Abstract: SA-PO0776
Atypical Hemolytic Uremic Syndrome in Lupus Nephritis Triggered by a CFI Variant and Infection
Session Information
- Glomerular Diseases: Lupus Nephritis, Monoclonal Gammopathy-Related Disease, and Transplantation
October 24, 2026 | Location: Exhibit Hall A, Convention Center
Abstract Time: 10:00 AM - 12:00 PM
Category: Glomerular Diseases
- 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics
Authors
- Gao, Xiyuan, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
- Zhuang, Jing, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
- Qu, Yue, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
- Aierken, Ailima, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
- Jiang, Hong, People's Hospital of Xinjiang Uygur Autonomous Region, Urumqi, Xinjiang, China
Introduction
Thrombotic microangiopathy (TMA) complicates 1-24% of lupus nephritis (LN) cases. Distinguishing secondary lupus-TMA from primary atypical hemolytic uremic syndrome (aHUS) is critical. We present a case of refractory LN complicated by aHUS, triggered by a CFI variant and infection, rescued with complement blockade.
Case Description
A 22-year-old female with 12-year refractory LN (unresponsive to multiple immunosuppressants) presented with generalized convulsions after a respiratory infection, accompanied by acute heart failure and anemia. Kidney biopsy showed Class IV+V LN with TMA-like changes. ADAMTS13 was normal (75.52%) and Shiga toxin negative. Tests revealed massive terminal complement activation (C5b-9 776 ng/ml, ref 72-252; CH50 22.2 U/mL). Exome sequencing identified a heterozygous CFI variant (c.1154G>A, p.S385N) and homozygous GSTT1 deletion. Diagnosed with aHUS triggered by infection amidst active LN, she received eculizumab, pulse steroids, and cyclophosphamide. Kidney function rapidly improved, platelets normalized, and dialysis was weaned. At long-term follow-up, complete lupus remission was achieved (SLEDAI 4), and she returned to normal daily life and school.
Discussion
Excessive alternative complement activation drives aHUS. This case highlights a "two-hit" model: genetic susceptibility (heterozygous CFI variant) coupled with an infectious trigger in a pro-thrombotic LN milieu. Additionally, the GSTT1 null genotype likely enhanced cyclophosphamide efficacy via delayed active metabolite detoxification, facilitating deep LN remission without severe toxicity. Early complement blockade rapidly reverses terminal complement activation, significantly reducing steroid dependence and enhancing the patient's quality of life.
Acknowledgment
We thank the technical support from the Clinical Research Center of Kidney Disease of Xinjiang Uygur Autonomous Region.
Figure 1: Kidney biopsy demonstrating Class IV+V lupus nephritis with glomerular microthrombi, consistent with thrombotic microangiopathy (TMA).
Table 1: Key Complement and Genetic Biomarkers.