Soluble interleukin 2-receptor α secretion is related to altered interleukin 2 production in thermally injured patients

This study examines the relationship between the capacity for interleukin-2 (IL2) production and the magnitude of the in vitro and in vivo secretion of IL2Rα in 43 patients with major burns (30-90 per cent total body surface area). Throughout the postburn period a significant (P < 0.001-0.05) proportion of patients studied demonstrated increasingly high levels of serum IL2 ranging from 2 to over 500 U/mL. Serum IL2Rα also increased, reaching its highest levels at 15-40 days postbum, while serum IL2 gradually declined. In this period in vitro IL2 production and IL2Rα secretion in patient's cultures were significantly reduced compared to control. However, in parallel cultures supplemented with exogenous IL2, IL2Rα levels could be significantly increased (2.5 fold). IL2Rα levels also approached normal in peripheral blood mononuclear cell cultures from recovering patients whose in vitro IL2 production had improved. These observations suggest that in the burn patient altered synthesis and/or secretion of the soluble form of IL2Rα may be related to IL2 content. Above physiological levels of IL2Rα and its ligand in postburn serum also indicate that thermal injury induces strong in vivo activation of the lymphoid system.