A method to amplify and detect TNF-alpha mRNA from primed Mono Mac 6 cells is described. A silica-based extraction system was utilised for preparation of cell extracts and specific oligonucleotide primers were designed for amplification of TNF-alpha mRNA by the NASBA process. Amplification products were detected using either a liquid hybridisation assay, with analysis by polyacrylamide gel electrophoresis, or a plate hybridisation system. The method has many potential applications for the study of inflammatory cytokines and cellular mRNAs in cell culture and clinical samples. (C) 1998 Elsevier Science B.V. All rights reserved.