Analysis Of Clinical,Pathology,Muscle MRI,and Specific Autoantibodies Of Dermatomyositis

Objective:To analyze and summarize the clinical,pathology,muscle MRI and specific autoantibodies characteristics of dermatomyositis,so as to provide reference for the clinical diagnosis and treatment of DM.Methods:Retrospective analysis of clinical data,skeletal muscle pathological changes,imaging manifestations,and DSAs types of 21 patients with DM who were treated in the Department of Neurology of Renmin Hospital of Henan University from 2017 to 2019.From the perspective of DSAs,the clinical,pathological and imaging manifestations of 21 DM patients with different types of antibody groups were analyzed and summarized,including 4 anti-Mi-2 antibody positive,2 anti-TIF1 γ antibody positive,4 anti-NXP2 antibody positive,6 anti-MDA5 antibody positive,3 anti-Jo-1 antibody positive and 2 antibody negative.Results:1 General clinical dateThe sexual prevalence was 1:2.antibody negative:2 females;anti-Mi-2 antibody positive:3 females and 1 males;anti-MDA5 antibody positive:5 females and 1 males;Their onset age were from 4 to 68 years old,mean age:45.6 years old;The average age of 2 DM patients with cancer was 64.5 years old.Their course of disease was from 2/3 months to 48 months.Limb weakness accounted for 62%(13 / 21),rash for 14%(3 / 21),fever and cough for 10%(2 / 21);The group of anti-Mi-2 antibody positive started with limb weakness(100%),2 cases of anti-TIF1γantibody positive group all developed rash(100%),and 2 cases of anti-MDA5 antibody positive group developed fever and cough(33%).Weak limbs and cervical flexor muscles accounted for 90%(19/21);muscle pain accounted for 48%(10/21);throat muscle involvement accounted for 43%(9/21),of which 3 patients with anti-NXP2 antibody positive group had this symptom(75%);respiratory muscle involvement accounted for 19%(4 / 21),of which 3 patients with anti-MDA5 antibody positive group had this symptom(50%);Edema accounted for 48%(10/21).DM with Raynaud phenomenon:anti-Jo-1 antibody positive group(33%);anti-MDA5 antibody positive group(33%);anti-Mi-2 antibody positive group(25%).DM with fever:anti-MDA5 antibody positive group(50%);anti-Jo-1 antibody positive group(33%)DM with arthritis:anti-Jo-1 antibody positive group(33%);anti-MDA5 antibody positive group(17%).DM with characteristic rash accounted for 76%(16/21),of which Gottron sign was the most common,the incidence was 62%(13/21),heliotrope rash accounted for 38%(8/21),cheek rash accounted for 33%(7/21).The group of anti-TIF1γ antibody positive had heliotrope rash and Gottron sign(100%).The group of anti-JO-1 antibody positive had Gottron sign(100%).V sign(29%)was significantly higher than shawl sign(10%).DM with tumors accounted for 10%(2/21).One male with anti-TIF1γ antibody positive,had lung cancer with extensive skin damage.His hands had severe skin lesions showing red and white plaques;the other one with antibodies negative,the skin of the knee joint was difficult to heal,diagnosis of Non Hodgkin’s lymphoma by skin biopsy and bone puncture.DM with interstitial lung disease accounted for 38%(8/21),anti-Jo-1 antibody positive group 67%(2/3),anti-MDA5 antibody positive group 67%(4/6),anti-Mi-2 antibody positive group 25%(1/4).There was no in The group of anti-TIF1γ、NXP2 antibody positive and antibody negative.2 Lower limb MRIThis retrospective analysis included 19 MRI scans,and one patient only did thighs MRI scans.The short time reversal recovery(STIR)sequence of MRI in both legs of all patients indicated different degrees of patchy edema.Lower limb muscle edema accounted for 100%(19/19),and 79%(15 / 19)of the patients had symmetrical muscle group involvement.Subcutaneous fat edema accounted for 53%(10/19);fascia edema accounted for 95%(18/19);In 4 cases of anti Mi-2 positive group,the anterior group,sartorius and gracilis of thigh muscle,the tibialis anterior and tibialis posterior of calf muscle were almost all involved,but the gastrocnemius medial head and gastrocnemius lateral head was not involved.In 3 cases of anti-NXP2 positive group,the thigh muscle(anterior group,medial group,posterior group)were involved,the calf muscle(anterior group,intermediate group)were involved except posterior group.3 Pathology of skeletal muscleTwenty patients with DM received skeletal muscle biopsy staining.Perifacial muscle fiber atrophy accounted for 60%(12/20);myofascial or endomysitis cell infiltration accounted for 65%(13/20);muscle fiber necrosis accounted for 60%(12/20);muscle fiber degeneration accounted for 90%(18/20).4 Detection of myositis antibodyTwenty-one cases were tested for myositis antibodies.Myositis-specific autoantibodies were positive in 90%(19/21)patients,anti-Mi-2 antibodies positive accounted for 19%(4/21),anti-TIF1γantibody positive accounted for 10%(2/21),anti-NXP2 antibody positive accounted for 19%(4/21),anti-MDA5 antibody positive accounted for 29%(6/21),anti-Jo-1 antibody positive accounted for 14%(3/21).Conclusion:DSAs has a significant correlation with different clinical phenotypes,muscle MRI involvement patterns,and skeletal muscle pathology.The detection of MSAs in clinic is of great significance in the diagnosis,classification and follow-up of dermatomyositis.Anti-MDA5 antibody and anti-Jo-1 antibody-positive patients need to undergo high-resolution CT examination of the chest to exclude the presence of interstitial lung.Patients with dermatomyositis should be screened for tumor in the early stage,especially those with cancer-releted dermatomyositis specific antibody.