Objective:To investigate the clinical and pathological characteristics and prognosis of children with lupus nephritis(LN)and thrombotic microangiopathy (TMA).Methods:In this retrospective case-control study, clinical and pathological data of LN children confirmed by renal biopsy from January 2008 to January 2023 in Xuzhou Children′s Hospital, Xuzhou Medical University were analyzed.There were 46 LN children complicated with TMA (LN-TMA group). With matched age, sex and pathology, 92 LN children (1∶2) without TMA were selected as the control group (LN group). The Kaplan-Meier method was used to evaluate the overall and renal survival rates of children with LN, and the Cox regression model was used to analyze the risk factors for the progression to end-stage renal disease (ESRD).Results:TMA was moderately associated with serum creatinine, serum C3, anti-C1q antibody (a-C1q), estimated glomerular filtration rate (eGFR), endocapillary proliferation, fibrinoid necrosis, and renal C1q deposition (all r>0.5). Serum a-C1q≥20 U/mL ( HR=8.724, 95% CI: 0.976-16.114, P=0.026) and eGFR≤60 mL/(min·1.73 m 2) ( HR=12.213, 95% CI: 1.147-25.048, P=0.038) were independent risk factors for TMA in children with LN.Glomerular sclerosis ( HR=7.228, 95% CI: 0.186-22.358, P=0.016), TMA ( HR=11.387, 95% CI: 3.426-42.554, P=0.009) and eGFR≤60 mL/(min·1.73 m 2) ( HR=3.116, 95% CI: 0.592-10.064, P=0.030) were independent risk factors for developing ESRD in LN children.The 5-year and 10-year renal survival rates in the LN-TMA group were lower than those in the LN group (97.44% vs.98.28%, 80.90% vs.87.27%, χ2=4.918, P=0.027). Conclusions:Children with LN-TMA present with severe symptoms and poor prognosis.TMA is an independent risk factor for progression to ESRD in children with LN, and the mechanism may be related to complement activation.