Effect of abatacept added to mycophenolate mofetil for refractory calcinosis in juvenile dermatomyositis

Calcinosis is an intractable condition in juvenile dermatomyositis (JDM). The effect of abatacept on calcinosis remains controversial. We describe a case of an 8-year-old boy in whom the addition of abatacept to mycophenolate mofetil was effective against calcinosis in JDM. The patient with antinuclear matrix protein 2 autoantibody suffered from refractory jJDM despite long-term treatment with corticosteroids and various immunosuppressive agents. Subcutaneous calcinosis with repeated spontaneous pain at the calcinosis site emerged 2 years after the start of treatment and gradually increased despite clinical improvement in muscle symptoms. The addition of intravenous abatacept to mycophenolate mofetil at the age of 6 years halted the increase in calcinosis. Spontaneous pain in calcinosis disappeared within 2 months. The calcinosis had significantly decreased by 1 year. An important strategy on calcinosis in JDM is getting complete control of the inflammation. Our case report suggests that abatacept may contribute to the improvement of calcinosis in JDM, at least as part of combination therapy with mycophenolate mofetil.