| Research Background:Dermatomyositis(DM)is characterized by erythematous edema,accompanied by muscle inflammation and degeneration,which mainly affects the skin and blood vessels.Dermatomyositis includes classic dermatomyositis and non-myopatic dermatomyositis.Interstitial lung disease is the most serious complication of dermatomyositis and the main cause of death.Dermatomyositis with interstitial lung disease is usually difficult to treat,progresses rapidly,and the mortality rate is 45%-60%.One of the most dangerous conditions is rapid progressive interstitial pneumonia,that is,progressive dyspnea and hypoxemia occur within 1 month after the onset of respiratory symptoms,and the 3-month survival rate is 52.4%.The 6-month survival rate of Chinese patients with dermatomyositis combined with rapidly progressing interstitial lung disease is only 40.8%.Myositis antibody profile is an important method for the diagnosis of inflammatory myopathy.Myositis specific antibodies(MSAs,myositis specific antibodies)refer to a class of antibodies that are specifically related to inflammatory diseases,and myositis-associated antibodies(MAAs,myositis-associated antibodies)refer to a class of antibodies that have certain inflammatory diseases.Correlations and are prevalent in other connective tissue diseases.Myositis antibody profiles are very important diagnostic and prognostic markers for inflammatory myopathy,and they are closely related to the clinical manifestations of the disease.It is widely used in the diagnosis and treatment of inflammatory myopathy.Anti-MDA-5(melanoma differentiation-associated gene 5)antibody is a type of myositis-specific antibody,mainly found in patients with dermatomyositis,about 19-35%.Anti-MDA-5 antibodies are widely recognized as specific antibodies for dermatomyositis with interstitial lung disease.Anti-MDA 5antibody-positive patients are often associated with rapid progression of highly invasive interstitial lung disease,which causes severe lung tissue destruction and progresses to fatal respiratory failure.For patients with MDA-5 antibody-positive dermatomyositis,interstitial lung disease progresses rapidly and is unsensitive to all kinds of treatment,often requiring large doses of corticosteroids combined with multiple immunosuppressive therapies.Objective:1.To summarize the clinical characteristics and clinical regimen efficacy of anti-MDA-5antibody-positive patients in order to achieve effectively diagnosis of anti-MDA-5antibody-positive dermatomyositis and to get better treatment of anti-MDA-5antibody-positive patients;2.To explore the clinical significance of anti-MDA-5 antibody.To investigate the relationship between the antibody level and disease activity,whether it is related to the occurrence of interstitial pneumonia,and the prognosis.Research methods:Collect and record the medical records of dermatomyositis patients who were hospitalized in the dermatology department of the First Affiliated Hospital of China Medical University from September 2017 to December 2019,and include the patients with anti-MDA-5 antibody-positive dermatomyositis.Serum samples were collected from patients before and 4 weeks after treatment.Serum anti-MDA-5 antibody levels were measured by ELISA.Patients were followed up and the risk factors affecting survival were analyzed using statistical methods.Results: 10 patients with anti-MDA5 antibody-positive dermatomyositis were collected.The first occurred symptoms were all skin damage(10/10,100%),and the muscle damage was grade 5-6.After finishing HRCT,all patients developed interstitial lung disease,of which 8 cases were rapid-progress interstitial lung disease.Of the 10 patients,all were treated with glucocorticoids(10/10,100%),and 4 of them were treated with methylprednisolone pulse treatment(4/10,40%).Four patients were complicated by pulmonary infection during hospitalization(4/10,40%).The 6-month survival rate of anti-MDA-5 antibody positive patients was 60%,and the 12-month survival rate was30%.After data analysis,it was found that serum ferritin and peripheral circulating CD4 T lymphocyte count are important factors affecting survival rate.Patients with anti-MDA-5 antibody-positive dermatomyositis had hyperserum ferritinemia(10/10,100%)on admission.As the treatment progresses,the patient's serum ferritin concentration gradually decreases.There was a statistically significant difference between whether the serum ferritin concentration at admission was greater than 400 ug / L and the 6-month survival rate(chi-square test,P = 0.035).MDA-5 antibody-positive patients also had CD4 T-lymphopenia(10/10,100%)on admission.There was a statistically significant difference between whether the difference in CD4 T cell counts on day 1 and day 29 of admission was greater than 200 cells / u L and 12-month survival rate(chi-square test,P = 0.011).Serum anti-MDA-5 antibody level is an important indicator to indicate the progress and prognosis of interstitial pneumonia.Before and after treatment,the level of anti-MDA5 antibody was significantly reduced(Manne Whitney U test,P = 0.011).Whether the level of anti-MDA-5 antibody was greater than 50 U / m L on the first day of admission and there was a significant statistical difference between the incidence of RP-ILD(chi-square test,P = 0.02);and a statistically significant difference with the 12-month survival rate(chi-square test,P = 0.016).Whether the serum anti-MDA-5 antibody level on day 29 was less than 45 U / m L and the6-month survival rate was significantly statistically different(chi-square test,P = 0.010);and the 12-month survival rate was statistically significant(chi-square test,P = 0.038).According to the survival situation at 6 months after the onset,the patients were divided into survival group and death group.In the survival group,anti-MDA5 antibody levels were significantly reduced before and after treatment(Wilcoxon signed rank test,P =0.028).In the death group,there was no statistical difference in anti-MDA5 antibody levels before and after treatment(Wilcoxon signed rank test,P = 0.068).Conclusion:1.Of those anti-MDA-5 antibody-positive dermatomyositis patients,most patients do not have muscle damage or have minor muscle damage.2.All patients developed interstitial pneumonia,and most of them developed rapidly progressing interstitial pneumonia.3.Serum ferritin and peripheral circulating CD4 T lymphocyte counts are important indicators for judging treatment effects and assessing prognosis.The 6-month survival rate was lower in patients with serum ferritin concentrations greater than 400 ug / L before treatment.The higher the serum ferritin level at admission,the worse the prognosis.Patients with a difference in CD4 T cell count greater than 200 cells / u L before treatment and 4 weeks after treatment had higher 12-month survival rates.4.Serum anti-MDA-5 antibody level is an important indicator of the progression and prognosis of interstitial pneumonia.Before and after treatment,patients' anti-MDA5 antibody levels were significantly reduced.Patients with anti-MDA5 antibody levels greater than 50 U / ml before treatment are more likely to progress to RP-ILD,with a12-month mortality rate that is a sign of poor prognosis.After 4 weeks of treatment,there is a close relationship between whether the patient's antibody level drops to 45 U / ml and the patient's prognosis.The lower the antibody level after treatment,the better the prognosis. |
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