Immunoglobulin G galactosylation levels are decreased in systemic sclerosis patients and differ according to disease subclassification.

Abstract

Objectives: Scleroderma is a connective tissue immune disease that features collagen overproduction and can be categorized into two subtypes, localized scleroderma (LSc) and systemic sclerosis (SSc). SSc is clinically classified into two subsets: limited cutaneous (lcSSc) and diffuse cutaneous (dcSSc) SSc. The immunoglobulin G-galactosylation (IgG-Gal) ratio is abnormal in a number of immune diseases and has not been evaluated in SSc.Method: The study recruited 93 LSc patients, 298 SSc patients, and 436 healthy controls. N-glycans of purified IgG were obtained from plasma and detected by tandem mass spectrometry. The IgG-Gal ratio was measured by calculating the relative intensities of agalactosylated (G0), monogalactosyl (G1), and digalactosyl (G2) N-glycans according to the formula G0/(G1 + G2 × 2). Furthermore, we examined whether the IgG-Gal ratio differed between different subtypes of SSc.Results: The IgG-Gal ratio was significantly higher in SSc patients (1.139 ± 0.870) than in LSc patients (0.485 ± 0.280) and controls (0.395 ± 0.190). The IgG-Gal ratio successfully distinguished SSc patients from LSc and controls (area under the curve = 0.88 and 0.81, respectively). The IgG-Gal ratio was significantly higher in dcSSc patients than in lcSSc patients and increased along with increases in modified Rodnan skin score (p = 6.03 × 10-5, Pearson's coefficient = 0.26) and erythrocyte sedimentation rate (p = 2.95 × 10-10, Pearson's coefficient = 0.38).Conclusion: IgG-Gal ratios were abnormal in SSc patients and were associated with disease severity. The IgG-Gal ratio therefore shows potential as a biomarker for the diagnosis of SSc.

• Authors: Q Liu, J Lin, J Han, Y Zhang, J Lu, W Tu, Y Zhao, G Guo, H Chu, W Pu, J Liu, Y Ma, X Chen, R Zhang, J Gu, H Zou, L Jin, W Wu, S Ren, J Wang
• Journal: Scandinavian journal of rheumatology (Scand J Rheumatol) Vol. 49 Issue 2 Pg. 146-153 (Mar 2020) ISSN: 1502-7732 [Electronic] England
• PMID: 31538512 (Publication Type: Journal Article)

Chemical References

• Immunoglobulin G
• Galactose

Topics

• Adult
• Blood Sedimentation
• Female
• Galactose (metabolism)
• Humans
• Immunoglobulin G (metabolism)
• Male
• Middle Aged
• Scleroderma, Localized (immunology)
• Scleroderma, Systemic (diagnosis, immunology, metabolism)