IgG4-Related Disease
Rheumatology · Other Rheumatologic Diseases 🎯 Practice these cards
IgG4-related disease is characterized by tumefactive infiltration of IgG4-bearing plasmablasts and other lymphocytes, along with ____ fibrosis, into one or multiple organs, with resultant organ enlargement, fibrosis, and dysfunction.
IgG4-related disease is characterized by tumefactive infiltration of IgG4-bearing plasmablasts and other lymphocytes, along with storiform fibrosis, into one or multiple organs, producing organ enlargement, fibrosis, and dysfunction.
Serum levels of IgG4 antibodies are elevated in approximately ____% of IgG4-RD cases.
Serum levels of IgG4 antibodies are elevated in approximately 80% of IgG4-RD cases.
Approximately ____% of patients with IgG4-RD have normal serum IgG4 concentrations despite classic histopathology, so a normal level does not exclude the disease.
Approximately 30% of patients have normal serum IgG4 concentrations despite classic histopathologic and immunohistochemical findings; such patients tend to have fewer affected organs.
The hallmark histopathology of IgG4-RD is a dense lymphoplasmacytic infiltrate, storiform fibrosis, and ____ (occlusion/inflammation of veins), with mild-to-moderate eosinophilia.
The hallmark pathology of IgG4-RD (consistent across organs) is a dense lymphoplasmacytic infiltrate, storiform fibrosis, and obliterative phlebitis, with mild-to-moderate eosinophilia.
Histologic features that argue AGAINST IgG4-RD include intense neutrophilic infiltration, leukocytoclasis, ____ inflammation, multinucleated giant cells, and fibrinoid necrosis.
Histologic features uncommon in IgG4-RD that mitigate against the diagnosis include intense neutrophilic infiltration, leukocytoclasis, granulomatous inflammation, multinucleated giant cells, and fibrinoid necrosis.
The typical IgG4-RD patient is a middle-aged to elderly ____; the male-to-female ratio is approximately ____:1.
The typical IgG4-RD patient is a middle-aged to elderly man; the male-to-female ratio is approximately 2:1, contrasting with most classic autoimmune diseases.
The 2019 ACR/EULAR IgG4-RD classification criteria require a total of ≥____ points, with entry requiring involvement of at least 1 of ____ specified organs.
The 2019 ACR/EULAR IgG4-RD classification criteria use a 3-step process (entry: ≥1 of 11 organs; 32 exclusion criteria; 8 weighted inclusion domains); a total of ≥20 points classifies IgG4-RD, with specificity ~98-99% and sensitivity ~82-86%.
First-line therapy for IgG4-RD is ____, typically begun as prednisone ____ mg/day and then tapered.
Glucocorticoids are first-line therapy for IgG4-RD, generally begun as prednisone 40 mg/day and tapered toward discontinuation or a 5 mg/day maintenance dose; response is swift but steroid-free remissions are uncommon.
For relapsing or glucocorticoid-resistant IgG4-RD, B-cell depletion with ____ (anti-CD20) is an excellent second-line therapy, commonly dosed as two ____-g IV infusions ~15 days apart.
For relapsing or glucocorticoid-resistant IgG4-RD, B-cell depletion with rituximab (anti-CD20) is an excellent second-line therapy, commonly dosed as two 1-g IV infusions separated by ~15 days.
In the MITIGATE phase 3 trial, the anti-CD19 antibody inebilizumab reduced the risk of IgG4-RD flare by ____%, and in April 2025 became the ____ FDA-approved therapy for IgG4-RD.
In the phase 3 MITIGATE trial, the anti-CD19 antibody inebilizumab reduced the risk of IgG4-RD flare by 87% (HR 0.13); in April 2025 it became the first FDA-approved therapy for IgG4-RD.
Obexelimab is a bifunctional antibody that co-engages CD19 and the inhibitory ____ receptor to suppress B cells WITHOUT depleting them; in the INDIGO trial it reduced first flare by ____%.
Obexelimab is a bifunctional antibody that co-engages CD19 and the inhibitory FcγRIIb receptor to suppress B cells WITHOUT depleting them; in the phase 3 INDIGO trial it reduced first flare by 56% (HR 0.44).
____ disease — enlargement of the lacrimal, parotid, and submandibular glands — was once considered a subset of ____ syndrome but is now recognized as a common presentation of IgG4-RD.
Mikulicz disease — enlargement of the lacrimal, parotid, and submandibular glands — was once considered a subset of Sjögren syndrome but is now recognized as one of the most common presentations of IgG4-RD.
The paradigm of IgG4-RD is type 1 (IgG4-related) autoimmune ____; imaging shows a diffusely enlarged '____-shaped' pancreas, mimicking adenocarcinoma.
The paradigm of IgG4-RD is type 1 (IgG4-related) autoimmune pancreatitis, presenting with a diffusely enlarged 'sausage-shaped' pancreas and obstructive jaundice that mimics pancreatic adenocarcinoma.
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