[Value of galactose-deficient IgA1 in the early diagnosis of Henoch-Schönlein purpura nephritis in children]

Increased Urinary IgA in Paediatric IgA Vasculitis Nephritis

IgA vasculitis (IgAV) is the most common form of paediatric vasculitis, with up to 50% of patients experiencing kidney inflammation. Much remains unknown about IgAV, but it is believed to arise due to galactose-deficient IgA1 promoting an auto-inflammatory response. This study assesses whether urinary IgA can be detected in children with IgAV to allow further evaluation of IgA1 and whether it has any relationship with nephritis. Urinary and serum IgA concentrations were measured using commercially available ELISA kits. Patients were grouped into IgAV nephritis (IgAVN) or IgAV without nephritis (IgAVwoN). Fifty-nine children were included: IgAVN n = 12, IgAVwoN n = 35, and healthy controls (HC) n = 12, with a mean age of 8.2 ± 4.1 years. Urinary IgA concentrations were statistically significantly higher in patients with IgAV (107.1 ± 136.3 μg/mmol) compared to HC (50.6 ± 26.3 μg/mmol; p = 0.027) and IgAVN (229.8 ± 226.3 μg/mmol) compared to both IgAVwoN (65.0 ± 37.8 μg/mmol; p = 0.002) and HC (p < 0.001). Urinary IgA concentrations were able to distinguish between renal status (AUC 0.838, 95%CI [0.704−0.973], p < 0.001) and did not correlate with proteinuria (r = 0.124; p = 0.407). Urinary IgA concentrations are increased in children with IgAVN, and it has the potential to act as a non-invasive biofluid to further evaluate nephritis in this disease.

Serum levels of degraded monosaccharides in children with Henoch-Schönlein purpura

OBJECTIVES

To examine the serum levels of degraded monosaccharides in children with Henoch-Schönlein purpura (HSP) and to study the clinical significance of degraded monosaccharides in HSP.

METHODS

A prospective analysis was performed on 132 children who were diagnosed with HSP from September 2019 to January 2022, and 132 healthy children were enrolled as the control group. High-performance liquid chromatography was used to determine the content of degraded monosaccharides in serum in both groups. The receiver operating characteristic (ROC) curve was used to evaluate the efficiency of degraded monosaccharides for the diagnosis of HSP.

RESULTS

Compared with the control group, the HSP group had significantly higher serum levels of mannose, glucosamine, aminogalactose, and galactose (P<0.001). The four degraded monosaccharides had an area under the ROC curve of 0.919, 0.913, 0.832, and 0.932 respectively for the diagnosis of HSP (P<0.05).

CONCLUSIONS

Children with HSP have higher serum levels of mannose, glucosamine, aminogalactose, and galactose than the healthy population. The levels of degraded monosaccharides may have an important value for the diagnosis of HSP.

[Expression and significance of follicular helper T cells and galactose-deficient IgA1 in children with Henoch-Schönlein purpura]

OBJECTIVE

To study the role of follicular helper T (Tfh) cells and galactose-deficient IgA1 (Gd-IgA1) in the pathogenesis of childhood Henoch-Schönlein purpura (HSP) and the correlation between them.

METHODS

A total of 36 children with newly-diagnosed HSP were enrolled. They were divided into two groups: HSP nephritis (HSPN) group with 11 children and non-HSPN group with 25 children according to the presence or absence of HSPN. Another 15 children who underwent physical examination at the outpatient service were enrolled as the healthy control group. Flow cytometry was used to measure the proportion of Tfh cells (CD4+CXCR5+ICOS+) in peripheral blood. ELISA was used to measure the levels of interleukin-21 (IL-21) and interleukin-6 (IL-6) in peripheral blood and the serum levels of IgA1 and Gd-IgA1. A Pearson correlation analysis was used to investigate the correlation of serum Gd-IgA1 concentration with Tfh cells and related factors expression in the children with HSP.

RESULTS

Both the HSPN and non-HSPN groups had significantly higher proportion of Tfh cells and expression levels of IL-21 and IL-6 in peripheral blood than the healthy control group (P<0.05). The HSPN group had significant increases in the above indices compared with the non-HSPN group (P<0.05). Both the HSPN and non-HSPN groups had significantly higher serum levels of IgA1 and Gd-IgA1 than the healthy control group (P<0.05). The HSPN group had significantly higher serum levels of IgA1 and Gd-IgA1 than the non-HSPN group (P<0.05). In the children with HSP, serum Gd-IgA1 level was positively correlated with Tfh cells proportion and IL-21 and IL-6 levels (P<0.05).

CONCLUSIONS

Tfh cells and related cytokines and serum Gd-IgA1 are involved in the development of HSP/HSPN. Tfh cells may mediate the increased production of Gd-IgA1.