目的　探讨体液免疫在严重急性呼吸综合征 (severeacuterespiratorysyndrome ,SARS)发病机制中作用。方法　应用光镜、电镜观察SARS尸检和 1例肺穿刺活检组织的病理形态变化 ;用免疫组化及组织化学方法检测组织自身抗体及免疫复合物。结果　SARS患者肺组织呈弥漫性重度损伤 ,肺气 血屏障结构严重破坏 ,血管内皮细胞损伤 ;多脏器血管纤维素样坏死 ,广泛免疫器官损伤及多个器官病变组织存在大量的自身抗体和免疫复合物。电镜下见血管基膜、肾小球系膜区电子致密物沉积。结论　SARS的组织损伤不仅是病毒直接损伤组织 ,而且伴有机体过度免疫反应 ,形成免疫复合物型变态反应 ,提示体液免疫在组织损伤中起重要作用 Objective To investigate the role of humoral immunity in the pathogenesis of severe acute respiratory syndrome (SARS). Methods The morphological changes of SARS autopsy and lung biopsy were observed by light microscope and electron microscope. The autoantibodies and immune complexes were detected by immunohistochemistry and histochemical methods. Results The lungs of SARS patients were diffusely and severely damaged, the structure of the blood-air barrier severely damaged and the vascular endothelial cells were damaged. The multiple organ vessel-like necrosis, extensive immune organ damage and multiple organ diseased tissues existed a large amount of autoantibodies and immunity Complex. Under electron microscope, vascular basement membrane, mesangial area electron dense deposits. Conclusion The tissue damage of SARS is not only the direct damage of the virus, but also the excessive immune response of the body to form immune complex allergy, which indicates that humoral immunity plays an important role in tissue injury