Increased circulating sclerostin levels in rheumatoid arthritis patients: an updated meta-analysis.

BACKGROUND: Sclerostin, a regulator of bone metabolism and vascular calcification involved in regulating the Wnt/ß-catenin signaling pathway, has been shown to be involved in the pathogenesis of rheumatoid arthritis (RA). However, current results regarding the circulating sclerostin level of RA patients are debatable. This study aimed to evaluate the circulating level of sclerostin in RA patients and briefly summarize its role. METHOD: PubMed, EMBASE, and the Cochrane Library databases were systematically searched till May 27, 2021, for eligible articles. Useful data from all qualified papers were systematically extracted and analyzed using Stata 12.0 software (Stata Corp LP, College Station, TX, USA). RESULTS: Overall, 13 qualifying studies including 1030 cases and 561 normal controls were analyzed in this updated meta-analysis. Forest plot of this meta-analysis showed that RA patients had higher circulating sclerostin levels (P < 0.001, standardized mean difference [SMD] = 0.916, 95% CI: 0.235-1.597) compared to normal controls. Subgroup analyses implied that age, region, and assay method were associated with sclerostin level in RA patients. CONCLUSION: RA patients have higher circulating sclerostin levels, and these was influenced by age, region, and assay method.

Circulating adiponectin levels and systemic lupus erythematosus: a two-sample Mendelian randomization study.

OBJECTIVES: Several studies have reported increased serum/plasma adiponectin levels in SLE patients. This study was performed to estimate the causal effects of circulating adiponectin levels on SLE. METHODS: We selected nine independent single-nucleotide polymorphisms that were associated with circulating adiponectin levels (P < 5 × 10-8) as instrumental variables from a published genome-wide association study (GWAS) meta-analysis. The corresponding effects between instrumental variables and outcome (SLE) were obtained from an SLE GWAS analysis, including 7219 cases with 15 991 controls of European ancestry. Two-sample Mendelian randomization (MR) analyses with inverse-variance weighted, MR-Egger regression, weighted median and weight mode methods were used to evaluate the causal effects. RESULTS: The results of inverse-variance weighted methods showed no significantly causal associations of genetically predicted circulating adiponectin levels and the risk for SLE, with an odds ratio (OR) of 1.38 (95% CI 0.91, 1.35; P = 0.130). MR-Egger [OR 1.62 (95% CI 0.85, 1.54), P = 0.195], weighted median [OR 1.37 (95% CI 0.82, 1.35), P = 0.235) and weighted mode methods [OR 1.39 (95% CI 0.86, 1.38), P = 0.219] also supported no significant associations of circulating adiponectin levels and the risk for SLE. Furthermore, MR analyses in using SLE-associated single-nucleotide polymorphisms as an instrumental variable showed no associations of genetically predicted risk of SLE with circulating adiponectin levels. CONCLUSION: Our study did not find evidence for a causal relationship between circulating adiponectin levels and the risk of SLE or of a causal effect of SLE on circulating adiponectin levels.

Association of PER2 gene single nucleotide polymorphisms with genetic susceptibility to systemic lupus erythematosus.

The circadian clock plays a crucial role in the progress of systemic lupus erythematosus (SLE). In this study, we performed a case-control study to explore the association between Period 2 (PER2) gene single nucleotide polymorphisms (SNPs) and the susceptibility of systemic lupus erythematosus (SLE). A total of 492 SLE patients and 493 healthy controls were included. The improved multiple ligase detection reaction (iMLDR) was used for genotyping. The correlations between four SNPs of PER2 (rs10929273, rs11894491, rs36124720, rs934945) and the genetic susceptibility and clinical manifestations of SLE were analyzed. Significant differences were observed in the distributions of allele frequencies and genotype under dominant model in rs11894491 between SLE patients and controls (p = 0.030, p = 022, respectively). We hypothesized that PER2 gene SNPs was related to the genetic susceptibility and clinical manifestations, implying the potential role of PER2 in the pathogenesis of SLE.

Seasonality and global public interest in psoriasis: an infodemiology study.

OBJECTIVE: Although patients with psoriasis frequently report seasonal changes in their symptoms, the seasonality of psoriasis has rarely been explored. This study aims to investigate the seasonal pattern of and global public interest in psoriasis using Google search data. METHODS: Internet search data were collected from Google Trends. Data on the relative search volume (RSV) from January 2004 to December 2018 were retrieved using the term psoriasis. Cosinor analyses were conducted to examine the seasonality of psoriasis using data from two southern hemisphere countries (Australia and New Zealand) and four northern hemisphere countries (USA, Canada, UK and Ireland). RESULTS: Overall, searches for psoriasis steadily decreased between 2004 and 2010, and then rose from 2011 to 2018. On cosinor analyses, RSV of 'psoriasis' displayed a significant seasonal variation worldwide (p<0.025). Further analyses confirmed the seasonality of psoriasis-related RSV in Australia, New Zealand, USA, Canada, UK and Ireland (p<0.025 for all), with peaks in the late winter/early spring months and troughs in the late summer/early autumn months. The top 11 rising topics were calcipotriol/betamethasone dipropionate, ustekinumab, apremilast, shampoo, eczema, guttate psoriasis, seborrhoeic dermatitis, dermatitis, psoriatic arthritis, atopic dermatitis and arthritis. CONCLUSION: There was a significant seasonal pattern for psoriasis, with peaks in the late winter/early spring and troughs in the late summer/early autumn. Further studies are warranted to confirm the seasonal pattern of psoriasis using clinical data and to explore the underlying mechanisms.

Elevated circulating asymmetric dimethylarginine levels in rheumatoid arthritis: a systematic review and meta-analysis.

Rheumatoid arthritis (RA) patients have increased risk of cardiovascular disease (CVD) death. Elevated asymmetric dimethylarginine (ADMA) levels have been reported to be an independent predictor of CVD morbidity and mortality, however, the role of ADMA in RA remains undetermined. To derive a more accurate estimation on circulating ADMA levels in RA patients, a meta-analysis was performed. Embase, PubMed, and The Cochrane Library database (up to October 7 2018) were used to acquire published literatures. Heterogeneity test was performed by the Q statistic and quantified using I2. Publication bias was evaluated using a funnel plot and Egger's linear regression test. A total of 174 articles were identified, 16 studies with 1365 subjects (666 RA patients and 699 healthy individuals) were ultimately included. Plasma/serum ADMA levels appeared to be higher in RA patients than healthy controls (SMD = 0.84, 95% CI 0.32, 1.35). By assessing the BMI, age, disease duration and disease activity as subgroups, BMI ≥ 24 and BMI < 24 groups both showed elevated ADMA levels than controls, disease duration ≥ 8, age < 50 and disease activity ≥ 3.2 and < 5.1 group had a higher ADMA level than control groups. However, disease duration < 8, disease activity ≥ 5.1 and age ≥ 50 groups showed no difference between two groups. Circulating ADMA levels are higher in RA patients compared with healthy controls. In addition, ADMA levels are influenced by age, disease duration and disease activity.

Leveraging Google Trends to investigate the global public interest in rheumatoid arthritis.

This study aims to investigate the global public interest in rheumatoid arthritis by evaluating search term popularity changes of the disease over a decade. Google Trends was applied to retrieve search popularity scores for the term 'rheumatoid arthritis' between January 2004 and December 2017, utilizing the category of "health". Overall, relative searches volume for rheumatoid arthritis steadily decreased from January 2004 to December 2010, and then slowly rose from January 2011 to December 2017. There were significant seasonal variations in relative searches volume for the term 'rheumatoid arthritis' (Amplitude = 3.11; Phase: Month = 4.3; Low point: Month = 10.3; p < 0.025). Relative searches volume peaked in April and reached the lowest level in October. The top 11 rising topics were scleroderma, Anna Marchesini, C-reaction protein, osteoarthritis, arthritis, joint pain, autoimmune disease, rheumatoid factor, rheumatology, methotrexate, and systemic lupus erythematosus, ranking from high to low by relative growth of topic regarding rheumatoid arthritis. In conclusion, the evidence from Google Trends analysis demonstrates a significant seasonal variation in rheumatoid arthritis, with a peak in April. In addition, the top rising search queries are beneficial for physicians to search the Internet themselves for websites that provide high-quality information to recommend to their patients.

Accelerated biological aging as a potential risk factor for rheumatoid arthritis.

OBJECTS: Previous studies have suggested a potential correlation between rheumatoid arthritis (RA) and biological aging, but the intricate connections and mechanisms remain elusive. METHODS: In our study, we focused on two specific measures of biological age (PhenoAge and BioAge), which are derived from clinical biomarkers. The residuals of these measures, when compared to chronological age, are defined as biological age accelerations (BAAs). Utilizing the extensive UK Biobank dataset along with various genetic datasets, we conducted a thorough assessment of the relationship between BAAs and RA at both the individual and aggregate levels. RESULTS: Our observational studies revealed positive correlations between the two BAAs and the risk of developing both RA and seropositive RA. Furthermore, the genetic risk score (GRS) for PhenoAgeAccel was associated with an increased risk of RA and seropositive RA. Linkage disequilibrium score regression (LDSC) analysis further supported these findings, revealing a positive genetic correlation between PhenoAgeAccel and RA. PLACO analysis identified 38 lead pleiotropic single nucleotide polymorphisms linked to 301 genes, providing valuable insights into the potential mechanisms connecting PhenoAgeAccel and RA. CONCLUSION: In summary, our study has successfully revealed a positive correlation between accelerated biological aging, as measured by BAAs, and the susceptibility to RA.

Association between ambient air pollution and tuberculosis risk: A systematic review and meta-analysis.

There is a growing body of evidence suggesting an association between air pollution exposure and tuberculosis (TB) incidence, but no meta-analysis has assembled all evidence so far. This review and meta-analysis aimed to derive a more reliable estimation on the association between air pollution and TB incidence. PubMed, Embase and Web of Science electronic databases were systemically searched for eligible literature. The PECO framework was used to form the eligibility criteria. Effect estimates and 95% confidence intervals (CIs) published in the included studies were pooled quantitatively. Seventeen articles met the inclusion criteria. The pooled estimates showed that long-term exposure to particulate matter with an aerodynamic diameter ≤10 µm (PM10) was associated with increased incidence of TB (per 10 µg/m3 increase in concentrations of PM10: risk ratios (RR) = 1.058, 95% CI: 1.021-1.095). Besides, long-term exposure to sulfur dioxide (SO2) and nitrogen dioxide (NO2) were significantly associated with TB incidence (per 1 ppb increase, SO2: RR = 1.016, 95% CI: 1.001-1.031; NO2: 1.010, 95% CI: 1.002-1.017). We did not find a significant association of PM2.5, ozone (O3) or carbon monoxide (CO) with TB risk, regardless of long-term or short-term exposure. However, in view of the 2016 ASA Statement and the biological plausibility of PM2.5 damaging host immunity, the association between PM2.5 and TB risk remains to be further established. This meta-analysis shows that long-term exposure to PM10, SO2 or NO2 is associated with increased odds of TB, and the specific biological mechanisms warrant further research.

Association between traffic-related air pollution and hospital readmissions for rheumatoid arthritis in Hefei, China: A time-series study.

Air pollution is an important risk factor for autoimmune diseases, but its association with the recurrence of rheumatoid arthritis (RA) remains unclear so far. This study aimed to investigate the short-term association between traffic-related air pollutants and hospital readmissions for RA in Hefei, China. Data on daily hospital readmissions for RA and traffic-related air pollutants, including particulate matter (PM2.5 and PM10), nitrogen dioxide (NO2), and carbon monoxide (CO), from 2014 to 2018 were retrieved. A time-series approach using generalized linear regression model was employed. The analysis was further stratified by sex, age and season. A total of 1153 readmissions for RA were reported during the study period. A significant association between high-concentration PM2.5 (90th percentile) and RA readmissions was observed on lag1 (relative risk (RR) = 1.09, 95% confidence interval (CI): 1.01-1.19) and lasted until lag3 (RR = 1.06, 95%CI: 1.01-1.12). From lag2 to lag5, high-concentration NO2 (90th percentile) was associated with increased risk of RA readmissions, with the highest RR observed at lag 4 (1.11, 95%CI: 1.05-1.17). Stratified analyses indicated that females and the elderly appeared to be more vulnerable to high-concentration PM2.5 and NO2 exposure. High-concentration PM2.5 and NO2 in cold seasons were consistently significantly associated with increased risk of RA readmissions. Exposure to high-concentration PM2.5 and NO2 was associated with increased risk of RA readmissions. Protective measures against the exposure to high-concentration PM2.5 and NO2 should be taken to reduce the recurrence risk in RA patients, especially in females, the elderly and during cold seasons.

Low ambient temperature increases hospital re-admissions for systemic lupus erythematosus in humid subtropical region: a time series study.

Currently, the correlation between ambient temperature and systemic lupus erythematosus (SLE) hospital admissions remains not determined. The aim of this study was to explore the correlation between ambient temperature and SLE hospital admissions in Hefei City, China. An ecological study design was adopted. Daily data on SLE hospital admissions in Hefei City, from January 1, 2007, to December 31, 2017, were obtained from the two largest tertiary hospitals in Hefei, and the daily meteorological data at the same period were retrieved from China Meteorological Data Network. The generalized additive model (GAM) combined with distributed lag nonlinear model (DLNM) with Poisson link was applied to evaluate the influence of ambient temperature on SLE hospital admissions after controlling for potential confounding factors, including seasonality, relative humidity, day of week, and long-term trend. There were 1658 SLE hospital admissions from 2007 to 2017, including 370 first admissions and 1192 re-admissions (there were 96 admissions with admission status not stated). No correlation was observed between ambient temperature and SLE first admissions, but a correlation was found between low ambient temperature and SLE re-admissions (RR: 2.53, 95% CI: 1.11, 5.77) (3.5 °C vs 21 °C). The effect of ambient temperature on SLE re-admissions remained for 2 weeks but disappeared in 3 weeks. Exposure to low ambient temperature may increase hospital re-admissions for SLE, and thus it is important for SLE patients to maintain a warm living environment and avoid exposure to lower ambient temperature.

Association of Leptin Gene Polymorphisms with Rheumatoid Arthritis in a Chinese Population.

BACKGROUND: Recently, increasing studies have revealed that leptin is involved in the development of rheumatoid arthritis (RA). This study is aimed at exploring the association of leptin gene single nucleotide polymorphisms (SNPs) with susceptibility to RA in a Chinese population. METHODS: We recruited 600 RA patients and 600 healthy controls from a Chinese population and analyzed their three leptin SNPs (rs10244329, rs2071045, and rs2167270) using the improved Multiplex Ligase Detection Reaction (iMLDR) assays. The associations of these SNPs with clinical manifestations of RA were also analyzed. Enzyme-linked immunosorbent assay (ELISA) was performed for plasma leptin determination. RESULTS: No significant difference in either allele or genotype frequencies of these three SNPs between RA patients and healthy controls was observed (all P > 0.05). Association between the genotype effects of dominant, recessive models was also not found (all P > 0.05). No significant difference in plasma leptin levels was detected between RA patients and controls (P > 0.05). CONCLUSION: Leptin gene (rs10244329, rs2071045, and rs2167270) polymorphisms are not associated with RA genetic susceptibility and its clinical features in the Chinese population.

Circulating Meteorin-like Levels in Patients with Type 2 Diabetes Mellitus: A Meta-Analysis.

BACKGROUND: Meteorin-like (Metrnl) is a newly identified adipokine implicated in the pathogenesis of type 2 diabetes mellitus (T2DM), yet data on the circulating levels of Metrnl in patients with T2DM are controversial. To derive a more precise estimation on circulating Metrnl levels in T2DM patients, we conducted this meta-analysis. METHODS: The existing studies on the circulating levels of Metrnl in patients with T2DM published up to 16 January 2020 were comprehensively retrieved from PubMed, Web of Science, EMBASE, and The Cochrane library database. Pooled standard mean difference (SMD) with 95% confidence interval (CI) was calculated using random-effects model. Heterogeneity was assessed and quantified by Cochrane's Q and I2 statistic. All statistical analyses were performed using Stata 12.0 software. RESULTS: Nine studies with 867 T2DM patients and 831 normal glucose tolerance (NGT) controls were included in the final analysis according to the inclusion criteria. No significant difference in circulating Metrnl levels was found between T2DM patients and NGT individuals (pooled SMD = -0.429, 95% CI = -1.077 to 0.219). Compared to controls, circulating Metrnl levels were significantly higher in the subgroups with BMI <25 kg/m2, using plasma sample and patient sample size ≥100, while circulating Metrnl levels were significantly lower in subgroups with age ≤50 years and homeostatic model assessment for insulin resistance (HOMA-IR) ≥4. CONCLUSION: This meta-analysis indicates no significant change in circulating Metrnl levels in T2DM patients. However, this result may be influenced by age, BMI, sample type, HOMA-IR and patients sample size. Further longitudinal studies are warranted to offer more insights into the relationship between Metrnl and T2DM.

Mortality and Disease Burden of Injuries from 2008 to 2017 in Anhui Province, China.

OBJECTIVE: To investigate the temporal trends in mortality and disease burden of injuries in Anhui province from 2008 to 2017, so as to provide reference for injury control and prevention. METHODS: Data of mortality were collected from 9 national surveillance points in Anhui province during 2008-2017 in the Information System for Death Cause Register and Management. The surveillance data were analyzed by using crude mortality, standardized mortality rate (SMR), potential year of life lost (PYLL), PYLL rate (PYLLR), and average of year life lost (AYLL). RESULTS: There were a total of 44855 people died from injury, accounted for 9.44% of the all-cause mortality, ranked as the fifth leading cause of deaths in the whole population, and denoted the first leading cause of deaths in the 0-44 year's group. The leading causes of injury deaths were road traffic accidents, suicide, accidental falls, drowning, and poisoning. Road traffic accidents was the primary cause of injury deaths among the male population, while suicide was the dominate cause of injury deaths among the female population. Drowning, traffic accidents, and suicide accounted for the most injury deaths among the population aged 0-14 years, 15-64 years, and above 60 years, respectively. The road traffic accidents accounted for the largest proportion of injury PYLL and PYLLR, and drowning caused the highest AYLL among injury deaths. CONCLUSION: In Anhui province, road traffic accidents, suicide, accidental falls, drowning, and poisoning were the top five causes of injury deaths that harm the health of local residents; corresponding injury prevention strategies should be formulated.

Plasma galectin-3 levels do not differ in systemic lupus erythematosus patients.

OBJECTIVE: To investigate the plasma galectin-3 levels in systemic lupus erythematosus (SLE) patients and its relations with clinical and laboratory features. METHODS: A total of 180 subjects with 90 patients with SLE (8 male, 82 female, mean age 37.86 ± 13.98 years) and 90 healthy controls (8 male, 82 female, mean age 36.54 ± 10.89 years) were included. Plasma galectin-3 levels were detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: There was no significant difference in age and gender distribution between SLE patients and healthy controls (both P > .05). Plasma galectin-3 level was not significantly different between SLE patients and controls (P = .982) (P > .05). No significant difference was found regarding galectin-3 levels between SLE with nephritis and those without nephritis (P > .05); no significant difference was found between less active SLE and more active SLE (P > .05). Galectin-3 levels were inversely related to immune globulin M (r = -.303, P < .05), while no significant correlation between galectin-3 levels and other quantitative laboratory parameters were observed (all P > .05). CONCLUSIONS: In summary, plasma galectin-3 level was not significantly different between SLE patients and controls (P = .982). Further studies are needed to elucidate the role of galectin-3 in SLE.

Circulating levels of prolactin are elevated in patients with rheumatoid arthritis: a meta-analysis.

BACKGROUND: Prolactin (PRL), an inflammatory hormone with cytokine properties, has long been proposed to play a crucial role in the pathogenesis of autoimmune disorders, including rheumatoid arthritis (RA). However, the circulating levels of PRL in RA were discordant among published studies. METHODS: PubMed, Embase, and The Cochrane Library database were systematically searched from inception up to 30 June 2018. The available studies were obtained from the initial search in accordance with the rigorous inclusion and exclusion criteria. Relevant data from the included literatures were extracted. Methodological quality was evaluated in order to refine the final search results. All statistical analyses were conducted using software STATA version 12.0. RESULTS: Of 698 articles were yielded for eligibility, a finally analysis involving 628 RA cases and 430 controls from 14 published studies were included. When compared to healthy controls, there was a significantly higher level of circulating PRL in patients with RA with a pooled SMD of 1.08 (95% CI = 0.41 to 1.74, P< 0.001), particularly in Asians, age ≥50, enzyme-linked immunosorbent assay (ELISA) group and subjects with erythrocyte sedimentation rate (ESR) ≥25 mm/h. CONCLUSIONS: Our meta-analysis demonstrates a significantly higher level of circulating PRL in RA patients when compared to healthy controls, and it was associated with region, age, measurement type and ESR.

Association between Interleukin 35 Gene Single Nucleotide Polymorphisms and Systemic Lupus Erythematosus in a Chinese Han Population.

Interleukin-35 (IL-35) exerts crucial roles in the pathogenesis and development of systemic lupus erythematosus (SLE), in this study we aim to explore the associations between IL-35 gene polymorphisms and the susceptibility, clinical features and plasma IL-35 levels of SLE patients, respectively. 490 SLE patients and 489 healthy controls were recruited in our study. The correlations between the polymorphisms of seven SNPs of IL-35 encoding gene and the susceptibility, main clinical manifestations of SLE were evaluated, respectively. Plasma IL-35 levels were assessed in 76 SLE patients, and the associations between plasma IL-35 levels and the polymorphisms of genotyped SNPs were explored. There were significant associations between the polymorphisms of rs4740 and the occurrence of renal disorder, hematological disorder in SLE patients, respectively (p = 0.001; p = 0.001). In addition, there were no significant associations observed between the genotype frequencies of genotyped SNPs and the risk of SLE, plasma IL-35 levels, respectively. The polymorphism of rs4740 of IL-35 encoding gene is associated with the occurrence of renal disorder and hematological disorder of SLE patients.

Factors influencing completion of treatment among pulmonary tuberculosis patients.

Objective: This study aimed to understand the influencing factors of treatment completion among pulmonary tuberculosis (PTB) patients in Anhui province, eastern People's Republic of China, in order to provide scientific evidence for improving the follow-up rate and treatment completion rate. Methods: A total of 262 PTB patients in six counties (districts) of Anhui province were investigated by questionnaire, and data about treatment interruption were collected. Results: The main causes of treatment interruption were forgetting to take medicine (24.5%), drug side effects (23.3%), and symptomatic improvement (19.5%). The education background, patient type, cause of interruption, and tracking method were factors influencing completion of treatment (all P<0.05). The education level was positively associated with the treatment completion rate. New smear-positive patients had a significantly higher completion rate than others. The patients interrupted by drug side effects had the highest risk of interruption. In terms of the tracking method, the completion rate of patients tracked by the rural medical staff was significantly lower. Conclusions: The management of PTB patients by medication supervision should be strengthened, especially for those with low education level and who had drug side effects, in order to improve their treatment completion rate.

Potential role of melatonin in autoimmune diseases.

Autoimmune diseases are a broad spectrum of disorders involved in the imbalance of T-cell subsets, in which interplay or interaction of Th1, Th17 and Tregs are most important, resulting in prolonged inflammation and subsequent tissue damage. Pathogenic Th1 and Th17 cells can secrete signature proinflammatory cytokines, including interferon (IFN)-γ and IL-17, however Tregs can suppress effector cells and dampen a wide spectrum of immune responses. Melatonin (MLT) can regulate the humoral and cellular immune responses, as well as cell proliferation and immune mediators. Treatment with MLT directly interferes with T cell differentiation, controls the balance between pathogenic and regulatory T cells and regulates inflammatory cytokine release. MLT can promote the differentiation of type 1 regulatory T cells via extracellular signal regulated kinase 1/2 (Erk1/2) and retinoic acid-related orphan receptor-α (ROR-α) and suppress the differentiation of Th17 cells via the inhibition of ROR-γt and ROR-α expression through NFIL3. Moreover, MLT inhibits NF-κB signaling pathway to reduce TNF-α and IL-1ß expression, promotes Nrf2 gene and protein expression to reduce oxidative and inflammatory states and regulates Bax and Bcl-2 to reduce apoptosis; all of which alleviate the development of autoimmune diseases. Thus, MLT can serve as a potential new therapeutic target, creating opportunities for the treatment of autoimmune diseases. This review aims to highlight recent advances in the role of MLT in several autoimmune diseases with particular focus given to novel signaling pathways involved in Th17 and Tregs as well as cell proliferation and apoptosis.

Association of Melatonin Pathway Gene's Single-Nucleotide Polymorphisms with Systemic Lupus Erythematosus in a Chinese Population.

OBJECTIVES: This study was to investigate the association of melatonin (MTN) pathway gene's single-nucleotide polymorphisms (SNPs) with susceptibility to systemic lupus erythematosus (SLE). METHODS: We recruited 495 SLE patients and 493 healthy controls, 11 tag SNPs in MTN receptor 1a (MTNR1a), MTNR1b, and arylalkylamine N-acetyltransferase (AANAT) genes were genotyped and analyzed. Serum MTN concentration was determined by enzyme-linked immunosorbent assay (ELISA) kits. RESULTS: Two SNPs of AANAT gene (rs8150 and rs3760138) associated with the risk of SLE; CC carriers of rs8150 had a lower risk as compared to GG (OR = 0.537, 95% CI: 0.361, 0.799), whereas GG carrier in rs3760138 had an increased risk (OR = 1.823, 95% CI: 1.154, 2.880) compared to TT. However, we did not find any genetic association between the other nine SNPs with SLE risk. Case-only analysis showed associations of rs2165667 and rs1562444 with arthritis, rs10830962 with malar rash, rs3760138 with immunological abnormality, and rs8150 with hematological abnormality. Furthermore, a significant difference between plasma MTN levels with different genotypes of rs1562444 was observed. Haplotype analyses revealed that haplotype of CCTAT, CTAGT, and GGG was significantly associated with the increased risk in SLE susceptibility, but TCTAT and CTG appeared to be a protective haplotype. CONCLUSIONS: The present study supported the genetic association of MTN pathway genes with SLE susceptibility and specific clinical manifestations, suggesting the potential role of MTN pathway genes in the pathogenesis and development of SLE.