Long-term outcomes and necessity of early intervention for IgG4-related disease.

IgG4-related disease is thought to show good prognosis because of positive responsiveness to corticosteroids. Increased long-term observations of IgG4-related disease have provided clinical data regarding the functional prognosis of organs. We analyzed the necessity for early intervention based on those findings and our own experience. It is important for the recovery and maintenance of salivary gland function to start corticosteroid treatment within 2 years after onset, and to maintain clinical remission in cases of IgG4-related dacryoadenitis and sialoadenitis (so-called Mikulicz's disease). Early intervention might be useful in cases of IgG4-related kidney disease because recovery of renal function is insufficient when estimated glomerular filtration before treatment is <60 ml/min. Corticosteroid treatment significantly suppresses relapse in patients with autoimmune pancreatitis showing a relatively high rate of spontaneous remission. Long-term observational studies have demonstrated the transformation of autoimmune pancreatitis into chronic pancreatitis presenting with pancreatic atrophy and stone formation. The treatment protocol and timing of initiation should thus be considered. Although organ dysfunction in IgG4-related disease proceeds more slowly than in conventional chronic inflammatory disorders, sustained IgG4-related lesions still cause accumulation of organ damage with expansion of fibrosis. Intervention as soon as possible would favorably impact IgG4-related disease, considering the side effects of treatments such as corticosteroids.