[ RNA-preserving fixative? ]

I need to sort infected material with a FACS and then I would like to  
perform qPCR on this sorted cells. Does anyone know a fixative agent/  
protocol that will preserve RNA?
Thank you

Clémentine SCHILTE
cschilte@pasteur.fr
unité ICD
bat metchnikoff
25 rue du docteur Roux
75724 Paris cedex 15
tel   33 (0)1 44 38 94 94
fax  33 (0)1 45 68 85 48