Would you intensify therapy in IgG4 related disease based solely on a persistently significantly elevated IgG4 level when all disease manifestations and inflammatory markers have normalized?  

While a perfect biomarker does not exist in IgG4-related disease (IgG4-RD), patients who have elevated serum IgG4 concentrations at baseline typically demonstrate a significant reduction of IgG4 concentrations after treatment and with improved disease activity. In patients treated with rituximab, on...