Abstract：
We report the case of an 80 year-old woman who developed bilateral lower extremity purpura and renal impairment with proteinuria a few days after a transient fever (day 0). High levels of both anti-streptolysin-O antibody (ASO) and anti-streptokinase antibody (ASK), as well as low levels of coagulation factor XIII in serum were noted. Skin biopsy was performed and showed a leukocytoclastic vasculitis with deposition of IgA and C3 in the cutaneous small vessels, indicating IgA vasculitis in the skin. After initiation of oral prednisolone, the skin lesions showed significant improvement. However, renal function and proteinuria gradually worsened from day 12. Kidney biopsy was performed on day 29, which demonstrated a necrotizing and crescentic glomerulonephritis with mesangial deposition of IgA and C3. In addition, the deposition of galactose-deficient IgA1 (Gd-IgA1) was positive on glomeruli and cutaneous small vessels, indicating that the purpura and glomerulonephritis both shared the same Gd-IgA1-related pathogenesis. In addition, the association between the acute streptococcal infection and the IgA vasculitis was confirmed by the deposition of nephritis-associated plasmin receptor (NAPlr) in glomeruli. The patient was treated with steroid pulse and intravenous cyclophosphamide, in addition to the oral prednisolone treatment. Renal function and proteinuria gradually improved, but did not completely recover, as is typically seen with courses of IgA vasculitis in the elderly. In this case, the streptococcal infectionrelated IgA vasculitis was confirmed pathologically by the deposition of both NAPlr and Gd-IgA1 in glomeruli, as well as Gd-IgA1 in the cutaneous small vessels.
摘要：
我们报告了一名80岁女性的病例，该女性在短暂发烧（第0天）后几天出现了双侧下肢紫癜和蛋白尿的肾功能损害。高水平的抗链球菌溶血素-O抗体（ASO）和抗链激酶抗体（ASK），以及血清中低水平的凝血因子XIII。进行皮肤活检，显示白细胞碎裂性血管炎，并在皮肤小血管中沉积IgA和C3。提示皮肤IgA血管炎。开始口服泼尼松龙后，皮损明显改善。然而,从第12天开始，肾功能和蛋白尿逐渐恶化。在第29天进行肾脏活检，显示坏死性和新月体性肾小球肾炎，并伴有IgA和C3的系膜沉积。此外,半乳糖缺陷型IgA1（Gd-IgA1）在肾小球和皮肤小血管上的沉积呈阳性，表明紫癜和肾小球肾炎具有相同的Gd-IgA1相关发病机制。此外,肾小球中肾炎相关纤溶酶受体(NAPlr)的沉积证实了急性链球菌感染与IgA血管炎之间的关联.患者接受类固醇脉冲和静脉注射环磷酰胺治疗，除了口服泼尼松龙治疗。肾功能和蛋白尿逐渐改善，但并没有完全恢复,与老年人IgA血管炎的典型病程一样。在这种情况下,通过NAPlr和Gd-IgA1在肾小球中的沉积，病理证实了链球菌感染相关的IgA血管炎，以及皮肤小血管中的Gd-IgA1。
