Serum levels of interleukin-1beta (IL-1beta), IL-1 receptor antagonist (IL-1ra), tumour necrosis factor alpha (TNF-alpha), IL-6, soluble IL-6 receptor (sIL-6R), soluble intercellular adhesion molecule-1 (sICAM-1) and soluble E-selectin were measured in 15 patients with newly diagnosed polymyalgia rheumatica (PMR) before and after 3 months of corticosteroid therapy. Both IL-6 and IL-1ra were significantly increased in untreated PMR and remained elevated compared with controls during therapy, although significantly only for sIL-1ra. sICAM-1 was raised in 12/15 (87%) patients at diagnosis and remained high in 10/14 (71%) patients; soluble E-selectin levels were initially raised in 6/15 (40%) patients and decreased with therapy in those with the highest levels. IL-6, IL-1ra and sICAM-1 are sensitive indicators of continuing immunological activation in PMR; the advantages of these markers in assessing the response to therapy should be investigated in a longitudinal study.