OBJECTIVETo study the response of specific antibodies against severe acute respiratory syndrome (SARS)-CoV in patients infected with SARS.

METHODSIgM-capture, indirect and antigen-sandwiched enzyme linked immunosorbent assay (ELISA) were used to detect the SARS-CoV specific IgM, IgG and total antibodies in sera of clinical SARS patients or non-SARS individuals.

RESULTSThe positive rates of IgM, IgG and total antibodies to SARS-CoV in 146 sera of SARS patients collected in different phases of the disease were 61.64%, 53.43% and 69.86%, respectively. The earliest detectable days after onset of the disease for IgM and IgG to SRAS-CoV were 7 and 12 days, respectively. The specific IgM disappeared as early as 42 days after the onset of SARS. Of 70 sera from hepatitis A patients, 2 showed false positive results, while 127 sera from other patients were all negative, detected by the 3 methods. Serum from one medical worker who had been close contact to SARS patients was positive for anti-SARS-CoV IgG and total antibodies. These 3 methods used for detection were all not influenced by rheumatoid factor (RF).

CONCLUSIONAll of the three methods were specific and sensitive for the detection of specific antibodies to SARS-CoV, and useful for epidemiological research and clinical diagnosis, but not for early diagnosis of SARS.