NEW YORK (Reuters Health) – Calcineurin inhibitors are effective when Kawasaki disease (KD) is resistant to intravenous immune globulin (IVIg), doctors say in a recent publication.
Nine of their 10 young patients with refractory KD responded quickly to cyclosporine. The tenth child received tacrolimus and also responded well.
Dr. Jane C. Burns, senior author of the report online April 6th in the Journal of Pediatrics, told Reuters Health by email that roughly 5% of children with KD are resistant to IVIg. They are “a challenging subset of patients to treat,” she said.
Steroids, infliximab, plasmapheresis, methotrexate, cyclophosphamide, and calcineurin inhibitors have all been tried before, with mixed results. One Japanese study showed particular success with cyclosporine, Dr. Burns and her co-authors said.
The 10 children in the current report all carried at least one risk allele for KD. The nine children given cyclosporine started off on IV therapy and then were switched to the oral micronized formulation. The child who received tacrolimus took it orally.
The authors say treatment was well tolerated and produced defervescence and resolution of inflammation in all 10 patients. Analysis in two patients showed a decrease in circulating activated CD8+ and CD4+ T effector memory cells.
Regulatory T-cells were not suppressed, however, suggesting that the calcineurin inhibitor, “selectively inhibits the proinflammatory T-cell compartments,” the research team wrote.
Dr. Burns added, “Calcineurin inhibitors target a key inflammation pathway identified by our genetic studies and can be an effective and safe therapy for these difficult patients.”
Experience with calcineurin inhibitors for treatment of other conditions may be the best guide to use in these patients, the authors say. “Given the small numbers of patients with highly resistant KD,” they conclude, “a prospective clinical trial would be challenging to design and execute.”
Dr. Burns is at Rady Children’s Hospital in La Jolla, California and the University of California, San Diego. She and her coauthors had no conflicts of interest to report.
J Pediatr 2012.