Department of Pathobiology and Diagnostic Investigation, College of Veterinary Medicine, Michigan State University, East Lansing, MI 48824, USA.
Vet Pathol. 2010 Jan;47(1):140-7. doi: 10.1177/0300985809352793.
Vasculitis is a hallmark lesion of the severe form of systemic porcine circovirus-associated disease (PCVAD). In 2 experimental studies with porcine circovirus type 2 serogroup b (PCV2b), 2 pigs developed fatal PCVAD with acute vasculitis, and 5 related pigs developed chronic lymphohistiocytic and plasmacytic peri- and endarteritis. Five of these pigs (1 with acute vasculitis and 4 with chronic vasculitis) had also been inoculated with bovine viral diarrhea virus type 1 (BVDV1) or BVDV1-like virus. Vascular lesions were similar, independent of whether pigs had been inoculated singly with PCV2b or dually with PCV2b and BVDV1 or BVDV1-like virus. The acute vasculitis was accompanied by marked pulmonary and mesenteric edema and pleural effusion. In situ hybridization demonstrated abundant intracytoplasmic porcine circovirus type 2 (PCV2) nucleic acid in endothelial, smooth muscle-like, and inflammatory cells within and around affected arteries. The pigs with lymphohistiocytic and plasmacytic vasculitis had lesions of systemic PCVAD, including multisystemic lymphoplasmacytic and histiocytic or granulomatous inflammation. PCV2 nucleic acid was detected in renal tubule epithelial cells, mononuclear inflammatory cells, and rare endothelial cells in noninflamed vessels in multiple tissues of these animals. The 2 pigs with acute vasculitis had no PCV2-specific antibodies (or a low titer of), whereas the pigs with lymphohistiocytic and plasmacytic vasculitis developed high antibody titers against this virus. These observations suggest that (1) acute vasculitis observed in the current studies is directly caused by PCV2b, (2) chronic vasculitis may in part be mediated by the subsequent immune response, and (3) host factors and viral strain may both contribute to vasculitis in animals infected with PCV2b.
血管炎是猪圆环病毒相关疾病（PCVAD）严重形式的标志性病变。在两项针对猪圆环病毒 2 型血清型 b（PCV2b）的实验研究中，2 头猪发生了致命的 PCVAD，伴有急性血管炎，5 头相关猪发生了慢性淋巴组织细胞性和浆细胞性动脉炎和动脉周炎。这 5 头猪（1 头急性血管炎和 4 头慢性血管炎）也接种了牛病毒性腹泻病毒 1 型（BVDV1）或 BVDV1 样病毒。无论猪单独接种 PCV2b 还是同时接种 PCV2b 和 BVDV1 或 BVDV1 样病毒，血管病变都是相似的。急性血管炎伴有明显的肺和肠系膜水肿和胸腔积液。原位杂交显示，受影响动脉内和周围的内皮细胞、平滑肌样细胞和炎症细胞中存在丰富的细胞质猪圆环病毒 2 型（PCV2）核酸。患有淋巴组织细胞性和浆细胞性血管炎的猪患有全身性 PCVAD 病变，包括多系统淋巴浆细胞性和组织细胞性或肉芽肿性炎症。在这些动物的多个组织的肾小管上皮细胞、单核炎症细胞和非炎症血管中的少数内皮细胞中检测到 PCV2 核酸。2 头发生急性血管炎的猪没有针对 PCV2 的特异性抗体（或抗体滴度较低），而发生淋巴组织细胞性和浆细胞性血管炎的猪则针对该病毒产生了高抗体滴度。这些观察结果表明：（1）当前研究中观察到的急性血管炎是由 PCV2b 直接引起的；（2）慢性血管炎部分可能是由随后的免疫反应介导的；（3）宿主因素和病毒株可能都导致感染 PCV2b 的动物发生血管炎。
