儿童期血栓性血小板减少性紫癜（TTP）非常罕见，本文总结1例系统性红斑狼疮（SLE）确诊4年后发生免疫介导TTP（iTTP）患儿的临床资料。患儿2岁时以“浮肿伴血尿蛋白尿”起病，诊断为SLE、狼疮性肾炎（Ⅳ+Ⅴ型），经糖皮质激素、他克莫司等治疗后缓解，5岁时停药。6岁时患儿因“突发皮肤出血点，乏力纳差”入院。入院后实验室检查：尿蛋白“++~+++”，尿红细胞计数78.1个/高倍视野、红细胞形态均一，血红蛋白85 g/L，红细胞平均体积80.5 fL，血小板7×10⁹/L，红细胞碎片阳性；乳酸脱氢酶998 U/L，肌酐34.2μmol/L，间接胆红素23.1μmol/L；抗核抗体均质型>1:1000，抗双链DNA>300 IU/mL，抗U1核糖核酸蛋白抗体“++”，抗核小体抗体“+”，抗核糖体P蛋白抗体“+”；补体C3为0.15 g/L、C4为0.05 g/L；血浆ADAMTS13活性0.72%、血浆 ADAMTS13抑制物阳性；直接抗人球蛋白试验阳性；血沉44 mm/h，PLASMIC评分7分。结合病史、临床表现和实验室检查，患儿明确诊断为SLE相关iTTP。予依库珠单抗治疗2次，同时联合糖皮质激素、血浆输注、免疫球蛋白、硫酸羟氯喹等治疗，患儿血小板快速恢复正常，血浆ADAMTS13活性回升至12%，血浆ADAMTS13抑制物转阴。依库珠单抗治疗儿童iTTP国内尚无病例报道，本例结果提示补体抑制剂对控制iTTP疾病活动有效。

Childhood-onset thrombotic thrombocytopenic purpura (TTP) is very rare, and this article summarizes the clinical data of a child with immune-mediated TTP (iTTP) that occurred 4 years after diagnosis of systemic lupus erythematosus (SLE). The patient was initially diagnosed with SLE and lupus nephritis (Ⅳ+Ⅴ) at the age of 2 years after presenting with edema, hematuria, and albuminuria, and went into remission after treatment with glucocorticoids and tacrolimus, which was discontinued at 5 years old. And one year later, the child was admitted to the hospital with a sudden onset of cutaneous hemorrhagic spots, fatigue, and poor appetite. Laboratory examinations after admission were as follows. Urine protein was "++~+++", and urine red blood cell count was 78.1 per high-power field, with uniform red blood cell morphology. Hemoglobin was 85g/L, mean corpuscular volume of red blood cells was 80.5 fL, platelets were 7×10⁹/L, erythrocyte fragmentation were positive, lactate dehydrogenase was 998 U/L, creatinine was 34.2μmol/L, and indirect bilirubin was 23.1μmol/L. Anti-nuclear antibody in homogeneous type was >1:1000, anti-double-stranded DNA was >300 IU/mL, anti-U1 ribonucleic acid protein antibody was "++", anti-nucleosome antibody was "+", anti-ribosomal P protein antibody was "+", complement C3 was 0.15 g/L, and complement C4 was 0.05 g/L. The activity of plasma ADAMTS13 was 0.72%, and the plasma ADAMTS13 inhibitor was positive. The direct antiglobulin test was positive, the erythrocyte sedimentation rate was 44mm/h, and the PLASMIC score was 7 points. Combined with the history, clinical manifestations and laboratory findings, the child was definitively diagnosed with SLE associated iTTP. After two administrations with eculizumab combined with glucocorticoids, plasma infusion, immunoglobulin, and hydroxychloroquine sulfate, the child’s platelets quickly returned to normal, plasma ADAMTS13 activity rebounded to 12%, and plasma ADAMTS13 inhibitor turned negative. There are no domestic case reports of iTTP in children treated with eculizumab, and the results of our case suggests that complement inhibitors are effective in controlling iTTP disease activity.