SARS冠状病毒对血液系统的影响及可能的机制

2002年11月在广东发现首例严重急性呼吸综合征（俗称“非典型性肺炎”）病例。2003年2月世界卫生组织（WHO）在越南河内正式确认此疾病为新的人类传染病，并命名为严重急性呼吸综合征（severe acute respiratory syndrome,SARS）。2003年3月在香港发现其病原体为新的冠状病毒（coronavirus)，称之为SARS冠状病毒（SARS-CoV）。SARS患常常出现异常的血液学改变，包括淋巴细胞减少（在成人为68%-90%；在儿童为100%，n=10），血小板减少（成人20%-45%，儿童50%),和白细胞减少（成人20%-34%，儿童70%）。同时在部份患D-二矣体水平可见升高。初步的研究表明SARS冠状病毒可侵犯造血细胞，但作用机制尚不清楚。我们推测其病理生理过程可能包括：（1）通过CD13或CD66a受体，SARS病毒直接侵入造血细胞或感染骨髓基质细胞等，加重细胞凋亡，引致造血抑制；（2）通过生成自身抗体或免疫复合物等免疫介导造成细胞损害。肺部损害也可部分解释血小板减少。肺部可能是成熟巨核细胞释出血小板的器官之一。SARS病人有广泛肺泡损害，包括充血、水肿、透明膜成，也引致血小板消耗及破坏增加。由于SARS病人常有淋巴细胞减少及免疫功能受损，我们认为造血生长因子如G-CSF，通过动员自身造血干细胞和内源性生长因子，可以增强免疫功能对抗病毒。造血生长因子和造血干细胞在SARS的治疗上，可能有一定的价值。

The Effect of SARS Coronavirus on Blood System: Its Clinical Findings and the Pathophysiologic Hypothesis

Severe acute respiratory syndrome (SARS) has recently recognized as a new human infectious disease. A novel coronavirus was identified as the causative agent of SARS. This report summarizes the hematological findings in SARS patients and proposes a hypothesis for the pathophysiology of SARS coronavirus related abnormal hematopoiesis. Hematological changes in patients with SARS were common and included lymphopenia (68%-90% of adults; 100% of children, n=10), thrombocytopenia (20%-45% of adults, 50% of children), and leukopenia (20%-34% of adults, 70% of children). The possible mechanisms of this coronavirus on blood system may include (1) directly infect blood cells and bone marrow stromal cells via CD13 or CD66a; and/or (2) induce auto antibodies and immune complexes to damage these cells. In addition, lung damage in SARS patients may also play a role on inducing thrombocytopenia by (1) increasing the consumption of platelets/megakaryocytes; and/or (2) reducing the production of platelets in the lungs. Since the most common hematological changes in SARS patients were lymphopenia and immunodeficiency. We postulate that hematopoietic growth factors such as G CSF, by mobilizing endogenous blood stem cells and endogenous cytokines, could become a hematological treatment for SARS patients, which may enhance the immune system against these virus.