IgG Patterns Suggest Autoimmune Changes in SSc, SLE, Sjögren's

January 20, 2015

IgG4 levels were low in this study for only systemic sclerosis and Sjögren's. But other patterns suggested aberrant immune regulation.

Zhang H, Li P, Wu D. Serum IgG Subclasses in Autoimmune Diseases .
Medicine. 2015;94(2):e387 doi: 10.1097/MD.0000000000000387

This study measured the IgG subclasses IgG1, IgG2, IgG3 and IgG4, as absolute values and ratios, in primary Sjögren syndrome (pSS), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), primary biliary cirrhosis (PBC) and healthy controls using the immunonephelometic assay. They compared the results for all of these groups.

Interestingly, levels of IgG4 were low. However, only 23 (6%) met the criterion for IgG4-related disease (IgG4 >135 mg/dL). 

Differences were statistically significant between IgG4 and healthy controls for pSS and SSc, but not for SLE and PBC.

The patterns of IgG1 and IgG3 expression suggested that affected individuals lost tolerance to autoantigens, and also exhibited aberrant immune regulation.

 pSS (n=102)SSc (n=102)SLE (n=100)PBC (n=59)Controls (n=40)
IgG11403924951880809
IgG2392412410607541
IgG3567054101

39

IgG44146584457
IgG1/IgG73646554

57

IgG2/IgG2228283837
IgG3/IgG35463
IgG4/IgG23434
*mg/dl  **%