Dynamic analysis of anti-Cov antibody and SARS coronavirus in the plasma of 25 SARS patients / 解放军医学杂志

ABSTRACT

Objective To observe dynamic responsive regularity of specific IgM and IgG antibodies in SARS patients. Methods 145 specimens of plasma from 25 cases of clinically diagnosed SARS patients were examined in the study. ELISA was employed to detect IgM and IgG antibodies against SARS coronaviral antigens. Nested RT-PCR was used to qualitatively determine SARS coronavirus (SARS-CoV). Results 49.0% (71/145) and 54.5% (79/145) of the samples were positive for IgM and IgG antibodies, respectively. Both antibodies were found to be detected in 84.0% of the patients. The antibodies were found to be detectable from the 2nd to 4th week after the onset of disease in most patients, and there was a fendeney of sising in positive rate until the 5th week after the onset. Thereafter, the detectable rate of IgM antibody began to decline, while that of IgG antibody remained to rise. Positive rate for serum SARS-CoV was 15.8% (18/114) for all samples or 40.0% (10/25) of patients. Most virus-positive samples were those which were collected within 4 weeks after disease onset. Conclusions Anti-SARS-CoV IgM/IgG antibody and detection of virus in plasma could serve as practical diagnostic indicators for SARS. In most cases, when the serum was pasitive for antibody the serum virus positive rate would soon declined. However, concomitant existence of antibody and viral sequence in plasma was observed in a few patients.