Abstract: TH-PO104

The Oxford IgA MEST Score Is Associated with Worse Kidney Outcomes in Childhood Onset Henoch Schönlein Purpura Nephritis

Session Information

Category: Glomerular

  • 1004 Clinical/Diagnostic Renal Pathology and Lab Medicine

Authors

  • Kellett, Sally Anne, The Hospital For Sick Children, Toronto, Ontario, Canada
  • Thorner, Paul S., The Hospital For Sick Children, Toronto, Ontario, Canada
  • Chami, Rose, The Hospital For Sick Children, Toronto, Ontario, Canada
  • Jawa, Natasha, The Hospital for Sick Children, Toronto, Ontario, Canada
  • Parekh, Rulan S., The Hospital For Sick Children, Toronto, Ontario, Canada
  • Noone, Damien Gerard, The Hospital for Sick Children, Toronto, Ontario, Canada
Background

Henoch-Schönlein Purpura (HSP) is one of the commonest forms of systemic small vessel vasculitis in children, with kidney involvement occurring in 40-50% of children. Current pathology classification systems have not proved useful in determining long-term kidney outcomes in children with HSP nephritis.

Aim: Determine if Oxford IgA MEST score is associated with long-term outcomes in childhood onset HSP.

Methods

This was a single-center, retrospective cohort study of children aged 0 to 18 yrs who presented with HSP nephritis between 2002 and 2016. Initial renal biopsies were scored based on the MEST criteria (M=mesangial hypercellularity, E=endocapillary hypercellularity, S=segmental glomerulosclerosis, T=tubular atrophy/interstitial fibrosis) and also for presence of crescents (C=cellular or fibrocellular crescents) and level of C3 deposition. Analyzed by logistic regression, we determined if MEST score was associated with clinical outcomes at last clinical follow-up with a composite outcome of proteinuria (protein:creatinine ratio >20mmol/mmol and/or eGFR <90ml/min/1.73m2) controlling for age at presentation and sex.

Results

We identified 44 children (F=63.6%) with biopsy data who were followed for at least 6 months. At presentation, median age was 8.3 yrs (IQR 5.8 – 11.5yrs) median protein:creatinine ratio was 239.6mg/mmol (IQR 151.5 – 608.9 mg/mmol). Median length of follow-up was 3 yrs (0.5 to 11yrs). Pathology review determined 34.1% had a combined MEST score ≥3, 63.6% had crescents (of those, 85.7% <50%) and 61.4% C3 staining >1+. A total of 79.5% were treated with steroids and 45.5% with an ACE inhibitor or angiotensin II receptor blocker. Median GFR at last follow up was 107.4ml/min/1.73m2 (IQR 83.6 to 146.2). A MEST score ≥3 had an adjusted odds of 8.3 [95% CI 1.3-52.2] of having a poor kidney outcome when adjusted for age and sex. The presence of crescents gave an adjusted odds of 5.4 [95% CI 1.2-25.5] of reaching the composite outcome. C3 was not significantly associated with the composite outcome with adjusted odds of 1.9 [95% CI 0.5-7.3].

Conclusion

MEST pathological score of ≥3 and presence of crescents on first biopsy in children with HSP nephritis is associated with a worse outcome by 3 years. This study suggests that Oxford IgA MEST score may be useful for disease prognosis.