Objective:To elucidate the pathophysiological mechanisms of idiopathic inflammatory myopathy subtypes by analyzing the gene expression profiles of peripheral blood mononuclear cells (PBMCs) from anti-MDA5 antibody-positive and anti-Jo-1 antibody-positive myositis patients.Methods:Gene expression profiling screening and analysis of PBMCs from 12 anti-MDA5 positive, 16 anti-Jo-1 positive myositis patients and 43 healthy controls were performed using Illumina HT-12 v4 expression profiling microarrays. Applying the unpaired t test with Benjamini-Hochberg correction, the genes with the absolute value of fold change (FC) in gene expression signal ≥2 and adjusted P<0.05 were selected as differentially expressed genes. Differential gene sets were subjected to Gene Ontology (GO) functional enrichment analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis, with P<0.05 as the threshold for being significantly enriched. Validation of differentially expressed genes by real time-PCR. The Kolmogorov-Smirnov test was used to test the normality of continuous variables. If the distribution was normal and the variance was homogeneous, analysis of variance (one-way ANOVA) was used.If the distribution was not normal, Kruskal-Wallis test was used, and P<0.05 was regarded as statistically significant difference. Results:Analysis of gene expression profiles of PBMCs from patients with positive anti-MDA5 and anti-Jo-1 antibody revealed significant differences in gene expression of PBMCs from patients with the two myositis subtypes. The number of differentially expressed genes that specifically up-regulated in anti-MDA5 antibody positive patients was 407, and the GO functional enrichment analysis was mainly enriched in biological processes such as innate immune response ( P<0.001), response to virus ( P<0.001) and type Ⅰ interferon signaling pathway ( P<0.001), and the KEGG pathway enrichment analysis was mainly enriched in the viral infection-associated pathway ( P<0.001), RIG-Ⅰ like receptor signaling pathway ( P<0.001) and Toll-like receptor signaling pathway ( P=0.002), etc. The 259 differential genes specifically down-regulated in the anti-MDA5 antibody positive group were mainly enriched in biological processes such as immune response ( P=0.006), TGF-β receptor signaling pathway ( P=0.010) and natural killer cell mediated immunity ( P=0.015) in GO functional enrichment analysis. There were 162 differentially expressed genes up-regulated specifically in anti-Jo-1 antibody positive patients, and GO functional enrichment analysis was mainly enriched in biological processes such as nucleosome assembly ( P<0.001), negative regulation of cell growth ( P=0.001), negative regulation of apoptotic process P=0.004), and innate immune response in mucosa ( P=0.012), and the KEGG pathway enrichment analysis mainly enriched in metabolic-related signaling pathways ( P<0.001) and immune-related pathways ( P<0.001), etc. Real-time PCR confirmed that IFIH1 ( P=0.037), ISG15 ( P=0.003), and DDX58 ( P=0.032) in the RIG-Ⅰ-like receptor pathway as well as chemokines MCP-1 ( P=0.003), MCP-2 ( P<0.001), and transcription factor BATF2 ( P=0.002), and inflammatory signaling pathway-associated MYD88 ( P<0.001) were highly expressed in PBMCs from anti-MDA5 antibody-positive myositis patients. Conclusion:The gene expression profile of PBMCs in anti-MDA5 antibody-positive patients suggests that the pathogenesis of patients with anti-MDA 5 antibody positive is closely related to biological processes such as innate immune response, viral infection, and interferon response.

Objective:To explore clinical factors of poor prognosis in patients with anti-melanoma differentiation-associated gene 5 andtibody positive dermatomyositis (MDA5-DM).Methods:One hundred and twenty-six enrolled adults with MDA5-DM were divided into the survival group and the deceased group according to the outcomes. Survival time, clinical manifestations, laboratory tests, pulmonary function tests, myositis antibodies and treatments were collected for statistical analysis. Serum concentrations of IL-15, HMGB1, and sCD163 were measured by ELISA in MDA5-DM patients and healthy controls. Mann-Whitney U nonparametric test and Student′s t-test were used to compare the continuous variables between the two groups, and χ2 or Fisher′s exact test were used for comparison of categorical variables. Cox regression analysis was used to assess the survival predictors in MDA5-DM patients. The cumulative survival rate was calculated by Kaplan-Meier curve analysis, and Log-rank tests were used to examine differences in survival curves. P<0.05 was considered statistically significant. Results:Cox multivariate regression analysis revealed that age > 57 years [ HR (95% CI)=3.05 (1.20, 7.80), P=0.020], RP-ILD [ HR (95% CI)=25.07 (5.42, 115.98), P<0.001], and levels of anti-Ro52 antibody [ HR (95% CI)=3.41 (1.36, 8.53), P=0.009] were important prognostic factors independent of multiple clinical parameters. The ELISA test results showed that the levels of serum IL-15[0.91 (0.66, 2.00)pg/ml vs. 0.51(0.39, 0.72)pg/ml, Z=-4.57, P<0.001] and HMGB1 [230.53(90.40, 394.31)ng/ml vs. 32.66 (17.82, 46.21)ng/ml, Z=-6.52, P<0.001] in MDA5-DM patients were significantly higher than those in healthy controls, but there were no significant differences in the level of serum IL-15 [1.21(0.63, 2.12)pg/ml vs. 0.91(0.68, 1.66)pg/ml, Z=-0.30, P=0.766], HMGB1[267.61(167.03, 444.23)ng/ml vs. 228.35(74.74, 344.32)ng/ml, Z=0.82, P=0.413], and sCD163 [112.70(93.45, 148.51)ng/ml vs. 132.72(96.79, 203.18)ng/ml, Z=-0.62, P=0.536] between the survival group and the deceased group. Conclusion:Older age, RP-ILD, and high levels of anti-Ro52 antibody significantly increase the risk of death in MDA5-DM patients. Intensive follow-up of patients with the above factors in the early stages may help to improve the prognosis.

Objective:To analyze the clinical features of MDA5 antibody positive dermatomyositis (MDA5-DM) and to provide evidence for early diagnosis and treatment.Methods:From March 2019 to June 2021, 272 patients with anti-MDA5-DM from the Nanjing Medical University myositis-associated interstitial lung disease cohort were enrolled, with 76 patients with anti-synthetase syndrome (ASS) as the control group. The clinical characteristics and the occurrence of interstitial lung disease were analyzed. T-test was used for normally distributed and variance-homogeneous independent samples, Mann-Whitney U test for non-normally distributed data, and chi-square test or Fisher′s exact test for dichotomous variables. Results:Among the 272 anti-MDA5-DM patients, 88.6% (241/272) developed interstitial lung disease (ILD), and 33.8% (92/272) developed rapidly progressive ILD (RP-ILD). The six-month all-cause mortality rate of anti-MDA5-DM patients was 16.9% (46/272), and it was as high as 47.8% (44/92) for those with RP-ILD. Compared with ASS patients, anti-MDA5-DM patients had a significantly higher proportion of males, arthritis, Gottron's sign, heliotrope rash, V-sign, periungual erythema, and skin ulcers ( P<0.05). The levels of ALT, AST, and ferritin were significantly increased ( P<0.05). Compared with non-RP-ILD patients, RP-ILD patients had a significantly higher proportion of males [35.9%(33/92) vs. 23.3%(42/180), χ2=4.79, P=0.029], higher levels of LDH [387 (276, 547) U/L vs. 310 (245, 400) U/L, Z=-3.67, P<0.001], ESR [45.5 (29.25, 63.25) mm/1 h vs. 31.2 (20, 51) mm/1 h, Z=-3.71, P<0.001], CRP [10.9 (4.1, 25.2) mg/L vs. 4.54 (2.58, 9.08) mg/L, Z=-4.97, P<0.001], ferritin [1 340 (650, 2 000) ng/ml vs. 556 (203, 1 186) ng/ml, Z=-4.40, P<0.001], and a higher proportion of anti-Ro52 antibody and anti-MDA5 antibody co-positivity [87.0%(80/92) vs. 52.2%(94/180), χ2=31.87, P<0.001]. Conclusion:Anti-MDA5-DM patients are prone to develop RP-ILD and have poor prognosis.

Objective:To investigate the clinical characteristics, risk factors, and prognosis of invasive pulmonary aspergillosis (IPA) in patients with dermatomyositis associated with positive anti-melanoma differentiation-associated gene 5 (MDA5-DM).Methods:A total of 55 patients with MDA5-DM were analyzed. Patients were divided into IPA (+) group (14 cases) and IPA (-) group (41 cases) based on the presence of IPA. Microbiological examination and clinical data were analyzed. Risk factor analysis was performed using Binary Logistic regression, and survival analysis was carried out using Kaplan-Meier method.Results:Aspergillus flavus (5/14, 35.7%) and Aspergillus fumigatus (4/14, 28.6%) were the most common species in MDA5-DM patients with IPA. Compared to the IPA (-) group, IPA (+) group had higher serum level of α-hydroxybutyrate dehydrogenase (246 U/L vs. 191 U/L, Z=-2.02, P=0.043) and ferritin [1 306.7(518.7, 2 977.8)ng/ml vs. 472.6(269.0, 792.1)ng/ml, Z=-2.09, P=0.036], lower CD8 + T lymphocyte counts {[111.5 (68.3, 214.0)]×10 6/L vs. [188.0(141.0, 270.0)]×10 6/L, Z=-2.18, P=0.029}, and more positive BALF GM tests [70.0%(7/10) vs. 18.9%(7/37), χ2=9.82, P=0.004]. Elevated serum ferritin was found to be an independent risk factor for IPA occurrence [adjusted OR (95% CI)=1.001 (1.000, 1.002), P=0.031)]. In addition, the 6-month cumulative survival rate was significantly lower in the IPA (+) group than in the IPA (-) group (78.6% vs. 97.6%, P=0.021). Conclusion:The mortality of MDA5-DM patients is increased after IPA infection. Elevated serum ferritin is an independent risk factor for IPA occurrence, and active prevention and treatment of IPA are expected to improve the prognosis of patients.

Objective:To investigate the clinical features and prognosis of male with anti-melanoma differentiation-associated gene 5 (MDA5) autoantibody.Methods:The clinical data of 246 patients with DM and anti-MDA5 autoantibodies hospitalized by Jiangsu Myositis Cooperation Group from 2017 to 2020 were collected and retrospectively analyzed. Chi-square test was performed to compared between counting data groups; Quantitative data were expressed by M ( Q1, Q3), and rank sum test was used for comparison between groups; Single factor survival analysis was performed by Kaplan-Meier method and Log rank test; Cox regression analysis were used for multivariate survival analysis. Results:①The male group had a higher proportion of rash at the sun exposure area [67.1%(47/70) vs 52.8%(93/176), χ2=4.18, P=0.041] and V-sign [50.0%(35/70) vs 30.7%(54/176), χ2=8.09, P=0.004] than the female group. The male group had higher levels of creatine kinase [112(18, 981)U/L vs 57 (13.6, 1 433)U/L, Z=-3.50, P<0.001] and ferritin [1 500 (166, 32 716)ng/ml vs 569 (18, 14 839)ng/ml, Z=-5.85, P<0.001] than the female group. The proportion of ILD [40.0%(28/70) vs 59.7%(105/176), χ2=7.82, P=0.020] patients and the red blood cell sedimentation rate[31.0(4.0, 101.5)mm/1 h vs 43.4(5.0, 126.5)mm/1 h, Z=-2.22, P=0.026] in the male group was lower than that of the female group, but the proportion of rapidly progressive interstitial lung disease (PR-ILD) [47.1%(33/70) vs 31.3%(55/176), χ2=5.51, P=0.019] was higher than that of the female group. ②In male patients with positive anti-MDA5 antibodies,the death group had a shorter course of disease[1.0(1.0, 3.0) month vs 2.5(0.5,84) month, Z=-3.07, P=0.002], the incidence of arthritis [16.7%(4/24) vs 42.2%(19/45), χ2=4.60, P=0.032] were low than those in survival group,while aspartate aminotransferase (AST)[64(22.1, 565)U/L vs 51(14,601)U/L, Z=-2.42, P=0.016], lactate dehydrogenase (LDH) [485(24,1 464)U/L vs 352(170, 1 213)U/L, Z=-3.38, P=0.001], C-reactive protein (CRP) [11.6(2.9, 61.7) mg/L vs 4.95(0.6, 86.4) mg/L, Z=-1.96, P=0.050], and ferritin levels [2 000(681, 7 676) vs 1 125 (166, 32 716)ng/ml, Z=-3.18, P=0.001] were higher than those in the survival group, and RP-ILD [95.8%(23/24) vs 22.2%(10/45), χ2=33.99, P<0.001] occurred at a significantly higher rate. ③Cox regression analysis indicated that the course of disease LDH level, and RP-ILD were related factors for the prognosis of male anti-MDA5 antibodies [ HR (95% CI)=0.203(0.077, 0.534), P=0.001; HR (95% CI)=1.002(1.001, 1.004), P=0.003; HR (95% CI)=95.674 (10.872, 841.904), P<0.001]. Conclusion:The clinical manifestations of male anti-MDA5 antibody-positive patients are different from those of female. The incidence of ILD is low, but the proportion of PR-ILD is high. The course of disease, serum LDH level, and RP-ILD are prognostic factors of male anti-MDA5 antibody-positive patients.

Objective:To test the hypothesis that Pertussis toxin (PTX) can promote the occurrence of interstitial lung disease (ILD) in experimental autoimmune myositis (EAM) model and clarify the potential pathogenic mechanism.Methods:EAM mice model were induced by Skeletal muscle thomogenate with or without PTX, and the relationship between ILD phenotypes and neutrophil extracellular traps (NETs) infiltration was analyzed by histopathological and serological studies in EAM with PTX group and EAM without PTX group. Healthy mice were given PTX alone intraperitoneally to clarify whether NETs formation could be induced in vivo, and neutrophils separated from healthy human blood were intervened with PTX to induce NETs formation in vitro. The data was tested for normality using Shapiro-Wilk. Statistical methods and were analyzed using t-test or ANOVA, and multiple comparisons between different groups were tested using Tukey test. Results:Compared with EAM without PTX group, lung tissues in EAM with PTX group had multiple pathological changes similar to polymyositis/dermatomyositis-related ILD. Nonspecific interstitial pneumonia and usual interstitial pneumonia were the main pathological types. The pulmonary interstitial lesions were accompanied by significant infiltration of NETs; and serum NETs markers levels were obviously elevated in EAM with PTX group, compared with the control group [ n=5, (87±10) ng/ml], cfDNA levels were statistically significantly elevated in both the EAM without PTX group [ n=4, (115±27) ng/ml] and the EAM with PTX group [ n=7, (150±50) ng/ml] ( F=4.24, P=0.038); Cit-H3-DNA levels were elevated in the EAM without PTX group ( n=4, 0.24±0.09), and in the EAM EAM with PTX group ( n=6, 0.33±0.11) compared with the control group ( n=4, 0.13±0.02) ( F=6.21, P=0.016). After PTX intervention, serum cfDNA levels were higher in the PTX group [ n=3, (100±40) ng/ml] than in the control group [ n=3, (45±12) ng/ml, t=2.27, P=0.086]; PTX also induced neutrophils to form NETs in vitro. Conclusion:PTX may promote the development of ILD in EAM mice model by inducing the formation of NETs, indicating that EAM mice can serve as a model for targeting NETs to study the pathogenesis ILD.

Objective:To analyze the differentially expressed genes in PBMCs of patients with systemic lupus erythematosus (SLE) by bioinformatics methods screening and analyzing the key genes related to ferroptosis, and explore the possible mechanism of ferroptosis involved in the pathogenesis of SLE at the transcription level.Methods:The data sets and samples of healthy people (HC) and SLE patients who met the screening criteria were retrieved from the Gene Expression Omnibus (GEO), a sub-database of the National Center for Biotechnology Information (NCBI). The differentially expressed genes, GO enrichment analysis and KEGG pathway enrichment analysis were analyzed by GEO2R, R language and related software packages. The protein interaction network (PPI) of differential genes was analyzed by STRING, Cytoscape and other tools to explore the key genes and pathways. In addition, real-time quantitative reverse transcription PCR (RT-qPCR) was used to verify the expression of key genes. Mann-Whitney U test was used to compare the expression of key genes in PBMCs between the two groups. Spearman rank correlation analysis was used to explore the relationship between SLE disease activity and the level of key genes. Results:Six data sets were included in this study. A total of 166 genes related to ferroptosis were differentially expressed between SLE and HC groups. The differential genes were specifically expressed in alveolar macrophages, neutrophils, CD49 + cells and CD31 + cells. GO enrichment analysis and KEGG pathway enrichment analysis showed that the differentially expressed genes were mainly involved in multiple signaling pathways closely related to SLE, such as oxidative stress response, infection and TNF signaling pathway. Hub genes screened by different algorithms all suggested RELA as a key gene, and RT-qPCR confirmed that compared with the RELA gene expression level in the HC group [0.75(0.37,1.13)], the expression level in SLE group [2.02 (1.19,4.06)] was increased, the difference was statistically significant ( Z=-3.08, P=0.002), and was positively correlated with the corresponding SLEDAI score of SLE samples ( r=0.52, P=0.019). Conclusion:The ferroptosis of many immune cells, including alveolar macrophages and CD49 + NK cells, is involved in the pathogenesis of SLE. RELA may be involved in the ferroptosis of PBMCs in SLE through the NF-κB pathway.

Objective:To summarize the clinical characteristics and factors that may affect the flare of patients with systemic lupus erythematosus (SLE).Methods:A total of 300 patients with SLE who were treated with standard treatment in the outpatient clinic of the department of rheumatology and immunology of the Second Affiliated Hospital of Air Force Military Medical University of PLA, were enrolled, and the patients were divided into 24 patients in the complete response group, 40 cases in the no response group, 192 cases in the treatment response group, and 44 cases in the low disease activity group according to the response to treatment. The differences in clinical characteristics and survival rates between the groups were compared and analyzed. Comparisons of count data were made using analysis of variance (ANOVA), comparisons of measurement data were made using the chi-square test or the Fisher′s ecact test, and survival rates were expressed as Kaplan-Meier curves. Cox regression analysis was adapted to explore risk factors for flare in these patients.Results:A total of 300 patients were followed. With a median follow-up time of 18 (1, 36) months, a total of 42 patients experienced flare. The clinical characteristics of the four groups were compared, and there were significant differences in age ( F=4.39, P=0.005), the presence of lupus nephritis ( χ2=12.66, P=0.005), hemoglobin level ( F=2.73, P=0.044), NLR level( F=3.88, P=0.010), cystatin C level( F=3.11, P=0.027), anti-RNP antibody ( χ2=12.04, P=0.007), anti-Sm antibody ( χ2=8.33, P=0.040), anti-SSB antibody ( P=0.014), anti-nucleosome antibody ( P=0.014), and anti-ribosomal P protein antibody ( χ2=11.83, P=0.008). There was no significant difference in survival between the four groups. Cox analysis showed that the combination of other autoimmune diseases [ HR(95%CI)=3.23(1.58, 6.57), P=0.001], anti-Sm antibody [ HR(95%CI)=2.15(1.04, 4.43), P=0.038], and anti-RNP antibody [ HR(95%CI)=2.54(1.13, 5.68), P=0.023] were risk factors for flare in patients with SLE who could reach the treatment target. Conclusion:Patients with SLE with different treatment responses have different clinical features, and all treatment can significantly improve the recurrence rate no matter what level of response to treatment. Patients concurrent with other autoimmune diseases, positive anti-Sm antibodies, and positive anti-RNP antibodies are at highrisk of flare.

Objective:To investigate the effect of tofacitinib on early atherosclerosis of patients with systemic lupus erythematosus and explore the possible relationship between lupus nephritis and early atherosclerosis of systemic lupus erythematosus.Methods:Sixteen 8-week-old female MRL/lpr mice with a body weight of 20~25 g were selected and randomly divided into the treatment group and placebo group, with 8 mice in each group. The treatment group diluted tofacitinib by normal saline, and given at a dose of 10 mg·kg -1·d -1, and the placebo group (starch tablets) administered the medication in the same way as the treatment group for a total of 8 weeks. The ELISA method was applied to detect serum anti-dsDNA antibody levels in the two groups of mice. Bradford method protein concentration was used to determine the level of urine protein in mice. Automatic biochemical analyzer was used to detect blood lipids, urea nitrogen, serum creatinine, complement C3, complement C4 levels. Western blotting was used to determine the protein expression levels of monocyte chemoattractant protein-1 (MCP-1), non-receptor protein tyrosine kinase family 1 (JAK1), signal transducer and activator of transcription 1 (STAT1) and signal transducer and activator of transcription 2 (STAT2) in aortic and kidney tissues. After the aortic arch section were prepared, oil red O was used to stain the sections, and the vascular plaque area and intimal thickness were evaluated by ImageJ software. The kidneys were dissected and stained with HE, and the active lesions of lupus nephritis were evaluated using the glomerular activity scoring system. SPSS 23.0 software was used for statistical analysis, in which the between-group comparison was performed using two independent samples t-test, and the correlation analysis was performed using the Spearman method. Results:①The serum anti-dsDNA antibody expression level in the treatment group [(5.2±1.0) U/ml] was lower than that in the placebo group [(6.9±1.2) U/ml], ( Z=-3.07, P=0.008), and the levels of complement C3 and complement C4 were higher than those in the placebo group [(293±10) mg/L vs. (260±19) mg/L, Z=2.72, P=0.017]; (16±6) mg/L vs. (8±9) mg/L, Z=3.78, P=0.006]. There was no significant difference in serum BUN and Scr between the treatment group and the placebo group [(10.6±0.7) mmol/L vs. (11.5±1.1) mmol/L, Z=-1.96, P=0.071; (17±5) μmol/L vs. (22±6) μmol/L, Z=-1.79, P=0.095]. ② Compared with the placebo group, the levels of LDL, TC and TG in the treatment group decreased [(0.83±0.15) mmol/L vs. (1.08±1.05) mmol/L, Z=-3.95, P=0.001; (2.90±0.08) mmol/L vs. (1.81±0.97) mmol/L, Z=-5.17, P=0.001; (1.10±0.08) mmol/L vs. (1.60±0.42) mmol/L, Z=-3.23, P=0.013], and HDL level increased [(2.02±0.99) mmol/L vs. (1.81±0.97) mmol/L, Z=4.42, P=0.001]. ③ Compared with the placebo group, the levels of aortic MCP-1, JAK1, STAT1 and STAT2 in the treatment group were reduced [(0.17±0.30) vs. (0.23±0.05), Z=-3.06, P=0.009; (0.83±0.09) vs. (1.05±0.19), Z=-3.07, P=0.008; (0.77±0.07) vs. (0.94±0.13), Z=-2.83, P=0.014; (0.70±0.07) vs. (0.82±0.09), Z=-2.83, P=0.013], the aortic plaque area and aortic intimal thickness were lower than those in the placebo group [(12±31) μm 2vs. (1 242±1 101) μm 2, Z=-3.12, P=0.016; (63±7) μm vs. (82.10±8.06) μm, Z=-5.13, P<0.001]. ④ Compared with the placebo group, the urine protein level and glomerulonephritis activity score in the treatment group were decreased [(0.08±0.03) mg/mL vs. (0.20±0.11) mg/mL, Z=-3.08, P=0.015; (1.79±0.38) vs. (2.79±0.14) points, Z=-7.08, P<0.001)], and renal tissue MCP-1, JAK1, STAT1.Compared with the placebo group, STAT2 levels were reduced [(0.364±0.040) vs. (0.425±0.021), Z=-3.85, P=0.003; (0.689±0.074) vs. (0.838±0.068), Z=-4.19, P=0.001; (0.508±0.070) vs. (0.646±0.019), Z=-2.85, P=0.015; (0.618±0.062) vs. (0.740±0.101), Z=-2.94, P=0.013. ⑤ The glomerular mobility scores of the two groups were positively correlated with LDL, TCHO, TG, aortic plaque area and aortic intimal thickness ( r=0.51, P=0.043; r=0.79, P<0.001; r=0.64, P=0.008; r=0.82, P<0.001; r=0.74, P=0.001), and negatively correlated with HDL ( r=-0.53, P=0.036). The urine protein levels in the two groups were positively correlated with LDL, TC, TG, aortic plaque area and aortic intimal thickness ( r=0.67, P=0.004; r=0.68, P=0.004; r=0.53, P=0.033; r=0.80, P<0.001; r=0.74, P=0.001), and negatively correlated with HDL ( r=-0.57, P=0.021). Conclusion:The severity of lupus nephritis is correlated with atherosclerosis and dyslipidemia in the early stage of systemic lupus erythematosus. Tofacitinib may reduce the degree of early arteriosclerosis and lupus nephritis in MRL/LPR mice, and reduce blood lipid levels, which may be effective in improving the prognosis of SLE and improving the survival rate of patients.

Objective:To analyze the bone turnover markers in systemic lupus erythematosus (SLE) patients with different disease activity and the risk factors of osteoporosis.Methods:In this retrospective study, a total of 417 SLE inpatients were enrolled from the Department of Rheumatology and Immunology, the First Affiliated Hospital of Xi′an Jiaotong University, from March 2019 to June 2020. According to SLEDAI score, the patients were divided into 3 groups: 281 patients disease with inactive disease group; 99 patients with mild active disease group; and 37 patients with moderate/severe active disease. ANOVA test was used to compare the differences in serum bone turnover markers (PTH, NOST, VITDT, β-crossl, TP1NP, Ca and P) and bone density (Spine L 1~4 and left femur) among the three groups, and Tukey's method was used for the two groups comparison. Logistic regression analysis was used to investigate the risk factors of osteoporosis. Results:Serum VITDT, β-crossl and Ca levels were significantly different among the 3 groups ( F=11.66, P<0.001; F=7.22, P<0.001; F=29.38, P<0.001). Compared with patients in the inactive group, patients with both the mild disease group (VITDT: t=3.94, P<0.001; Ca: t=5.10, P<0.001) and the moderate/severe disease group (VITDT: t=3.33, P<0.001; Ca: t=7.19, P<0.001) had lower VITDT levels [(20.3±9.7) ng/ml vs. (15.9±9.3) ng/ml vs. (14.8±7.4) ng/ml] and serum Ca levels [(2.19±0.15)mmol/L vs. (2.09±0.21)mmol/L vs. (2.00±0.16)mmol/L]. Moreover, the moderate/severe disease group patients had much lower serum Ca levels ( t=2.36, P<0.05), compared with patients with the mild disease group. Compared with the patients with inactive group, both the mild activey group ( t=3.06, P<0.01) and the moderate/severe activie group ( t=2.99, P<0.01) patients had higher serum β-crossl levels [(419±316) pg/ml vs. (543±424) pg/ml vs. (586±343) pg/ml]. Compared with patients with the inactive disease group both patienes with the mild active group and the moderate/severe disease group patients had significantly decreased spine BMD ( t=2.75, P<0.01; t=2.71, P<0.01), Z-score ( t=5.65, P<0.001; t=4.70, P<0.001), T-score ( t=3.02, P<0.01; t=3.37, P<0.001), whereas, no difference was found between the mild disease group and moderate/severe disease group. Compared with the inactive group patients, both the mild active group and moderate/severe disease group patients had lower left femur BMD levels ( t=2.83, P<0.001; t=2.65, P<0.001) and T-score ( t=2.24, P<0.05; t=1.977, P<0.05) and no difference was found between the mild disease group and the moderate/severe disease group. Logistic regression analysis showed that age [ HR (95% CI)=1.080 (1.052, 1.109), P<0.001], BMI [ HR (95% CI)=0.801 (0.704, 0.911), P<0.001], SLEDAI score [ HR (95% CI)=1.047 (1.025, 1.076), P<0.05] and cumulative glucocorticoids dose [1.046 (1.006, 1.087), P<0.05] were associated with osteoporosis of SLE patients. Conclusion:Abnormal bone metabolism and decreased bone density are associated with SLE disease activity in SLE patients, especially in those with advanced age, low BMI and receiving high cumulative dose of glucocorticoids. Osteoporosis should be proactively prevented in the SLE patients.