Value of serum YKL-40 in the diagnosis of anti-MDA5-positive patients with dermatomyositis complicated with severe pulmonary injury / 北京大学学报(医学版)

OBJECTIVE@#To investigate the value of serum and bronchoalveolar lavage fluid (BALF) chitinase-3-like-1 protein (YKL-40) in the diagnosis of anti-melanoma differentiation-associated gene 5 (MDA5)-positive dermatomyositis (DM) patients complicated with serious pulmonary injury, including rapidly progressive interstitial lung disease (RP-ILD) and pulmonary infection.@*METHODS@#Anti-MDA5 antibodies positive patients with DM who were hospitalized in the Department of Rheumatology of China-Japan Friendship Hospital from 2013 to 2018 were involved in this study. Demographic information, clinical, laboratory and imaging data were retrospectively collected. ELISA was used to detect the serum and BALF levels of YKL-40. The receiver operating characteristic (ROC) curve was drawn, and the area under ROC curve (AUC) was used to evaluate the diagnostic value of serum YKL-40 for pulmonary injury.Interstitial lung disease (ILD) was confirmed by chest high-resolution CT (HRCT). RP-ILD was defined as progressive respiratory symptoms such as dyspnea and hypoxemia within 3 months, and/or deterioration of interstitial changes or appearace of new pulmonary interstitial lesions on chest HRCT. Pulmonary infection was considered as positive pathogens detected in qualified sputum, blood, bronchoalveolar lavage fluid or lung biopsy specimens.@*RESULTS@#A total of 168 anti-MDA5-positive DM patients including 108 females and 60 males were enrolled in the study. Of these patients, 154 had ILD, and 66(39.3%) of them presented RP-ILD. Seventy patients with pulmonary infection were confirmed by etiology. In the patients with RP-ILD, 39 (59.1%) of them were complicated with pulmonary infection. While only 31 cases(30.4%) had pulmonary infection in the non-RP-ILD patients. The incidence of pulmonary infection in the patients with RP-ILD was significantly higher than that of those with non-RP-ILD (P < 0.001). The serum YKL-40 levels in the RP-ILD patients with pulmonary infection were the highest compared with RP-ILD without pulmonary infection, non-RP-ILD with pulmonary infection and non-RP-ILD without pulmonary infection groups among all the patients [83 (42-142) vs. 42 (21-91) vs. 43 (24-79) vs. 38 (22-69), P < 0.01].The sensitivity, specificity and AUC of serum YKL-40 in the diagnosis of RP-ILD complicated with pulmonary infection were 75%, 67%, and 0.72, respectively. The AUC of diagnosed of anti-MDA5 positive DM patients complicated with RP-ILD and pulmonary infection was higher than that of patients complicated with only RP-ILD and only pulmonary infection (0.72 vs. 0.54 and 0.55, Z=2.10 and 2.11, P < 0.05).@*CONCLUSION@#The prognosis of anti-MDA5-positive DM patients with RP-ILD and pulmonary infection were poor. Serum YKL-40 level can be used as a helpful tool for the diagnosis of coexistence of these conditions in the patients.

Clinical and pathological characteristics of immune mediated necrotizing myopathy / 北京大学学报(医学版)

OBJECTIVE@#To investigate the clinical and pathological features of immune-mediated necrotic myopathies (IMNM) with different myositis-specific antibodies (MSAs).@*METHODS@#In the study, 104 IMNM patients who met any of the following three criteria were selected from idiopathic inflammatory myopathy patients who had MSAs results and underwent muscle biopsy from 2008 to 2018 in China-Japan Friendship Hospital: (1) Anti-signal recognition particle (SRP) antibody positive; (2) Anti-3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGCR) antibody positive; (3) MSAs negative and consistent with the pathological diagnostic criteria of IMNM defined by the European Neuromuscular Centre in 2004. The clinical, laboratory and muscle pathological information of the IMNM patients were retrospectively collected and compared in anti-SRP, anti-HMGCR and MSAs negative groups.@*RESULTS@#Of 104 IMNM patients, 47 patients (45.2%) were positive for anti-SRP antibody, 23 (22.1%) were positive for anti-HMGCR antibody, and 34 (32.7%) were negative for MSAs. The common symptoms of IMNM patients were muscle weakness (92.3%), elevated serum creatine kinase level (92.3%), dysphagia (33.7%) and interstitial lung diseases (ILD) (49.5%). The anti-HMGCR-positive patients were more frequent to have "V" sign (30.4% vs. 4.3% and 5.9%, P<0.01) as compared with the anti-SRP-positive and MSAs-negative patients. The incidence of ILD in the anti-SRP-positive patients was higher than that in the anti-HMGCR-positive and MSAs negative patients (64.4% vs. 34.8% and 29.0%, P<0.01). The prevalence of the patients combined with other connective tissue diseases in MSAs-negative IMNM was higher than that in the other two groups (32.4% vs. 8.5% and 4.3%, P<0.01). 93.3% of the anti-SRP-positive patients were found with antinuclear antibody positivity, higher than those of the anti-HMGCR-positive and MSAs-negative patients (93.3% vs. 36.4% and 58.8%, P<0.001). The common pathological features of IMNM were muscle fibre necrosis (94.2%), regeneration (67.3%) and phagocytosis (65.4%), overexpression of major histocompatibility complex1 on sarcolemma (78.8%), infiltration of CD4+ T cells (81.7%) and CD68+ macrophage (79.8%) and expression of membrane attack complex (MAC) (77.8%). The endomysial infiltration of CD4+ T cells and CD68+ macrophage and MAC expression on sarcolemma in the MSAs-negative group were more common than that in the anti-SRP and anti-HMGCR groups (88.2% vs. 57.4% and 60.9%, 91.2% vs. 59.1% and 38.1%, 76.5% vs. 45.5% and 42.9%, respectively, P<0.01).@*CONCLUSION@#There is heterogeneity in anti-SRP-positive, anti-HMGCR-positive or MSAs-negative patients. The detection of MSAs and performing of muscle biopsy are useful for distinguishing different types of IMNM.

Effects of integrin metalloproteinases on osteogenic differentiation / 北京大学学报(医学版)

OBJECTIVE@#To study the effects of disintegrin and metalloproteinase (ADAM) 9, 15 and 17 on the osteogenic differentiation of bone marrow mesenchymal stem cells (BMMSCs).@*METHODS@#BMMSCs of ADAM9, ADAM15, ADAM17 conditional knockout mice and wild type mice (WT) were induced and cultured. Alkaline phosphatase (ALP) activity was measured by colorimetry, early osteogenic transcription factors Runx and Osterix were detected by Real-time PCR, and mineral formation was analyzed by alizarin red staining.@*RESULTS@#ALP activity was lower in ADAM9 group (8.08±0.34), ADAM15 group (6.46±3.40), ADAM17 group (9.30±2.30) than that in WT group (9.44±2.50), but there was no significant difference (P>0.05). Stimulated with bone morphogenetic protein 2(BMP2),there was significant difference (P<0.05) between ADAM9 group (14.22±3.25), ADAM15 group (10.14±2.40) and WT group (20.89±3.40), and ADAM 17 group (23.56±2.50) was higher than WT group (20.89±3.40), but no significant difference (P>0.05). Similarly, cultured by osteogenic induction medium (OST), compared with WT group (12.97±1.30), ADAM9 group (9.63±1.00) and ADAM15 group (7.75±1.30) were lower, ADAM17 group (20.09±1.68) was higher, and the difference was statistically significant (P<0.05). Using stimulated culture by BMP2 and OST combined, ADAM9 group (15.75±1.30), ADAM 15 group (12.43±1.30) were less than WT group (26.15 ±1.50), while ADAM17 group (29.55±2.10) was higher than WT group were statistically significant (P<0.05). The expression of Runx2 in ADAM9 group (2.02±0.24), ADAM15 group (3.09±0.19), ADAM17 group (3.89±0.91) had no significant difference compared with WT (2.02±0.21) group (P>0.05). ADAM9 group stimulated by BMP2 (7.00±0.23), ADAM15 group (6.04±0.23) were lower than WT group (12.6±0.23), ADAM17 group (18.52±1.39) was higher than WT group (12.6±0.23), and the difference was statistically significant (P<0.05). In non-stimulating culture, there was no significant difference in Osterix expression between ADAM9 group (9.60±3.87), ADAM17 group (12.40±3.00) and WT group (10.9±1.10, P>0.05), but in ADAM15 group (6.50±1.51) it was slightly lower than that in WT group (P<0.05). After BMP2 stimulation, ADAM9 group (39.20±3.23) and ADAM15 group (20.50±4.80) were less than WT group (60.30±5.93), while ADAM17 group (80.20±3.30) was higher than WT group (P<0.05). Alizarin red staining showed no obvious orange-red mass in the non-induction group. Local calcified nodules could be seen in the BMP2, OST, OST + BMP2 induction culture conditions in all the experimental groups, but there was no significant difference in quantitative analysis (P>0.05).@*CONCLUSION@#ADAM9, 15, 17 took part in the osteogenic differentiation of BMMSCs, and provided new targets for its regulation.

Experimental autoimmune myositis in rat / 中华风湿病学杂志

Objective The aim of our study is to establish and characterize the animal model for au- toimmune myositis.Methods Fifty male SD rats were randomly divided into 2 groups:model group(n=40) and control group(n=10).The model group rats were immunized with muscle homogenate every week for 5 weeks and received an injection of 2?g pertussis toxin at the first and second week.As controls,10 SD rats were injected with an equal volume of normal saline.Tissue specimens from limb skeletal muscles were ob- tained at 1,2,3,4,5 weeks after injection.At the same time,the blood samples were collected,and the level of CPK was measured.Results The model group had significantly elevated serum CPK levels.There were multiple inflammatory lesions in the skeletal muscles.Local degeneration and necrosis of muscle fibers with disappeared transverse striation,mononuelear cell infiltration in the interstitial could be observed.The patho- logic grade was mainly 2a.The infiltrating mononuclear cells were predominantly CD8~+T cells that mainly lo- cated in the endnmysium.MHC classⅠantigen expression on muscle fiber membranes in the model group was upregulated.Conclusion The experimental autoimmune myositis induced by syngeneic skeletal muscle ho- mogenate in SD rat is pathologically similar to human myositis.It can be used as a good model for human myositis and provides the basis for the etiopathology and therapeutical studies.

KL-6 as a useful serum marker for interstitial lung disease in patients with idiopathic inflammatory myopathies / 中华风湿病学杂志

Objective To determine the serum level of KL-6 in patients with polymyositis(PM)and dermatomyositis(DM),and to investigate the possible diagnostic value for interstitial lung diseases(ILD)in pa- tients with PM/DM.Methods Serum KL-6 concentrations were measured by ELISA in 53 adult PM/DM pa- tients,the control groups of 22 patients with infectious lung disease,and 50 healthy subjects.The association with clinical features and serum KL-6 levels was analyzed.Results The serum levels of KL-6 were(1543?761)、(429?106)、(336?196)and(289?105)U/ml in PM/DM patients with ILD and without ILD,patients with infectious lung disease and healthy controls,respectively.Serum KL-6 levels in the PM/DM patients with ILD were significantly higher compared with PM/DM patients without ILD,patients with infectious lung disease and healthy controls(all P＜0.01 ).However,no significant differences of serum KL-6 levels was found among PM/ DM patients without ILD,patients with infectious lung disease and healthy controls(P＞0.05).Significant cor- relations were found between the elevated levels of serum KL-6 and the presence of ILD in patients with PM/ DM(P＜0.01).The sensitivity and specificity of serum abnormal KL-6 levels for ILD in patients with PM/DM were 90.9% and 80.6%.Additionally,follow-up study showed the mean serum levels of KL-6 in six patients who died were significantly higher than that in other PM/DM patients with ILD(P＜0.01).Conclusion Serum KL-6 level is a reliable serum marker for ILD in idiopathic inflammatory myopathies,which may contribute to early differentiate ILD from lung infectious disease.Increased serum level of KL-6 may predict a poor out- come.