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Leptin is abnormally elevated in the plasma of patients with systemic lupus erythematosus (SLE), where it is thought to promote and/or sustain pro-inflammatory responses. Whether this association could reflect an increased genetic susceptibility to develop SLE is not known, and studies of genetic associations with leptin-related polymorphisms in SLE patients have been so far inconclusive. Here we genotyped DNA samples from 15,706 SLE patients and healthy matched controls from four different ancestral groups, to correlate polymorphisms of genes of the leptin pathway to risk for SLE. It was found that although several SNPs showed weak associations, those associations did not remain significant after correction for multiple testing. These data do not support associations between defined leptin-related polymorphisms and increased susceptibility to develop SLE.

Objective T cells from patients with systemic lupus erythematosus (SLE) express increased amounts of PP2Ac, which contributes to decreased production of interleukin-2 (IL-2). Because IL-2 is important in the regulation of several aspects of the immune response, it has been proposed that PP2Ac contributes to the expression of SLE. This study was designed to determine whether genetic variants of PPP2AC are linked to the expression of SLE and specific clinical manifestations and account for the increased expression of PP2Ac. Methods We conducted a trans-ethnic study of 8,695 SLE cases and 7,308 controls of 4 different ancestries. Eighteen single-nucleotide polymorphisms (SNPs) across PPP2CA were genotyped using an Illumina custom array. PPP2CA expression in SLE and control T cells was analyzed by real-time polymerase chain reaction. Results A 32-kb haplotype comprising multiple SNPs of PPP2CA showed significant association with SLE in Hispanic Americans, European Americans, and Asians, but not in African Americans. Conditional analyses revealed that SNP rs7704116 in intron 1 showed consistently strong association with SLE across Asian, European American, and Hispanic American populations (odds ratio 1.3 [95% confidence interval 1.14-1.31], meta-analysis P = 3.8 × 10−7). In European Americans, the largest ethnic data set studied, the risk A allele of rs7704116 was associated with the presence of renal disease, anti-double-stranded DNA, and anti-RNP antibodies. PPP2CA expression was ∼2-fold higher in SLE patients carrying the rs7704116 AG genotype than those carrying the GG genotype ( P = 0.007). Conclusion Our data provide the first evidence of an association between PPP2CA polymorphisms and elevated PP2Ac transcript levels in T cells, which implicates a new molecular pathway for SLE susceptibility in European Americans, Hispanic Americans, and Asians. [ABSTRACT FROM AUTHOR]

Objective. SLE is an autoimmune disorder characterized by abnormal complement activation. Numerous new biomarkers have recently been used to diagnose or monitor disease activity in patients with SLE. We checked the levels of erythrocyte-bound C4d (E-C4d), an activation-derived fragment of C4 that is deposited on the erythrocytes, under different conditions of SLE in order to correlate these levels with disease activity.Methods. We conducted a cross-sectional investigation of three groups of patients: (i) 63 patients with SLE; (ii) 43 patients with other diseases; and (iii) 26 healthy controls. Erythrocytes were analysed by flow cytometry to determine the levels of E-C4d.Results. We found a significant elevation in the mean levels of E-C4d in SLE patients compared with patients with other diseases or healthy controls. In SLE patients, the levels of E-C4d were correlated with the SLEDAI and inversely correlated with serum C3/C4 levels. In the subgroup of SLE patients with haemolytic anaemia (HA), a significantly higher level of E-C4d was observed than that in SLE patients without HA. However, in SLE patients with HA, there was no correlation between the levels of E-C4d and other markers of disease activity, including SLEDAI and levels of anti-dsDNA, C3 and C4.Conclusion. E-C4d levels are useful diagnostic markers for SLE and can serve as biomarkers of disease activity in patients with SLE. However, E-C4d is of limited value in monitoring disease activity in SLE patients with HA. [ABSTRACT FROM PUBLISHER]

Abstract We evaluated plasma glutamine levels and basal mitochondrial oxygen consumption rate (mOCR B) and basal extracellular acidification rate (ECAR B) of peripheral blood mononuclear cells (PBMCs) of systemic lupus erythematous (SLE) patients and healthy controls (HCs). Lower plasma glutamine levels correlated with higher SLE disease activity indexes (p = 0.025). Incubated in DMEM containing 100 mg/dL glucose, SLE-PBMCs displayed lower mOCR B (p = 0.018) but similar ECAR B (p = 0.467) to those of HC-PBMCs, and their mOCR B got elevated (p < 0.001) without altering ECAR B (p = 0.239) by supplementation with 2 or 4 mM glutamine. We conclude that impaired mitochondrial respiration of SLE-PBMCs could be improved by glutamine under euglycemic condition. Highlights • Lower plasma glutamine levels were found to correlate with higher disease activity of SLE. • SLE PBMCs had lower mitochondrial oxygen consumption rate than did healthy controls. • Impaired mitochondrial respiration of SLE-PBMCs could be improved by glutamine supplement under euglycemic condition. [ABSTRACT FROM AUTHOR]

SLE is characterized by an increased production of detrimental autoantigens, exaggerated effects of pro-inflammatory cytokines, dysregulated functioning of immunocompetent cells including lymphocytes and leukocytes, and devastating tissue and organ damage. All of these derangements can be potentiated or attenuated by the abnormal energy expenditure and overproduction of reactive oxygen species (ROS). Mitochondrial heteroplasmy or dysfunction has been recognized to play a role in these abnormalities. Abnormal redox reaction, decreased functioning of biogenesis-related enzymes, increased NETosis, harmful cytokine effects, and aberrant lymphocyte behavior have been shown to be associated with the pathological state of mitochondria. There is accumulating data which support the importance of abnormal oxygen metabolism and mitochondrial disorders in the immunopathogenesis of SLE. Further laboratory as well as clinical data are required to expand our understanding of SLE pathogenesis. [ABSTRACT FROM AUTHOR]

Abstract: Objectives: To determine the safety of and immunogenicity induced by A/H1N1 influenza vaccination in patients with systemic lupus erythematosus (SLE). Research design and methods: The study population comprised 21 SLE patients and 15 healthy control subjects who underwent split-virion, inactivated monovalent A/H1N1 vaccination between December 2009 and January 2010. Sera were obtained before, three weeks after, and six months after vaccination. SLE disease activity index (SLEDAI) scores and autoantibodies were measured at every visit in SLE patients. Haemagglutination inhibition and the serum immunoglobulin G (IgG) level were calculated using the World Health Organization (WHO) procedure to evaluate the antibody responses. We also recorded current medications and past seasonal influenza vaccinations to analyse the interactions between vaccinations and the autoimmunity of SLE patients. Results: The mean age of the enrolled population was 34.3 years for SLE patients and 39.4 years for control subjects. The average SLEDAI score for SLE patients was 4.1 at vaccination, 4.5 at three weeks, and 4.3 at six months. The seroprotection rate at three weeks was 76.2% in SLE patients and 80.0% in healthy control subjects; by six months, the seroprotection rate was 66.7% in SLE patients and 60% in healthy control subjects. The seroconversion rate was 76.2% in SLE patients and 80% in healthy controls at three weeks; by six months, the seroconversion rate was 52.4% in SLE patients and 53.3% in healthy controls. The response in SLE patients met the criteria of the European Committee for Proprietary Medicinal Products guidelines at three weeks, while the percentage of seroprotection did not at six months. The clinical disease activity and SLEDAI scores did not differ significantly from before to after vaccination in SLE patients, although the level of anticardiolipin IgG increased at three weeks after vaccination, but with no apparent clinical manifestations. Conclusions: The A/H1N1 influenza vaccine is safe and effective in SLE patients and has no obvious adverse clinical effects. Treatment with a single immunosuppressive agent or combination therapy also leads to effective humoral immunity in these patients. [Copyright &y& Elsevier]