Clinical manifestations and pathological correlation of immunoglobulin A nephropathy in children.

Background: IgA nephropathy in children has various clinical manifestations. Kidney biopsy is a gold standard for diagnosis by using Oxford classification 2016 with few studies about the correlation between clinical and pathology manifestations. This study aims to find these correlations at the time of diagnosis and during short-term follow-up.

Method: In this retrospective cohort study, 47 pediatric patients who underwent renal biopsy from 2010 to 2021 in Thailand, were included. Oxford classification 2016 has been used to score patients' pathology. Univariate and multivariate associations have been used for correlation between clinical and pathologic parameters.

Results: The most common clinical manifestations were microscopic hematuria and proteinuria. There were 68% of children with mesangial hypercellularity (M1), 42% with segmental glomerulosclerosis (S1), 25% with moderate to severe crescent (C1/C2), 23% with endocapillary hypercellularity (E1), and 14% with moderate to a severe tubular atrophy/interstitial fibrosis (T1/T2). Microscopic hematuria was strongly associated with mesangial hypercellularity (M1) OR 7.14 (95%CI 1.83 - 27.88, p-value 0.005) and hypertension was strongly associated with segmental glomerulosclerosis (S1) adjusted OR 7.87 (95%CI 1.65 - 37.59, p-value 0.01). Intensive treatment was used more in the patients with tubular atrophy/interstitial fibrosis lesion on renal biopsy than other lesions from MEST-C scores OR 4.98 (95%CI 1.17-21.24, p-value 0.03). Furthermore, pulse methylprednisolone and cyclophosphamide were used in patients with crescentic lesions significantly than other lesions with OR 15.5 (95%CI 3.16- 75.93, p-value 0.001) and OR 5.75 (95%CI 1.31-25.29, p-value 0.021), respectively.

Conclusion: Tubular atrophy/interstitial fibrosis and crescent lesions were correlated to intensive treatment in short-term outcomes.