Abstract
Thirty percent of acute liver graft rejection episodes are resistant to steroids. As interleukin-1 (IL-1) is an important target of steroid therapy, we examined the possible involvement of reduced sensitivity of IL-1 production to steroids or defective production of its antagonist, IL-1Ra. Patients were assessed during steroid-sensitive or -resistant rejection and 2 years later. In situ IL-1beta and IL-1Ra expression was evaluated by immunohistochemistry; their production was assayed by enzyme-linked immunosorbent assay and the gene polymorphisms by reverse transcriptase-polymerase chain reaction on blood cells. Hepatic IL-1beta and IL-1Ra expression were enhanced during rejection. IL-1 production and its inhibition by steroids were similar in steroid-responsive and steroid-resistant rejection. However, IL-1Ra production was lower in steroid-resistant than in steroid-responsive rejection, and this difference was still observed 2 years after rejection. IL-1beta and IL-1Ra gene polymorphisms did not differ between patients with and without steroid resistance. Low IL-1Ra production is associated with steroid resistance of acute rejection and is due to a constitutional defect. The early identification of such patients might qualify them for stronger anti-rejection therapy, including IL-1Ra.