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Abstract: SA-PO595

The Difference of Activation Pattern of Complement System Between Pediatric and Adult Lupus Nephritis

Session Information

  • Pediatric Nephrology - II
    November 05, 2022 | Location: Exhibit Hall, Orange County Convention Center‚ West Building
    Abstract Time: 10:00 AM - 12:00 PM

Category: Pediatric Nephrology

  • 1800 Pediatric Nephrology

Authors

  • Park, Minji, Kyungpook National University Hospital, Daegu, Korea (the Republic of)
  • Cho, Min Hyun, Kyungpook National University Hospital, Daegu, Korea (the Republic of)
Background

Lupus nephritis has an etiopathogenesis caused by activation of the complement system. The purpose of this study is to investigate the differences and clinical implication of the activation pattern of complement system between pediatric and adult lupus nephritis patients.

Methods

We retrospectively reviewed medical records of 14 pediatric and 26 adult patients whose tissue specimens were stored among patients diagnosed with lupus nephritis through renal biopsy. The activation of complement system was evaluated by performing IHC staining for C4d (a component of the lectin pathway) and IF staining for C1q (a component of the classical pathway) and C3 (a component of the alternative pathway) in renal tissue.

Results

The study enrolled 14 pediatric and 26 adult patients, and the proportion of female was significantly higher in both groups. The average age at diagnosis of pediatric patients was 11.7 ± 2.9 years, and the average age of adult patients was 37.3 ± 13.5 years. Except for age and C3 level, the baseline clinical characteristics of pediatric and adult patients were similar. Age-adjusted mean C3 value were significantly lower in pediatric patients, 33.0mg/dL in pediatric patients and 50.8 mg/dL in adult patients (p=0.003). As a result of complement staining of kidney tissue, the C3 and C1q positivity rate in pediatric/adult patients were 92.9/76.9% and 85.7/80.8%, respectively and there was no significant difference. However, the C4d positivity was 35.7% in pediatric patients and 76.9% in adult patients (p=0.010), which was significantly higher in adult patients than in pediatric patients. Although there was no correlation between C4d activation and initial laboratory findings and prognosis in both groups, the C4d/C1q(+/+) group among adult patients had poor prognosis (defined as CRF, dialysis or death) than the C4d/C1q(+/-) group (82% vs 33%, p=0.027).

Conclusion

Pediatric lupus nephritis patients had significantly lower C4d activation compared to adult lupus nephritis patients and the co-positivity for C4d and C1q can be considered as a poor prognostic factor for lupus nephritis patients. Therefore, we conclude that the pattern of complement activation system plays an important role in determining the age difference and prognosis in lupus nephritis.