SARS患者7年随访血清抗体变化规律及胃肠道免疫组化研究

目的 连续7年随访严重急性呼吸综合征(SARS)患者血清特异性IgM、IgG及N蛋白抗体滴度变化,应用胃肠镜观察胃肠道的病理改变并进行免疫组织化学研究.方法 应用免疫荧光(IFA)和双抗原夹心ELISA方法,对SARS患者发病1年后采用每隔1年检测一次血清SARS病毒(SARS-CoV)特异性IgM、IgG及N蛋白抗体滴度;用抗SARS-CoV N蛋白单克隆抗体对SARS恢复期患者胃肠道组织进行免疫组化研究.结果 14例SARS患者特异性IgG抗体1年后平均滴度为1/71(95%CI:1/58～1/85),连续追踪7年呈下降趋势,7年后大部分患者IgG抗体滴度消失,特异性IgM抗体1年后消失,N蛋白抗体1年后平均滴度为1/146(95%CI:1/122～1/171),与IgG抗体变化同时呈下降趋势.7年后其中9例患者检测N蛋白抗体全部为阴性,另5例临床症状较重的患者,N蛋白抗体仍检测阳性,其中3例N蛋白抗体滴度维持在1/156～1/210之间,2例N蛋白抗体滴度接近正常.该5例患者行胃肠镜检测和细胞免疫组化试验,血中N蛋白抗体检测阳性的3例患者胃组织黏液腺上皮细胞免疫组化呈阳性表达,大部呈胞浆着色.其中1例患者在肠组织浆液柱状上皮及间质细胞亦有表达,另2例血清N蛋白抗体检测接近正常的患者,细胞免疫组化为阴性.5例患者病理活检:1例明确诊断为"胃印戒细胞癌并直肠多发转移"、1例"胃息肉"、1例"浅表性胃窦炎",其余2例正常.结论 SARS患者血清特异性IgM、IgG、N蛋白抗体在恢复期呈下降趋势,7年后大部分消失;N蛋白抗体变化规律与病情轻重程度有关.

Study on the changing regularity of special antibody and expression of stomach and enteric involvement on SARS-coronavirus infection in the recovery period of severe acute respiratory syndrome

Objective To study the change of special antibodies titer IgG, IgM and nucleocaspid to SARS coronavirus (CoV) and observing the expression of stomach and enteric involvement on SARS-CoV infection by monoclonal antibody against N protein of SARS-CoV in the 7- year recovery period among family clustering cases of severe acute respiratory syndrome. Methods Special antibody titer to SARS-CoV of 14 patients from 5 different families and their 10 kinfolks continuously tested by IFA and antigen-capturing ELISA methods. Samples were taken in the 1st-7th year periods after SARS patients infected by SARS-CoV, being diluted and measured on it titers of three kinds of antibodies. Immunochemical staining with monoclonal antibody (mAb) against N protein of SARS-CoV was used to determine the stomach and enteric tissues among 5 SARS patients with their nucleocaspid antibody titer ascended obviously after 1st-7th year. Results When testing the IgG antibody titer of the 14 SARS patients by IFA method, the average titer was 1/71 (95%CI:1/58-1/85) in the 1st year, but began to descend in the following years, and the IgG antibody of the most SARS patients disappeared in the 7th year. Regarding the IgM titer, it disappeared in most of the SARS patients 1 year later. The average value of nucleocaspid antibody titer was 1/146 (95% CI:1/122-1/171) in the 1st year, and it descended as the IgG antibody titer did. In 5 cases, differences appeared.The nucleocaspid antibody titer was between 1/156 and 1/210 in 3 cases, and 2 cases were normal.Immunochemical staining with mAb against N protein of SARS-CoV was identified in the stomach and enteric tissues of 5 SARS patients with the nucleocaspid antibody titer increased significantly, 1st-7th year later. The five patients were detected by gastroscopy detection and cell immunohistochemistry test. 3 cases showed N protein antibody positive in the serum, and positive immunohistochemical expression in most of the cytoplasm in the gastric tissue mucous gland epithelial cells. 1 case also expressed in the intestinal tissue slurry columnar epithelium and interstitial cells. The other two cases showed negative on both serum N protein antibody and immunohistochemical expression. The biopsy results of the 5 patients were as follows: 1 case diagnosed as "signet-ring cell carcinoma of the stomach and rectum multiple transfer", 1 case of gastric polyp, 1 case of superficial antral gastritis and 2 cases were normal. Conclusion By testing the special IgG, IgM, nucleocaspid antibody to SARS-CoV of the 14 family clustering cases , we found that they all decreased in the 7th year, and most of them disappeared. The nucleocaspid antibody titer was related to pathogenetic condition. SARS-CoV was proved to be still present in stomach and enteric tissues of SARS patients with the nucleocaspid antibody titer increased significantly after the 7th year.