IL2RA and adult-onset Still disease: In the present study, not only positive correlations between SUVmax of the spleen and those laboratory profiles of AOSD including the levels of LDH, ferritin, and IL-2R were observed, but also the hypermetabolism of the spleen showed a higher correlation coefficient with systemic score and more frequent occurrence in patients with AOSD than those of the bone marrow and LNs.