ANALYSIS OF FALSE-POSITIVE ASSOCIATED WITH ANTIBODY TESTS FOR SARS-COV IN SLE PATIENTS
WANG Yun Shan SHEN Hong SUN Shan Hui JIANG Li Hua LIU Yang ZHU Zhi Wei XIAO Dong Jie HUANG Ping YANG Bo DU Xi Yan ZHANG Yuan Chao ( Centrol Laboratory, Jinan Centrol Hospital, Clinmal Medical College of Shandong University Jinan 250013; Department of Rheumatology, Shandong People's Hospital, Jinan 250021)
To discuss the fasle-positive of serological diagnostic testing for coronavirus antibody in patients with systemic lupus erythematosus(SLE), 66 normal individual and 31 SLE with non-SARS patients were detected for SARS-associated coronavirus (SARS-CoV) antibody and RNA by enzyme-linked immunosorbent assays(ELISA) and reverse transcriptase-polymerase chain reaction(RT-PCR). The result showed 2/66 cases(3. 0%) were positive of SARS-CoV-IgG antibody and 66 cases were negative of SARS-CoV-IgM antibody in the 66 cases healthy controls; in 31 cases with SLE, positive rates of SARS-CoV-IgG and IgM antibody were 58. 1 % ( 18/31 ) and 29% (9/31), respectively, in which 7 cases(22. 6% ) were positive of both SARS-CoV-IgG and IgM antibody. All samples of positive SARS-CoV-IgG and IgM antibody were negative by RT-FCR. The ELISA kit coated by non-purification antigen may induce the false-positive of SARS-CoV antibody in patients with SLE. This result suggested that the specificity of ELISA tests for SARS was excellent and has low fasle-positive rates when using SARS-CoV-IgG and IgM antibody tests .A possible cause of false-positive of SARS-CoV-IgG and IgM antibody in SLE patients is coated antigens with SARS-CoV and Vero-E6 cells in ELISA methods.