Reply: Further Progress in Understanding Fibrosing Mediastinitis
Year: 2015
Type: letter
Abstract: pathologic findings, the authors propose that measurement of serum IgG4 may be useful in patients with FM.We write to report a study of serum IgG4 levels in 40 serial patients with FM diagnosed by established clinical and radiographic criteria (1-3, 7).We tested serum IgG subclasses (IgG1, IgG2, IgG3, IgG4) using quantitative nephelometry at ARUP Laboratories (Salt Lake City, UT).IgG subsets were normal in all 40 patients with FM (mean IgG4, 32.3 mg/dl; SD, 24.7 mg/dl; median IgG4, 23.5 mg/dl; interquartile range, 32.3 mg/dl).None had a serum IgG4 above 140 mg/dl, a level recently described to have 96% negative predictive value (8).Our cohort included a broad severity of FM, from unilateral disease with minimal symptoms to bilateral disease with life-threatening complications, and we found no correlation of disease severity with IgG4 levels.More information is needed to understand the discordance between FM tissue and serum IgG4, but it seems possible that for a focal process such as FM, the burden of IgG4-producing plasma cells is not sufficient to increase the level in sera.
Authors: Tobias Peikert, Blair Westerly, Ulrich Specks
Institution: Mayo Clinic
Language: English
Subfield: Rheumatology
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2186651574