Genetics of human systemic lupus erythematosus: the emerging picture

Prevalence of oral mucosal lesions in patients with systemic Lupus Erythematosus: a systematic review and meta-analysis

BACKGROUND

Systemic lupus erythematosus (SLE) is a chronic autoimmune disease that can cause a range of symptoms, including oral mucosal lesions (OMLs). The prevalence of OMLs in SLE patients and their associated factors have been studied in various regions, but the results are inconsistent. This study aims to evaluate the prevalence of OMLs in patients with SLE.

METHODS

Observational studies of OML prevalence in SLE patients published before 2022 were retrieved from PubMed, Embase, Web of Science, Google Scholar, and the Cochrane Library without language restriction. The quality of the studies was assessed using the Newcastle-Ottawa Scale (NOS) and Agency for Healthcare Research and Quality (AHRQ).

RESULTS

Our meta-analysis included 113 studies with a total of 53,307 SLE patients. We found that the prevalence of OMLs in SLE patients was 31% (95% CI: 28%, 35%), with oral ulcers being present in 30% of SLE patients (95% CI: 26%, 33%). Subgroup analysis showed that the prevalence of OMLs varied significantly by region, disease activity, and sample size (p ≤ 0.01). However, gender and year of publication had little effect on the prevalence of OMLs (p = 0.78 and 0.30, respectively). Oral ulcers were significantly associated with age of onset (p = 0.02), geographic location (p < 0.01), and race (p < 0.01). We also found that the prevalence of oral erythema was 9%, oral candidiasis was 9%, petechiae was 8%, cheilitis was 6%, and white plaque was 3%.

CONCLUSIONS

Our analysis showed that the prevalence of OMLs varied significantly by region and disease activity, and child-onset patients of Indian, Malay, and Caucasian descent were more likely to have oral ulcers. The high prevalence of OML in SLE patients emphasizes the importance of regular oral examination and management in the comprehensive care of individuals with SLE.

Lymphopenia, Lymphopenia-Induced Proliferation, and Autoimmunity

Immune homeostasis is a tightly regulated system that is critical for defense against invasion by foreign pathogens and protection from self-reactivity for the survival of an individual. How the defects in this system might result in autoimmunity is discussed in this review. Reduced lymphocyte number, termed lymphopenia, can mediate lymphopenia-induced proliferation (LIP) to maintain peripheral lymphocyte numbers. LIP not only occurs in normal physiological conditions but also correlates with autoimmunity. Of note, lymphopenia is also a typical marker of immune aging, consistent with the fact that not only the autoimmunity increases in the elderly, but also autoimmune diseases (ADs) show characteristics of immune aging. Here, we discuss the types and rates of LIP in normal and autoimmune conditions, as well as the coronavirus disease 2019 in the context of LIP. Importantly, although the causative role of LIP has been demonstrated in the development of type 1 diabetes and rheumatoid arthritis, a two-hit model has suggested that the factors other than lymphopenia are required to mediate the loss of control over homeostasis to result in ADs. Interestingly, these factors may be, if not totally, related to the function/number of regulatory T cells which are key modulators to protect from self-reactivity. In this review, we summarize the important roles of lymphopenia/LIP and the Treg cells in various autoimmune conditions, thereby highlighting them as key therapeutic targets for autoimmunity treatments.

Association of AIRE (rs2075876), but not CTLA4 (rs231775) polymorphisms with systemic lupus erythematosus

BACKGROUND

The AIRE (rs2075876) and CTLA4 (rs231775) variants have a crucial function in controlling the negative selection and suppression of T lymphocytes. Numerous reports studied the association of AIRE and CTLA4 variants with different autoimmune disorders, but with inconclusive conclusions. The main purpose of this work is to evaluate the association of these two variants with SLE susceptibility among Egyptian patients.

SUBJECTS AND METHODS

A total of 247 participants (100 SLE patients and 147 healthy controls) were enrolled in this case-controlled study. The genomic DNA of these dual variants was genotyped using the TaqMan genotyping method.

RESULTS

The AIRE (rs2075876) variant conferred protection against developing SLE disease under allelic [A allele vs. G allele; OR = 0.16, 95%CI = 0.09-0.28], and dominant [GA + AA vs. GG; OR = 0.14, 95%CI = 0.05-0.34] models. Moreover, patients with AIRE rs2075876 (A/A) genotype revealed a statistically significant with lower levels of complement 3 (p-value = 0.007). Nonetheless, the CTLA4 (rs231775) variant was not associated with increased risk of SLE under all genetic association models (p-value > 0.05). However, CTLA4 rs231775 (G/G) genotype observed significant difference with recurrent infection and hematuria.

CONCLUSIONS

Our findings indicated that the AIRE (rs2075876) variant conferred protection against developing SLE disease, but not the CTLA4 (rs231775) variant.

Discovery of new serum biomarker panels for systemic lupus erythematosus diagnosis

OBJECTIVE

Clinical diagnosis of SLE is currently challenging due to its heterogeneity. Many autoantibodies are associated with SLE and are considered potential diagnostic markers, but systematic screening and validation of such autoantibodies is lacking. This study aimed to systematically discover new autoantibodies that may be good biomarkers for use in SLE diagnosis.

METHODS

Sera from 15 SLE patients and 5 healthy volunteers were analysed using human proteome microarrays to identify candidate SLE-related autoantibodies. The results were validated by screening of sera from 107 SLE patients, 94 healthy volunteers and 60 disease controls using focussed arrays comprised of autoantigens corresponding to the identified candidate antibodies. Logistic regression was used to derive and validate autoantibody panels that can discriminate SLE disease. Extensive ELISA screening of sera from 294 SLE patients and 461 controls was performed to validate one of the newly discovered autoantibodies.

RESULTS

A total of 31, 11 and 18 autoantibodies were identified to be expressed at significantly higher levels in the SLE group than in the healthy volunteers, disease controls and healthy volunteers plus disease control groups, respectively, with 25, 7 and 13 of these differentially expressed autoantibodies being previously unreported. Diagnostic panels comprising anti-RPLP2, anti-SNRPC and anti-PARP1, and anti-RPLP2, anti-PARP1, anti-MAK16 and anti- RPL7A were selected. Performance of the newly discovered anti-MAK16 autoantibody was confirmed by ELISA. Some associations were seen with clinical characteristics of SLE patients, such as disease activity with the level of anti-PARP1 and rash with the level of anti-RPLP2, anti-MAK16 and anti- RPL7A.

CONCLUSION

The combined autoantibody panels identified here show promise for the diagnosis of SLE and for differential diagnosis of other major rheumatic immune diseases.

Study of familial aggregation of autoimmune rheumatic diseases in Asian Indian patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) and other autoimmune rheumatic diseases (AIRD) tend to co-aggregate in families, making positive familial history a risk factor. We aimed to estimate familial aggregation of AIRD in SLE patients and to compare between ones having a positive and negative family history of autoimmunity in our cohort. We included families of 157 consecutive SLE patients in a hospital-based, cross-sectional design for a three-generation pedigree study. Clinical and laboratory parameters of these patients were recorded. AIRD was seen in families of 39 SLE patients amounting to a familial prevalence of 24.8% [95% confidence interval (CI) 18.1, 31.6] with a relative risk (λ) of 4.3 for first-degree relatives (FDRs) and 1.1 for second-degree relatives (SDRs). SLE was the commonest AIRD seen in families of 19 patients with a familial prevalence of 12.1% (95% CI 7.0, 17.2) and λ of 78.2 for FDRs and 18.1 for SDRs. AIRD as a whole and SLE alone were seen more commonly with parental consanguinity (p < 0.05). Familial aggregation in SLE patients also showed a relatively higher percentage of affected males and lesser presentation with constitutional features (p < 0.05) than sporadic SLE patients. Rheumatoid arthritis (RA) was the second most common AIRD seen in 16/39 (41%) families with a RR of 3.1 in FDRs of SLE patients. In conclusion, Asian Indian SLE patients seem to have a high familial aggregation of AIRD, which is more pronounced in the background of parental consanguinity. SLE is the commonest AIRD seen amongst FDRs and SDRs of SLE patients, followed by RA, with FDRs being at highest risk.

MiRNA and mRNA Profiling in Systemic Lupus Reveals a Novel Set of Cytokine - Related miRNAs and their Target Genes in Cases With and Without Renal Involvement

BACKGROUND/AIMS

MiRNAs transpire as promising elements in molecular medicine for the identification of new diagnostic, prognostic and targeting therapeutic biomarkers. This study consisted of four steps: First, to investigate one or a group of specific diagnostic miRNAs for Systemic Lupus Erythematosus (SLE) disease in patients with and without renal involvement, second, to identify cytokines genes' expression profiling, third, comparing the profiles with related amounts in the serum and finally, to study target-gene-mediated functional roles of miRNAs, which have been correlated to disease development and progression.

METHODS

In order to use in microarray assays total RNA and miRNAs were isolated from blood and serum samples that were obtained from 16 SLE patients (9 with renal involvement and 7 without renal involvement). Taking coexistence of factors such as hypocomplementemia, positive ANA and anti-DNA into account, obtained data were processed. For each differentially expressed miRNA, potential target genes were predicted by microRNAorg, TargetScan and PITA prediction tools. Obtained mRNA profiling data were interrogated for the target genes. MiRNA and mRNA microarray results were confirmed by QRT-PCR. Finally, the amounts of cytokines were measured by multiplex ELISA method.

RESULTS

The results of study showed that among differentially expressed miRNAs in SLE patients with renal involvement compared to those without renal involvement, hsa-miR-766-3p, may play pivotal roles in PI3K-AKT-mTOR pathway. In addition according to the obtained data it is suggested that blood-borne proinflammatory cytokines such as IL-4, IL-6 and TNF-α alongside with disease stage and severity may contribute to this differential expression of these miRNA which may be leading to insulin resistance. Finally, hsa-miR-621, which was differentially expressed in hypertensive SLE patients without renal involvement and a positive ANA test with its predicted target gene "Kallikrein-related peptidase 9" may play a role in the pathophysiology of hypertension in SLE.

CONCLUSIONS

We reported some human miRNAs which were differentially expressed in SLE patients according to disease activity and renal involvement. Larger studies are necessary to confirm our findings and detect further biomarkers.

Vitamin D receptor gene FokI polymorphism in Egyptian children and adolescents with SLE: A case-control study

Background Childhood-onset systemic lupus erythematosus (cSLE) is a lifelong autoimmune disorder. The vitamin D receptor (VDR) gene is a potential candidate gene for cSLE susceptibility. In this study, we aimed to investigate the FokI polymorphism in the VDR gene in Egyptian children and adolescents with SLE, to determine whether this polymorphism could be a genetic marker for cSLE susceptibility or disease activity and we also measured the serum level of 25-hydroxyvitamin D [25(OH) D] to assess its relation to such polymorphism. Methods This was a case-control study, which included 300 patients with cSLE and 300 age, sex, and ethnicity-matched healthy controls. All participants were genotyped for the VDR gene FokI (rs2228570) polymorphism by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP), while the serum [25(OH) D] levels were measured by enzyme-linked immunosorbent assay (ELISA). Results The VDR FokI FF genotype and F allele were overrepresented among cSLE patients compared with the controls, [odds ratio (OR) = 2.7; 95% confidence interval (CI): 1.6-4.4 for the FF genotype; p = 0.000; and OR = 1.6; 95% CI: 1.27-2.05 for the F allele; p = 0.000, respectively]. We found a significant association between VDR FokI FF genotype with lupus nephritis (OR: 4.8; 95% CI: 2.2-10.6; p = 0.002); and high disease activity index score ( p = 0.01). Conclusions The FokI polymorphism in the VDR gene may contribute to susceptibility to SLE in Egyptian children and adolescents. Moreover, the FF genotype constituted a risk factor for the development of lupus nephritis and was associated with low serum [25(OH) D] levels as well as higher disease activity index score among studied patients with cSLE.

Associations between TNFAIP3 gene polymorphisms and systemic lupus erythematosus risk: an updated meta-analysis

In order to determine whether tumor necrosis factor alpha inducible protein 3 (TNFAIP3) gene polymorphisms confers susceptibility to systemic lupus erythematosus (SLE) in ethnically different populations. A meta-analysis was conducted to examine the association between TNFAIP3 polymorphisms and susceptibility to SLE. A systematic literature search was conducted to identify all relevant studies. Pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to estimate the strength of the association. A total of 23 studies from 20 articles, involving 18,501 patients with SLE and 30,435 healthy controls were included in this meta-analysis. Overall, we found significant association between SLE and the TNFAIP3 rs2230926, rs5029937, rs5029939, and rs3757173 polymorphisms (all P < 0.001). Stratification by ethnicity indicated that rs5029939 polymorphism was associated with SLE in Europeans, while rs2230926, rs5029937, and rs3757173 polymorphisms were associated with SLE both in Europeans and Asians (all P < 0.001). The results of our meta-analysis suggest that TNFAIP3 (rs2230926, rs5029937, rs5029939, and rs3757173) polymorphisms are associated with susceptibility to SLE.

Serum interleukin-17 in Egyptian children with systemic lupus erythematosus: is it related to pulmonary affection?

Objective Pulmonary involvement in paediatric systemic lupus erythematosus (pSLE) is not an uncommon finding; however, subclinical affection occurs more frequently. Many studies have reported that cytokine dysregulation as interleukin-17 (IL-17) over-expression plays a key role in the pathogenesis of systemic lupus erythematosus (SLE). We aim to assess serum levels of IL-17 A and their association with pulmonary involvement in children with SLE. Methods Serum IL-17A levels - determined by solid phase sandwich ELISA - were assessed in forty-two pSLE patients and compared to 45 age-matched healthy controls. All patients were subjected to pulmonary function tests to detect subclinical pulmonary affection. High-resolution CT (HRCT) chest scan was carried out in patients with abnormal pulmonary function tests (PFTs) and those with chronic respiratory symptoms. Results Abnormal PFTs were found in 73% of patients; of them, only 25% had abnormal findings in HRCT chest. Serum levels of IL-17 A were significantly elevated in pSLE patients as compared to healthy controls ( p < 0.001). The serum levels of IL-17 A had a highly significant positive correlation with SLEDAI ( r = 0.811 and p < 0.001) Strong negative correlation was found between serum levels of IL-17A with both FEV1 and FVC ( p < 0.05). Conclusions Serum IL-17A is elevated in pSLE patients, which correlates with disease activity. IL-17 seems to have a possible role in the pathogenesis of subclinical lung affection. Abnormal PFTS may be found in pSLE patients even with normal radiology.

FcγRIIB Gene Polymorphisms Are Associated with Disease Risk and Clinical Manifestations of Systemic Lupus Erythematosus in Koreans

Systemic lupus erythematosus (SLE) is chronic autoimmune disease with various autoantibodies, which are involved in tissue damage. Fc gamma receptors (FcγRs) bind the constant region of the immunoglobulin G and transmit stimulatory or inhibitory signal to immune cells. The FcγR genes map to 1q23, a susceptible locus for SLE. We have screened single nucleotide polymorphisms (SNPs) in one of FcγR gene, FcγRIIB, which is the only inhibitory receptor, after considering gene map and reported SNPs. There were 3 SNPs in FcγRIIB: 10849 T>C (rs1050501) in exon 5 and 10950 T>G (rs6666965) and 11045 G>T (rs12117530) in intron 5 in Koreans. The frequency of the minor allele (T) of rs12117530 was significantly higher in SLE patients (50 patients, 20.4%) than healthy controls (17 patients, 12%, p = 0.041). Leukopenia occurred more frequently in SLE patients carrying the minor allele (T) of rs12117530 (p = 0.032). Among 5 haplotypes, the frequency of decreased complement was significantly lower in SLE patients with haplotype 1 [TTG] (p = 0.045). Nephritis, lymphopenia and anti-dsDNA antibody were significantly less frequent in SLE patients with haplotype 2 [TGG] (p = 0.046, p = 0.018, p = 0.002, respectively). The frequency of thrombocytopenia and anti-dsDNA antibody was significantly higher in SLE patients with haplotype 3 [CTG] (p < 0.001, p = 0.04, respectively). These data reveal that genetic polymorphisms within FcγRIIB are associated with disease susceptibility and phenotypes of SLE in Koreans. Furthermore, FcγRIIB rs12117530 polymorphism (T allele) may be an important risk factor in SLE.

Evaluating the association of interleukin-10 gene promoter -592 A/C polymorphism with lupus nephritis susceptibility

Background

Interleukin-10 (IL-10) is an important immunoregulatory cytokine. There are few studies evaluating the association between IL-10 and lupus nephritis (LN). The aim of this study was to evaluate the association of IL-10 gene promoter -592 A/C with LN susceptibility.

Methods

The study was conducted on 84 patients with systemic lupus erythematosus (SLE). Patients were divided into LN group (Group I, 48 patients) and non-LN group (Group II, 36 patients). The -592 A/C polymorphisms in IL-10 promoter gene were determined by polymerase chain reaction and restriction fragment length polymorphism in both groups. IL-10 was determined by enzyme-linked immunosorbent assay. Frequencies of the genotypes were compared between LN and non-LN patients and among LN patients with different pathologic classes.

Results

There was a significant increase in serum level of IL-10 (P = 0.001) in Group I compared with Group II and significant positive correlation between serum IL-10 and SLE disease activity index (r = 0.466, P = 0.001) in Group I. There were no significant differences in the distribution of the IL-10 gene promoter -592 A/C genotypes or the allele frequencies between Groups I and II. There was no significant difference between AC/CC and AA genotypes with SLE disease activity index, proteinuria, hematuria, anti-double-stranded DNA, and IL-10 in Group I. There was no significant difference in the distribution of AC and CC genotypes among different pathologic LN classes.

Conclusion

IL-10 suggested to play a role in pathogenesis and development of LN. However, the promoter -592 A/C of IL-10 gene suggested to be not associated with serum IL-10 levels or LN susceptibility. In addition, it appears that promoter -592 A/C of IL-10 gene not associated with LN activity or the pathologic classes of LN.

Association of the IRF5 rs2070197 polymorphism with systemic lupus erythematosus: a meta-analysis

The aim of this study was to explore whether the interferon regulatory factor 5 (IRF5) gene rs2070197 polymorphism was associated with systemic lupus erythematosus (SLE) in multiple ethic populations. A meta-analysis was conducted on the C allele of the IRF5 rs2070197 polymorphism. A total of 7 published case-control studies with 12 comparisons involving 8171 SLE patients and 8904 controls were available for this meta-analysis. This meta-analysis demonstrated the IRF5 rs2070197 polymorphism conferred susceptibility to SLE in all subjects (odds ratio (OR) = 2.128, 95 % confidence interval (CI): 1.856-2.441, P < 0.001) without inter-study heterogeneity. The IRF5 rs2070197 polymorphism was identified as risk factors for SLE in Caucasian populations (OR 1.82, 95 % CI 1.70-1.96), but it had no effects (monomorphic) in Asians. Large-scale multicenter epidemiological studies in selected populations with other risk factors were urgently required.

Chinese SLE Treatment and Research group (CSTAR) registry: V. gender impact on Chinese patients with systemic lupus erythematosus

Introduction

Many studies have shown that differences were observed between male and female lupus patients. Although systemic lupus erythematosus (SLE) affects mostly females (female:male ratio 9:1), male SLE patients show higher mortality due to kidney and neurological disease. Currently there are limited epidemiological data concerning lupus in the Chinese population. As such, the Chinese SLE Treatment and Research group (CSTAR) developed the first online registry of Chinese lupus patients in 2009, and represents a multicenter observational study that attempts to describe and compile the major clinical characteristics of lupus in Chinese patients.

Objective

To investigate the effect of gender on the phenotypes of Chinese SLE patients.

Patients and methods

Data for 2104 SLE patients were prospectively collected and included in the CSTAR registry. Patients fulfilled the 1997 American College of Rheumatology (ACR) SLE classification criteria. We conducted a cross-sectional case-control study to analyze patient clinical and laboratory data at onset and at enrollment. SLE disease activity scores (SLEDAI) were also measured at enrollment.

Results

This study included 1914 women and 190 men. Males and females showed no differences in mean ages at onset, delay of diagnosis and disease duration. Males presented more frequently with fever ( p = 0.003), while musculoskeletal involvement ( p = 0.001) and cytopenia ( p = 0.017) was more common in females as the initial manifestation at onset of SLE. For manifestations at enrollment, males presented more frequently with fever ( p = 0.005), renal disease ( p = 0.019), vasculitis ( p = 0.032) and neuropsychiatric lupus ( p = 0.007). For cumulative manifestations at enrollment, males presented more frequently with discoid rash ( p < 0.001) and neuropsychiatric lupus ( p = 0.036), while less frequently with arthritis ( p = 0.011). However, the laboratory data showed no significant differences between the two groups at enrollment. Males also had higher SLEDAI scores at enrollment ( p = 0.002).

Conclusions

Renal disease, vasculitis and neuropsychiatric lupus are more common in male SLE patients with higher SLEDAI scores compared to female SLE patients in China.

Interleukin-6 promotes systemic lupus erythematosus progression with Treg suppression approach in a murine systemic lupus erythematosus model

Our aim is to reveal the role of interleukin 6 (IL-6) in the pathogenesis of systemic lupus erythematosus (SLE) in a murine model of SLE. Normal female C57BL/6 mice were immunized with syngeneic-activated lymphocyte-derived DNA (ALD-DNA) to induce SLE. Non-immunized mice were used as control. SLE-associated markers, including anti-double-stranded DNA (anti-dsDNA) Abs, urine protein, and kidney histopathology, were assayed to ensure the induction of the disease. Compared with control mice, ALD-DNA immunized mice exhibited high levels of anti-dsDNA Abs, IL-6 expression in vivo and in vitro. We also found that IL-6 knockout (IL-6KO) mice were resistant to ALD-DNA-induced SLE. The activation of CD4(+) T cells in immunized IL-6KO mice was lower than in immunized wild-type (Wt) mice. Intracellular cytokine staining showed that Foxp3 expression in immunized IL-6KO mice was higher than in immunized Wt mice, which might be associated with the disease severity. We further discovered that ALD-DNA-stimulated dendritic cells supernatants could result in higher IL-6 and TNF-α expression and could suppress Foxp3 expression. In addition, blocking IL-6 could up-regulate Foxp3 expression. Therefore, our findings show that IL-6 promotes the progression of SLE via suppressing Treg differentiation.

Diagnosis and early detection of CNS-SLE in MRL/lpr mice using peptide microarrays

Background

An accurate method that can diagnose and predict lupus and its neuropsychiatric manifestations is essential since currently there are no reliable methods. Autoantibodies to a varied panel of antigens in the body are characteristic of lupus. In this study we investigated whether serum autoantibody binding patterns on random-sequence peptide microarrays (immunosignaturing) can be used for diagnosing and predicting the onset of lupus and its central nervous system (CNS) manifestations. We also tested the techniques for identifying potentially pathogenic autoantibodies in CNS-Lupus. We used the well-characterized MRL/lpr lupus animal model in two studies as a first step to develop and evaluate future studies in humans.

Results

In study one we identified possible diagnostic peptides for both lupus and altered behavior in the forced swim test. When comparing the results of study one to that of study two (carried out in a similar manner), we further identified potential peptides that may be diagnostic and predictive of both lupus and altered behavior in the forced swim test. We also characterized five potentially pathogenic brain-reactive autoantibodies, as well as suggested possible brain targets.

Conclusions

These results indicate that immunosignaturing could predict and diagnose lupus and its CNS manifestations. It can also be used to characterize pathogenic autoantibodies, which may help to better understand the underlying mechanisms of CNS-Lupus.

Association between TNF promoter -308 G>A and LTA 252 A>G polymorphisms and systemic lupus erythematosus

Tumor necrosis factor (TNF) and lymphotoxin alpha (LTA) are pivotal cytokines in the pathogenesis of systemic lupus erythematosus (SLE). To investigate the possible association of the polymorphism of the TNF promoter gene -308 and that of the LTA gene 252 with susceptibility to SLE and with phenotypic disease features in Egyptian patients. A case control study involving 100 SLE patients and 100 unrelated healthy controls. Polymerase chain reaction and restriction fragment length polymorphism methods were applied to detect genetic polymorphism. We found that TNF-308 genotype AA was significantly increase by 26 % in SLE patients compared to 10 % in the control group (p = 0.003; OR 3.16; CI 1.43-6.98) and the frequency of the A allele of the TNF promoter -308 was significantly higher in the SLE patients (42 %) than in the control subjects (24 %) (p < 0.001; OR 2.29; 95 % CI 1.49-3.52). Genotype LTA 252 GG showed a significant increase by 22 % in SLE patients compared to 6 % in the control group (p = 0.001; OR 4.42; 95 % CI 1.71-11.44), and the frequency of the G allele of the LTA was significantly higher in the SLE patients (38 %) than in the control subjects (21 %) (p < 0.001; OR 2.31; 95 % CI 1.48-3.6). Genotype (AA+GA) of TNF was significantly associated with clinical manifestations as malar rash, arthritis, oral ulcers, serositis and systemic lupus erythematosus disease activity index. Genotype (GG+GA) of LTA was significantly associated with arthritis. These results suggest that TNF and LTA genetic polymorphisms contribute to SLE susceptibility in the Egyptian population and are associated with disease characteristics. TNF-308 and LTA+252 polymorphic markers may be used for early diagnosis of SLE and early prediction of clinical manifestations, like arthritis.

Association of FAS and FAS ligand genes polymorphism and risk of systemic lupus erythematosus

FAS/FASL pathway plays a critical role in maintaining peripheral immune tolerance; therefore, the apoptosis genes, Fas and Fas ligand (FasL), could be suitable candidate genes in human SLE susceptibility. Materials and Methods. In this case-control study, 106 SLE patients and 149 sex, age, and ethnicity matched healthy controls were genotyped for the Fas A-670G and FasLC-844T polymorphisms by polymerase chain reaction-restriction fragment length polymorphism method (PCR-RFLP). Results. The frequency of -670AA genotype was significantly higher in SLE patients than control group and the risk of SLE was 2.1-fold greater in subjects with AA genotype (P = 0.03). The frequency of -670A allele was significantly higher in SLE patients than in controls too (58% versus 49%, P = 0.03). The -844CC genotype frequency was significantly higher in SLE patients than in healthy controls and the risk of SLE was 2.8-fold greater in these subjects (P = 0.01). The C allele frequency was significantly higher in patients than in controls (69% versus 49%, P = 0.001). Increased SLE risk was observed in individuals with combined effect of Fas-670AA and FasL-844CC genotypes (P = 0.001). Conclusion. Fas-670AA and FasL-844CC genotypes were associated with SLE risk, and combined effect of -670AA and -844CC genotypes might increase SLE susceptibility.

Association study of TLR-9 polymorphisms and systemic lupus erythematosus in northern Chinese Han population

BACKGROUND

Systemic lupus erythematosus (SLE) is an autoimmune disease, with multiple genetic and environmental factors involving in its etiology. The toll-like receptor 9 (TLR9) gene has been reported to have important roles in the development and progression of SLE. We performed a case-control study to investigate the effects of 4 SNPs in the TLR9 gene in the development of SLE in Northern Chinese population.

METHODS

Four SNPs including rs187084, rs5743836, rs352139 and rs352140 were genotyped using the SNaPshot® method. A group of 430 SLE patients were compared to 424 normal controls. Data were analyzed by SPSS 17.0 and HaploView v 4.1 software.

RESULTS

The frequency distributions of SNP rs351240 and haplotype H2 (TGCT) and H3 (CATT) were found to differ significantly between patient and control groups (p<0.05), while other SNPs and haplotypes showed no significant difference between the two cohorts (p>0.05).

CONCLUSION

The results revealed that variations in the TLR9 gene are associated with SLE, indicating that TLR9 may play an important role in the pathogenesis of SLE in the northern Chinese Han population.

Contemporary role of medical genetics in internal medicine

Molecular biology and medical genetics, one of the most dynamically developing fields of medicine, nowadays is also a base for development of basic and clinical research in internal medicine. Understanding of crucial genetic pathomechanisms of many common diseases was possible due to the newest and modern molecular methods and tools. Moreover, development of genetics also made possible the discovery and understanding of the pathogenesis of many different diseases. However, not so long ago, we discovered precise pathomechanisms leading from damage of a single gene to a related pathological phenotype. Now, we have just started to explain molecular mechanisms of complex, multifactorial diseases. To achieve these goals, we need permanent development of genetic tests, genomics and proteomics. After fulfilling these conditions, we will get a chance to implement all molecular and genetic hopes, particularly their practical application in the clinic.

Biomarkers in systemic lupus erythematosus: challenges and prospects for the future

The search for lupus biomarkers to diagnose, monitor, stratify, and predict individual response to therapy is currently more intense than ever before. This effort is essential for several reasons. First, epidemic overdiagnosis and underdiagnosis of lupus, even by certified rheumatologists, leads to errors in therapy with concomitant side effects which may be more serious than the disease itself. Second, identification of lupus flares remains as much an art as it is a science. Third, the capacity to stratify patients so as to predict those who will develop specific patterns of organ involvement is not currently possible but would potentially lead to preventive therapeutic strategies. Fourth, only one new drug for the treatment of lupus has been approved by the US Food and Drug Administration in over 50 years. A major obstacle in this pipeline is the dearth of biomarkers available to prove a patient has responded to an experimental therapeutic intervention. This review will summarize the challenges faced in the discovery and validation of lupus biomarkers, the most promising lupus biomarkers identified to date, and the promise of future directions.

Use of biomarkers in the management of children with lupus

Childhood systemic lupus erythematosus (SLE) is known to have a worse prognosis than adult-onset disease, and monitoring and treatment of the disease are still a challenge. Thus, there is an urgent need for highly reliable, non-invasive biomarkers for early detection of relapses, to avoid long-term complications and to optimize the management of children with LN. Recent studies of pediatric patients have yielded novel specific biomarkers for SLE diagnosis which can be used for monitoring disease activity and response to treatment. The most promising biomarkers in juvenile-onset SLE include cell-bound complement activation products, some genomic profiles, and urinary proteins such as neutrophil gelatinase-associated lipocalin, monocyte chemoattractant protein-1, and alpha-1-acid glycoprotein. None of these might be suitable for use as a single SLE-biomarker. More likely a combination of novel biomarkers with traditionally used data, including autoantibodies and complement, might help to enhance sensitivity and specificity for early diagnosis, disease monitoring, and prediction of relapses.cp.

Effect of gender on clinical presentation in systemic lupus erythematosus

The incidence of SLE is markedly increased in females of child-bearing age. Although males are protected in terms of incidence of disease, it is unclear whether a distinct phenotype of male lupus exists in those who do develop SLE. We sought to explore through a detailed literature review whether gender exerts an influence on the clinical presentation and outcome of SLE. We found that males experience less of the typical mucocutaneous and musculoskeletal symptoms commonly present at diagnosis in women. On the other hand, there is limited evidence to support a negative prognostic association between male gender and disease activity or mortality.

Mannose-binding lectin blunts macrophage polarization and ameliorates lupus nephritis

Background

Deficiency in clearance of self nuclear antigens, including DNA, is the hallmark of systemic lupus erythematosus (SLE), a chronic autoimmnue disease characterized by the production of various autoantibodies, immune complex deposition and severe organ damage. Our previous studies revealed that administration of syngeneic BALB/c mice with activated lymphocyte-derived DNA (ALD-DNA) could induce SLE disease. Mannose-binding lectin (MBL), a secreted pattern recognition receptor with binding activity to DNA, has been proved to be a modulator of inflammation, but whether MBL takes responsibility for DNA clearance, modulates the DNA-mediated immune responses, and is involved in the development of DNA-induced SLE disease remain poorly understood.

Methodology/Principal Findings

The levels of serum MBL significantly decreased in lupus mice induced by ALD-DNA and were negatively correlated with SLE disease. MBL blunted macrophage M2b polarization by inhibiting the MAPK and NF-κB signaling while enhancing the activation of CREB. Furthermore, MBL suppressed the ability of ALD-DNA–stimulated macrophages to polarize T cells toward Th1 cells and Th17 cells. Importantly, MBL supplement in vivo could ameliorate lupus nephritis.

Conclusion/Significance

These results suggest MBL supplement could alleviate SLE disease and might imply a potential therapeutic strategy for DNA-induced SLE, which would further our understanding of the protective role of MBL in SLE disease.

Association of the interleukin-10 gene polymorphism (-1082A/G) with systemic lupus erythematosus: a meta-analysis

OBJECTIVE

The interleukin-10 (IL-10) gene polymorphism (-1082A/G) has been shown to be associated with systemic lupus erythematosus (SLE), but findings are not consistent across studies. The aim of our meta-analysis was to assess the association between the -1082A/G polymorphism in the IL-10 gene and SLE.

METHODS

We searched all publications on the association between the IL-10 (-1082A/G) polymorphism and SLE in PubMed, Elsevier Science Direct, Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI) and Wanfang (Chinese). Meta-analysis was conducted using software Stata version 10.1. Meta-odds ratios (ORs) and 95% confidence intervals (CIs) based on fixed-/random-effects models depended on Cochran's Q-statistic and I(2) values.

RESULTS

A total of 17 studies with 2396 cases and 3653 controls were included in this meta-analysis. Meta-analysis was performed for genotypes GG versus AA, GG + AG versus AA, GG versus AG + AA, and G allele versus A allele. Significant differences were found in genotype distribution between SLE and normal controls in whole-population GG versus AA (OR = 1.428, 95% CI = 1.006-2.208). Similar results were detected in the dominant genetics effect of the G allele (OR = 1.202, 95% CI = 1.030-1.403). No significant association was found in allele distribution in whole-population G versus A (OR = 1.125, 95% CI = 0.998-1.269). In subgroup analysis by ethnicity, significant association was found when GG + AG versus AA was performed in a European population (OR = 1.240, 95% CI = 1.022-1.503) and GG versus AG + AA was performed in an Asian population (OR = 3.596, 95% CI = 1.389-9.311). Significant association was found between genotype distribution in Asians (OR = 4.491, 95% CI = 1.552-13.000). Publication year was detected as the source of heterogeneity. In the stratified analysis by publication year, the pooled OR was 1.049 (95% CI = 0.940-1.171; P (heterogeneity) = 0.431; I(2) ( )= 0.4%) in subgroup 1 (publication years 1999-2004). No significant association was found between the IL-10 (-1082 G) allele and SLE in subgroup 1 (Z = 0.85, p = 0.431). In subgroup 2 (publication years 2005-2011), the pooled OR was 1.327 (95% CI = 1.125-1.565; P (heterogeneity) = 0.143; I(2) ( )= 35.8%). Significant association was found between the IL-10 (-1082 G) allele and SLE (Z = 3.36, p = 0.001).

CONCLUSIONS

This meta-analysis demonstrates the association between the IL-10 (-1082A/G) polymorphism and SLE. However, further studies are needed for a definitive conclusion.

MicroRNA-101, mitogen-activated protein kinases and mitogen-activated protein kinases phosphatase-1 in systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is the prototype of human autoimmune disease in which various inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin (IL)-1, IL-6 and interferon (IFN) play crucial pathogenic roles. The production of these cytokines is responsible for the mitogen-activated protein kinases (MAPKs), which can also generate mitogen-activated protein kinases phosphatases (MKPs). MKP-1, a prototypical member of the MKP family that can influence outcomes of autoimmune diseases and reduce the inflammatory cytokines by dephosphorylation of p38 and JNK MAPK, plays a critical role in the expression of inflammatory mediators at transcriptional and post-transcriptional levels. MicroRNA-101 (miR) is a small non-coding RNA that regulates the MAPK response by targeting MKP-1 mRNA 3′-UTR, and affects the secretion of the downstream inflammatory cytokines. However, the interaction among the above three in the pathogenesis of SLE has not previously been reported. This review discusses the current understanding of the role of the MAPK/MKP/miR-101 axis in regulating immune responses and the pathogenesis of SLE to provide new ideas for clinical treatment of SLE.

Receptor for advanced glycation end products (RAGE) polymorphisms are associated with systemic lupus erythematosus and disease severity in lupus nephritis

OBJECTIVE

Interaction of advanced glycation end products (AGEs) with their receptors (RAGE) plays an important role in inflammation in auto-immune diseases. Several functional polymorphisms of RAGE have been described. In this study we analysed the role of RAGE polymorphisms in disease susceptibility for systemic lupus erythematosus (SLE). In addition, we investigated whether these polymorphisms in SLE are associated with serum levels of soluble RAGE (sRAGE), renal involvement (lupus nephritis (LN)) and its outcome.

METHODS

For this cross-sectional study DNA samples of 97 SLE patients, 114 LN patients and 429 healthy controls (HC) were genotyped for four RAGE polymorphisms: -429 T/C, -374 T/A, 2184 A/G and Gly82Ser. Differences in genotype frequencies and allele frequencies were tested between patients and HCs. In SLE patients, sRAGE was measured by enzyme-linked immunosorbent assay (ELISA). In addition, association of genotypes with sRAGE and disease severity in LN was analysed.

RESULTS

The C allele of -429 T/C, the T allele of -374 T/A and the G allele of 2184 A/G were significantly more prevalent in SLE and LN compared with HC. In LN, the C allele of RAGE -429 T/C, the A allele of -374 T/A and the G allele of RAGE 2184 A/G polymorphism were significantly associated with more proteinuria and worse renal function during the first two years of treatment. No association of genotype with sRAGE was found.

CONCLUSION

RAGE polymorphisms are associated with susceptibility to SLE and LN. In addition, some of these polymorphisms are likely to be associated with disease severity and initial response to treatment in LN.

Male versus female lupus: a comparison of ethnicity, clinical features, serology and outcome over a 30 year period

Objective: To review the differences between male and female lupus patients with respect to clinical features, serology and outcome over a thirty year period. Material and methods: An observational study of all SLE patients seen at University College of London Hospital between 1976 and 2005 was performed. Demographic, clinical and serological data and outcome were retrospectively collected from hospital records or questionnaires and reviewed. Comparisons between continuous variables were made using the Kruskal–Wallis test and Student’s t-test. Chi-square test or Fisher´s exact test were used for categorical variables when it was appropriate. Results: A total of 484 patients (439 females and 45 males) were identified between 1976 and 2005. Their mean age at diagnosis was 29.3 years (SD 12.6) with no significant differences between men and women. There were no significant differences between the number of men and women diagnosed over the different decades or in the mean age at diagnosis. Female gender was significantly associated with the presence of oral ulcers (29.2% vs. 13.3%, p < 0.05) and Ig M ACA (9.9% vs. 0%, p < 0.05). There were no significant differences in the comparison of other variables. With respect to outcome, although renal failure and death were higher in females (6.8% vs. 4.4% and 13.2% vs. 6.6% respectively), no statistically significant differences were found. Cardiovascular disease was the commonest cause of death in men. Conclusion: Over this thirty year follow-up period, relatively few differences have emerged comparing the frequencies of clinical and serological features or outcome in male and female lupus patients.

Biomarkers for systemic lupus erythematosus

The urgent need for lupus biomarkers was demonstrated in September 2011 during a Workshop sponsored by the Food and Drug Administration: Potential Biomarkers Predictive of Disease Flare. After 2 days of discussion and more than 2 dozen presentations from thought leaders in both industry and academia, it became apparent that highly sought biomarkers to predict lupus flare have not yet been identified. Even short of the elusive biomarker of flare, few biomarkers for systemic lupus erythematosus (SLE) diagnosis, monitoring, and stratification have been validated and employed for making clinical decisions. This lack of reliable, specific biomarkers for SLE hampers proper clinical management of patients with SLE and impedes development of new lupus therapeutics. As such, the intensity of investigation to identify lupus biomarkers is climbing a steep trajectory, lending cautious optimism that a validated panel of biomarkers for lupus diagnosis, monitoring, stratification, and prediction of flare may soon be in hand.

Interleukin 6 gene polymorphisms are associated with systemic lupus erythematosus in Koreans

OBJECTIVE

Interleukin 6 (IL-6) gene polymorphisms are known to play a role in chronic inflammatory disorders. We searched for polymorphisms in the IL-6 gene and described their pathogenic role in Korean patients with systemic lupus erythematosus (SLE).

METHODS

Genomic DNA was extracted from 151 patients with SLE and 151 controls, and about 1.4 kb-sized IL-6 genes located between promoter region and exon 2 region were amplified by polymerase chain reaction. The promoter activity was analyzed by luciferase reporter assay in Hep3B cells and HeLa cells.

RESULTS

We identified 4 single-nucleotide polymorphisms (SNP; -572 C > G, -278 A > C in the promoter, and 330 T > G, and 334 A > T in exon 2) and a -373 A(n)T(n) tract polymorphism in the IL-6 gene. The genotype frequency, -373 A(10)T(11), -278 C, and 334 T allele were significantly associated with SLE (p < 0.001, p = 0.03 and p = 0.005, respectively). Patients with SLE carrying the -572 G allele had anti-dsDNA more frequently (p = 0.007). In addition, thrombocytopenia was significantly more common in patients carrying the -278 C allele (p = 0.006). In the haplotype analysis, patients with SLE had more frequently haplotype HT3 (CA(10)T(11)ATA, dominant model, p = 0.012) that was associated with arthritis, leukopenia, anti-dsDNA, and hypocomplementemia. Promoter reporter structures carrying the -278 C allele displayed significantly higher promoter activity than the -278 A allele in Hep3B cells (p < 0.001) and HeLa cells (p < 0.001).

CONCLUSION

These data suggest that IL-6 gene polymorphisms are associated with disease susceptibility and phenotype of SLE. In addition, promoter polymorphisms may be involved in regulation of IL-6 expression.

Lack of Association of C-C Chemokine Receptor 5 Δ32 Deletion Status with Rheumatoid Arthritis, Systemic Lupus Erythematosus, Lupus Nephritis, and Disease Severity

Objective.

C-C chemokine receptor 5 (CCR5) plays an important role in inflammation. A 32 base-pair (Δ32) deletion in the CCR5 gene leads to a nonfunctional receptor. This deletion has been reported to have a protective effect on the development and progression of several autoimmune diseases. We investigated whether the Δ32 deletion is associated with disease susceptibility in a population of patients with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and lupus nephritis (LN); and whether it is associated with disease severity.

Methods

DNA samples from 405 RA patients, 97 SLE patients, 113 LN patients, and 431 healthy controls were genotyped for the CCR5 Δ32 deletion. Differences in genotype frequencies were tested between patients and controls. Association of genotypes with disease severity was analyzed.

Results

Genotype frequencies of each group were in Hardy-Weinberg equilibrium. The genotype frequencies of patients did not differ significantly from controls (CCR5/Δ32, Δ32/Δ32: RA 18.3% and 1.2%, respectively; SLE 17.5% and 2.1%; LN 13.3% and 1.8%; controls 20.0% and 2.8%). However, there was a trend for lower Δ32 deletion allele frequency in LN patients compared to controls (p = 0.08). There was no significant association between the CCR5 status and disease severity in RA, SLE, or LN.

Conclusion.

Although an association with LN cannot be excluded, the CCR5 Δ32 deletion does not seem to be a disease susceptibility genotype for RA, SLE, or LN. No significant effect of the Δ32 deletion on disease severity was demonstrated.

TNIP1, SLC15A4, ETS1, RasGRP3 and IKZF1 are associated with clinical features of systemic lupus erythematosus in a Chinese Han population

Systemic lupus erythematosus (SLE) is an autoimmune disease with heterogeneous clinical manifestations influenced by genetic and environmental factors. Five novel susceptibility genes (TNIP1, SLC15A4, ETS1, RasGRP3 and IKZF1) for SLE have been identified in a recent genome-wide association study of a Chinese Han population. This study investigated their relationships with disease subphenotypes, including renal nephritis, photosensitivity, antinuclear antibody (ANA), age at diagnosis, malar rash, discoid rash, immunological disorder, oral ulcer, hematological disorder, neurological disorder, serositis, arthritis and vasculitis. Significant associations were found for the single nucleotide polymorphism rs10036748 of TNIP1 with photosensitivity (odds ratio (OR) = 0.87, p = 0.01) and vasculitis (OR = 1.18, p = 0.04); rs10847697 of SLC15A4 with discoid rash (OR = 1.18, p = 0.02); rs6590330 of ETS1 with SLE of age at diagnosis <20 years (OR = 1.24, p = 8.91 x 10(-5)); rs13385731 of RasGRP3 with malar rash (OR = 1.20, p = 0.01), discoid rash (OR = 0.78, p = 0.02) and ANA (OR = 0.72, p = 0.004); rs4917014 of IKZF1 with renal nephritis (OR = 1.13, p = 0.02) and malar rash (OR = 0.83, p = 0.00038), respectively. The study suggested that these susceptibility genes might not only play important roles in the development of SLE, but also contribute to the complex phenotypes of SLE.

Association of TNF-alpha gene polymorphisms with systemic lupus erythematosus in Taiwanese patients

Tumour necrosis factor-alpha (TNF-alpha), an important proinflammatory cytokine, exerts a variety of physiological and pathogenic effects that lead to tissue destruction. Studies on the association of TNF-alpha genetic polymorphisms with systemic lupus erythematosus (SLE) have yielded inconclusive results. We investigated the association of TNF-alpha genetic polymorphisms (-1031T/C, -863C/A, -857T/C, -308A/G and +489A/G) with SLE in Taiwanese patients and controls. Our results indicate that 1) the frequency of the A-allele at -863 position was significantly higher in SLE patients (odds ratio = 1.46; 95% CI = 1.02-2.08); 2) the frequency of the A-allele at +489 position was significantly higher in SLE patients (odds ratio = 1.79; 95% CI = 1.21-2.65); 3) the AA or GA genotype frequencies at +489 position were significantly increased in SLE patients (AA genotype: odds ratio = 11.20; 95% CI = 1.36-92.55; GA genotype: odds ratio = 1.63; 95% CI = 1.03-2.58); 4) no significant association of TNF-alpha haplotypic distributions was observed, except for the haplotypes TCCGA, CACGA and CCCGG; and 5) the genotype frequency of the polymorphisms at -1031 was significantly different in patients with antinuclear antibodies (P = 0.022). The allele and genotype frequencies of the polymorphisms at -863 were not significantly different. The genotype frequency of the polymorphisms at -857 was significantly different in patients with haematological disorder (P = 0.025). The frequency of A allele of the polymorphisms at -308 was significantly increased in patients with malar rash (P = 0.033), discoid rash (P = 0.023), photosensitivity (P = 0.037), oral ulcers (P = 0.002) and serositis (P = 0.029). The genotype frequency of the polymorphisms at +489 was significantly different in patients with discoid rash and photosensitivity (data not shown; discoid rash, P = 0.031; photosensitivity, P = 0.044). These results suggest that TNF-alpha genetic polymorphisms contribute to SLE susceptibility in the Taiwanese population.

Association of the BANK 1 R61H variant with systemic lupus erythematosus in Americans of European and African ancestry

Recently an association was demonstrated between the single nucleotide polymorphism (SNP), rs10516487, within the B-cell gene BANK1 and systemic lupus erythematosus (SLE) as a consequence of a genome wide association study of this disease in European and Argentinean populations. In a bid for replication, we examined the effects of the R61H non-synonymous variant with respect to SLE in our genotyped American cohorts of European and African ancestry. Utilizing data from our ongoing genome-wide association study in our cohort of 178 Caucasian SLE cases and 1808 Caucasian population-based controls plus 148 African American (AA) SLE cases and 1894 AA population-based controls we investigated the association of the previously described non-synonymous SNP at the BANK1 locus with the disease in the two ethnicities separately. Using a Fisher’s exact test, the minor allele frequency (MAF) of rs10516487 in the Caucasian cases was 22.6% while it was 31.2% in Caucasian controls, yielding a protective odds ratio (OR) of 0.64 (95% CI 0.49-0.85; one-sided p = 7.07 × 10⁻⁴). Furthermore, the MAF of rs10516487 in the AA cases was 18.7% while it was 23.3% in AA controls, yielding a protective OR of 0.75 (95% CI 0.55–1.034; one-sided p = 0.039). The OR of the BANK1 variant in our study cohorts is highly comparable with that reported previously in a South American/European SLE case-control cohort (OR = 0.72). As such, R61H in the BANK1 gene confers a similar magnitude of SLE protection, not only in European Americans, but also in African Americans.

Cytokines and cytokine profiles in human autoimmune diseases and animal models of autoimmunity

The precise pathomechanisms of human autoimmune diseases are still poorly understood. However, a deepened understanding of these is urgently needed to improve disease prevention and early detection and guide more specific treatment approaches. In recent years, many new genes and signalling pathways involved in autoimmunity with often overlapping patterns between different disease entities have been detected. Major contributions were made by experiments using DNA microarray technology, which has been used for the analysis of gene expression patterns in chronic inflammatory and autoimmune diseases, among which were rheumatoid arthritis, systemic lupus erythematosus, psoriasis, systemic sclerosis, multiple sclerosis, and type-1 diabetes. In systemic lupus erythematosus, a so-called interferon signature has been identified. In psoriasis, researchers found a particular immune signalling cluster. Moreover the identification of a new subset of inflammatory T cells, so-called Th17 T cells, secreting interleukin (IL)-17 as one of their major cytokines and the identification of the IL-23/IL-17 axis of inflammation regulation, have significantly improved our understanding of autoimmune diseases. Since a plethora of new treatment approaches using antibodies or small molecule inhibitors specifically targeting cytokines, cellular receptors, or signalling mechanisms has emerged in recent years, more individualized treatment for affected patients may be within reach in the future.

Rheumatoid arthritis does not share most of the newly identified systemic lupus erythematosus genetic factors

OBJECTIVE

Rheumatoid arthritis (RA) and systemic lupus erythematosus (SLE) share some genetic factors such as HLA, PTPN22, STAT4, and 6q23. The aim of this study was to determine whether 9 other SLE genetic factors are also implicated in RA susceptibility.

METHODS

A characteristic single-nucleotide polymorphism (SNP) in each of 9 genetic factors, ITGAM (rs1143679), C8orf13-BLK (rs13277113), TYK2 (rs2304256), 1q25.1 (rs10798269), PXK (rs6445975), KIAA1542 (rs4963128), MECP2 (rs17435), BANK1 (rs17266594), and LY9 (rs509749), was studied in 1,635 patients with RA and 1,906 control subjects from Spain. The rs7574865 SNP in STAT4 was also included. Analyses were conducted globally and after stratification by sex and clinical features (anti-cyclic citrullinated peptide and rheumatoid factor, shared epitope, rheumatoid nodules, radiographic changes, sicca syndrome, and pneumonitis).

RESULTS

No association was observed between RA and any of the 9 newly identified SLE genetic factors. A meta-analysis using previous data was consistent with these results. In addition, there were no significant differences between individuals with and those without each of the clinical features analyzed, except the frequency of the minor allele in the C8orf13-BLK locus that was decreased in patients with sicca syndrome (14.6% versus 22.4% in controls; P = 0.003).

CONCLUSION

None of the 9 recently identified SLE risk factors showed association with RA. Therefore, common genetic factors affecting the pathogenesis of these 2 disorders seem to be limited, revealing that the genetic component contributes to the different expression of these diseases.

The search for lupus biomarkers

Few biomarkers for systemic lupus erythematosus (SLE) have been validated and employed for making clinical decisions. The lack of reliable, specific biomarkers for SLE hampers the proper clinical management of patients with SLE and impedes the development of new lupus therapeutics. This void has led to renewed enthusiasm for identifying biomarkers that precisely and specifically reflect the pathophysiological and clinical changes of SLE. Several laboratory markers have shown early promise as biomarkers for lupus susceptibility, diagnosis and monitoring. These include polymorphisms and copy-number variations of complement C4 and Fcgamma receptor genes (disease susceptibility), cell-bound complement C4d (diagnosis and/or disease activity), CD27(high) plasma cells (disease activity), 'interferon signature' (disease activity) and anti-C1q and anti-NMDA (disease activity and organ involvement). Although these and other promising candidate biomarkers have been identified, they still need to be validated through rigorous, large-scale multicentre studies. This article briefly reviews the historical aspects of lupus biomarkers and summarises current efforts to advance the field.

C-Reactive Protein Gene Polymorphisms in Disease Susceptibility and Clinical Manifestations of Korean Systemic Lupus Erythematosus

Objective.

C-reactive protein (CRP) is a sensitive marker of inflammation. It is hypothesized that polymorphism of CRP gene contributes to susceptibility to systemic lupus erythematosus (SLE). We tested this hypothesis by identifying CRP gene polymorphisms in Korean patients with SLE.

Methods.

Approximately 1.5 kb of CRP promoter region was screened for single nucleotide polymorphism (SNP) using direct sequencing and 3 SNP in CRP exons by restriction fragment length polymorphism. The basal levels of CRP were measured by immunoturbidimetry. The effect of −390 C>A or T polymorphism on the promoter activity was analyzed by luciferase reporter assay in Hep3B cells.

Results.

Allele frequency at polymorphisms within CRP promoter and exon in our Korean patients with SLE differed from that of Caucasians. The A allele was a major allele at position 2043 in Korean SLE patients, whereas G is a major allele in Caucasian SLE. Our SLE patients had minor allele in the −390 polymorphism more frequently versus controls (p = 0.033). CRP 1185 polymorphism was associated with thrombocytopenia (p = 0.043). The basal levels of CRP were significantly higher in individuals who had minor allele in −390 and 2043 polymorphisms (p = 0.03. p = 0.024, respectively). Promoter-reporter construct carrying the −390 A or T allele displayed significantly higher promoter activity than that with the −390 C allele (p < 0.001).

Conclusion.

CRP gene −390 polymorphism plays a role in disease susceptibility of SLE through regulation of serum CRP level. Our results suggest that elevated basal CRP level may be important in the pathogenesis of SLE, even though CRP responsiveness to noninfectious inflammation of SLE is decreased.

The MHC haplotype H2b converts two pure nonlupus mouse strains to producers of antinuclear antibodies

Studies of mouse lupus models have linked the MHC H2(b) haplotype with the earlier appearance of antinuclear autoantibodies and the worsening of nephritis. However, it is unknown whether H2(b) by itself, in the context of pure nonlupus strains, is "silent" or sufficient with regard to loss of tolerance to chromatin (nucleosomes). In this study we show that, beginning approximately 6-9 mo of age, H2(b)-congenic BALB/c (denoted BALB.B) mice, unlike BALB/c (H2(d)) and H2(k)-congenic BALB/c (denoted BALB.K) mice, develop strikingly increased serum levels of anti-chromatin Ab dominated by the IgG2a subclass, along with minor increase of Abs to DNA and moderately increased total serum IgG2a. The BALB.B mice did not have glomerulonephritis or an increased mortality rate. H2(b)-congenic C3H/He mice (designated C3.SW mice), unlike C3H/He (H2(k)) mice, showed low but measurable serum levels of chromatin-reactive IgG2a Abs and minor but significant hypergammaglobulinemia. By immunofluorescence, IgG2a of sera from both H2(b)-congenic strains stained HEp-2 cell nuclei, confirming the presence of antinuclear autoantibodies. Thus, in the context of two pure nonlupus genomes, the MHC H2(b) haplotype in homozygous form is sufficient to induce loss of tolerance to chromatin.