A novel serological technique: polymerase chain reaction enhanced immunoassay. Application to enterovirus IgM diagnosis

The polymerase chain reaction (PCR) method is a sensitive, specific and rap id technique for virus detection. The principles of a PCR enhanced immunoas say (PIA) are described. The method combines solid phase serological techni ques with the PCR, providing a versatile and sensitive method for antibody detection. By linking the antigenicity of virus particles with their conten t of nucleic acid, the method provides new possibilities for virus serology : for example, antibody specificity can be coupled to viral sequence in pat ients with chronic infections caused by highly variable viruses such as HIV and HCV. An application of the PIA technique is described for the detectio n of anti-enterovirus IgM. IgM is captured to anti-human IgM-coated microwe ll plates. The anti-enterovirus IgM is allowed to bind crude enterovirus an tigen. Bound virus is heat denatured and the released RNA is used as a temp late for reverse transcription PCR (RT-PCR) amplification. Amplicons are de tected by hybridisation to an affinity labelled probe in a microwell colori metric assay. In a pilot study, 18 serum specimens from patients with enter ovirus infections were examined. Using a mixture of ten crude enterovirus a ntigens, the frequency of IgM positivity was 6/18 (33%). Titres between 1/5 00 and 1/100 000 were recorded. Predominantly type-specific antibodies were detected. The results were compared with a procapsid enterovirus radioimmu noassay (RIA). After further optimisation, the PIA has the potential to be a clinically useful assay for the detection of antiviral antibodies. (C) 19 99 Published by Elsevier Science B.V. All rights reserved.