抗中性粒细胞胞浆抗体滴度检测对微型多动脉炎肾损害活动性的诊…

目的 研究抗中性粒细胞胞浆抗体（ＡＮＣＡ）滴度的动态变化与微型多动脉炎（ＭＰＡ）肾损害病情活动性的关系。方法 动态观察５例活动性微型多动脉炎肾损害患者经甲基强的松龙和环磷酰胺双冲击治疗前后血清抗髓过氧化物酶抗体（ＭＰＯＡＮＣＡ），荧光法ＡＮＣＡ（ＩＦ－ＡＮＣＡ）滴度的动态变化，分析治疗前后患者临床实验室检查和肾组织病理变化。结果（１）病情处于急性活动期，ＭＰＯ－ＡＮＣＡ，ＩＦ－ＡＮＣ滴度升高，（２     

血清抗中性粒细胞胞浆抗体滴度检测对移植肾急性血管排斥的诊断价值

动态观察了４例移植肾急性血管排斥患者经甲基泼尼松龙和环磷酰胺双冲击治疗前后血清抗中性粒细胞胞浆抗体（ＡＮＣＡ）滴度的动态变化，分析患者治疗前后临床实验室检查和肾组织病理变化。结果：（１）病情处于急性排斥期，血清ＡＮＣＡ滴度升高；（２）治疗后，临床症状减轻，肾功能改善，肾组织病理趋于正常时，ＡＮＣＡ滴度降低；（３）随访半年，移植肾排斥缓解，４例患者血清抗髓过氧化物酶抗体（ＭＰＯ－ＡＮＣＡ）均转为阴性，２例荧光法ＡＮＣＡ（ＩＦ－ＡＮＣＡ）转为阴性。结果表明，血清ＡＮＣＡ滴度的动态变化可以作为监测移植肾急性血管排斥的一项指标，对早期诊断和指导治疗有重要意义     

肾移植患者血清抗中性粒细胞胞浆抗体检测的临床意义

目的：评价在肾移植急性血管性排斥反应诊断中用间接免疫荧光法（ＩＦ）检测血清抗中性粒细胞胞浆抗体（ＡＮＣＡ）和ＥＬＩＳＡ法检测血清抗髓过氧化物酶抗体（ＭＰＯ－ＡＮＣＡ）同步检测的意义。方法：回顾性总结了４１例经肾活检确诊的肾移植排斥反应患者ＡＮＣＡ的检出率,了解ＡＮＣＡ阳性的肾移植排斥反应的种类及其临床病理特点。结果：①４１例肾移植患者有１１例血清ＩＦ－ＡＮＣＡ阳性,有１５例血清ＭＰＯ－ＡＮＣＡ阳性     

结节性多动脉炎肾脏损害的早期诊断

总结了２２例经临床和病理确诊的结节性多动脉炎（ＰＡＮ）分析其临床及病理特征，发现（１）微型ＰＡＮ占绝大多数，肾小球和肾小管－间质损害严重，所有确诊病例均非病程早期；（２）肾外以心脏、消化道、肝脏、神经系统损害多见，贫血及高血压发生率较高；（３）半数病例肾脏有免疫复合物沉积；（４）抗中性粒细胞胞浆抗体（ＮＡＣＡ）阳性率低（２９．３％）．对ＰＡＮ的早期诊断及治疗选择有赖于早期肾活检，ＡＮＣＡ只能作为辅助诊断工具，阴性并不能否定ＰＡＮ诊断。     

酶酚酸酯联合小剂量糖皮质激素治疗MPO-ANCA阳性狼疮性肾炎的观察

酶酚酸酯 (ＭＭＦ)是近几年出现的一种新型免疫抑制剂 ,具有独特的免疫抑制效应[1] ,研究表明 ,ＭＭＦ对狼疮性肾炎 (ＬＮ)伴袢坏死和间质血管炎者有良好的治疗作用。抗髓过氧化物酶抗体 (ＭＰＯ -ＡＮＣＡ)是抗中性粒细胞浆抗体 (ＡＮＣＡ)的一种 ,见于多种血管炎性疾病和自身免疫性疾病 ,ＬＮ伴ＭＰＯ -ＡＮＣＡ阳性的现象已有报道 ,与坏死性肾炎、新月体肾炎关系密切 ,可能标志ＬＮ一种特殊类型的病变 ,为探讨ＭＰＯ -ＡＮＣＡ阳性ＬＮ的临床和病理特点及对ＭＭＦ治疗的反应 ,我们用ＭＭＦ治疗 15例ＭＰＯ -ＡＮＣＡ阳性ＬＮ患者 ,现总结…     

氟烷七氟醚对酶诱导缺氧大鼠脂过氧化反应的影响（氟烷性肝炎的研究Ⅰ）

雄性ＳＤ大鼠饮用含苯巴比妥（１ｍｇ／ｍｌ）的饮水一周后，随机分为６组，每组６例：ＮＣ，２１％Ｏ２／７９％Ｎ２；ＨＣ，１４％０；１８６％Ｎｅ；ＮＨ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ氟烷；ＨＨ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ氟烷；ＮＳ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ七氟醚；ＨＳ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ七氟醚。吸入时间１ｈ，２４ｈ后测定血浆及肝匀浆中ＭＤＡ、ＳＯＤ、游离琉基的含量。结果ＨＨ、ＮＨ组肝匀浆及血浆中ＭＤＡ、ＳＯＤ的含量均高于其它各组（Ｐ＜０．０１，Ｐ＜０．０５），余各组间均无显著差异（Ｐ＞０．０５）。ＮＨ、ＨＨ组血浆及肝匀浆中游离琉基的含量显著低于其它各组（Ｐ＜０．０１）。提示氟烷所致的肝脂过氧化反应增强的作用可能与其肝毒性有关，而七氟醚无促进肝脏脂过氧化反应增强的作用。     

抗肾小球基底膜抗体伴抗中性粒细胞胞浆抗体阳性肾炎(四例报告及文献复习)

目的　了解抗肾小球基底膜抗体（ Ａｎｔｉ Ｇ Ｂ Ｍ） 伴抗中性粒细胞胞浆抗体（ Ａ Ｎ Ｃ Ａ） 阳性患者的临床病理特点。方法　对我科近４ 年来６８ 例 Ａｎｔｉ Ｇ Ｂ Ｍ 和（ 或） Ａ Ｎ Ｃ Ａ 阳性患者进行 Ａｎｔｉ Ｇ Ｂ Ｍ 及 Ａ Ｎ Ｃ Ａ 检测,对其中４ 例两者均阳性患者进行临床病理分析。结果　６８ 例患者中４ 例两者均阳性,占全部 Ａｎｔｉ Ｇ Ｂ Ｍ 阳性患者的２４ ％ ,占全部 Ａ Ｎ Ｃ Ａ 阳性患者的７ ％ 。该４ 例患者 Ａｎｔｉ Ｇ Ｂ Ｍ 的百分结合率较单纯 Ａｎｔｉ Ｇ Ｂ Ｍ 阳性患者低。４ 例中３ 例髓过氧化物酶 Ａ Ｎ Ｃ Ａ（ Ｍ Ｐ Ｏ Ａ Ｎ Ｃ Ａ） 阳性,１ 例蛋白酶３ Ａ Ｎ Ｃ Ａ（ Ｐ Ｒ３ Ａ Ｎ Ｃ Ａ） 阳性,全身系统表现较多,与单纯性 Ａ Ｎ Ｃ Ａ 阳性患者相似。所检病例肾脏病理多为新月体肾炎,免疫荧光检查多为 Ｉｇ Ｇ、 Ｃ３ 呈细颗粒样分布于 Ｇ Ｂ Ｍ。虽经积极治疗,多数患者预后较差,类似单纯 Ａｎｔｉ Ｇ Ｂ Ｍ 肾炎。结论　 Ａｎｔｉ Ｇ Ｂ Ｍ 伴 Ａ Ｎ Ｃ Ａ 阳性患者全身表现类似单纯 Ａ Ｎ Ｃ Ａ 相关小血管炎患者,但治疗效果及预后相对较差又类似于 Ａｎｔｉ Ｇ Ｂ Ｍ 肾炎患者     

感染休克病人血中一氧化氮和乳酸浓度的变化

目的：探讨血中一氧化氮（ＮＯ）和乳酸（ＬＡ）在感染休克中的致病机制及与预后的关系。方法：应用荧光分光光度法和光电比色法测定３０例感染休克病人（其中１０例术后并发ＭＯＦ，６例死亡）血中ＮＯ及ＬＡ的动态变化，与３０例择期手术病人进行对照。并观察血中ＮＯ、ＬＡ与平均动脉压（ＭＡＰ）和中心静脉压（ＣＶＰ）以及病情预后的关系。结果：感染休克组ＮＯ和ＬＡ明显高于择期手术组，ＮＯ值与ＭＡＰ、ＣＶＰ呈明显负相关，与ＬＡ值呈明显正相关。ＭＯＦ组ＮＯ和ＬＡ明显高于非ＭＯＦ组，６例死亡病人死亡前达峰值。结论：ＮＯ和ＬＡ在感染休克病人的发病以及组织氧合中起重要作用，可作为预测感染休克病人预后和转归的重要指标之一。     

一氧化氮在大鼠肝硬变门静脉高压症形成中的作用及其对血液动力学的影响

目的探讨一氧化氮（ＮＯ）在肝硬变门静脉高压症（ＰＨＴ）形成过程中的作用。方法采用比色法和鲎试验改良基质显色法，对大鼠肝硬变ＰＨＴ形成过程中，外周血ＮＯ、内毒素浓度和血液动力学的变化进行检测，观察了ＮＯ合成酶抑制剂Ｌ－ＮＭＭＡ对ＰＨＴ大鼠血液动力学的影响。结果（１）在大鼠肝硬变ＰＨＴ形成过程的早、中、晚三期，血浆ＮＯ和内毒素水平显著升高。（２）在肝硬变形成各期门静脉阻力（ＰＶＲ）和门静脉压力（ＰＶＰ）均显著升高，平均动脉压（ＭＡＰ）和内脏血管阻力（ＳＶＲ）显著下降，门静脉血流量（ＰＶＦ）变化不明显。（３）ＮＯ水平和内毒素、ＰＶＰ呈显著正相关。（４）注射Ｌ－ＮＭＭＡ，肝硬变大鼠ＭＡＰ、ＳＶＲ、ＰＶＲ显著升高；ＰＶＦ显著下降；ＰＶＰ变化不明显。结论ＮＯ参与了ＰＨＴ时高动力循环状态的形成，在肝硬变ＰＨＴ的形成和维持中起着重要的作用     

氟烷七氟醚对酶诱导缺氧大鼠脂过氧化反应的影响（氟烷性肝炎的…

雄性ＳＤ大鼠饮用含苯巴比妥（１ｍｇ／ｍｌ）的饮水一周后，随机分为６组，每组６例：ＮＣ，２１％Ｏ２／７９％Ｎ２；ＨＣ，１４％Ｏ２／８６％Ｎ２；ＮＨ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ氟烷；ＨＨ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ氟烷；ＮＳ，２１％Ｏ２／７９％Ｎ２／１．２ＭＡＣ七氟醚；ＨＳ，１４％Ｏ２／８６％Ｎ２／１．２ＭＡＣ七氟醚。吸入时间１ｈ，２４ｈ后测定血浆及肝匀浆中ＭＤＡ、ＳＯＤ、游离巯基     

The inhibition of myeloperoxidase by ceruloplasmin can be reversed by anti-myeloperoxidase antibodies

BACKGROUND: The purpose of this study was to characterize the recently reported inhibition of myeloperoxidase (MPO) by ceruloplasmin and to determine whether this may be disturbed in the presence of anti-MPO antibodies. METHODS: Specificity of the binding between ceruloplasmin and MPO was confirmed by Western blotting and enzyme-linked immunosorbent assay (ELISA), and the enzymatic activity of MPO was measured in the presence of ceruloplasmin, affinity-purified anti-MPO antibodies, or both. The affinity of the binding between MPO and ceruloplasmin and MPO and the anti-MPO antibodies was measured using a biosensor, with the results confirmed by chaotrope ELISA. RESULTS: Affinity-purified anti-MPO antibodies from patients with microscopic polyangiitis and florid renal vasculitis inhibited the binding between ceruloplasmin and MPO to a maximum of 72.9 +/- 12.8%, whereas those from patients with Wegener's granulomatosis and only minimal renal involvement inhibited the binding to a maximum of only 36.8 +/- 10.9% (P < 0. 001), with comparable reversal of the ceruloplasmin-mediated inhibition of MPO activity. Measurement of the affinity of the interactions demonstrated that binding between MPO and the anti-MPO antibodies is stronger than that between MPO and ceruloplasmin (1.61 x 107 to 1.33 x 108 vs. 7.46 x 106 m-1), indicating that binding to the autoantibody would be favored in vivo. CONCLUSIONS: This study confirms a role for ceruloplasmin as a physiological inhibitor of MPO, and demonstrates how the inhibition may be disrupted in the presence of anti-MPO antibodies. Because a majority (16 of 21) of the antibodies did not themselves inhibit MPO activity, their interference with the inhibition mediated by ceruloplasmin may be brought about by steric hindrance consequent upon the binding of the antibody to a dominant epitope at or near the active site.     

Relationship between ANCA and disease activity in small vessel vasculitis patients with anti-MPO ANCA.

BACKGROUND: We analysed the usefulness of antineutrophil cytoplasmic antibodies (ANCA) as a marker of clinical activity in patients with small vessel vasculitis associated with anti-myeloperoxidase (MPO) ANCA. METHODS: We studied a group of 25 patients, 15 with microscopic polyangitis and 10 with renal limited vasculitis, so-called rapidly progressive glomerulonephritis type III. The clinical and serological follow-up was accomplished quarterly over an average of 2.79 +/- 2.08 years (range 0.25-6 years). ANCA was analysed by indirect immunofluorescence and enzyme-linked immunosorbent assays (ELISAs). RESULTS: At the time of diagnosis, all patients were ANCA positive (P-ANCA and anti-MPO). Following a standardized treatment, all patients except one achieved complete remission of vasculitis in <3 months. One patient suddenly died during the active phase (1 month of follow-up) and with positive ANCA. Seroconversion from positive to negative occurred in 24/25 patients (96%). Eighteen of these 24 patients (75%) achieved the seroconversion within the first 6 months. During the follow-up, two patients had four major relapses, all of them associated with positive ANCA. ANCA seroconversion from negative to positive was observed in one patient with microscopic polyangitis without clinical relapse of vasculitis. CONCLUSION: ANCA should be used in conjunction with other markers of disease activity in the management of microscopic polyangitis and renal limited vasculitis patients with anti-MPO ANCA.     

A case of anti-myeloperoxidase antibodies-associated idiopathic crescentic glomerulonephritis with pulmonary hemorrhage]

We report a case of idiopathic crescentic glomerulonephritis with pulmonary hemorrhage associated with anti-myeloperoxidase antibodies (anti-MPO ab). A 74 year-old female was admitted to our hospital because of rapidly progressive glomerulonephritic syndrome and dyspnea with bloody sputum. On admission anti-MPO ab, one of anti-neutrophil cytoplasmic antibodies, were detected but anti-GBM antibodies and immune complexes were not detected. Renal biopsy showed crescentic glomerulonephritis and lung biopsy showed massive alveolar hemorrhage. Both tissue had pauci-immune deposit by immunofluorescence microscopy. Hemodialysis and steroid administration were started. Pulmonary hemorrhage was improved remarkably, but renal failure progressed rapidly to end stage kidney, then hemodialysis was continued. Although subsequent 3 years uneventful maintenance hemodialysis had been performed, she admitted to our hospital again because of progressive dyspnea with hemoptysis after upper respiratory tract infection. On admission anti-MPO ab were detected again and steroid administration was started. Pulmonary hemorrhage was improved with decreased anti-MPO ab titer. While tapering the dosis of steroid, anti-MPO ab again increased and pulmonary hemorrhage recurred. Although pulse methylprednisolone therapy and plasma exchange were performed, respiratory failure progressed rapidly and she died of sepsis. Postmortem examination showed no evidence of systemic vasculitis. In this case, titer of anti-MPO ab was associated with not only idiopathic crescentic glomerulonephritis but also with pulmonary hemorrhage. We tried to detect enzymatically active MPO in serum. Titer of serum MPO was also associated with disease activity and anti-MPO ab. It is suggested that both anti-MPO ab and serum MPO are closely related to the pathogenesis of idiopathic crescentic glomerulonephritis and pulmonary hemorrhage.     

Antimyeloperoxidase antibodies in patients with extracapillary glomerulonephritis

The sera of 64 patients with extracapillary glomerulonephritis were investigated by enzyme-linked immunosorbent assay for the presence of antibody to human neutrophil myeloperoxidase (MPO). In all, circulating anti-MPO were found in 30% and antineutrophil cytoplasm antibodies (ANCA) detected by indirect immunofluorescence in 44% of the patients. Autoantibody to components of neutrophil granulocytes was not found in patients with other forms of glomerulonephritis. The incidence of ANCA (16/23) was higher than that of anti-MPO (5/23) in patients with a diagnosis of Wegener's granulomatosis. By contrast, anti-MPO was found in a majority of vasculitis patients without extrarenal symptoms (6/9), including 3 patients treated with hydralazine. One of the patients treated with hydralazine had circulating ANCA in combination with anti-MPO. Anti-MPO was also found in 1 out of 6 patients with Goodpasture's syndrome. The findings emphasize that autoantibodies to distinct components of neutrophil granulocytes partly differ with regard to diagnostic specificity.     

MPO-ANCA necrotizing glomerulonephritis related to rheumatoid arthritis

Two patients with rheumatoid arthritis (RA) developed necrotizing crescentic glomerulonephritis with high titers of anti-myeloperoxidase antibodies (MPO) in the absence of overt extrarenal vasculitis. We therefore suggest that in some patients with RA, MPO-ANCA necrotizing glomerulonephritis (GN) may occur as a kidney-limited form of rheumatoid vasculitis, and that RA should be added to the list of diseases potentially associated with necrotizing GN with anti-MPO antibodies. These observations also point out the importance of repeatedly evaluating titers of anti-MPO antibodies in the course of RA, especially if renal impairment or abnormal urinary sediment are present. (Am J Kidney Dis 1998 Nov;32(5):E6)     

Antineutrophil-cytoplasmic antibodies and antiglomerular basement membrane antibodies in Goodpasture's syndrome and in Wegener's granulomatosis.

Antiglomerular basement membrane (anti-GBM) diseases-including Goodpasture's (GP) syndrome-and Wegener's granulomatosis (WG) are systemic diseases, which may be diagnosed by means of circulating autoantibodies. Possible overlap syndromes may exist; however, they remain imperfectly defined. We analyzed sera from 31 patients with WG and from 23 patients with anti-GBM disease. All underwent biopsy. Anti-cytoplasmic antibodies (ANCA) were demonstrated by indirect immunofluorescence (IIF); a perinuclear (P-ANCA) or diffuse-cytoplasmic (C-ANCA) staining was discerned. In addition, myeloperoxidase (MPO) antibodies (P-ANCA) and protein 3 (SP3) antibodies (C-ANCA) were analyzed by specific ELISA systems. Anti-GBM antibodies (anti-NC1 antibodies) were detected by ELISA and immunoblotting; the globular domain NC1 of collagen IV was employed as antigen. All 31 WG patients, as defined by clinical and histological criteria, showed ANCA by IIF. Twenty-nine of 31 showed a C-ANCA pattern; all were also positive for SP3 antibodies by ELISA. Three of 31 WG patients were P-ANCA positive by IIF and also had anti-MPO antibodies by ELISA. In one of these patients, SP3 antibodies were additionally found by IIF and by ELISA (double positive). No patient with WG had anti-NC1 antibodies. All 23 serum samples from patients with GP syndrome (N = 19) or anti-GBM glomerulonephritis (N = 4) had anti-NC1 antibodies. In seven of these patients, low titers of anti-MPO antibodies were detected by ELISA; however, the IIF for ANCA was negative. None of these seven patients had extraglomerular vasculities. In addition, the clinical prognosis of these patients was similar to that of those patients who lacked these antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)     

Endothelium myeloperoxidase-antimyeloperoxidase interaction in vasculitis.

Antibodies to myeloperoxidase (MPO) are found in the sera of patients with microscopic polyarteritis and idiopathic crescentic glomerulonephritis. Their pathogenicity is unknown. Studies were carried out on the binding of MPO to cultured human umbilical vein endothelial cells and the recognition of endothelium-bound MPO by antibody to MPO. Endothelial cells were cultured from human umbilical veins. The binding of MPO to endothelial cells and its inhibition by poly-D-lysine was detected using a monoclonal antibody to MPO and direct staining with APAAP and also by an enzyme-linked immunoassay (ELISA). The binding of anti-MPO antibody in the sera of patients with microscopic polyarteritis to endothelium-coated MPO was detected by ELISA. MPO bound to endothelial cells both on direct staining and ELISA and this binding was inhibited by the polycation poly-D-lysine, suggesting that it was charge mediated. Binding of anti-MPO antibody in the sera of patients with microscopic polyarteritis to endothelium-coated MPO was significantly higher than the binding of sera from normal subjects (P = 0.04), patients with idiopathic glomerulonephritis (P = 0.0005), and patients with lupus nephritis (P = 0.009). MPO binds to cultured human umbilical vein endothelium probably by a charge mechanism, and can react with anti-MPO antibodies in the sera of patients with microscopic polyarteritis as well as with a mouse monoclonal anti-MPO antibody. This binding of anti-MPO antibody to MPO fixed to the endothelial cell surface provides a mechanism by which endothelial injury and inflammation might occur in microscopic polyarteritis.     

Asymptomatic autoantibodies associate with future anti-glomerular basement membrane disease

The pathophysiology of anti-glomerular basement membrane (anti-GBM) disease before clinical presentation is unknown. The presence of anti-GBM, anti-proteinase 3 (PR3), and anti-myeloperoxidase (MPO) antibodies associate with the disease at the time of diagnosis, but little is known about the presence of these autoantibodies before diagnosis. We used serum samples from the Department of Defense Serum Repository to conduct a case-control study involving 30 patients diagnosed with anti-GBM disease and 30 healthy controls matched for the age, gender, race, and age of the serum samples. We analyzed a maximum of three samples from each subject: the most recent sample before diagnosis, the penultimate sample before diagnosis, and the oldest sample available; the average time between the most recent sample and diagnosis was 195 days (range, 4 to 1346 days). Elevated anti-GBM levels (≥3 U/ml) were present in four patients, all less than 1 year before diagnosis but in no controls. Detectable anti-GBM antibody levels (≥1 U/ml but <3 U/ml) in a single serum sample before diagnosis were more frequent in cases than controls (70% versus 17%, P < 0.001). Only study patients had detectable anti-GBM levels in multiple samples before diagnosis (50% versus 0%, P < 0.001). Almost all patients had detectable anti-PR3 and/or anti-MPO that preceded the onset of disease. Among patients with a clear antecedent antibody, anti-PR3 or anti-MPO always became detectable before the anti-GBM antibody. In summary, our data describe the subclinical formation of autoantibodies, which improves our understanding of the pathophysiology of anti-GBM disease.     

Anti-neutrophil cytoplasmic antibodies and effector CD4+ cells play nonredundant roles in anti-myeloperoxidase crescentic glomerulonephritis

Most humans with microscopic polyarteritis and anti-myeloperoxidase (anti-MPO), anti-neutrophil cytoplasmic antibodies (ANCA) develop "pauci-immune" crescentic glomerulonephritis. For dissection of the roles of ANCA and cell-mediated effectors in microscopic polyarteritis, experimental autoimmune anti-MPO glomerulonephritis was induced by immunizing C57BL/6 mice with human MPO. Autoimmunity to mouse MPO (ANCA and CD4+ cell reactivity) was induced. Challenge with anti-glomerular basement membrane globulin resulted in accumulation of neutrophils, CD4+ cells and macrophages, and significant numbers of crescentic glomeruli compared with similarly challenged control-immunized mice. MPO-deficient (Mpo(-/-)) mice immunized with MPO developed similar immune responses to MPO but failed to recruit effector cells to glomeruli or develop significant crescent formation, suggesting that MPO is acting as a planted glomerular autoantigen. Effector CD4+ cell depletion in this model attenuated crescentic glomerulonephritis and effector cell influx without altering ANCA titers. However, B cell-deficient mice, with no ANCA, still developed severe crescentic glomerulonephritis with accumulation of effector cells. Intravital microscopy studies demonstrated that passive transfer of sera from MPO-immunized Mpo(-/-) mice to LPS-primed mice rapidly induced glomerular neutrophil accumulation and release of MPO. These studies provide in vivo evidence in a relevant vascular bed for both humoral and cellular anti-MPO responses as key inducers of injury. ANCA induces glomerular neutrophil infiltration and MPO deposition. Subsequently, anti-MPO CD4+ cells recognize MPO as a planted glomerular antigen and act with macrophages to amplify severe glomerular injury.     

Mechanisms of ANCA-mediated leukocyte-endothelial cell interactions in vivo

Anti-myeloperoxidase (anti-MPO) antibodies have been implicated in the pathogenesis of small-vessel vasculitis, but the molecular mechanisms by which these antibodies contribute to disease are unknown. For determination of how anti-MPO antibodies affect inflammatory cell recruitment in small-vessel vasculitis, intravital microscopy was used to monitor leukocyte behavior in the accessible cremasteric microvessels under various experimental conditions. After local pretreatment of the cremaster muscle with cytokines (TNF-alpha, IL-1beta, or keratinocyte-derived chemokine), administration of anti-MPO IgG to wild-type mice reduced leukocyte rolling in favor of augmented adhesion to and transmigration across the endothelium. This led to a decrease in the number of systemic circulating leukocytes and, similar to the early events in the development of vasculitic lesions, an increase in leukocyte recruitment to renal and pulmonary tissue. TNF-alpha led to the greatest recruitment of inflammatory cells, and IL-1beta led to the least. When anti-CD18 was co-administered, anti-MPO IgG did not affect leukocyte rolling, adhesion, or transmigration; similarly, anti-MPO IgG did not produce these effects in Fc receptor gamma chain-/- mice. This study provides direct in vivo evidence of enhanced leukocyte-endothelial cell interactions in the presence of anti-MPO IgG and highlights the critical roles of Fcgamma receptors and beta2 integrins in mediating these interactions. In addition, it suggests that neutrophils primed by cytokines in the presence of anti-MPO IgG can have systemic effects and target specific vascular beds.