The detection and quantitation of inflammation in the central nervous system during experimental allergic encephalomyelitis using the radiopharmaceutical 99mTc-RP128.

Abstract RP128 is a novel agent which readily chelates 99m Tc to form a radiopharmaceutical which binds in vivo to the tuftsin receptor located specifically on neutrophils and monocyte-macrophages, therefore removing the need for in vitro cell labelling prior to intravenous administration. We have assessed the ability of 99m Tc-RP128 to detect central nervous system (CNS) inflammation in experimental allergic encephalomyelitis (EAE), an animal model of the human disease multiple sclerosis. The radiopharmaceutical was recorded at significantly increased levels in all EAE diseased CNS tissues, compared to normal and control samples, at 0.5, 1 and 3 h post-injection using a dual radioisotope technique to correct for non-extravasated tracer ( P 99m Tc-RP128 successfully monitored glucocorticoid suppression of inflammation ( P 99m Tc-RP128 can quantitatively detect CNS inflammation and assess responses to therapy indicating potential value as an imaging agent both clinically and as a research aid. Furthermore, the rapid in vivo labelling by 99m Tc-RP128 of specific inflammatory cells combined with the ability to monitor the progress of anti-inflammatory therapeutics may recommend the agent for use in a variety of inflammatory conditions.