title: Serum IgG subclasses in autoimmune diseases.
abstract: To characterize serum IgG subclass levels in several autoimmune diseases, including primary Sjogren syndrome (pSS), systemic sclerosis (SSc), systemic lupus erythematosus (SLE), and primary biliary cirrhosis (PBC). We aimed to analyze serum IgG subclass distribution and to test whether serum IgG4 levels are elevated in these diseases. Serum IgG subclass levels from 102 pSS, 102 SSc, 100 SLE, and 59 PBC patients, as well as 40 healthy controls (HCs), were measured using the immunonephelometric assay. The distribution of IgG subclasses among these autoimmune diseases was analyzed. In this cross-sectional study, serum IgG1 (IgG1/IgG) and/or IgG3 (IgG3/IgG) were significantly increased, compared with those in HCs. Only 6.34% of patients had levels of serum IgG4 >135 mg/dL. There were no significant differences in the frequency of elevated serum IgG4 levels between patients and HC. In pSS, serum IgG1 levels were much higher than those in other disease groups, whereas serum IgG2 and IgG3 levels were most prominently increased in PBC. A strikingly different serum IgG subclass distribution was detected in patients with autoimmune diseases compared with HCs. Serum IgG subclass levels also showed distinct characteristics among different autoimmune diseases. Serum IgG4 levels in these patients were lower or not much higher than those in HCs, which differed from IgG4-related diseases.
authors.affiliation: From the Department of Rheumatology, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
authors.forename: Haoze
authors.initials: H
authors.lastname: Zhang
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Di
authors.initials: D
authors.lastname: Wu
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.forename: Yong
authors.initials: Y
authors.lastname: Hou
authors.forename: Qian
authors.initials: Q
authors.lastname: Wang
authors.forename: Mengtao
authors.initials: M
authors.lastname: Li
authors.forename: Yongzhe
authors.initials: Y
authors.lastname: Li
authors.forename: Xiaofeng
authors.initials: X
authors.lastname: Zeng
authors.forename: Fengchun
authors.initials: F
authors.lastname: Zhang
authors.forename: Qun
authors.initials: Q
authors.lastname: Shi
mesh_terms: D000328:Adult; D002681:China; D003430:Cross-Sectional Studies; D003627:Data Interpretation, Statistical; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood / Q000145:classification; D008105:Liver Cirrhosis, Biliary / Q000097:blood*; D008180:Lupus Erythematosus, Systemic / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012595:Scleroderma, Systemic / Q000097:blood*; D012859:Sjogren's Syndrome / Q000097:blood*
chemical_list: D007074:Immunoglobulin G