An International Multispecialty Validation Study of the IgG4-Related Disease Responder Index

Objective IgG4-related disease (IgG4-RD) can cause fibro-inflammatory lesions in nearly any organ, leading to organ dysfunction and failure. The IgG4-RD Responder Index (RI) was developed to help investigators assess the efficacy of treatment in a structured manner. We sought to validate the RI in a multi-national investigation.