新型冠状病毒肺炎患者自身抗体表达特点分析

Expression characteristic of autoantibodies and association with outcome in COVID-19 patients

目的分析不同临床分型新型冠状病毒肺炎(COVID-19)患者自身抗体阳性率的差异及表达特点,探讨自身抗体对COVID-19患者生存的影响。方法收集2020年1月30日至3月16日于武汉大学中南医院就诊的COVID-19患者的病历资料、自身抗体[抗核抗体谱(ANA),抗心磷脂抗体(ACA)]、炎症因子及一般实验室检查结果进行回顾性分析,同时设置性别年龄匹配的疾病对照组(肺部感染排除2019-nCoV感染和自身免疫性疾病)和健康对照组(健康体检人群)。其中,参与ANA检测COVID-19组72例(危重/重型17例,普通型55例),疾病对照组37例,健康对照组44名;参与ACA检测COVID-19组111例(危重/重型37例,普通型74例),疾病对照组37例,健康对照组40名。比较COVID-19患者不同临床分型自身抗体阳性率及表达水平、ANA阳性与阴性患者炎症因子及其他检验结果差异;Spearman等级相关分析ACA表达水平与其他实验室参数间的相关性;Kaplan-Meier法绘制生存曲线,log-rank时序检验分析自身抗体对生存的影响。结果COVID-19组自身抗体阳性率高于疾病、健康对照组[ANA荧光:22.22%(16/72)、5.41%(2/37)、6.82%(3/44);ANA抗体谱:26.39%(19/72)、8.11%(3/37)、9.09%(4/44);ACA:37.84%(42/111)、8.11%(3/37)、5.00%(2/40);P均<0.05],且危重/重型患者ANA荧光及抗体谱阳性率、ACA-IgM亚型阳性率及表达水平高于普通型[ANA荧光:47.06%(8/17)比14.55%(8/55),ANA抗体谱:66.67%(9/17)比18.18%(10/55),ACA-IgM:30.43%(10/37)比9.46%(7/74);P均<0.05]。COVID-19患者ANA阳性组与阴性组的红细胞指标(红细胞绝对值、血红蛋白浓度、红细胞压积)、活化部分凝血活酶时间、COVID-19相关炎症因子(C-反应蛋白、白细胞介素-6及血清淀粉样蛋白A)比较,差异均有统计学意义(P均<0.05)。ACA-IgM水平与白细胞计数(r=0.354,P<0.001)、中性粒细胞绝对值(r=0.344,P<0.001)、血小板计数(r=0.198,P=0.038)、D2聚体(r=0.260,P=0.009)、丙氨酸转氨酶(r=0.214,P=0.024)、γ-谷氨酰转移酶(r=0.283,P=0.003)、尿素氮(r=0.223,P=0.019)呈正相关,与超氧化物岐化酶呈负相关(r=-0.228,P=0.020)。生存分析显示,ANA阳性或ACA-IgM阳性患者无病累积生存率低于其阴性组(P<0.05)。结论COVID-19患者体内有ANA和ACA自身抗体产生,并且病情越重自身抗体阳性率和表达水平越高,其中ANA、ACA-IgM可为COVID-19生存预后提供参考价值。

Objective To investigate the difference and characteristics of autoantibodies expression in patients infected by 2019-nCoV with various severity,and explore the associations between expression profile of autoantibodies and prognosis of COVID-19 patients.Methods This retrospective study was conducted on patients with COVID-19 admitted to Zhongnan Hospital,Wuhan University from January 30,2020 to March 16,2020.Data on medical records,expression of autoantibodies including antinuclear antibody profile(ANA),anticardiolipin antibody(ACA),inflammatory factor and other laboratory indexes were collected and analyzed.The age and sex matched disease controls(cases of pulmonary infection unrelated to 2019-nCoV infection and autoimmune disease)and healthy controls(healthy check-up individuals)were also included.Following groups were established,ANA test groups:72 cases of COVID-19 group(including 17 critical and severe cases,and 55 mild cases),37 disease controls and 44 healthy controls;ACA test groups:111 cases of COVID-19 group(including 37 critical and severe cases,and 74 mild cases),37 disease controls and 40 healthy controls.The difference of positive rate or expression level of autoantibodies among various groups was analyzed,and the difference of inflammatory biomarkers and other parameters were compared between patients with ANA positive results and negative results.The Spearman correlation test was applied to determine the relationship between ACA and other parameters.Kaplan-Meier estimation was used to plot survival curves,the log-rank analysis was utilized to explore the association between antibodies and outcome of COVID-19 patients.Results The positive rate of antibodies was significantly higher in the COVID-19 group than disease and healthy control groups,the ANA fluorescence:22.22%(16/72),5.41%(2/37),6.82%(3/44);ANA spectrum:26.39%(19/72),8.11%(3/37),9.09%(4/44);and ACA:37.84%(42/111),8.11%(3/37),5.00%(2/40);all P<0.05.The positive rate of ANA,ACA-IgM and the expression level of ACA-IgM were significantly higher in severe COVID-19 subgroups(critically and severe COVID-19 patients)than in the mild COVID-19 patients(the ANA fluorescence:47.06%[8/17]vs.14.55%[8/55],ANA spectrum:66.67%[9/17]vs.18.18%[10/55],ACA-IgM:30.43%[10/37]vs.9.46%[7/74];all P<0.05).There were significant differences in the number of red blood cells,hemoglobin concentration,hematocrit,activated partial thromboplastin time,C-reactive protein,interleukin-6 and serum amyloid A between COVID-19 ANA-positive group and COVID-19 ANA-negative group(all P<0.05).The level of ACA-IgM was positively correlated with white blood cell count(r=0.354,P<0.001),neutrophil count(r=0.344,P<0.001),platelet count(r=0.198,P=0.038),D-Dimer(r=0.260,P=0.009),glutamic-pyruvic transaminase(r=0.214,P=0.024),γ-glutamyl transpeptidase(r=0.283,P=0.003),blood urea nitrogen(r=0.223,P=0.019),and negatively correlated with superoxide dismutase(r=-0.228,P=0.020).Survival analysis showed that cumulative survival rate of event-free survival(EFS)was lower in patients with positive ANA/ACA-IgM results than in patients with negative ANA/ACA-IgM results(P<0.05).Conclusions ANA and ACA autoantibodies can be detected in COVID-19 patients.The positive rate and the expression level of ANA and ACA increase in proportion with the severity of COVID-19 patients.ANA and ACA-IgM could be used as risk stratification determinants for predicting survival of COVID-19 patients.