Control of lupus activity during pregnancy via the engagement of IgG sialylation: novel crosstalk between IgG sialylation and pDC functions

Immunoglobulin G N-glycan markers of mild cognitive impairment in a Chinese population with cerebrovascular stenosis: A case-control study

BACKGROUND

Immunoglobulin G (IgG) N-glycans have been shown to regulate the inflammatory response in the context of disease. In recent years, it has been found to be associated with several neurodegenerative disorders. In this study, we examined the relationship between IgG N-glycans and mild cognitive impairment (MCI) in a high-risk population for MCI, specifically patients with cerebrovascular stenosis.

METHODS

In a case-control study, we investigated IgG N-glycans and cytokines in MCI and non-MCI patients in a population with cerebrovascular stenosis. A multifactorial logistic regression analysis was employed to investigate the potential association between IgG N-glycoprotein and MCI, with familial error rates being corrected for using the Benjamin-Hochberg method. To construct discriminatory models, logistic stepwise regression was employed and evaluated for their diagnostic efficacy.

RESULTS

A statistically significant difference was found in eight of the IgG-GPs between the two groups. Three IgG-GPs were correlated with MCI, with an overall false discovery rate <0.05. Specifically, IgG-GP7 (non-sialylated glycan) was positively correlated with MCI, while IgG-GP14 (digalactosylated glycans) and IgG-GP18 (bis-sialylated glycan) were negatively correlated with MCI. The model constructed by combining IgG N-glycans (IgG-GP7, IgG-GP14, IgG-GP18) and cytokines (IL-1β, IL-10, BDNF and VEGF) demonstrated the highest diagnostic efficacy [AUC: 0.939, 95 % CI: (0.910-0.967)].

DISCUSSION

In the present study, we observed that agalactosylation and no-sialylation play a role in the progression of MCI by influencing the pro-inflammatory impact of IgG. The integration of IgG N-glycan and cytokines into a discriminative model demonstrated strong diagnostic efficacy, suggesting its potential use as a screening tool for early prediction of MCI in patients with cerebrovascular stenosis.

Immunomodulation of Antibody Glycosylation through the Placental Transfer

Establishing an immune balance between the mother and fetus during gestation is crucial, with the placenta acting as the epicenter of immune tolerance. The placental transfer of antibodies, mainly immunoglobulin G (IgG), is critical in protecting the developing fetus from infections. This review looks at how immunomodulation of antibody glycosylation occurs during placental transfer and how it affects fetal health. The passage of maternal IgG antibodies through the placental layers, including the syncytiotrophoblast, stroma, and fetal endothelium, is discussed. The effect of IgG subclass, glycosylation, concentration, maternal infections, and antigen specificity on antibody transfer efficiency is investigated. FcRn-mediated IgG transport, influenced by pH-dependent binding, is essential for placental transfer. Additionally, this review delves into the impact of glycosylation patterns on antibody functionality, considering both protective and pathological effects. Factors affecting the transfer of protective antibodies, such as maternal vaccination, are discussed along with reducing harmful antibodies. This in-depth examination of placental antibody transfer and glycosylation provides insights into improving neonatal immunity and mitigating the effects of maternal autoimmune and alloimmune conditions.

Metabolic Markers and Association of Biological Sex in Lupus Nephritis

Lupus nephritis (LN) is a serious complication for many patients who develop systemic lupus erythematosus, which primarily afflicts women. Our studies to identify biomarkers and the pathogenic mechanisms underlying LN will provide a better understanding of disease progression and sex bias, and lead to identification of additional potential therapeutic targets. The glycosphingolipid lactosylceramide (LacCer) and N-linked glycosylated proteins (N-glycans) were measured in urine and serum collected from LN and healthy control (HC) subjects (10 females and 10 males in each group). The sera from the LN and HC subjects were used to stimulate cytokine secretion and intracellular Ca2+ flux in female- and male-derived primary human renal mesangial cells (hRMCs). Significant differences were observed in the urine of LN patients compared to HCs. All major LacCers species were significantly elevated and differences between LN and HC were more pronounced in males. 72 individual N-glycans were altered in LN compared to HC and three N-glycans were significantly different between the sexes. In hRMCs, Ca2+ flux, but not cytokine secretion, was higher in response to LN sera compared to HC sera. Ca2+ flux, cytokine secretion, and glycosphingolipid levels were significantly higher in female-derived compared to male-derived hRMCs. Relative abundance of some LacCers and hexosylceramides were higher in female-derived compared to male-derived hRMCs. Urine LacCers and N-glycome could serve as definitive LN biomarkers and likely reflect renal disease activity. Despite higher sensitivity of female hRMCs, males may experience greater increases in LacCers, which may underscore worse disease in males. Elevated glycosphingolipid metabolism may poise renal cells to be more sensitive to external stimuli.

Total serum N-glycans mark visceral leishmaniasis in human infections with Leishmania infantum

Visceral leishmaniasis (VL) is a clinical form of leishmaniasis with high mortality rates when not treated. Diagnosis suffers from invasive techniques and sub-optimal sensitivities. The current (affordable) treatment with pentavalent antimony as advised by the WHO is possibly harmful to the patient. There is need for an improved diagnosis to prevent possibly unnecessary treatment. N-glycan analysis may aid in diagnosis. We evaluated the N-glycan profiles from active VL, asymptomatic infections (ASYMP) and controls from non-endemic (NC) and endemic (EC) areas. Active VL has a distinct N-glycome profile that associates with disease severity. Our study suggests that the observed glycan signatures could be a valuable additive to diagnosis and assist in identifying possible markers of disease and understanding the pathogenesis of VL. Further studies are warranted to assess a possible future role of blood glycome analysis in active VL diagnosis and should aim at disease specificity.