CHICAGO — A diagnosis of IgG4-related disease must take into account a variety of factors, including the patient’s clinical presentation, blood tests or serology, radiological findings and pathology data, according to a draft of the American College of Rheumatology/EULAR classification criteria for the condition.
“This is a disease that was completely unknown 15 years ago,” John H. Stone, MD, MPH, of Massachusetts General Hospital, who directed the panel of experts that developed the new criteria, told attendees at the ACR/ARHP 2018 Annual Meeting. “No one knew the name of this disease, and I think it is remarkable that an international group of investigators has come together in only 15 years and developed classification criteria for the disease.”
The ACR/EULAR draft represents the first classification criteria for IgG4-related disease, an immune-mediated disease that may affect different organ systems and often mimics other diseases, such as Sjögren’s syndrome, pancreatic cancer, granulomatosis with polyangiitis, giant cell arteritis and systemic lupus erythematosus. In addition, it can cause fibro-inflammatory lesions in nearly any organ or multiple organs. Current estimates suggest that the disease affects about 180,000 individuals in the United States and many more across the world.
A diagnosis of IgG4-related disease must take into account a variety of factors, according to a draft of the American College of Rheumatology/EULAR classification criteria.
According to Stone, the international panel of 79 experts that drafted the criteria included investigators from rheumatology and other specialties, hailing from five continents. They used multi-criteria decision analysis to develop eight domains concerning clinical, serological, radiological and pathological features of IgG4-related disease.
The criteria describe a three-step process in classifying patients with the disease, in which providers must carefully assess data from four domains. These are clinical presentation, the results of blood tests or serology, the radiological findings and the pathology data. All of these domains must be included in the assessment, as there is no single diagnostic test for IgG4-related disease, Stone said.
According to Stone, the criteria have a “remarkable” sensitivity of 85.5% and a specificity of 99.2%.
“The criteria are really quite robust, holding up with high sensitivity and specificity across a range of thresholds, so I think they are going to perform very well in research and in recruiting participants for studies that are now beginning,” he said. “For the first time, we are preparing to do multicentered, international clinical trials, so the timing of the availability of the ACR/EULAR validated classification criteria for this disease is really perfect.” – by Jason Laday
Disclosure: Stone reports no relevant financial disclosures.
Stone JH. ACR/EULAR Classification Criteria for IgG4-Related Disease. Presented at ACR/ARHP Annual Meeting, Oct. 20-24, 2018; Chicago.