Use of a quantitative measurement of genomic RNA and mRNA of the Feline coronavirus in peripheral blood mononuclear cells as a tool for diagnosing feline infectious peritonitis

Abstract

With the development of the real-time RT-PCR reaction new diagnostic methods can be designed for FIP. This study examined the quantitative measurement of the genomic RNA and mRNA in peripheral blood mononuclear cells in cats suspected of FIP. Two different detection methods were used for this measurement and compared. One uses a TaqMan probe and the other uses SYBR Green chemistry. SYBR Green was shown to be a bit less efficient than the TaqMan probe (87% and 94 % respectively). In CRFK cells infected with the FIPV 79-1146 SYBR Green detects a higher amount of gRNA of the FCoV than the TaqMan probe. Bloodsamples were obtained from different veterinary clinics in the Netherlands and samples were divided in groups on likelihood of having FIP. Clinical samples are analyzed for gRNA with both the TaqMan probe and SYBR Green and for mRNA with only SYBR Green. Cats pathological confirmed with FIP show a higher amount of gRNA copies compared to healthy cats and cats with other diseases than FIP. Unfortunately there is a huge variance within each group of cats and therefore this test is not useful a tool for diagnosing FIP. Only a high amount of gRNA copies makes FIP more likely and those cats are probably the ones with specific clinical symptoms. The mRNA measurement in peripheral blood mononuclear cells does not show significant differences between groups of cats. Also the reaction is not specific enough and should be optimized for a better result in the future.