Quantification of Serum IgG Subclasses by Use of Subclass-Specific Tryptic Peptides and Liquid Chromatography-Tandem Mass Spectrometry

摘要

BACKGROUND: Measurement of IgG subclasses is a useful tool for investigation of humoral immune deficiency in the presence of total IgG within reference intervals and IgG4-related disease. Nephelometry has been the method of choice for quantification. We describe an LC-MS/MS method that can multiplex all 4 subclasses along with total IgG by use of either IgG subclass-specific peptide stable isotope-labeled internal standards or a surrogate digest standard for quantification and does not rely on antigen/antibody reactions.