WATCHING the immune system rev up in response to a tumour or attack the body鈥檚 own tissue may one day give doctors an edge in monitoring and treating disease.
A surge in immune cells can be a first sign of cancer, while a reduction is a clue that a treatment for autoimmune diseases, such as rheumatoid arthritis or lupus, is working. However, these cells are difficult to detect as they are dispersed throughout the body and do not show up using conventional imaging techniques.
To make them more visible, Owen Witte and colleagues at the University of California, Los Angeles, developed a molecular 鈥渢ag鈥� called FAC that binds preferentially to immune cells over other types, and then lights up during a ) scan.
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When the researchers injected FAC into mice and took a PET scan, tissues rich in immune cells, such as spleen and lymph nodes, lit up, indicating that the FAC was working. In mice infected with a virus, and in mutant mice with autoimmune disorders, those tissues lit up more brightly than in uninfected mice or mice without autoimmune disease (Nature Medicine, ). If the technique works in people, it should give doctors an easier way to monitor disease.
