process (down-regulating cytokine biosynthesis, transcripts involved in lymphocyte differentiation and cell proliferation, and cytokine-cytokine receptor interaction) and to regulate genes engaged in homeostasis, secretion, body fluid levels, response to hypoxia, cell division, and cell-to-cell communication and signalling. Results were confirmed and extended analysing the secretome, which showed significant reduction of the release of 14 cytokines and chemokines. These effects are predicted to be mediated by interaction with different transcription factors. Aminaphtone was able to modulate the expression of inflammatory molecules relevant to the pathogenesis of several conditions in which the endothelial dysfunction is the main player and early event, like scleroderma, lung fibrosis, or atherosclerosis.

The HLA-B*35 allele modulates ER stress, inflammation and proliferation in PBMCs from Limited Cutaneous Systemic Sclerosis patients

Introduction

HLA-B*35 is associated with increased risk of developing pulmonary hypertension in SSc patients. We previously reported that HLA-B*35 induces endothelial cell dysfunction via activation of ER stress/UPR and upregulation of the inflammatory response. Because PBMCs from lcSSc-PAH patients are also characterized by activation of ER stress/UPR and inflammation, the goal of this study was to assess whether the presence of HLA-B*35 contributes to those characteristics.

Methods

PBMCs were purified from healthy controls (n = 49 HC) and lcSSc patients, (n = 44 with PAH, n = 53 without PAH). PBMCs from each group were stratified for the presence of HLA-B*35. Global changes in gene expression in response to HLA-B*35, HLA-B*8 or empty lentivirus were investigated by microarray analysis in HC PBMCs. Total RNA was extracted and qPCR was performed to measure gene expression.

Results

ER stress markers, in particular the chaperones BiP and DNAJB1 were significantly elevated in PBMC samples carrying the HLA-B*35 allele. IL-6 expression was also significantly increased in HLA-B*35 lcSSc PBMCs and positively correlated with ER stress markers. Likewise, HMGB1 was increased in HLA-B*35-positive lcSSc PBMCs. Global gene expression analysis was used to further probe the role of HLA-B*35. Among genes downregulated by HLA-B*35 lentivirus were genes related to complement (C1QB, C1QC), cell cycle (CDNK1A) and apoptosis (Bax, Gadd45). Interestingly, complement genes (C1QC and C1QB) showed elevated expression in lcSSc without PAH, but were expressed at the low levels in lcSSc-PAH. The presence of HLA-B*35 correlated with the decreased expression of the complement genes. Furthermore, HLA-B*35 correlated with decreased expression of cyclin inhibitors (p21, p57) and pro-apoptotic genes (Bax, Gadd45) in lcSSc B35 subjects. FYN, a tyrosine kinase involved in proliferation of immune cells, was among the genes that were positively regulated by HLA-B*35. HLA-B*35 correlated with increased levels of FYN in lcSSc PBMCs.

Conclusions

Our study demonstrates that HLA-B*35 contributes to the dysregulated expression of selected ER stress, inflammation and proliferation related genes in lcSSc patient PBMCs, as well as healthy individuals, thus supporting a pathogenic role of HLA-B*35 in the development of PAH in SSc patients.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0881-1) contains supplementary material, which is available to authorized users.

Pathogenesis of Systemic Sclerosis

Systemic scleroderma (SSc) is one of the most complex systemic autoimmune diseases. It targets the vasculature, connective tissue-producing cells (namely fibroblasts/myofibroblasts), and components of the innate and adaptive immune systems. Clinical and pathologic manifestations of SSc are the result of: (1) innate/adaptive immune system abnormalities leading to production of autoantibodies and cell-mediated autoimmunity, (2) microvascular endothelial cell/small vessel fibroproliferative vasculopathy, and (3) fibroblast dysfunction generating excessive accumulation of collagen and other matrix components in skin and internal organs. All three of these processes interact and affect each other. The disease is heterogeneous in its clinical presentation that likely reflects different genetic or triggering factor (i.e., infection or environmental toxin) influences on the immune system, vasculature, and connective tissue cells. The roles played by other ubiquitous molecular entities (such as lysophospholipids, endocannabinoids, and their diverse receptors and vitamin D) in influencing the immune system, vasculature, and connective tissue cells are just beginning to be realized and studied and may provide insights into new therapeutic approaches to treat SSc.

HLA markers for poor prognosis in systemic sclerosis Brazilian patients

Objectives. The aim of this study was to evaluate human leukocyte antigen (HLA) involvement in the disease expression and poor prognostic clinical features (pulmonary fibrosis and pulmonary arterial hypertension) in patients diagnosed with systemic sclerosis (SSc) in a multiethnic population. Methods. SSc patients followed up between 2008 and 2011 were included, and clinical data were obtained through records review. Molecular HLA typing was performed (polymerase chain reaction amplification technique using specific primer sequences). The statistical analysis involved Fisher's exact test and Pearson's corrected chi-square test. P  values ≤ 0.05 were considered significant. The delta method was used to estimate the variance of the prevalence ratio (PR). Results. A total of 141 patients (120 women and 21 men) with SSc were studied, including 33.3% with diffuse cutaneous SSc (dcSSc), 62.4% with limited cutaneous SSc (lcSSc), and 4.3% with sine scleroderma. Pulmonary fibrosis was present in 61 patients (43.3%), and the HLA-A∗30 and DQB1∗04 alleles were related to susceptibility. In contrast, the HLA-DRB1∗01 and DQB1∗05 alleles were protective. Pulmonary arterial hypertension was diagnosed in 19 patients (13.5%) and was associated with HLA-B∗35 and C∗04; in contrast, C∗03 seemed to be protective. Conclusions. Our current study documents the association of some classes I and II HLA alleles with the most severe clinical manifestations in a multiethnic case series. Our findings differed slightly from the previous data in other populations.

Increased expression of endoplasmic reticulum stress and unfolded protein response genes in peripheral blood mononuclear cells from patients with limited cutaneous systemic sclerosis and pulmonary arterial hypertension

OBJECTIVE

Pulmonary arterial hypertension (PAH), a common complication of limited cutaneous systemic sclerosis (lcSSc), is associated with alterations of markers of inflammation and vascular damage in peripheral blood mononuclear cells (PBMCs). Endoplasmic reticulum (ER) stress and the unfolded protein response (UPR) have been implicated in autoimmune and inflammatory diseases. The goal of this study was to assess whether markers of ER stress and the UPR are present in PBMCs from lcSSc patients with PAH.

METHODS

PBMCs were purified from 36 healthy controls, 32 lcSSc patients with PAH, and 34 lcSSc patients without PAH. Gene expression in healthy control PBMCs stimulated with thapsigargin was analyzed by DNA microarray. Genes were validated by quantitative real-time reverse transcription-polymerase chain reaction in PBMCs from healthy controls and lcSSc patients.

RESULTS

Several ER stress/UPR genes, including BiP, activating transcription factor 4 (ATF-4), ATF-6, and a spliced form of X-box binding protein 1, were up-regulated in PBMCs from lcSSc patients, with the highest levels in patients with PAH. Thapsigargin up-regulated heat-shock proteins (HSPs) and interferon (IFN)-regulated genes in PBMCs from healthy controls. Selected HSP genes (particularly DnaJB1) and IFN-related genes were also found at significantly elevated levels in PBMCs from lcSSc patients, while IFN regulatory factor 4 expression was significantly decreased. There was a positive correlation between DnaJB1 and severity of PAH (measured by pulmonary artery pressure) (r = 0.56, P < 0.05) and between ER stress markers and interleukin-6 levels (r = 0.53, P < 0.0001) in PBMCs from lcSSc patients.

CONCLUSION

This study demonstrates an association between select ER stress/UPR markers and lcSSc with PAH, suggesting that ER stress and the UPR may contribute to the altered function of circulating immune cells in lcSSc.

HLA-B35 and dsRNA induce endothelin-1 via activation of ATF4 in human microvascular endothelial cells

Endothelin 1 (ET-1) is a key regulator of vascular homeostasis. We have recently reported that the presence of Human antigen class I, HLA-B35, contributes to human dermal microvascular endothelial cell (HDMEC) dysfunction by upregulating ET-1 and proinflammatory genes. Likewise, a Toll-like receptor 3 (TLR3) ligand, Poly(I:C), was shown to induce ET-1 expression in HDMECs. The goal of this study was to determine the molecular mechanism of ET-1 induction by these two agonists. Because HLA-B35 expression correlated with induction of Binding Immunoglobulin Protein (BiP/GRP78) and several heat shock proteins, we first focused on ER stress and unfolded protein response (UPR) as possible mediators of this response. ER stress inducer, Thapsigargin (TG), HLA-B35, and Poly(I:C) induced ET-1 expression with similar potency in HDMECs. TG and HLA-B35 activated the PERK/eIF2α/ATF4 branch of the UPR and modestly increased the spliced variant of XBP1, but did not affect the ATF6 pathway. Poly(I:C) also activated eIF2α/ATF4 in a protein kinase R (PKR)-dependent manner. Depletion of ATF4 decreased basal expression levels of ET-1 mRNA and protein, and completely prevented upregulation of ET-1 by all three agonists. Additional experiments have demonstrated that the JNK and NF-κB pathways are also required for ET-1 upregulation by these agonists. Formation of the ATF4/c-JUN complex, but not the ATF4/NF-κB complex was increased in the agonist treated cells. The functional role of c-JUN in responses to HLA-B35 and Poly(I:C) was further confirmed in ET-1 promoter assays. This study identified ATF4 as a novel activator of the ET-1 gene. The ER stress/UPR and TLR3 pathways converge on eIF2α/ATF4 during activation of endothelial cells.

Systemic sclerosis: genetics and epigenetics

Systemic sclerosis (SSc) is an autoimmune disease characterized by immune abnormalities, vascular obliteration, excessive extracellular matrix deposition, and fibrosis of the skin and/or internal organs. To date, the exact etiology of this complicated disease remains unknown. Over the past few years, however, the role of genetic susceptibility and epigenetic modifications caused by environmental factors have been intensively studied in relation to the pathogenesis of this disease, and important advances have been made. This review focuses on the recent progress in the field of SSc research, including HLA and non-HLA susceptibility genes identified in genome-wide association studies (GWAS), and aberrant epigenetic modifications of gene loci associated with SSc. HLA genes most closely linked with SSc susceptibility include HLA-A, -B, -C, -DR, -DP and -DQ. A large number of non-HLA genes were also reported. It has also been noted that different genetic variants can be linked to specific clinical patterns. Finally, DNA demethylation of regulatory genes (eNOS, CD40L and CD70), therapeutic effects associated with Trichostatin A (TSA) treatment, and abnormal expression of a large spectrum of microRNAs (miR-21, -31, -146, -503, -145, -29b, etc.) are all observed in SSc. Overall, the findings presented in this review illustrate how both genetic and epigenetic aberrations play important roles in the development of SSc; however, several unanswered questions continue to impede our understanding of this complex disease. Future research should focus on the identification of new biomarkers for early diagnosis and prognosis, which will help improve the clinical outcome of patients with SSc.

Churg-strauss syndrome as an unusual aetiology of stroke with haemorrhagic transformation in a patient with no cardiovascular risk factors

Background

We present here a case of haemorrhagic brain infarction in a middle-aged and physically active male, who had never smoked. This case report aims to remind the internist and neurologist to bear in mind unusual aetiologies of brain infarcts in patients without classical cardiovascular risk factors.

Case Description

A 49-year-old male with pulmonary asthma and a prior history of nasal polyps had a wake-up stroke with left-sided symptoms and speech disturbance. A head MRI and MR angiography revealed a recent haemorrhagic infarct in the right putamen and corona radiata. The left hemiparesis progressed to sensory-motor hemiplegia on the 4th day. In the head CT, it was shown that the haemorrhagic infarct had progressed to a large haematoma. A pansinusitis was also diagnosed. The aetiological investigations revealed a minor atrial septal defect (ASD) with shunting and a heterozygotic clotting factor V R506Q mutation. A remarkable blood eosinophilia of 9.80 E9/l (42%) together with fever, sinusitis, wide-spread bilateral nodular pulmonary infiltrates that did not respond to wide-spectrum antimicrobial treatment, positive anti-neutrophilic cytoplasmic antibodies, a high myeloperoxidase antibody level and slightly positive anti-proteinase 3 antibodies suggested the diagnosis of Churg-Strauss syndrome. These inflammatory symptoms and findings promptly responded to treatment with corticosteroids and cyclophosphamide.

Conclusions

Even after the concomitant findings of the low risk factors, i.e. small ASD and heterozygotic clotting factor mutation, continued search for the final aetiology of stroke revealed Churg-Strauss syndrome, which was the key to the treatment.

A 3-factor epistatic model predicts digital ulcers in Italian scleroderma patients

BACKGROUND

The genetic background may predispose systemic sclerosis (SSc) patients to the development of digital ulcers (DUs).

METHODS

Twenty-two functional cytokine single nucleotide polymorphisms (SNPs) and 3 HLA class I and II antigens were typed at the genomic level by polymerase chain reaction in 200 Italian SSc patients. Associations with DUs were sought by parametric models and with the Multifactor Dimensionality Reduction (MDR) algorithm to depict the presence of epistasis. Biological models consistent with MDR results were built by means of Petri nets to describe the metabolic significance of our findings.

RESULTS

On the exploratory analysis, the diffuse cutaneous subset (dcSSc) was the only single factor statistically associated with DUs (p=0.045, ns after Bonferroni correction). Gene-gene analysis showed that a 3-factor model comprising the IL-6 C-174G, the IL-2 G-330T SNPs and the HLA-B*3501 allele was predictive for the occurrence of DUs in our population (testing accuracy=66.9%; p<0.0001, permutation testing).

CONCLUSION

Biological interpretation via Petri net showed that IL-6 is a key factor in determining DUs occurrence and that this cytokines may synergise with HLA-B*3501 to determine DUs onset. Owing to the limited number of patients included in the study, future research are needed to replicate our statistical findings as well as to better determine their functional meaning.

HLA-B35 upregulates endothelin-1 and downregulates endothelial nitric oxide synthase via endoplasmic reticulum stress response in endothelial cells

The presence of the HLA-B35 allele has emerged as an important risk factor for the development of isolated pulmonary hypertension in patients with scleroderma, however the mechanisms underlying this association have not been fully elucidated. The goal of our study was to determine the molecular mechanisms that mediate the biological effects of HLA-B35 in endothelial cells (ECs). Our data demonstrate that HLA-B35 expression at physiological levels via adenoviral vector resulted in significantly increased endothelin-1 (ET-1) and a significantly decreased endothelial NO synthase (eNOS), mRNA, and protein levels. Furthermore, HLA-B35 greatly upregulated expression of chaperones, including heat shock proteins (HSPs) HSP70 (HSPA1A and HSPA1B) and HSP40 (DNAJB1 and DNAJB9), suggesting that HLA-B35 induces the endoplasmic reticulum (ER) stress and unfolded protein response in ECs. Examination of selected mediators of the unfolded protein response, including H chain binding protein (BiP; GRP78), C/Ebp homologous protein (CHOP; GADD153), endoplasmic reticulum oxidase, and protein disulfide isomerase has revealed a consistent increase of BiP expression levels. Accordingly, thapsigargin, a known ER stress inducer, stimulated ET-1 mRNA and protein levels in ECs. This study suggests that HLA-B35 could contribute to EC dysfunction via ER stress-mediated induction of ET-1 in patients with pulmonary hypertension.

Role of protein kinase C in the expression of endothelin converting enzyme-1

Increased expression of endothelin converting enzyme-1 (ECE-1) is associated with diabetic nephropathy. The molecular mechanisms underlying this association, as yet unknown, possibly involve protein kinase C (PKC) pathways. In the present study, we examined the effects of high glucose and PKC activation on ECE-1 expression in primary human umbilical vein endothelial cells (HUVECs) and in HUVEC line (EA.hy926). Increasing glucose concentration, but not mannitol, from 5.5-22.2 mmol/liter for 3 d, enhanced prepro endothelin-1 (ET-1) mRNA expression, ET-1 levels, ECE-1 protein, and mRNA expressions by 7, 4, 20, and 2.6-fold, respectively. High glucose increased ECE-1 protein expression dose and time dependently. By Western blot analysis, PKC-beta1, -beta2, and -delta isoform levels were significantly increased relative to other isoforms when glucose level was increased. Treatment with Rottlerin, a PKC-delta isoform inhibitor, reduced significantly the glucose-induced ET-1 secretion, and ECE-1 protein expression, but (S)-13-[(dimethylamino)methyl]-10,11,14,15-tetrahydro-4,9:16,21-dimetheno 1H,1(3)H-dibenzo[e,k]pyrrolo[3,4-h] (1, 4, 3) oxadiaza-cyclohexadecene-1,3(2H)-dione or Gö6976, specific PKC-beta and -alpha inhibitors, respectively, did not. Overexpression of PKC-delta but not PKC-alpha or -beta1 isoforms by adenovirus vector containing the respective cDNA in HUVECs incubated with 5.5 mmol/liter glucose, increased in parallel PKC proteins, and glucose-induced endothein-1 and ECE-1 protein expression by 4- to 6-fold. These results show that enhanced ECE-1 expression induced by hyperglycemia is partly due to activation of the PKC-delta isoform. Thus, inhibition of this PKC isoform may prevent diabetes-related increase in ET-1.

Aminaftone, a derivative of 4-aminobenzoic acid, downregulates endothelin-1 production in ECV304 Cells: an in vitro Study

BACKGROUND AND OBJECTIVE

Endothelin-1 (ET-1) plays a central role in the pathogenesis of several vascular diseases. Aminaftone is a drug used for the treatment of capillary disorders but which has a mechanism of action that is not fully understood. We investigated whether aminaftone may exert its effect by interfering with the production of ET-1.

METHODS

Human ECV304 endothelial cells were incubated with interleukin-1beta (IL-1beta) 100 IU/mL with or without the addition of increasing concentrations of aminaftone (2, 4 or 6 microg/mL). ET-1 concentrations in surnatants were quantified by enzyme immunoassay kit at 3, 6 and 12 hours. Pre-pro-endothelin-1 (PPET-1) gene expressions were also analysed by real-time polymerase chain reaction (RT-PCR) at the same time points. Endothelin-converting enzyme (ECE) activity was also determined.

RESULTS

Incubation with IL-1beta increased concentrations of ET-1 and PPET-1 relative gene expression. Incubation with aminaftone significantly reduced production of ET-1 in a concentration-dependent manner. A strong direct correlation was found between ET-1 concentrations and PPET-1 relative gene expression, but aminaftone did not influence ECE activity.

CONCLUSION

Aminaftone inhibits ET-1 production in cell cultures by interfering with transcription of the PPET-1 gene. These findings may account for the clinical efficacy of aminaftone in the treatment of capillary disorders and may encourage conduct of further clinical trials.

Association of Chlamydia pneumoniae infection with HLA-B*35 in patients with coronary artery disease

The immune system may interplay between Chlamydia pneumoniae infection and coronary artery disease (CAD). Major histocompatibility complex genes regulate innate and adaptive immunity. Patients with CAD (n = 100) and controls (n = 74) were enrolled. Human leukocyte antigens (HLA-A, HLA-B, and HLA-DRB1), four lymphotoxin alpha single-nucleotide polymorphisms, and complement C4A and C4B allotypes were typed, and their haplotypes were inferred. The presence of serum C. pneumoniae immunoglobulin A (IgA) (titer, > or =40) or IgG (titer, > or =128) antibodies or immune complex (IC)-bound IgG antibodies (titer, > or =2) was considered to be a serological marker suggesting chronic C. pneumoniae infection. C. pneumoniae IgA antibodies were found more frequently in patients than in controls (P = 0.04). Among the patients, multiple logistic regression analysis showed the HLA-B*35 allele to be the strongest-risk gene for C. pneumoniae infection (odds ratio, 7.88; 95% confidence interval, 2.44 to 25.43; P = 0.0006). Markers of C. pneumoniae infection were found more frequently in patients with the HLA-A*03-B*35 haplotype than in those without the haplotype (P = 0.007 for IgA; P = 0.008 for IgG; P = 0.002 for IC). Smokers with HLA-B*35 or HLA-A*03-B*35 had markers of C. pneumoniae infection that appeared more often than in smokers without these genes (P = 0.003 and P = 0.001, respectively). No associations were found in controls. In conclusion, HLA-B*35 may be the link between chronic C. pneumoniae infection and CAD.