Scientists have succeeded in using magnetic resonance imaging (MRI) to visualize therapeutic cells transplanted into patients. The technique, described in the November 2005 issue of Nature Biotechnology, should be useful for improving numerous experimental therapies based on transplanting various types of cells, such as immune cells and stem cells.
'Dendritic cells' are specialized immune cells that are being investigated as a means of fighting cancer. To understand why clinical trials using dendritic cells have been less successful than scientists had hoped, Figdor and colleagues wished to determine what happens to the cells after they are transplanted. Adapting an approach that has been demonstrated in animals, they coaxed cultured dendritic cells to take up tiny magnetic particles made of iron oxide. The iron-containing cells were then injected into the lymph nodes of melanoma patients. Imaging with MRI gave a clearer picture of the cells compared with an X-ray method and revealed that, in half the patients, the injection had missed the lymph node altogether, explaining the lack of clinical efficacy. Because the success of any cell therapy depends on getting the cells to the correct site in the body and assuring their survival, the ability to image transplanted cells with MRI will likely facilitate the optimization of many such therapies.
Carl Figdor (Radboud University Nijmegen Medical Centre, The Netherlands)
Additional contact for comment on paper:
Laurence Zitvogel (Institut Gustave Roussy (IGR), Villejuif, France)
Abstract available online.
(C) Nature Biotechnology press release.
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