Purpose: Our aim was to evaluate the expression of interleukin-18 (IL-18), interleukin-1-beta (IL-1ß) and the amount of elastase activity in gingival crevicular fluid (GCF) from inflamed gingival sites in patients with juvenile systemic lupus erythematosus (JSLE), and compare these to the expression in GCF from inflamed sites in generally healthy controls. In addition, the local inflammation in periodontal tissues was related to systemic inflammation by the assessment of IL-18 levels in plasma. Materials and Methods: GCF from 16 patients with JSLE and 14 controls were collected using a washing device. Elastase activity was measured with a specific substrate, and IL-18 and IL-1ß were measured by ELISA. Results: The percentage of visible plaque index, gingival bleeding index and attachment level were similar in JSLE and controls, while the percentage of probing depth greater or equal to 3 mm was significantly higher in the controls. The total amount of IL-1ß and IL-18 in GCF were significantly decreased in JSLE, while the total amount and the percentage of free elastase activity were significantly higher in JSLE when compared with the controls. The plasma levels of IL-18 and the erythrocyte sedimentation rate were significantly higher in JSLE patients. Conclusion: We found more active elastase in GCF from inflamed sites in JSLE patients even in the presence of significantly lower levels of IL-18 and IL-1ß. The increased elastase activity suggests a hyperactivity of neutrophils in JSLE, possibly generated by a priming effect caused by the higher plasma levels of IL-18 found in these JSLE patients. Schlagwörter: elastase, IL-18, IL1-ß, juvenile systemic lupus erythematosus, periodontitis