Effects of 1,25(OH)2 D3 and vitamin D receptor on peripheral CD4+ /CD8+ double-positive T lymphocytes in a mouse model of systemic lupus erythematosus

This study aims to explore effects of 1,25(OH)₂D₃ and vitamin D receptor (VDR) on peripheral CD4⁺/CD8⁺ double‐positive (DP) T lymphocytes in systemic lupus erythematosus (SLE). MRL‐LPr/LPr mice with SLE (n = 20) and normal MRL mice (n = 20) were assigned into the control group (normal mice, without feeding with 1,25(OH)₂D₃), the 1,25(OH)₂D₃ group (SLE mice, feeding with 1,25(OH)₂D₃), the VDR‐knock‐in + 1,25(OH)₂D₃ group (SLE mice, VDR‐knock‐in, feeding with 1,25(OH)₂D₃) and the VDR‐knockout group (normal mice, VDR‐knockout, without feeding with 1,25(OH)₂D₃) (n = 10 per group). Levels of T lymphocytes were measured by flow cytometry. The mRNA and proteins expressions of inflammatory factors were measured by qRT‐PCR and ELISA. Extracellular signal‐regulated kinase‐1/2 (ERK1/2) expression was measured by Western blotting. Compared with normal mice, SLE mice showed reduced levels of CD4⁺, CD4⁺/CD8⁺ ratio, and DP lymphocytes. The levels of SLE‐related indicators all increased significantly, followed with severe skin ulcers and urinary system infection. With the increase in time, skin ulcers and urinary system infection were significantly improved, levels of CD4⁺, CD4⁺/CD8⁺ ratio, and DP lymphocytes increased, and levels of SLE‐related indicators all decreased in the 1,25(OH)₂D₃ group. There were no significant changes in bioindicators in the control and the VDR‐knock‐in + 1,25(OH)₂D₃ groups. The symptoms of SLE gradually occurred in the VDR‐knockout group. This study demonstrates that VDR and 1,25(OH)₂D₃ could elevate CD4⁺/CD8⁺ DP T lymphocytes and reduce expressions of inflammatory factors, thus inhibiting the development and progression of SLE.

Combined role of vitamin D status and CYP24A1 in the transition to systemic lupus erythematosus

OBJECTIVE

We examined whether measures of vitamin D were associated with transitioning to systemic lupus erythematosus (SLE) in individuals at risk for SLE.

METHODS

436 individuals who reported having a relative with SLE but who did not have SLE themselves were evaluated at baseline and again an average of 6.3 (±3.9) years later. Fifty-six individuals transitioned to SLE (≥4 cumulative American College of Rheumatology criteria). 25-Hydroxyvitamin D (25[OH]D) levels were measured by ELISA. Six single-nucleotide polymorphisms in four vitamin D genes were genotyped. Generalised estimating equations, adjusting for correlation within families, were used to test associations between the vitamin D variables and the outcome of transitioning to SLE.

RESULTS

Mean baseline 25[OH]D levels (p=0.42) and vitamin D supplementation (p=0.65) were not different between those who did and did not transition to SLE. Vitamin D deficiency (25[OH]D <20 ng/mL) was greater in those who transitioned compared with those who did not transition to SLE (46% vs 33%, p=0.05). The association between 25[OH]D and SLE was modified by CYP24A1 rs4809959, where for each additional minor allele increased 25[OH]D was associated with decreased SLE risk: zero minor alleles (adjusted OR: 1.03, CI 0.98 to 1.09), one minor allele (adjusted OR: 1.01, CI 0.97 to 1.05) and two minor alleles (adjusted OR: 0.91, CI 0.84 to 0.98). Similarly, vitamin D deficiency significantly increased the risk of transitioning to SLE in those with two minor alleles at rs4809959 (adjusted OR: 4.90, CI 1.33 to 18.04).

CONCLUSIONS

Vitamin D status and CYP24A1 may have a combined role in the transition to SLE in individuals at increased genetic risk for SLE.

Vitamin D receptor gene BsmI polymorphisms in Egyptian children and adolescents with systemic lupus erythematosus: A case-control study

Systemic lupus erythematosus (SLE) is a multisystemic autoimmune disease. The vitamin D receptor (VDR) gene is a candidate gene for susceptibility to autoimmune disorders. To date, only a few studies concerned the association of the VDR gene polymorphisms with childhood-onset SLE.In this study, we aimed to investigate the BsmI polymorphisms in the VDR gene, for the first time in Egyptian children and adolescents with SLE, to determine whether this polymorphism could be a marker of susceptibility to or severity of SLE and we also measured the serum level of 25-hydroxyvitamin D (25[OH] D) to assess its relation to such polymorphism.This was a case-control study including 100 patients with SLE and matched with age, sex, and ethnicity and 100 healthy controls. All subjects were genotyped for the VDR gene BsmI polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), whereas the serum 25(OH) D levels were measured by enzyme-linked immunosorbent assay method.Compared to the contros subjects, the VDR BsmI BB genotype and B allele were overrepresented among SLE patients (odda ratio [OR]: 5.5; 95% confidence interval [CI]: 1.9-15.9; P = 0.002 and OR: 1.84; 95% CI: 1.21-2.80; P = 0.003; respectively). We found a significant association between VDR BsmI BB genotype with lupus nephritis (OR: 6.8; 95% CI: 1.18-50.5; P = 0.001). However, we did not observe any significant association of studied polymorphisms with other clinical manifestations, laboratory profiles of SLE, or disease activity score. Our data revealed no association between VDR BsmI genotypes or alleles and serum 25-hydroxyvitamin D levels among studied patients with SLE (all P > 0.05).We demonstrate for the first time, to the best of our knowledge, that the VDR BsmI gene polymorphisms may contribute to susceptibility to SLE in Egyptian children and adolescents. Moreover, we found that the BB genotype constituted a risk factor for the development of nephropathy among studied patients with SLE. However, we did not find any significant association of the VDR BsmI gene variants with other clinical manifestations, laboratory profiles of SLE, disease activity index score, or serum 25-hydroxyvitamin D levels.

Single nucleotide polymorphisms in the vitamin D pathway associating with circulating concentrations of vitamin D metabolites and non-skeletal health outcomes: Review of genetic association studies

Polymorphisms in genes encoding proteins involved in vitamin D metabolism and transport are recognised to influence vitamin D status. Syntheses of genetic association studies linking these variants to non-skeletal health outcomes are lacking. We therefore conducted a literature review to identify reports of statistically significant associations between single nucleotide polymorphisms (SNP) in 11 vitamin D pathway genes (DHCR7, CYP2R1, CYP3A4, CYP27A1, DBP, LRP2, CUB, CYP27B1, CYP24A1, VDR and RXRA) and non-bone health outcomes and circulating levels of 25-hydroxyvitamin D (25[OH]D and 1,25-dihydroxyvitamin D (1,25[OH]₂D). A total of 120 genetic association studies reported positive associations, of which 44 investigated determinants of circulating 25(OH)D and/or 1,25(OH)₂D concentrations, and 76 investigated determinants of non-skeletal health outcomes. Statistically significant associations were reported for a total of 55 SNP in the 11 genes investigated. There was limited overlap between genetic determinants of vitamin D status and those associated with non-skeletal health outcomes: polymorphisms in DBP, CYP2R1 and DHCR7 were the most frequent to be reported to associate with circulating concentrations of 25(OH)D, while polymorphisms in VDR were most commonly reported to associate with non-skeletal health outcomes, among which infectious and autoimmune diseases were the most represented.

Association of germline genetic variants in RFC, IL15 and VDR genes with minimal residual disease in pediatric B-cell precursor ALL

Minimal residual disease (MRD) enables reliable assessment of risk in acute lymphoblastic leukemia (ALL). However, little is known on association between MRD status and germline genetic variation. We examined 159 Caucasian (Slavic) patients with pediatric ALL, treated according to ALL-IC-BFM 2002/2009 protocols, in search for association between 23 germline polymorphisms and MRD status at day 15, day 33 and week 12, with adjustment for MRD-associated clinical covariates. Three variants were significantly associated with MRD: rs1544410 in VDR (MRD-day15); rs1051266 in RFC (MRD-day33, MRD-week12), independently and in an additive effect with rs10519613 in IL15 (MRD-day33). The risk alleles for MRD-positivity were: A allele of VDR (OR = 2.37, 95%CI = 1.07–5.21, P = 0.03, MRD-day15); A of RFC (OR = 1.93, 95%CI = 1.05–3.52, P = 0.03, MRD-day33 and MRD-week12, P < 0.01); A of IL15 (OR = 2.30, 95%CI = 1.02–5.18, P = 0.04, MRD-day33). The risk for MRD-day33-positive status was higher in patients with risk alleles in both RFC and IL15 loci than in patients with risk alleles in one locus or no risk alleles: 2 vs. 1 (OR = 3.94, 95% CI = 1.28–12.11, P = 0.024), 2 vs. 0 (OR = 6.75, 95% CI = 1.61–28.39, P = 0.012). Germline variation in genes related to pharmacokinetics/pharmacodynamics of anti-leukemic drugs and to anti-tumor immunity of the host is associated with MRD status and might help improve risk assessment in ALL.

Vitamin D level and vitamin D receptor genetic variations contribute to HCV infection susceptibility and chronicity in a Chinese population

Vitamin D and vitamin D receptor (VDR) are involved in multiple immune-mediated disorders including chronic hepatitis C virus (HCV) infection. The aim of this study was to determine the association between plasma vitamin D level, VDR genetic polymorphisms and risk of HCV infection susceptibility and chronicity. Seven single nucleotide polymorphisms (SNPs) in VDR gene were genotyped and plasma 25-hydroxyvitamin D [25(OH)D] levels were measured in a Han Chinese population of 898 HCV persistent infection cases, 558 spontaneous clearance subjects and 1136 uninfected controls with high risk of HCV infection. In this case-control study, the average plasma 25(OH)D level in persistent infection patients was significantly lower than that in spontaneous clearance cases (P=0.039) and controls (P=0.005). Logistic analyses indicated that rs7975232-C, rs2239185-T and rs11574129-T alleles were significantly associated with a decreased risk of HCV infection susceptibility (all PBonferroni<0.05, in additive/dominant models; Ptrend=9.000×10(-4), combined effects in a locus-dosage manner). The protective effects of three favorable alleles were more evident among males, females and subjects aged ≤50years (all P<0.05). Haplotype analyses suggested that compared with the most frequent haplotype Ars7975232Trs731236Crs11574129, CTT was correlated with a reduced risk of HCV infection susceptibility (P=2.200×10(-3)). These findings implied that low vitamin D levels might be associated with an increased risk for HCV infection and chronicity, and favorable VDR variants (rs7975232-C, rs2239185-T and rs11574129-T) might contribute to a decreased susceptibility to HCV infection in a high-risk Chinese population.

Possible risk factors associated with greater damage in systemic lupus erythematosus patients: an Egyptian multicenter study

OBJECTIVES

Systemic lupus erythematosus (SLE) is a prototypic multisystem autoimmune disorder. The total damage in a patient with SLE may result from SLE itself or from any other pathologic process. The aim of this study was to assess risk factors of greater damage in a sample of Egyptian SLE patients.

METHODS

This Egyptian multicenter retrospective study included 100 SLE patients: 64 patients from Cairo University Hospitals and 36 patients from Zagazig University Hospitals. The Systemic Lupus International Collaborative Clinics (SLICC)/American College of Rheumatology (ACR) Damage Index (ACR-DI) was used to document the damage in each patient.

RESULTS

The total SLICC/ACR-DI score ranged from 0 to 8. A higher DI score was found in hypertensive patients, compared to normotensive patients; and among those with positive anti-phospholipid antibodies, compared to those with negative anti-phospholipid antibodies. This difference was statistically significant (p < 0.01). Also, a higher DI score was found in cyclophosphamide users, compared to non-users; and in those with proteinuria and seizures, compared to those without; and the difference was statistically significant (p < 0.05). There was a significant positive correlation between the DI and patient age (p < 0.05).

CONCLUSIONS

Damage in SLE cannot be prevented completely, as SLE disease is considered an aggressive disease treated by aggressive medications, but rheumatologists should try to minimize damage as much as possible to maintain the patients' health, functioning and general wellbeing.

Impact of the polymorphism in vitamin D receptor gene BsmI and the risk of systemic lupus erythematosus: an updated meta-analysis

The etiology of system lupus erythematosus (SLE) still remains unclear, and vitamin D is associated with immune response. Although a few studies are conducted to investigate the association between polymorphism in vitamin D receptor (VDR) genes and SLE risk, their results are conflicting. Following the guideline of PRISMA, we conducted a systematic search and meta-analysis of the BsmI polymorphism rs1544410 and the risk of SLE. The pooled odds ratios (OR) and its 95 % confidential interval (CI) were calculated by using Stata Version 10 with dominant and recessive model and allele analyses. Nine studies were included in our meta-analysis with a total of 1247 SLE cases and 1687 controls. No significant association was found in both models in the overall population. Only Bb + BB genotypes showed a significantly elevated SLE risk in Asian subgroup with an OR of 3.26 (95 % CI = 1.30-8.17) while no significance was observed in Caucasian population. Notably, B allele significantly increased the SLE risk among Asian population with an OR of 2.29 (95 % CI = 1.14-4.61). No positive findings were reported in Caucasian population and in the overall analysis. In Asian population, Bb + BB genotype and B allele can significantly increase the SLE risk.

Genetic Factors in Systemic Lupus Erythematosus: Contribution to Disease Phenotype

Genetic factors exert an important role in determining Systemic Lupus Erythematosus (SLE) susceptibility, interplaying with environmental factors. Several genetic studies in various SLE populations have identified numerous susceptibility loci. From a clinical point of view, SLE is characterized by a great heterogeneity in terms of clinical and laboratory manifestations. As widely demonstrated, specific laboratory features are associated with clinical disease subset, with different severity degree. Similarly, in the last years, an association between specific phenotypes and genetic variants has been identified, allowing the possibility to elucidate different mechanisms and pathways accountable for disease manifestations. However, except for Lupus Nephritis (LN), no studies have been designed to identify the genetic variants associated with the development of different phenotypes. In this review, we will report data currently known about this specific association.

SLE: Another Autoimmune Disorder Influenced by Microbes and Diet?

Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. Despite years of study, the etiology of SLE is still unclear. Both genetic and environmental factors have been implicated in the disease mechanisms. In the past decade, a growing body of evidence has indicated an important role of gut microbes in the development of autoimmune diseases, including type 1 diabetes, rheumatoid arthritis, and multiple sclerosis. However, such knowledge on SLE is little, though we have already known that environmental factors can trigger the development of lupus. Several recent studies have suggested that alterations of the gut microbial composition may be correlated with SLE disease manifestations, while the exact roles of either symbiotic or pathogenic microbes in this disease remain to be explored. Elucidation of the roles of gut microbes - as well as the roles of diet that can modulate the composition of gut microbes - in SLE will shed light on how this autoimmune disorder develops, and provide opportunities for improved biomarkers of the disease and the potential to probe new therapies. In this review, we aim to compile the available evidence on the contributions of diet and gut microbes to SLE occurrence and pathogenesis.

Immune Response Modulation by Vitamin D: Role in Systemic Lupus Erythematosus

Vitamin D plays key roles as a natural immune modulator and has been implicated in the pathophysiology of autoimmune diseases, including systemic lupus erythematosus (SLE). This review presents a summary and analysis of the recent literature regarding immunoregulatory effects of vitamin D as well as its importance in SLE development, clinical severity, and possible effects of supplementation in disease treatment.