Clinical analysis and literature review of juvenile idiopathic inflammatory myopathy with positive anti-NXP2 antibody / 中华风湿病学杂志

ABSTRACT

Objective:To investigate the clinical characteristics, muscle pathological features and treatment in patients with Juvenile idiopathic inflammatory myopathy (JIIM) with positive anti-nuclear matrix protein 2 (NXP2) antibody.Methods:The clinical data of 8 IMM patients with positive anti-NXP2 antibody were collected and the clinical manifestations, auxiliary examinations, muscle pathological changes and therapeutic effects were retrospectively analyzed.Results:The ratio of male to female was 1:3. The median age of disease onset was (6.1±3.8) years. Eight cases had proximal muscle weakness, 7 had dermatomyositis-like rash, 5 had myalgia,4 had calcinosis,3 had skin ulcer, 2 had edema and 1 had abdominal pain. Five cases had elevated serum creatine kinase. Eight cases with lower limb muscle MRI showed abnormal signals in muscle, space between muscles and fat tissue, 3 cases with chest high-resolution CT (HRCT) showed interstitial lung disease. Abdominal CT of 1 case showed irregular thickening, edema and peripheral inflammatory exudation in ascending colon and proximal transverse colon. Pathological biopsy of skeletal muscle showed perifascicular atrophy, inflammatory cell infiltration in fascicular membrane and around small vessels and muscle fiber space. Edema, hyperplasia could be seen in interstitium; but dissolved necrosis, and regenerated muscle fibers were rarely seen. Treatments included glucocorticoids, immunosuppressive agents and biological agents (1 case). After 6 months of follow-up, 5 cases had good outcomes and 3 cases had poor outcomes.Conclusion:Dermatomyositis is the major clinical manifestation of idiopathic inflammatory myopathy with positive anti-NXP2 antibody.It is associated with myasthenia, calcinosis, skin ulcers and intestinal vasculitis. The pathological changes in skeletal muscle are relatively slightmild. Glucocorticoids combined with immunosuppressive agents are effective in most cases.