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Abstract: PO2337

Comparison of Clinicopathological Findings Between Childhood IgA Nephropathy and IgA Vasculitis Nephritis Using Oxford Classification

Session Information

Category: Pediatric Nephrology

  • 1700 Pediatric Nephrology

Authors

  • Shima, Yuko, Pediatrics, Wakayama Medical University, Wakayama, Wakayama, Japan
  • Nakanishi, Koichi, Pediatrics, Graduate School of Medicine, University of the Ryukyus, Okinawa, Okinawa, Japan
  • Mukaiyama, Hironobu, Pediatrics, Wakayama Medical University, Wakayama, Wakayama, Japan
  • Tanaka, Yu, Pediatrics, Wakayama Medical University, Wakayama, Wakayama, Japan
  • Wada, Takuzo, Pediatrics, Wakayama Medical University, Wakayama, Wakayama, Japan
  • Nozu, Kandai, Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
  • Tanaka, Ryojiro, Pediatric Nephrology, Hyogo Prefectural Kobe Children’s Hospital, Kobe, Hyogo, Japan
  • Iijima, Kazumoto, Pediatrics, Graduate School of Medicine, Kobe University, Kobe, Hyogo, Japan
  • Yoshikawa, Norishige, Clinical Research Center, Takatsuki General Hospital, Kobe, Hyogo, Japan
Background

IgA nephropathy (IgAN) and IgA vasculitis nephritis (IgAVN) are nephritis with a common pathological feature of significant mesangial IgA deposition, but it remains controversial whether they are the same disease.

Methods

We compared clinical and pathological findings between 148 patients with IgAN and 100 patients with IgAVN who underwent renal biopsy from April 2000 to April 2019 to clarify the differences.

Results

Clinical findings showed significant differences in onset age (IgAVN vs IgAN, 7.4 vs 10.7 years, p<0.0001), episode of gross hematuria (8.0 vs 24.3%, p=0.0007), duration from onset to renal biopsy (1.7 vs 6.6 months, p<0.0001), and amount of proteinuria (1.8 vs 0.5 g/gCr, p<0.0001). Pathological findings by Oxford classification showed significant differences in the frequency of M1 (94.0 vs 59.2%, p<0.0001), S1 (21.0 vs 42.2%, p=0.0004), T present (28.0 vs 46.1%, p=0.004), C present (72.0 vs 58.1%, p=0.03) and G present (8.0 vs 19.1%, p=0.01), but no difference in that of E1 (52.8 vs 55.0%, p=0.75). Fluorescence findings showed significant difference in the frequency of fibrinogen deposition (93.3 vs 74.6%, p=0.0004) but not in that of glomerular peripheral capillary IgA deposition (9.5 vs 3.5%, p=0.10). Electron microscopic findings showed significant difference in the frequency of GBM lysis (35.2 vs 12.0%, p=0.0001). Degree of proteinuria is positively correlated with the frequency of M1 in IgAVN.

Conclusion

IgAVN has higher frequency of M1 lesion regardless of degree of proteinuria, lower frequency of chronic lesions such as S, T, and G, and higher frequency of acute lesions such as M and C compared with IgAN. Although IgAVN had some pathological similarities to that of IgAN, there seems to be differences which cannot be explained by the timing of renal biopsy.