Serum KL-6 elevation in a uveitis patient with Behçet's disease treated with adalimumab

PURPOSE: To report a case of uveitis with Behçet's disease in which serum levels of Krebs von den Lungen (KL)-6, a marker of interstitial lung disease, were elevated during treatment with adalimumab and returned to baseline after discontinuation of the agent. OBSERVATIONS: A 67-year-old man complaining of vision disturbance was referred to our hospital. The patient had a history of recurrent episodes of bilateral uveitis and oral ulcers, and had been diagnosed with Behçet's disease. While uveitis activity was not well controlled under administration of oral prednisolone and cyclosporin, cataract of the right eye developed and required surgery. Biweekly administration of adalimumab 40 mg was therefore initiated with prednisolone at 15 mg/day. Uveitis became well controlled and cataract surgery was successfully carried out for the right eye. However, serum KL-6 gradually elevated to 1002 U/ml by 6 months after adalimumab initiation and 1277 U/ml at 9 months. Because serum KL-6 >1000 U/ml has been reported to predict interstitial lung disease, we discontinued adalimumab and started cyclosporine at 100 mg/day. Serum KL-6 gradually decreased and returned to baseline levels, no interstitial lung disease developed and exacerbation of uveitis was avoided. CONCLUSIONS AND IMPORTANCE: This case implies the clinical importance of monitoring serum KL-6 in patents with non-infectious uveitis being treated with adalimumab.