Serum IgG galactosylation as a potential biomarker for the diagnosis of echinococcosis

Echinococcosis is a serious and potentially fatal parasitic zoonosis, which can be divided into two subtypes in humans including cystic echinococcosis (CE) and alveolar echinococcosis (AE). It poses a great threat to patients' lives, making timely diagnosis and subtype discrimination crucial. AE is easily confused with hepatocellular carcinoma (HCC) due to their highly similar features, so differential diagnosis is also imperative. In this work, the galactosylation level of serum IgG was analyzed by Matrix-Assisted Laser Desorption/Ionization Time of Flight Mass Spectrometry (MALDI-TOF-MS) in a cohort comprising patients, including 100 diagnosed with CE, 27 with AE and 29 with HCC. The relative quantification of IgG digalactosylated (G2), monogalactosylated (G1), and agalactosylated (G0) N-glycans with the formula G0/(G1 + G2 × 2) (IgG Gal-ratio) was obtained and found to effectively distinguish between echinococcosis patients, CE and AE patients, and healthy controls, respectively. Meanwhile, the IgG Gal-ratio was evidently related to different types of CE (from CE1 to CE5) and the follow-up CE disease progress. Furthermore, the IgG Gal-ratio shows the potential differential diagnosis of AE and HCC. Thus, the results demonstrate that the IgG Gal-ratio has the potential to be a biomarker for diagnosis and discrimination of echinococcosis, which also needs to be verified in further studies.