Effectiveness of tacrolimus on IgG4-related disease

IgG4-related disease (IgG4-RD) is an immune-mediated systemic disease characterized by the development of mass lesions in or the enlargement of multiple organs. Whereas the optimum treatment has not been established yet, moderate to high dose of glucocorticoids is recommended as an initial treatment, and the response of the disease to glucocorticoids is generally good 1. After remission induction, glucocorticoids can be tapered gradually, even stopped in some cases, however, 15–33% of patients have been reported to relapse along with glucocorticoids dose reduction 2–4. Various immunosuppressive agents have been tried in such refractory cases; azathioprine has been the most frequently reported drug, followed by mycofenolate mofetil, methotrexate, calcineurin inhibitors, and cyclophosphamide 5. Even the use of biological agents such as rituximab and abatacept has been reported 6,7. However, the selection of a steroid-sparing agent is still challenging because of the lack of evidence on the efficacy of those drugs. Here, we report the effectiveness of tacrolimus, a calcineurin inhibitor, in patients with IgG4-RD.