Comparative study on clinicopathological features and prognosis of IgA vasculitis nephritis and IgA nephropathy in children

Abstract

Background IgA vasculitis nephritis (IgAVN) and IgA nephropathy (IgAN) share several clinical and pathological characteristics, though distinctions also exist. Their interrelation, however, remains undefined. This study investigates the clinicopathological divergences and prognostic disparities in pediatric patients with IgAVN and IgAN. Methods Our study encompasses 809 pediatric patients with IgAVN and 236 with IgAN, all of whom underwent kidney biopsy. We utilized the Semiquantitative Classification (SQC) scoring system to juxtapose the pathologies of the two conditions, and performed a COX regression analysis to examine factors influencing their prognoses. Results Both patient groups demonstrated a predominance of males. A seasonality was observed, with a higher incidence of IgAN in the summer, and IgAVN in the fall (P < 0.0001). Patients with IgAN exhibited more severe tubulointerstitial injury, higher chronicity index, and total biopsy scores compared to those with IgAVN (P < 0.0001). Mesangial deposition intensity of complement C3, and the rate of pure IgA deposition, were found to be greater in patients with IgAVN compared to those with IgAN (P < 0.0001). The intensity of IgA deposition was also significantly higher in IgAVN patients (P = 0.003). IgAVN demonstrated a superior prognosis, with a higher rate of kidney remission (P < 0.0001). COX regression analysis indicated that interstitial fibrosis, as identified in the SQC pathology system, was associated with the prognosis of both conditions. Furthermore, the findings suggest that IgA deposition levels (IgA + + and IgA + + +) could potentially influence the prognosis of IgAVN. Conclusions Compared to IgAVN, IgAN manifests more severely with regard to renal impairment, interstitial damage, and prognosis. The disparities in immune complex deposition levels and locations within the kidneys support the hypothesis of IgAVN and IgAN as distinct diseases. Interstitial fibrosis may serve as a key pathological indicator within the SQC system associated with kidney prognosis in children with IgAVN and IgAN. The degree of IgA deposition could also be linked with the prognosis of IgAVN.

Single‐cell RNA sequencing of pediatric renal tissues revealed the potential relationship between immunoglobulin A nephropathy and immunoglobulin A vasculitis with nephritis

“…3,4 Renal fibrosis is often synonymous with the gradual deterioration of renal function and the progression to end-stage renal disease. 5 Recently, Lv et al 6 reported that IgAN patients had higher pathological scores for complete tubular atrophy, interstitial fibrosis as well as interstitial and periglomerular inflammation compared to IgAVN patients, which is consistent with our data and strongly supports our conclusions.…”

Predictors of Gastrointestinal Involvement in Children with IgA Vasculitis: Results from a Single-Center Cohort Observational Study

“…Gastrointestinal involvement is relatively common in IgAV, but can vary in severity, from mild nausea to gastrointestinal bleeding and intussusception that may require surgical intervention: in a recent study about 50% of IgAV cases had gastrointestinal involvement, and 48.9% of them were classified as severe [4]. In general terms, IgAV has an overall positive prognosis with complete recovery, highly dependent on the deposition of IgA at the renal level alone [5].…”