Clinical and immunological factors associated with lupus nephritis in patients from northwestern Colombia

A cross-sectional and multicenter study was undertaken to analyze the clinical and immunological characteristics at diagnosis associated with nephritis in northwestern Colombian patients with systemic lupus erythematosus (SLE). Thirty-nine patients with lupus nephritis were included and were compared to 100 SLE patients without nephritis. A multivariate analysis was performed. The patients who developed nephritis had a higher frequency of oral ulcers (41% vs. 21%, OR = 3.1, 95% CI: 1.3-7.5 p = 0.01) and malar erythema (77% vs. 45%, OR = 4.4, 95% CI: 1.8-10.8 p = 0.001). Lupus nephritis was observed in 77% of cases during the first year of the disease. The frequency of anti-DNA antibodies was higher in patients with nephritis, however, differences were not statistically significant (83% vs 64%, OR = 2.6, 95% CI: 1.03-6.41, p = 0.06). The presence of other autoantibodies (anti-Ro, anti-La, anti-RNP, anti-Sm and anticardiolipin) at diagnosis was similar in both groups. This autoantibody profile remained unchanged throughout the evolution of the disease. Patients with lupus nephritis had a higher prevalence of arterial hypertension (60% vs 10%, OR = 13.7, 95% IC: 5-37, p = 0.00001) and hyperlipidemia (30% vs 7%, OR = 8.1, 95% IC: 2.5-27, p = 0.0006) at onset. Finally, patients with lupus nephritis required more hospitalizations (> 1) over the course of disease (89% vs 60%, OR = 7.8, 95% CI: 2.1-29, p = 0.002). In conclusion, lupus nephritis appears early during the course of SLE. Malar erythema, oral ulcers, hypertension and hyperlipidemia at onset of disease are associated factors. Lupus nephritis is a major risk factor leading to repeated hospitalizations. This study may help to assist in public health policies in our population in order to improve patient outcomes while simultaneously reducing disease costs.     

The spectrum of renal thrombotic microangiopathy in lupus nephritis

Introduction

Among various lupus renal vascular changes, thrombotic microangiopathy (TMA) presented with the most severe clinical manifestations and high mortality. The pathogenesis of TMA in systemic lupus erythematosus (SLE) was complicated. The aim of this study was to assess clinical manifestations, laboratory characteristics, pathological features and risk factors for clinical outcomes of lupus nephritis patients co-existing with renal TMA in a large cohort in China.

Methods

Clinical and renal histopathological data of 148 patients with biopsy-proven lupus nephritis were retrospectively analyzed. Serum complement factor H, A Disintegrin and Metalloprotease with Thrombospondin type I repeats 13 (ADAMTS-13) activity, antiphospholipid antibodies and C4d deposition on renal vessels were further detected and analyzed.

Results

In the 148 patients with lupus nephritis, 36 patients were diagnosed as co-existing with renal TMA based on pathological diagnosis. Among the 36 TMA patients, their clinical diagnoses of renal TMA were as followings: 2 patients combining with thrombotic thrombocytopenic purpura-hemolytic uremic syndrome, 2 patients combining with anti-phospholipid syndrome, 2 patients with malignant hypertension, 1 patient with scleroderma and the other 29 patients presenting with isolated renal TMA. Compared with the non-renal TMA group, patients with renal TMA had significantly higher urine protein (7.09 ± 4.64 vs. 4.75 ± 3.13 g/24h, P = 0.007) and serum creatinine (159, 86 to 215 vs. 81, 68 to 112 μmol/l, P <0.001), higher scores of total activity indices (AI) (P <0.001), endocapillary hypercellularity (P <0.001), subendothelial hyaline deposits (P = 0.003), interstitial inflammation (P = 0.005), glomerular leukocyte infiltration (P = 0.006), total chronicity indices (CI) (P = 0.033), tubular atrophy (P = 0.004) and interstitial fibrosis (P = 0.018). Patients with renal TMA presented with poorer renal outcome (P = 0.005) compared with the non-TMA group. Renal TMA (hazard ratio (HR): 2.772, 95% confidence interval: 1.009 to 7.617, P = 0.048) was an independent risk factor for renal outcome in patients with lupus nephritis. The renal outcome was poorer for those with both C4d deposition and decreased serum complement factor H in the TMA group (P = 0.007).

Conclusions

There were various causes of renal TMA in lupus nephritis. Complement over-activation via both classical and alternative pathways might play an important role in the pathogenesis of renal TMA in lupus nephritis.     

Primary respiratory disease in patients with systemic lupus erythematosus: data from the Spanish rheumatology society lupus registry (RELESSER) cohort

Background

The purpose of this study was to assess the prevalence, associated factors, and impact on mortality of primary respiratory disease in a large systemic lupus erythematosus (SLE) retrospective cohort.

Methods

All adult patients in the RELESSER-TRANS (Registry of Systemic Lupus Erythematosus Patients of the Spanish Society of Rheumatology [SER], cross-sectional phase) registry were retrospectively investigated for the presence of primary pleuropulmonary manifestations.

Results

In total 3215 patients were included. At least one pleuropulmonary manifestation was present in 31% of patients. The most common manifestation was pleural disease (21%), followed by lupus pneumonitis (3.6%), pulmonary thromboembolism (2.9%), primary pulmonary hypertension (2.4%), diffuse interstitial lung disease (2%), alveolar hemorrhage (0.8%), and shrinking lung syndrome (0.8%).In the multivariable analysis, the variables associated with the development of pleuropulmonary manifestation were older age at disease onset (odds ratio (OR) 1.03, 95% confidence interval (CI) 1.02–1.04), higher SLEDAI (Systemic Lupus Erythematosus Disease Activity Index) scores (OR 1.03, 95% CI 1.00–1.07), the presence of Raynaud’s phenomenon (OR 1.41, 95% CI 1.09–1.84), secondary antiphospholipid syndrome (OR 2.20, 95% CI 1.63–2.97), and the previous or concomitant occurrence of severe lupus nephritis, (OR 1.48, 95% CI 1.12–1.95) neuropsychiatric manifestations (OR 1.49, 95% CI 1.11–2.02), non-ischemic cardiac disease (OR 2.91, 95% CI 1.90–4.15), vasculitis (OR 1.81, 95% CI 1.25–2.62), hematological manifestations (OR 1.31, 95% CI 1.00–1.71), and gastrointestinal manifestations, excluding hepatitis (OR 2.05, 95% CI 1.14–3.66). Anti-RNP positivity had a clear tendency to significance (OR 1.32, 95% CI 1.00–1.75; P = 0.054).The development of pleuropulmonary manifestations independently contributes to a diminished survival (hazard ratio of 3.13). However, not all complications will influence the prognosis in the same way. Whereas the occurrence of pleural disease or pulmonary thromboembolism has a minimal impact on the survival of these patients, the remaining manifestations have a major impact on mortality.

Conclusion

Except for pleural disease, the remaining respiratory manifestations are very uncommon in SLE (<4%). Pleuropulmonary manifestations independently contributed to a decreased survival in these patients.

     

Autoantigen microarrays reveal autoantibodies associated with proliferative nephritis and active disease in pediatric systemic lupus erythematosus

IntroductionPediatric systemic lupus erythematosus (pSLE) patients often initially present with more active and severe disease than adults, including a higher frequency of lupus nephritis. Specific autoantibodies, including anti-C1q, anti-DNA and anti-alpha-actinin, have been associated with kidney involvement in SLE, and DNA antibodies are capable of initiating early-stage lupus nephritis in severe combined immunodeficiency (SCID) mice. Over 100 different autoantibodies have been described in SLE patients, highlighting the need for comprehensive autoantibody profiling. Knowledge of the antibodies associated with pSLE and proliferative nephritis will increase the understanding of SLE pathogenesis, and may aid in monitoring patients for renal flare.MethodsWe used autoantigen microarrays composed of 140 recombinant or purified antigens to compare the serum autoantibody profiles of new-onset pSLE patients (n = 45) to healthy controls (n = 17). We also compared pSLE patients with biopsy-confirmed class III or IV proliferative nephritis (n = 23) and without significant renal involvement (n = 18). We performed ELISA with selected autoantigens to validate the microarray findings. We created a multiple logistic regression model, based on the ELISA and clinical information, to predict whether a patient had proliferative nephritis, and used a validation cohort (n = 23) and longitudinal samples (88 patient visits) to test its accuracy.ResultsFifty autoantibodies were at significantly higher levels in the sera of pSLE patients compared to healthy controls, including anti-B cell-activating factor (BAFF). High levels of anti-BAFF were associated with active disease. Thirteen serum autoantibodies were present at significantly higher levels in pSLE patients with proliferative nephritis than those without, and we confirmed five autoantigens (dsDNA, C1q, collagens IV and X and aggrecan) by ELISA. Our model, based on ELISA measurements and clinical variables, correctly identified patients with proliferative nephritis with 91 % accuracy.ConclusionsAutoantigen microarrays are an ideal platform for identifying autoantibodies associated with both pSLE and specific clinical manifestations of pSLE. Using multiple regression analysis to integrate autoantibody and clinical data permits accurate prediction of clinical manifestations with complex etiologies in pSLE.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0682-6) contains supplementary material, which is available to authorized users.     

Association of TNFAIP3 interacting protein 1, TNIP1 with systemic lupus erythematosus in a Japanese population: a case-control association study

Introduction

TNFAIP3 interacting protein 1, TNIP1 (ABIN-1) is involved in inhibition of nuclear factor-κB (NF-κB) activation by interacting with TNF alpha-induced protein 3, A20 (TNFAIP3), an established susceptibility gene to systemic lupus erythematosus (SLE) and rheumatoid arthritis (RA). Recent genome-wide association studies revealed association of TNIP1 with SLE in the Caucasian and Chinese populations. In this study, we investigated whether the association of TNIP1 with SLE was replicated in a Japanese population. In addition, association of TNIP1 with RA was also examined.

Methods

A case-control association study was conducted on the TNIP1 single nucleotide polymorphism (SNP) rs7708392 in 364 Japanese SLE patients, 553 RA patients and 513 healthy controls.

Results

Association of TNIP1 rs7708392C was replicated in Japanese SLE (allele frequency in SLE: 76.5%, control: 69.9%, P = 0.0022, odds ratio [OR] 1.40, 95% confidence interval [CI] 1.13-1.74). Notably, the risk allele frequency in the healthy controls was considerably greater in Japanese (69.9%) than in Caucasians (24.3%). A tendency of stronger association was observed in the SLE patients with renal disorder (P = 0.00065, OR 1.60 [95%CI 1.22-2.10]) than in all SLE patients (P = 0.0022, OR 1.40 [95%CI 1.13-1.74]). Significant association with RA was not observed, regardless of the carriage of human leukocyte antigen DR β1 (HLA-DRB1) shared epitope. Significant gene-gene interaction between TNIP1 and TNFAIP3 was detected neither in SLE nor RA.

Conclusions

Association of TNIP1 with SLE was confirmed in a Japanese population. TNIP1 is a shared SLE susceptibility gene in the Caucasian and Asian populations, but the genetic contribution appeared to be greater in the Japanese and Chinese populations because of the higher risk allele frequency. Taken together with the association of TNFAIP3, these observations underscore the crucial role of NF-κB regulation in the pathogenesis of SLE.     

Role of an intronic polymorphism in the <Emphasis Type="Italic">PDCD1</Emphasis> gene with the risk of sporadic systemic lupus erythematosus and the occurrence of antiphospholipid antibodies

Recently, a polymorphism in intron 4 (G/A) of the programmed cell death 1 (PDCD1) gene was shown to be associated with systemic lupus erythematosus (SLE) risk in familial and sporadic patients of European, European American, and Mexican origin. In this investigation, we examined the role of this polymorphism in 311 SLE patients (276 European Americans and 35 African Americans) and 390 age-matched healthy controls (359 European Americans and 31 African Americans). The frequency of the A allele was significantly higher in European American controls than in African American controls (0.107 vs. 0.048; P=0.046). There was no significant difference in the frequency of the A allele between SLE cases and controls in either the European American (0.107 vs. 0.129; P=0.84) or African American (0.048 vs. 0.100; P=0.25) cohort. However, after adjustment for the status of the antiphospholipid antibodies (APA) in the logistic regression analysis, the risk for SLE associated with the PDCD1 polymorphism was statistically significant. The APA-adjusted odds ratio (OR) between A allele carriers (AA + AG genotypes) versus the GG genotype showed a modest association with SLE risk in European Americans (OR=1.52, 95% CI: 1.02–2.27; P=0.039), African Americans (OR=2.89, 95% CI: 0.61–13.76; P=0.183), and the ethnicity-combined sample (OR=1.59, 95% CI: 1.08–2.34; P=0.019). Furthermore, we observed that the A allele carriers were protected against the occurrence of APA in both controls (OR=0.399, 95% CI: 0.19–0.82; P=0.0098) and SLE cases (OR=0.566, 95% CI: 0.32–1.01; P=0.054). Our data indicate polymorphism in intron 4 of the PDCD1 gene affects the occurrence of APA and may slightly modify the risk of sporadic SLE.     

TLR7 single-nucleotide polymorphisms in the 3' untranslated region and intron 2 independently contribute to systemic lupus erythematosus in Japanese women: a case-control association study

Introduction

The Toll-like receptor 7 (TLR7) gene, encoded on human chromosome Xp22.3, is crucial for type I interferon production. A recent multicenter study in East Asian populations, comprising Chinese, Korean and Japanese participants, identified an association of a TLR7 single-nucleotide polymorphism (SNP) located in the 3' untranslated region (3' UTR), rs3853839, with systemic lupus erythematosus (SLE), especially in males, although some difference was observed among the tested populations. To test whether additional polymorphisms contribute to SLE in Japanese, we systematically analyzed the association of TLR7 with SLE in a Japanese female population.

Methods

A case-control association study was conducted on eight tag SNPs in the TLR7 region, including rs3853839, in 344 Japanese females with SLE and 274 healthy female controls.

Results

In addition to rs3853839, two SNPs in intron 2, rs179019 and rs179010, which were in moderate linkage disequilibrium with each other (r ² = 0.53), showed an association with SLE (rs179019: P = 0.016, odds ratio (OR) 2.02, 95% confidence interval (95% CI) 1.15 to 3.54; rs179010: P = 0.018, OR 1.75, 95% CI 1.10 to 2.80 (both under the recessive model)). Conditional logistic regression analysis revealed that the association of the intronic SNPs and the 3' UTR SNP remained significant after we adjusted them for each other. When only the patients and controls carrying the risk genotypes at the 3' UTR SNPpositionwere analyzed, the risk of SLE was significantly increased when the individuals also carried the risk genotypes at both of the intronic SNPs (P = 0.0043, OR 2.45, 95% CI 1.31 to 4.60). Furthermore, the haplotype containing the intronic risk alleles in addition to the 3' UTR risk allele was associated with SLE under the recessive model (P = 0.016, OR 2.37, 95% CI 1.17 to 4.80), but other haplotypes were not associated with SLE.

Conclusions

The TLR7 intronic SNPs rs179019 and rs179010 are associated with SLE independently of the 3' UTR SNP rs3853839 in Japanese women. Our findings support a role of TLR7 in predisposition for SLE in Asian populations.     

Polymorphisms of the ITGAM gene confer higher risk of discoid cutaneous than of systemic lupus erythematosus

Background

Lupus erythematosus (LE) is a heterogeneous disease ranging from mainly skin-restricted manifestations (discoid LE [DLE] and subacute cutaneous LE) to a progressive multisystem disease (systemic LE [SLE]). Genetic association studies have recently identified several strong susceptibility genes for SLE, including integrin alpha M (ITGAM), also known as CD11b, whereas the genetic background of DLE is less clear.

Principal Findings

To specifically investigate whether ITGAM is a susceptibility gene not only for SLE, but also for cutaneous DLE, we genotyped 177 patients with DLE, 85 patients with sporadic SLE, 190 index cases from SLE families and 395 population control individuals from Finland for nine genetic markers at the ITGAM locus. SLE patients were further subdivided by the presence or absence of discoid rash and renal involvement. In addition, 235 Finnish and Swedish patients positive for Ro/SSA-autoantibodies were included in a subphenotype analysis. Analysis of the ITGAM coding variant rs1143679 showed highly significant association to DLE in patients without signs of systemic disease (P-value  = 4.73×10⁻¹¹, OR  = 3.20, 95% CI  = 2.23–4.57). Significant association was also detected to SLE patients (P-value  = 8.29×10⁻⁶, OR  = 2.14, 95% CI  = 1.52–3.00), and even stronger association was found when stratifying SLE patients by presence of discoid rash (P-value  = 3.59×10⁻⁸, OR  = 3.76, 95% CI  = 2.29–6.18).

Significance

We propose ITGAM as a novel susceptibility gene for cutaneous DLE. The risk effect is independent of systemic involvement and has an even stronger genetic influence on the risk of DLE than of SLE.     

Polymorphisms of complement receptor 1 and interleukin-10 genes and systemic lupus erythematosus: a meta-analysis

A number of studies have tested the association of the complement receptor 1 (CR1) and Interleukin-10 (IL10) polymorphisms with systemic lupus erythematosus (SLE), but reported conflicting results. The aim of the study is to explore whether the CR1 and IL10 genes are associated with SLE susceptibility. We surveyed studies on the CR1 and IL10 polymorphisms and SLE using comprehensive Medline search and review of the references. A meta-analysis was conducted in a fixed effects model or random effects model based on between-study heterogeneity. Eighteen comparisons from 13 studies were included in the CR1 meta-analysis and a total of 16 separate comparisons were used for the IL10 meta-analysis. The CR1 meta-analysis showed no significant association of the CR1 functional polymorphisms with SLE. In contrast, the S structural variant of the CR1 showed a significant association (OR=1.544, 95% CI, 1.217–1.959, P<0.001). Stratification by ethnicity indicated that the CR1 S variant was associated with SLE in Caucasians (OR=1.667, 95% CI, 1.193–2.357, P=0.003). The IL10 meta-analysis showed a significant association between SLE and the G11 allele of IL10.G (OR=1.279, 95% CI; 1.027–1.593, P=0.028) in whole populations, and IL10 promoter −1082G allele was associated with SLE in Asians (OR=1.358, 95% CI; 1.015–1.816, P=0.039). In conclusion, the CR1 meta-analysis revealed the association of the S structural variant of the CR1 with SLE and the IL10 meta-analysis showed the association of IL10.G11 allele and SLE in whole populations and the association between promoter -A1082G polymorphism and SLE in Asians.     

The Association of Platelet Count with Clinicopathological Significance and Prognosis in Renal Cell Carcinoma: A Systematic Review and Meta-Analysis

ObjectiveElevated platelet count (PC), a measure of systemic inflammatory response, is inconsistently reported to be associated with poor prognosis in patients with renal cell carcinoma (RCC). We conducted a systematic review and meta-analysis to clarify the significance of PC in RCC prognosis.MethodsPubMed, Embase, and Web of Science databases were searched to identify eligible studies to evaluate the associations of PC with patient survival and clinicopathological features of RCC.ResultsWe analyzed 25 studies including 11,458 patients in the meta-analysis and categorized the included articles into three groups based on RCC stage. An elevated PC level was associated with poor overall survival (OS, hazard ratio [HR] 2.24, 95% confidence interval [CI] 1.87-2.67, P<0.001) and cancer-specific survival (CSS, HR 2.59, 95% CI 1.92-3.48, P<0.001) when all stages were examined together; with poor CSS (HR 5.09, 95% CI 2.41-10.73, P<0.001) and recurrence-free survival (HR 6.68, 95% CI 3.35-13.34, P<0.001) for localized RCC; with poor OS (HR 2.00, 95% CI 1.75-2.28, P<0.001) for metastatic RCC; and with poor OS (HR 2.05, 95% CI 1.04-4.03, P = 0.038), CSS (HR 3.38, 95% CI 1.86-6.15, P<0.001), and PFS (HR 2.97, 95% CI 1.47-6.00, P = 0.002) for clear cell RCC. Furthermore, an elevated PC level was significantly associated with TNM stage (OR 3.11, 95% CI 1.59-6.06, P = 0.001), pathological T stage (OR 3.13, 95% CI 2.60-3.77, P<0.001), lymph node metastasis (OR 4.01, 95% CI 2.99-5.37, P<0.001), distant metastasis (OR 3.85, 95% CI 2.46-6.04, P<0.001), Fuhrman grade (OR 3.70, 95% CI 3.00-4.56, P<0.001), tumor size (OR 4.69, 95% CI 2.78-7.91, P<0.001) and Eastern Cooperative Oncology Group score (OR 5.50, 95% CI 3.26-9.28, P<0.001).ConclusionAn elevated PC level implied poor prognosis in patients with RCC and could serve as a readily available biomarker for managing this disease.     

Alpha-actinin-binding antibodies in relation to systemic lupus erythematosus and lupus nephritis

This study investigated the overall clinical impact of anti-α-actinin antibodies in patients with pre-selected autoimmune diseases and in a random group of anti-nuclear antibody (ANA)-positive individuals. The relation of anti-α-actinin antibodies with lupus nephritis and anti-double-stranded DNA (anti-dsDNA) antibodies represented a particular focus for the study. Using a cross-sectional design, the presence of antibodies to α-actinin was studied in selected groups, classified according to the relevant American College of Rheumatology classification criteria for systemic lupus erythematosus (SLE) (n = 99), rheumatoid arthritis (RA) (n = 68), Wegener's granulomatosis (WG) (n = 85), and fibromyalgia (FM) (n = 29), and in a random group of ANA-positive individuals (n = 142). Renal disease was defined as (increased) proteinuria with haematuria or presence of cellular casts. Sera from SLE, RA, and Sjøgren's syndrome (SS) patients had significantly higher levels of anti-α-actinin antibodies than the other patient groups. Using the geometric mean (± 2 standard deviations) in FM patients as the upper cutoff, 20% of SLE patients, 12% of RA patients, 4% of SS patients, and none of the WG patients were positive for anti-α-actinin antibodies. Within the SLE cohort, anti-α-actinin antibody levels were higher in patients with renal flares (p = 0.02) and correlated independently with anti-dsDNA antibody levels by enzyme-linked immunosorbent assay (p < 0.007) but not with other disease features. In the random ANA group, 14 individuals had anti-α-actinin antibodies. Of these, 36% had SLE, while 64% suffered from other, mostly autoimmune, disorders. Antibodies binding to α-actinin were detected in 20% of SLE patients but were not specific for SLE. They correlate with anti-dsDNA antibody levels, implying in vitro cross-reactivity of anti-dsDNA antibodies, which may explain the observed association with renal disease in SLE.     

Identification of urinary metabolites that distinguish membranous lupus nephritis from proliferative lupus nephritis and focal segmental glomerulosclerosis

Introduction

Systemic lupus erythematosus (SLE or lupus) is a chronic autoimmune disease, and kidney involvement with SLE, a.k.a. lupus nephritis (LN), is a frequent and severe complication of SLE that increases patient morbidity and mortality. About 50% of patients with SLE encounter renal abnormalities which, if left untreated, can lead to end-stage renal disease. Kidney biopsy is considered the criterion standard for diagnosis and staging of LN using the International Society of Nephrology/Renal Pathology Society (ISN/RPS) classification, which was developed to help predict renal outcomes and assist with medical decision-making. However, kidney biopsy-based classification of LN is highly invasive and impractical for real-time monitoring of LN status. Here, nuclear magnetic resonance (NMR) spectroscopy-based metabolic profiling was used to identify urinary metabolites that discriminated between proliferative and pure membranous LN as defined by the ISN/RPS classification, and between LN and primary focal segmental glomerulosclerosis (FSGS).

Methods

Metabolic profiling was conducted using urine samples of patients with proliferative LN without membranous features (Class III/IV; n = 7) or pure membranous LN (Class V; n = 7). Patients with primary FSGS and proteinuria (n = 10) served as disease controls. For each patient, demographic information and clinical data was obtained and a random urine sample collected to measure NMR spectra. Data and sample collection for patients with LN occurred around the time of kidney biopsy. Metabolic profiling analysis was done by visual inspection and principal component analysis.

Results

Urinary citrate levels were 8-fold lower in Class V LN compared to Class III/IV patients, who had normal levels of urinary citrate (P < 0.05). Class III/IV LN patients had > 10-fold lower levels of urinary taurine compared to Class V patients, who had mostly normal levels (P < 0.01). Class V LN patients had normal urinary hippurate levels compared to FSGS patients, who completely lacked urinary hippurate (P < 0.001).

Conclusions

This pilot study indicated differences in urinary metabolites between proliferative LN and pure membranous LN patients, and between LN and FSGS patients. If confirmed in larger studies, these urine metabolites may serve as biomarkers to help discriminate between different classes of LN, and between LN and FSGS.     

Mutations in genes encoding complement inhibitors CD46 and CFH affect the age at nephritis onset in patients with systemic lupus erythematosus

Introduction

Inherited deficiencies of several complement components strongly predispose to systemic lupus erythematosus (SLE) while deficiencies of complement inhibitors are found in kidney diseases such as atypical hemolytic uremic syndrome (aHUS).

Methods

The exons of complement inhibitor genes CD46 and CFH (factor H) were fully sequenced using the Sanger method in SLE patients with nephritis originating from two cohorts from southern and mid Sweden (n = 196). All identified mutations and polymorphisms were then analyzed in SLE patients without nephritis (n = 326) and in healthy controls (n = 523).

Results

We found nonsynonymous, heterozygous mutations in CFH in 6.1% patients with nephritis, in comparison with 4.0% and 5.4% in patients without nephritis and controls, respectively. No associations of SLE or nephritis with common variants in CFH (V62I/Y402H/E936D) were found. Furthermore, we found two nonsynonymous heterozygous mutations in CD46 in SLE patients but not in controls. The A353V polymorphism, known to affect function of CD46, was found in 6.6% of nephritis patients versus 4.9% and 6.1% of the non-nephritis SLE patients and controls. The presence of mutations in CD46 and CFH did not predispose to SLE or nephritis but was associated with earlier onset of nephritis. Furthermore, we found weak indications that there is one protective and one risk haplotype predisposing to nephritis composed of several polymorphisms in noncoding regions of CD46, which were previously implicated in aHUS.

Conclusions

SLE nephritis is not associated with frequent mutations in CFH and CD46 as found in aHUS but these may be modifying factors causing earlier onset of nephritis.     

CTLA-4 polymorphisms and systemic lupus erythematosus (SLE): a meta-analysis

Several reports demonstrate association between variants of the cytotoxic T lymphocyte antigen-4 (CTLA-4) and autoimmune diseases. CTLA-4 may generate autoimmunity by immune dysregulation, making CTLA-4 an attractive candidate gene for systemic lupus erythematosus (SLE) susceptibility. Previous CTLA-4 association studies with SLE, however, have produced inconsistent results. We have performed a meta-analysis to better assess the purported associations. A total of 14 independent studies (to July 2004) testing association between one or more CTLA-4 polymorphisms and SLE were used in this analysis. We have compared allele and genotype frequencies at four polymorphic sites found in exon-1 (at +49), the promoter region (at –318 and –1722), and the 3 untranslated region (3UTR) (dinucleotide repeat). We have evaluated both fixed and random effect models, depending on the presence of between-study heterogeneity. The data demonstrate that the exon-1 +49 polymorphism is significantly associated with SLE susceptibility. The overall risk, measured by odds ratio (OR), for exon-1 +49 GG genotype is 1.287 [95% confidence interval (CI)=1.031–1.562, P=0.011]. Stratification by ethnicity indicates the exon–1 +49 GG genotype is associated with SLE, at least in Asians (OR=1.293, 95% CI=1.031–1.620, P=0.026). European-derived populations have an effect of similar magnitude (OR=1.268, 95% CI=0.860–1.870, P=0.230), though not significant. Similar trends are found in allele-specific risk estimates and disease association. The OR for the exon-1 +49 risk allele (G) in Asians is 1.246 (95% CI=1.057–1.469, P=0.009), while Europeans have no evidence of allelic association (OR=0.978, 95% CI=0.833–1.148, P=0.780). In conclusion, this meta-analysis supports the CTLA-4 exon-1 +49 (A/G) polymorphism influencing the risk for developing SLE, especially in Asians.     

Serum levels of autoantibodies against C-reactive protein correlate with renal disease activity and response to therapy in lupus nephritis

Introduction  

Serum levels of C-reactive protein (CRP) seldom reflect disease activity in systemic lupus erythematosus (SLE). We have previously shown that autoantibodies against neo-epitopes of CRP often occur in SLE, but that this does not explain the modest CRP response seen in flares. However, we have repeatedly found that anti-CRP levels parallel lupus disease activity, with highest levels in patients with renal involvement; thus, we aimed to study anti-CRP in a material of well-characterized lupus nephritis patients.     

Fetal microchimerism in kidney biopsies of lupus nephritis patients may be associated with a beneficial effect

IntroductionMicrochimeric male fetal cells (MFCs) have been associated with systemic lupus erythematosus, and published studies have further correlated MFC with lupus nephritis (LN). In the present study, we evaluated the frequency of MFC in the renal tissue of patients with LN.MethodsTwenty-seven renal biopsies were evaluated: Fourteen were from women with clinical and laboratory findings of LN, and thirteen were from controls. Genomic DNA was extracted from kidney biopsies, and the male fetal DNA was quantified using real-time quantitative polymerase chain reactions for the detection of specific Y chromosome sequences.ResultsMFCs were detected in 9 (64%) of 14 of patients with LN, whereas no MFCs were found in the control group (P = 0.0006). No differences in pregnancy history were found between patients with LN and the control group. Significantly higher amounts of MFCs were found in patients with LN with serum creatinine ≤1.5 mg/dl. Furthermore, women with MFCs had significantly better renal function at the time of biopsy (P = 0.03). In contrast, patients with LN without MFCs presented with more severe forms of glomerulonephritis (World Health Organization class IV = 60% and class V = 40%).ConclusionsOur data indicate a high prevalence of MFCs in renal biopsy specimens from women with LN, suggesting a role for MFCs in the etiology of LN. The present report also provides some evidence that MFCs could have a beneficial effect in this disease.

Electronic supplementary material

The online version of this article (doi:10.1186/s13075-015-0615-4) contains supplementary material, which is available to authorized users.     

PTPN22 1858C>T gene polymorphism in patients with SLE: association with serological and clinical results

To assess the association between PTPN22 1858C>T gene polymorphism and susceptibility to, and clinical presentation of, systemic lupus erythematosus (SLE). Our study included 135 SLE patients (120 women and 15 men; mean age 45.1 years; mean course of disease from 0.5 to 31 years) and 201 healthy subjects. The PTPN22 1858C>T gene polymorphism was genotyped by polymerase chain reaction restriction fragment length polymorphism. A significantly higher incidence of genotype CT in patients with SLE (36.3 %) was found, compared with the control group (24.9 %). The frequencies of C1858 and T1858 alleles were 78.1 and 21.9 % in SLE patients and 86.1 and 13.9 % in controls, respectively. Significantly higher SLE susceptibility was observed in patients carrying at least one T allele (p = 0.009; OR 1.86; 95 % CI 0.14–3.05). Significant association of the PTPN22 T1858 allele (CT + TT vs.CC) and secondary antiphospholipid syndrome was observed (p = 0.049). In SLE patients carrying the T1858 allele, higher levels of antiphospholipid antibodies (anticardiolipin antibodies and/or lupus anticoagulant) were found (p = 0.030; OR 2.17; 95 % CI 1.07–4.44).