# Significance of the 50％ hemolytic complement in hemolysis assessment and efficacy of eculizumab in patients with paroxysmal nocturnal hemoglobinuria

## TL;DR

This study shows that CH50 levels can indicate the effectiveness of eculizumab in treating PNH by tracking complement inhibition and hemolysis improvement.

## Contribution

The study demonstrates CH50 as a potential biomarker for eculizumab efficacy in PNH patients.

## Key findings

- CH50 levels dropped significantly after eculizumab treatment, indicating effective complement inhibition.
- LDH levels decreased and HGB levels increased, showing reduced hemolysis and improved anemia.
- Baseline CH50 correlated with LDH, but this correlation disappeared after treatment.

## Abstract

回顾性收集2023年1月至2024年6月北京协和医院、北京中医药大学东方医院收治的阵发性睡眠性血红蛋白尿症（PNH）患者数据，选择经过足量依库珠单抗治疗至少3个月，并完成了依库珠单抗治疗前、治疗后3个月的总补体活性（CH50）水平检测的25例患者，其中24例患者完成了6个月治疗及CH50检测。依库珠单抗治疗3及6个月后，所有PNH患者症状显著改善，乳酸脱氢酶（LDH）从基线（1 814.4±924.8）U/L下降至（248.5±61.0）U/L和（239.3±44.8）U/L。HGB水平从基线（73.9±14.4）g/L上升至（99.9±21.3）g/L和（99.6±19.8）g/L。CH50基线水平为（32.4±14.7）％，治疗后3和6个月分别下降至2.0％（1.0％～8.0％）和1.0％（1.0％～4.0％）。基线时CH50水平与LDH呈线性相关（P<0.001，r＝0.789），且CH50水平在依库珠治疗后3和6个月与LDH均明显下降，变化趋势相似，但在用药3及6个月的CH50水平与LDH及其他参数不存在线性相关。提示血清CH50水平可能是依库珠单抗诱导的补体阻断的标志物，可一定程度上反映PNH血管内溶血及依库珠单抗疗效。