NEW AGENTS FOR SCINTIGRAPHY IN RHEUMATOID-ARTHRITIS

Radiopharmaceuticals have been used as investigative tools for the det ection and treatment of arthritis activity in rheumatoid arthritis (RA ) since the 1950s. Against the background of the pathophysiology of RA , the current status of joint scintigraphy and possible future develop ments are reviewed. Both non-specific (radiolabelled leucocytes and te chnetium-99m labelled human immunoglobulin) and specific targeting rad iopharmaceuticals (including radiolabelled antibodies) are considered. The use of radiopharmaceuticals in the detection of arthritis activit y has the advantages of allowing direct imaging of joints by means of whole-body scintigraphy and of joints that are difficult to assess cli n ically or radiographically. Promising results have been obtained wit h radiolabelled anti-CD4 and anti-E-selectin antibodies and with somat ostatin receptor imaging, but more data are available regarding Tc-99m -IgG scintigra phy, which differentiates between the various degrees o f arthritis activity and thus facilitates the choice of antirheumatic drug. Newer promising approaches to the imaging of RA include the use of radiolabelled J001 and cytokines, though studies on these are limit ed at present.