Angiotensin-converting enzyme gene polymorphism in relation to HLA-DR in sarcoidosis

Advance in pathogenesis of sarcoidosis: Triggers and progression

Sarcoidosis, a multisystemic immune disease, significantly impacts patients' quality of life. The complexity and diversity of its pathogenesis, coupled with limited comprehensive research, had hampered both diagnosis and treatment, resulting in an unsatisfactory prognosis for many patients. In recent years, the research had made surprising progress in the triggers of sarcoidosis (genetic inheritance, infection and environmental factors) and the abnormal regulations on immunity during the formation of granuloma. This review consolidated the latest findings on sarcoidosis research, providing a systematic exploration of advanced studies on triggers, immune-related regulatory mechanisms, and clinical applications. By synthesizing previous discoveries, we aimed to offer valuable insights for future research directions and the development of clinical diagnosis and treatment strategies.

Sarcoidosis and Autoimmune Inflammatory Syndrome Induced by Adjuvants

Currently, sarcoidosis remains one of the diseases with unknown etiology, which significantly complicates its diagnosis and treatment. Various causes of sarcoidosis have been studied for many years. Both organic and inorganic trigger factors, provoking the development of granulomatous inflammation are considered. However, the most promising and evidence-based hypothesis is the development of sarcoidosis as an autoimmune disease, provoked by various adjuvants in genetic predisposed individuals. This concept fits into the structure of the autoimmune/inflammatory syndrome, induced by adjuvants (ASIA) that was proposed in 2011 by Professor Shoenfeld Y. In this paper, the authors reveal the presence of major and minor ASIA criteria for sarcoidosis, propose a new concept of the course of sarcoidosis within the framework of ASIA, and point out the difficulties in creating a model of the disease and the selection of therapy. It is obvious that the data obtained not only bring us closer to understanding the nature of sarcoidosis, but also potentiate new studies confirming this hypothesis by obtaining a model of the disease.

Classical Examples of the Concept of the ASIA Syndrome

Autoimmune/inflammatory syndrome induced by adjuvants (ASIA) was first introduced in 2011 by Shoenfeld et al. and encompasses a cluster of related immune mediated diseases, which develop among genetically prone individuals as a result of adjuvant agent exposure. Since the recognition of ASIA syndrome, more than 4400 documented cases have been reported so far, illustrated by heterogeneous clinical manifestations and severity. In this review, five enigmatic conditions, including sarcoidosis, Sjögren's syndrome, undifferentiated connective tissue disease, silicone implant incompatibility syndrome (SIIS), and immune-related adverse events (irAEs), are defined as classical examples of ASIA. Certainly, these disorders have been described after an adjuvant stimulus (silicone implantation, drugs, infections, metals, vaccines, etc.) among genetically predisposed individuals (mainly the HLA-DRB1 and PTPN22 gene), which induce an hyperstimulation of the immune system resulting in the production of autoantibodies, eventually leading to the development of autoimmune diseases. Circulating autonomic autoantibodies in the sera of patients with silicone breast implants, as well as anatomopathological aspects of small fiber neuropathy in their skin biopsies have been recently described. To our knowledge, these novel insights serve as a common explanation to the non-specific clinical manifestations reported in patients with ASIA, leading to the redefinition of the ASIA syndrome diagnostic criteria.

The opposite effect of human leukocyte antigen genotypes in sarcoidosis and tuberculosis: a narrative review of the literature

Sarcoidosis and tuberculosis share several similar clinical and pathogenic characteristics that make some researchers consider a common pathogenesis for these diseases. Human leukocyte antigen (HLA) genotypes are studied both in sarcoidosis and tuberculosis patients, but to our knowledge, there are no comparative studies of genetic predisposition for sarcoidosis and tuberculosis development.

The aim of this review was to analyse the relationship between HLA genotypes and the development of sarcoidosis and tuberculosis. Original and review articles published in various online databases from 1960 to 2019 were studied.

The search results showed opposite effects of the HLA genotypes on predisposition to sarcoidosis or tuberculosis. It was revealed that the genotypes predisposing to the development of sarcoidosis (HLA-DRB1*03/07/15) have protective properties against the development of tuberculosis. Moreover, genotypes causing the development of tuberculosis (HLA-DRB1*04) have a protective effect on the development of sarcoidosis.

The results of this narrative review of the literature may allude to the existence of genetic predispositions that lead to the development of an antibacterial or autoimmune response to mycobacteria.

The HLA-DRB1*03/07/15 genotypes predispose to the development of sarcoidosis and have protective properties against the development of tuberculosis, while the HLA-DRB1*04 genotype has an opposite effect on the development of these diseaseshttps://bit.ly/2Tl2rj1

Sarcoidosis as an Autoimmune Disease

Despite the large number of performed studies, the etiology and pathogenesis of sarcoidosis still remain unknown. Most researchers allude to the possible autoimmune or immune-mediated genesis of the disease. This review attempts an integral analysis of currently available information suggesting an autoimmune genesis of sarcoidosis and is divided into four categories: the evaluation of clinical signs described both in patients with sarcoidosis and “classic” autoimmune diseases, the role of triggering factors in the development of sarcoidosis, the presence of immunogenic susceptibility in the development of the disease, and the analysis of cellular and humoral immune responses in sarcoidosis. Studying the etiology and pathogenesis of sarcoidosis will improve diagnostic procedures as well as the prognosis and patients' quality of life.

Association of serum TNF-α, IL-8 and free light chain with HLA-DR B alleles expression in pulmonary and extra-pulmonary sarcoidosis

Background

Sarcoidosis is a systemic disease of unknown etiology characterized histologically by the observation of non-caseating granulomas and several immunological abnormalities. Sarcoidosis is a multi-organ disorder which involves formation of granulomas in many tissues including the lungs (pulmonary) and others such as skin, bone, heart (extra pulmonary). Associations between human leukocyte antigens (HLA), the encoded cell surface receptor (HLA-DR) and sarcoidosis have been reported in several studies. Several HLA-DR alleles have been described as potential risk factors for sarcoidosis in distinct ethnic groups however evidence for a relationship between HLA-DR alleles and pulmonary and extra-pulmonary sarcoidosis (EPS) is still scarce. Although the etiology of the disease remains unclear, infectious and environmental factors have been postulated. Inflammatory cytokines and chemokines may play important roles in the pathogenesis of sarcoidosis and serum free light chain (FLC) numbers have been implicated in several immunologic disorders.

Purpose of the study

The aim of the present study was to investigate HLA associations with serum cytokines and FLC in Iranian patients with pulmonary (n = 86) and EPS (n = 46).

Results

We found that among the 16 HLA DRB alleles only *7 and *12 were different in sarcoidosis patients. The levels of TNF-α and IL-8 in pulmonary sarcoidosis patients were higher than in EPS (P < 0.05) whereas the levels of FLC subunits in EPS were higher than in pulmonary sarcoidosis.

Conclusion

This data may suggests a link between HLA-DRB *12 and sarcoidosis in Iranian population.

Distribution of human leukocyte antigen alleles in systemic lupus erythematosus patients with angiotensin converting enzyme insertion/deletion polymorphism

Systemic Lupus Erythematosus is one of the classic examples of autoimmune diseases among human beings and is a rare disease in Pakistani population. Clinically it is a quite diverse and complicated autoimmune disease in a sense that it involves multiple organs of the body and mimics with other diseases as well. This study focused on the distribution of HLA alleles in SLE patients with ACE I/D Polymorphism. A total of 122 individuals were enrolled in this study, 61 were the SLE patients who fulfilled revised ACR criteria and 61 were the healthy controls. Mean age of SLE patients at diagnosis was 30.35 ± 1.687 years (Range: 12-68 years). ACE gene I/D polymorphism was performed by nested PCR and DNA based HLA typing technique was used. ACE gene I/D polymorphism of Intron16 was studied and found to be involved in the activity of SLE. There is high frequency of HLA-A*01, HLA-B*40, HLA-DRB1*01 alleles in SLE patients with ACE DD genotype. The distribution of HLA-A, -B, -DRB1 alleles was analyzed in SLE patients with various disease phenotypes. HLA-A*01 and HLA-B*40 was the most common allele found in SLE patients with the involvement of skin. HLA-A*01, -A*03, HLA-B*13 and -B*46 were common in SLE patients with arthritis while HLA-A*26 and -A*69 were commonly found in Lupus nephritis cases. SLE patients involving both skin and kidney had an allele HLA-DRB1*01 common in them.

HLA class I and class II frequencies in patients with sarcoidosis from Croatia: role of HLA-B8, ?DRB1*0301, and ?DQB1*0201 haplotype in clinical variations of the disease

Sarcoidosis is an immune-mediated, multiorgan, granulomatous disease triggered by a combination of environmental and genetic factors. Numerous studies have reported about an association of human leukocyte antigen (HLA) alleles with sarcoidosis, with variation of alleles in different ethnic groups. Therefore, we investigated 142 Croatian sarcoidosis patients treated at the University Hospital for Lung Diseases Jordanovac, Zagreb, Croatia. Diagnosis was based on the presence of typical clinical features, chest X-ray findings and biopsy evidence of granuloma. Patients and control subjects (n = 190) were typed for HLA class I antigens by serology, while for HLA class II, they were tested by the polymerase chain reaction-sequence specific primers (PCR-SSP) method. Results indicated that HLA-B8, -DRB1*0301, and -DQB1*0201 positive patients have a significantly higher risk of acute onset of the disease (AOD), radiological stage I erythema nodosum (EN), Löfgren's syndrome, no-medicament therapy, and pulmonary sarcoidosis. On the other hand, the group of non-treated patients (corticosteroids and/or immunosuppressive) showed a significantly lower presence of HLA-B15 antigen in comparison to controls and treated patients (P = 0.0490 and P = 0.0379, respectively) and for DRB1*04 specificity (P = 0.0078 and P = 0.0065, respectively). In the group of patients with AOD, those who were positive for DRB1*16 specificity have a statistically significant chance to develop EN, as opposed to those who are positive for DRB1*15 specificity.

Role of genetic polymorphisms in ACE and TNF-alpha gene in sarcoidosis: a meta-analysis

A great number of association studies have been performed to identify the genes involved in the etiology and prognosis of sarcoidosis. We performed a systematic review of case-control studies through the PubMed database and evaluated them for a possible inclusion into a meta-analysis in order to assess whether the reported genetic polymorphisms are the risk factors of sarcoidosis. Case-control studies with clear diagnostic criteria and interventions were included. Only investigations of a single polymorphism/gene involvement in sarcoidosis reported more than five times were selected. Aggregating data from 12 studies on ID/ACE polymorphisms, the odds ratio (OR) for sarcoidosis, if the polymorphism was considered under the dominant genetic model, was not significantly increased: 1.19 (95% CI 0.98-1.43); OR under the recessive model was 1.20 (95% CI 0.98-1.46). In seven case-control studies on -308/TNF-alpha polymorphism, the OR for sarcoidosis if the polymorphism considered under the dominant genetic model was significantly increased at 1.47 (95% CI 1.03-2.08); the OR under the recessive model was 1.39 (95% CI 0.67-2.90). In conclusion, the results showed that the TNF-alpha genotype could be a significant risk factor for sarcoidosis, whereas the risk of sarcoidosis due to the ACE genotype was not substantially elevated.

Genetic association studies in cardiology

The last decade has witnessed the emergence of the genetic association study into the mainstream clinical literature. Technological advances and the Human Genome Project have resulted in widespread interest in exploring these new variables in clinical disease. Although the concept of relating genetic variation to disease is exciting, this excitement must be tempered by the many limitations of such analyses. Here we offer a perspective piece on genetic association studies in cardiology. We begin with a fundamental research and clinical interest-linking genes with disease. We then concentrate the body of the article on the statistical aspects of these studies that are often overlooked or underemphasized. We then use specific examples from the literature to illustrate some of our statistical considerations. We then focus on the distinction between association and causation and conclude with perspectives on how this field of study may move forward in a productive manner.

Serum levels of chitotriosidase as a marker of disease activity and clinical stage in sarcoidosis

BACKGROUND

Sarcoidosis is a systemic granulomatous disease characterized by T-lymphocyte activation and lymphocyte migration into involved organs, usually the lungs. The amounts of a number of biochemical markers, such as angiotensin converting enzyme (ACE) activity, increase in the serum of patients with sarcoidosis. Chitotriosidase is an enzyme secreted by activated macrophages able to catalyze the hydrolysis of both chitin and chitin-like substrates. Chitotriosidase is involved in defense against, and in degradation of chitin-containing pathogens such as fungi, nematodes, and insects.

METHODS

Forty-three patients affected by chronic sarcoidosis, in active (23 patients) or inactive (20 patients) phase, were studied. Serum levels of chitotriosidase and ACE activity were evaluated and compared with those of 32 healthy subjects. Serum chitotriosidase concentration and ACE activity were also correlated with radiographic stage of disease.

RESULTS

Individuals with chronic sarcoidosis have higher serum chitotriosidase concentrations and ACE activity than those of normal subjects. Sarcoidosis patients in the active phase of the disease had significantly higher chitotriosidase and ACE levels than those in the inactive phase. In contrast to serum ACE activity, a significant relationship between serum levels of chitotriosidase and the four radiographic stages of the disease was observed.

CONCLUSION

Although the data need to be validated by further investigation, the observations made in this study seem to indicate that serum chitotriosidase concentrations may be a useful marker for monitoring sarcoidosis disease activity and prognosis.

Clinical and immunologic components of sarcoidosis

Sarcoidosis is a multisystem granulomatous disease of unknown etiology that affects the lungs and the lymphatic system. It is seen by specialists in allergy, rheumatology, and pulmonary disease. Although there are no clues to etiology, an environmental basis has been implicated primarily on the basis of epidemiologic and anecdotal data. The majority of patients are very readily diagnosed and should not be confused with other pulmonary disorders. Sarcoidosis can become an issue if it occurs in the presence of other significant pulmonary disease, such as patients with asthma or hypersensitivity pneumonitis. Most patients remain asymptomatic and many are diagnosed when picked up on a routine screening exam. Steroids can be used to manage some patients but caution should be exercised to choose the appropriate dose and to treat patients for a limited period of time to avoid the complications of steroids. A minority of patients do progress to significant disease, including morbidity and mortality, and further research is needed to determine more appropriate and specific therapy for such situations.

Human Leukocyte Antigen Class I Alleles and the Disease Course in Sarcoidosis Patients

Several lines of evidence suggest a genetic predisposition to sarcoidosis, and strong associations have been shown with the major histocompatibility complex gene complex. In this study on Scandinavian sarcoidosis patients, we investigated any influence on the outcome of disease by human leukocyte antigen (HLA) class I alleles alone and in combination with selected class II alleles. HLA-B*07 independently increased the risk for persistent sarcoidosis (odds ratio [OR], 1.9; 95% confidence interval [CI], 1.0-3.7), as well as for resolving disease (OR, 2.7; CI, 1.1-6.2), suggesting an influence on factors common to both forms of sarcoidosis. The common allele combination A*03, B*07, DRB1*15 was most strongly associated with persistent disease (OR, 4.7; CI, 2.2-10.2) and was found in 25.3% of patients with persistent disease versus 7.1% of healthy control subjects. HLA-B*08 tended to increase separately the risk for resolving disease (OR, 2.4; CI, 0.7-8.0), as well as for persistent disease (OR, 2.2; CI, 0.8-6.1). Other HLA class I associations were mainly secondary to their linkages to DRB1*03 and DRB1*15, respectively. The influence of HLA class I alleles on sarcoidosis thus seems more pronounced than previously thought, and both HLA class I and class II should be relevant to evaluate in the clinical management of sarcoidosis patients.

Angiotensin-converting enzyme gene polymorphisms in patients with pulmonary sarcoidosis: impact on disease severity

Angiotensin converting enzyme (ACE) is a metallopeptidase with a key function in the regulation of blood pressure and volume. The ACE1 gene, on chromosome 17, contains a insertion/deletion (I/D) polymorphism in intron 16. The D allele of this polymorphism is linked with raised serum ACE (sACE) levels. Sarcoidosis is a systemic disease of granulomatous inflammation that primarily affects the lung and lymph system. It is often accompanied by elevated sACE related to ACE production from granuloma cells. The ACE I/D polymorphism has been tested for association or linkage with the risk of sarcoidosis. Though published results are conflicting, there seems to be suggestive evidence of a minor pro-inflammatory influence of the ACE D allele in sarcoidosis. At present, a more accurate interpretation of sACE levels in diagnosis and monitoring of sarcoidosis seems to be the main value of ACE I/D genotyping.

HLA-DRB1*1101: a significant risk factor for sarcoidosis in blacks and whites

Sarcoidosis is a granulomatous disorder of unknown etiology, associated with an accumulation of CD4+ T cells and a TH1 immune response. Since previous studies of HLA associations with sarcoidosis were limited by serologic or low-resolution molecular identification, we performed high-resolution typing for the HLA-DPB1, HLA-DQB1, HLA-DRB1, and HLA-DRB3 loci and the presence of the DRB4 or DRB5 locus, to define HLA class II associations with sarcoidosis. A Case Control Etiologic Study of Sarcoidosis (ACCESS) enrolled biopsy-confirmed cases (736 total) from 10 centers in the United States. Seven hundred six (706) controls were case matched for age, race, sex, and geographic area. We studied the first 474 ACCESS patients and case-matched controls. The HLA-DRB1 alleles were differentially distributed between cases and controls (P<.0001). The HLA-DRB1*1101 allele was associated (P<.01) with sarcoidosis in blacks and whites and had a population attributable risk of 16% in blacks and 9% in whites. HLA-DRB1-F(47) was the amino acid residue most associated with sarcoidosis and independently associated with sarcoidosis in whites. The HLA-DPB1 locus also contributed to susceptibility for sarcoidosis and, in contrast to chronic beryllium disease, a non-E(69)-containing allele, HLA-DPB1*0101, conveyed most of the risk. Although significant differences were observed in the distribution of HLA class II alleles between blacks and whites, only HLA-DRB1*1501 was differentially associated with sarcoidosis (P<.003). In addition to being susceptibility markers, HLA class II alleles may be markers for different phenotypes of sarcoidosis (DRB1*0401 for eye in blacks and whites, DRB3 for bone marrow in blacks, and DPB1*0101 for hypercalcemia in whites). These studies confirm a genetic predisposition for sarcoidosis and present evidence for the allelic variation at the HLA-DRB1 locus as a major contributor.