Gene-function studies in systemic lupus erythematosus

IL12B and IL17 genes polymorphisms associated with differential susceptibility to juvenile idiopathic arthritis and juvenile-onset systemic lupus erythematosus in Chinese children

Genetic factors play a crucial role in the immune response of juvenile idiopathic arthritis (JIA) and juvenile-onset systemic lupus erythematosus (JSLE). This study aimed to investigate the association of IL12B (rs3212227, rs6887695) and IL17 (rs2275913, rs763780) gene polymorphisms with the susceptibility of JIA and JSLE in Chinese children. A total of 303 healthy controls and 304 patients including 160 JIA and 144 patients were analyzed, and the genetic polymorphisms were genotyped by using a Sequenom MassArray system. There was a significant association between the IL12B rs3212227 genotype and the increased risk of JSLE (P = .01). For rs6887695, the minor allele C was significantly associated with the increased risk of JIA (odds ratio = 1.48, 95% confidence interval [CI] = 1.12-1.95, P = .005). Moreover, rs6887695 genotype was significantly associated with both JIA and JSLE susceptibility (P < .05). Besides, IL12B haplotype GC significantly associated with the increased risk of JIA (P = .016). However, no significant difference was found between the IL17 (rs2275913, rs763780) gene polymorphisms and JIA or JSLE susceptibility (P > .05). And similar genotype distributions of IL12B and IL17 polymorphisms were found between the patients with nephritis and without nephritis in JSLE (P > .05). Our results indicated that IL12B polymorphisms was associated with an increased risk for the development of JIA and JSLE in Chinese children, highlighting the involvement of inflammation in the pathogenesis of JIA and JSLE. Moreover, there was a risk haplotype in IL12B which could increase the risk of JIA.

Polymorphism of the ITGAM gene (rs7193943) and bioelectric impedance analysis as potential predictors of cachexia in chronic heart failure

Cardiac cachexia (CC) is an unfavorable metabolic syndrome leading to exacerbation of chronic heart failure (CHF) and a higher risk of death. The main factor contributing to the development of cachexia is the ongoing inflammatory process mediated by genes (e.g. Integrin Subunit Alpha M-ITGAM). The study aimed to assess the relationship between a single nucleotide polymorphism (SNP) -323G > A of the ITGAM and the occurrence of nutritional disorders in patients with CHF. 157 CHF patients underwent clinical and nutritional screening. Body composition was evaluated by bioelectrical impedance analysis (BIA). Patients with cachexia were characterized by significantly lower weight, body mass index (BMI), lower fat mass (FM), albumin, and hemoglobin. Lower values of BIA parameters: capacitance of membrane (Cm), phase angle (PA), and impedance ratio (Z200/Z5) were noted in women. Those patients demonstrated significantly higher values of creatinine, c-reactive protein (CRP), N-terminal prohormone of brain natriuretic peptide (NT-proBNP), and pulmonary artery systolic pressure (PASP). A significantly higher risk of cachexia was reported in patients: aged ≥ 74 years (OR 3.55), with renal failure (OR 3.75), New York Heart Association classification (NYHA) III-IV (OR 2.83), with moderate or severe malnutrition according to the score of subjective global assessment (SGA) (OR 19.01) and AA genotype of ITGAM gene (OR 2.03). Determination of the -323G > A SNP in the ITGAM may prove to be a useful marker (after confirmation in further studies and appropriate validation) in the assessment of the risk of nutritional disorders in patients with CHF.

Clinical Significance of TNFRSF1A36T/C Polymorphism in Cachectic Patients with Chronic Heart Failure

Introduction: One of the main factors contributing to the development of nutritional deficits in chronic heart failure (CHF) patients is the systemic inflammatory process. Progressing inflammatory response leads to exacerbation of the disease and could develop into cardiac cachexia (CC), characterized by involuntary weight loss followed by muscle wasting. The aim of this study was to assess the relationship between rs767455 (36 T/C) of the TNFRSF1A and the occurrence of nutritional disorders in CHF patients with cachexia. Materials and Methods: We enrolled 142 CHF individuals who underwent cardiac and nutritional screening in order to assess cardiac performance and nutritional status. The relationship between TNFRSF1A rs767455 genotypes and patients' features was investigated. Results: A greater distribution of the TT genotype among cachectic patients in contrast to non-cachectic individuals was found (TT frequencies of 62.9% and 37.1%, respectively; p = 0.013). We noted a significantly lower albumin concentration (p = 0.039) and higher C-reactive protein (CRP) levels (p = 0.019) in patients with the TT genotype. Regarding cardiac parameters, CHF individuals bearing the TT genotype demonstrated a significant reduction in ejection fraction (EF) (p = 0.033) in contrast to other genotype carriers; moreover, they had a significantly higher concentration of N-terminal prohormone of brain natriuretic peptide (NT-proBNP) in the blood (p = 0.018). We also noted a lower frequency of TT genotype carriers among individuals qualified as grades I or II of the New York Heart Association (NYHA) (p = 0.006). The multivariable analysis selected the TT genotype as an unfavorable factor related to a higher chance of cachexia in CHF patients (Odds ratio (OR) = 2.56; p = 0.036). Conclusions: The rs767455TT genotype of TNFRSF1A can be considered as an unfavorable factor related to a higher risk of cachexia in CHF patients.

Redox Regulation of Tolerogenic Dendritic Cells and Regulatory T Cells in the Pathogenesis and Therapy of Autoimmunity

Significance: Autoimmune diseases are progressively affecting westernized societies, as the proportion of individuals suffering from autoimmunity is steadily increasing over the past decades. Understanding the role of reactive oxygen species (ROS) in modulation of the immune response in the pathogenesis of autoimmune disorders is of utmost importance. The focus of this review is the regulation of ROS production within tolerogenic dendritic cells (tolDCs) and regulatory T (Treg) cells that have the essential role in the prevention of autoimmune diseases and significant potency in their therapy. Recent Advances: It is now clear that ROS are extremely important for the proper function of both DC and T cells. Antigen processing/presentation and the ability of DC to activate T cells depend upon the ROS availability. Treg differentiation, suppressive function, and stability are profoundly influenced by ROS presence. Critical Issues: Although a plethora of results on the relation between ROS and immune cells exist, it remains unclear whether ROS modulation is a productive way for skewing T cells and DCs toward a tolerogenic phenotype. Also, the possibility of ROS modulation for enhancement of regulatory properties of DC and Treg during their preparation for use in cellular therapy has to be clarified. Future Directions: Studies of DC and T cell redox regulation should allow for the improvement of the therapy of autoimmune diseases. This could be achieved through the direct therapeutic application of ROS modulators in autoimmunity, or indirectly through ROS-dependent enhancement of tolDC and Treg preparation for cell-based immunotherapy. Antioxid. Redox Signal. 34, 364-382.

Polymorphism of The Regulatory Region of the ITGAM Gene (-323G>A) as a Novel Predictor of a Poor Nutritional Status in Head and Neck Cancer Patients Subjected to Intensity-Modulated Radiation Therapy

Background: The most serious disturbance of the nutritional status is neoplastic cachexia. The main factor contributing to the development of cachexia is the ongoing inflammatory process. The gene associated with the development of the inflammatory response is ITGAM. Therefore, the aim of the study was to assess the relationship between a single nucleotide polymorphism (SNP)-323G>A of the ITGAM gene and the occurrence of nutritional disorders in patients undergoing radiotherapy (RT) due to head and neck cancers (HNC). Methods: The study involved 71 patients with HNC treated with intensity-modulated radiotherapy (IMRT). SNP analysis of the ITGAM gene (-323G>A) was performed using commercial molecular probes and Real-Time PCR. Results: The presence of the A allele of the ITGAM gene significantly (over 14-fold) reduced the risk of severe disturbances in nutritional status assessed according to the subjective global assessment (SGA) scale (odds ratio (OR) = 0.07; p = 0.0213). The GG genotype of this gene was associated with an over three-fold higher risk of shortened overall survival (OR = 3.01; p = 0.0376). Conclusions: Determination of the SNP (-323G>A) of the ITGAM gene may prove to be a useful marker in the assessment of the risk of nutritional disorders in patients with HNC undergoing RT.

Genetic Alleles Associated with SLE Susceptibility and Clinical Manifestations in Hispanic Patients from the Dominican Republic

PURPOSE

Systemic lupus erythematosus (SLE) is a complex autoimmune disease with marked disparities in prevalence and disease severity among different ethnic groups. The purpose of this study is to characterize a Latin American cohort and identify genetic risk factors for developing SLE and its end-organ manifestations in this Latin Hispanic cohort.

METHODS

A total of 201 SLE cases and 205 non-diseased controls were recruited in the Dominican Republic (DR). Cases were defined according to the 1997 revised American College of Rheumatology criteria for the classification of SLE. Genomic DNA was prepared from whole blood and applied to genotyping analyses for 42 single nucleotide polymorphisms (SNPs) that have been implicated in autoimmune diseases, including SLE, in other ethnic populations. Data were analyzed by Fisher's Exact Probability Test.

RESULTS

In this cohort, SNP rs9271366 (tag SNP for HLA-DRB1*15:01) confers the highest risk for SLE among the 13 MHC gene alleles that display association with SLE (p = 8.748E-10; OR = 3.5). Among the 26 non-MHC gene alleles analyzed, SNP rs2476601 in PTPN22 gene confers the highest risk for SLE (p = 0.0001; OR = 5.6). ITGAM, TNFSF4, TNIP1, STAT4, CARD11, BLK, and TNXB gene alleles were confirmed as SLE-susceptible alleles in the DR cohort. However, IRF5 and TNFAIP3 gene alleles, established risk factors for SLE in populations of European and Asian ancestry, are not significantly associated with SLE in this cohort. We also defined a novel HLA-DRA haplotype that confers an increased risk for lupus nephritis (LN) and alleles in HLA-DRA2 and TNFSF4 genes as genetic risk factors for developing neuropsychiatric (NP) SLE.

CONCLUSION

Our data suggest that the Latin American population shares some common genetic risk factors for SLE as other populations, but also has distinct risk gene alleles that contribute to SLE susceptibility and development of LN and NPSLE. This is the first study focusing on genetic risk factors for SLE in the DR, a Latin American population that has never been characterized before.

β2 Integrins-Multi-Functional Leukocyte Receptors in Health and Disease

β2 integrins are heterodimeric surface receptors composed of a variable α (CD11a-CD11d) and a constant β (CD18) subunit and are specifically expressed by leukocytes. The α subunit defines the individual functional properties of the corresponding β2 integrin, but all β2 integrins show functional overlap. They mediate adhesion to other cells and to components of the extracellular matrix (ECM), orchestrate uptake of extracellular material like complement-opsonized pathogens, control cytoskeletal organization, and modulate cell signaling. This review aims to delineate the tremendous role of β2 integrins for immune functions as exemplified by the phenotype of LAD-I (leukocyte adhesion deficiency 1) patients that suffer from strong recurrent infections. These immune defects have been largely attributed to impaired migratory and phagocytic properties of polymorphonuclear granulocytes. The molecular base for this inherited disease is a functional impairment of β2 integrins due to mutations within the CD18 gene. LAD-I patients are also predisposed for autoimmune diseases. In agreement, polymorphisms within the CD11b gene have been associated with autoimmunity. Consequently, β2 integrins have received growing interest as targets in the treatment of autoimmune diseases. Moreover, β2 integrin activity on leukocytes has been implicated in tumor development.