Perhaps even better, studies in Europe have found that RT-qPCR testing for IgG4 RNA can be effective. This type of testing is easier than ELISPOT, and “they are finding the sensitivity to be much superior to nephelometry for immunoglobulin levels,” Dr. Khosroshahi said.
The higher the levels of IgG4, the more likely an IgG4-related disease diagnosis is warranted, and higher levels tend to lead to worse outcomes, she said.
She waved a caution flag, though: Other diseases can involve elevated IgG4, and even a normal IgG4 level does not necessarily rule out the disease. Other evaluations really form the cornerstone of the diagnosis of IgG4-related disease, she said.
“There should be characteristic histology and of course IgG4-staining, but more importantly, pattern of organ involvement. It’s very important,” Dr. Khosroshahi said. “If there is a mass in the pancreas and there is salivary gland and parotid gland swellings and other features of that going on, you are more concerned that that is a process going on.”
Dr. Khosroshahi had no relevant disclosures.