Inclusion criteria definitions
| Immunostaining |
| IgG+cells can be identified using either IgG staining or CD138 staining. |
| Head and neck gland involvement |
| A ‘set’ of glands refers to both lacrimal glands or both submandibular glands among others. If a gland has been surgically removed for the purpose of diagnosis, it can be considered to have been involved if confirmed by pathology. |
| Involvement of the lacrimal glands and the major salivary glands in IgG4-related disease (IgG4-RD) is bilateral (but can be asymmetric). Involvement of the glands can be determined by either a clinical examination or a radiological study (eg, positron emission tomography scan or CT scan). |
| Chest |
| Peribronchovascular and septal thickening in the lung must be determined by a cross- sectional imaging study of the chest. |
| The paravertebral band-like soft tissue in the thorax is usually right-sided, located between T8 and T11, and does not encase the aorta. |
| Pancreas and biliary tree |
| Diffuse pancreas enlargement usually encompasses more than two-thirds of the pancreas. |
| The type of biliary involvement that is highly consistent with IgG4-related sclerosing cholangitis involves the proximal biliary tract (ie, intrahepatic and extrapancreatic portions of the extrahepatic bile ducts). The bile duct walls often have smooth thickening. |
| Kidney |
| Hypocomplementemia pertains to low serum levels of C3, C4 or both. |
| Renal pelvic wall thickening can be either unilateral or bilateral, usually without severe stenosis or luminal irregularity. |
| Low-density areas in both renal cortices can be seen only on contrast-enhanced CT and are usually patchy or round- shaped in appearance. |
| Retroperitoneum |
| The location of IgG4-related retroperitoneal fibrosis or periaortitis is typically circumferential or on the anterolateral sides of the aorta. The segment of aorta involved tends to be the infrarenal aorta, often extending to include the iliac vessels. |