A single-centre, real-world study on the efficacy and recovery of inflammatory cytokine levels of C5 complement inhibitor therapy in patients with paroxysmal nocturnal haemoglobinuria.

Paroxysmal nocturnal haemoglobinuria (PNH) is a rare clonal disorder caused by PIG-A mutations and characterized by complement-mediated haemolysis. C5 inhibitors are recommended as first-line therapy for PNH with high disease activity. We retrospectively analysed 57 patients treated with eculizumab or crovalimab. Luminex® liquid-phase chip technology was used to detect changes in complement and cytokine levels in patients pre- and post-treatment. Haemolysis control (LDH ≤ 1.5 × ULN) was achieved in 78.9% of patients, and 68.3% became transfusion-independent. Mean haemoglobin rose from 76 to 99 g/L at week 24. Infections were the most common adverse events, but none were severe, and no discontinuations occurred. Post-treatment, C5 and C5a levels increased significantly. Baseline levels of C5, C5a, C3, C1q, granulocyte colony-stimulating factor (G-CSF) and tumour necrosis factor-α (TNF-α) were higher in non-responders than in responders or controls. Our findings confirm the efficacy and safety of C5 inhibitors in Chinese PNH patients and indicate that complement and cytokine profiles may serve as predictive biomarkers.