The Characteristics of Pediatric Patients with Familial Mediterranean Fever Treated with Anti-Interleukin-1 Treatment.

Objective: Interleukin-1 inhibitors are effective agents used in colchicine resistance or intoler- ance during the treatment of familial Mediterranean fever. This study aims to review the char- acteristics of patients treated with interleukin-1 inhibitors and their long-term follow-up in a large pediatric cohort of familial Mediterranean fever patients.

Materials And Methods: The study was conducted in a pediatric rheumatology reference cen- ter. The patients treated with interleukin-1 inhibitors for at least 6 months were included and compared to other patients with familial Mediterranean fever. Clinical and laboratory charac- teristics of the cohort were recorded.

Results: Among 542 patients with familial Mediterranean fever, 6.1% (n = 33) were treated with interleukin-1 inhibitors. Colchicine resistance was the reason in 82.8% and renal amyloidosis in 17.2% of the patients. Patients with interleukin-1 inhibitors had earlier disease onset and higher frequencies of acute arthritis, chest pain, and erysipelas-like erythema with pathogenic exon 10 mutations of the MEFV gene (all P < .04). All patients diagnosed with renal amyloidosis also received interleukin-1 inhibitors. Six patients were switched from anakinra to canakinumab or vice versa to control ongoing disease activity. Attack frequency was reduced in all patients.

Conclusion: Interleukin-1 inhibitors are used in a relatively small number of pediatric patients with familial Mediterranean fever. Patients presenting with earlier disease onset, acute arthri- tis, chest pain, and erysipelas-like erythema and carrying pathogenic exon 10 mutations of the MEFV gene may show a higher need for interleukin-1 inhibitors. In pediatric familial Mediterranean fever patients who are resistant to colchicine, interleukin-1 inhibitors seem to be highly effective agents.