Case Series on the Efficacy and Safety of Tocilizumab in IVIG-Resistant Kawasaki Disease: A Retrospective Analysis of Five Patients

Jiayun Ling,1 Fang Xie,1 Qingfang Zhou,1 Qian Ouyang,1 Lin Li,1 Wei Zhao,2 Xiaohui Liu1 1Department of Rheumatology and Immunology, Jiangxi Children’s Hospital, Jiangxi Medical College, Nanchang, Jiangxi, People’s Republic of China; 2Pediatric Cardiology Treatment Center, Jiangxi Children’s Hospital, Jiangxi Medical College, Nanchang, Jiangxi, People’s Republic of ChinaCorrespondence: Xiaohui Liu, Department of Rheumatology and Immunology, Jiangxi Children’s Hospital, Jiangxi Medical College, Nanchang, Jiangxi, People’s Republic of China, Email [email protected]: Kawasaki disease (KD) is a leading cause of acquired heart disease in children in developed countries. While intravenous immunoglobulin (IVIG) is the standard treatment, 10– 20% of patients do not respond to IVIG. Given the significant role of interleukin-6 (IL-6) in KD pathophysiology, targeting IL-6 may offer a therapeutic option for IVIG-resistant KD.Objective: This study aims to evaluate the efficacy and safety of tocilizumab (an IL-6 receptor antagonist) in the treatment of IVIG-resistant KD through a retrospective analysis of clinical data.Methods: Clinical data from five KD patients treated with tocilizumab (TCZ) at Jiangxi Children’s Hospital from January 2023 to February 2024 were retrospectively analyzed. All patients met the 2017 American Heart Association diagnostic criteria for KD and received a single dose of TCZ. Data on clinical manifestations, laboratory indicators, and coronary artery changes before and after TCZ treatment were collected.Results: Four of the five patients had a KOBAYASHI score > 4, and initial IVIG and glucocorticoid treatments were ineffective. Following TCZ administration, body temperature normalized within 12 hours in three patients, and inflammatory markers, including C-reactive protein and interleukin-6, returned to normal levels. Coronary artery dilation was observed in 75% of patients pre-TCZ; post-TCZ, coronary arteries normalized in three patients, while one patient experienced progressive right coronary artery dilation. No adverse events were reported following TCZ administration.Conclusion: Tocilizumab effectively controls systemic inflammation and improves coronary artery outcomes in IVIG-resistant KD patients, with no observed adverse events. Larger studies are necessary to confirm these findings and further investigate long-term effects on coronary artery health.Keywords: Kawasaki disease, tocilizumab, IVIG-resistant, coronary arteries, inflammatory markers