Elevation of serum KL-6 in patients with psoriasis treated with anti-tumour necrosis factor-α therapy.

We report three patients with psoriasis whose serum level of Krebs Von Den Lungen (KL)-6 increased during therapy with anti-tumour necrosis factor (TNF)-α. A diagnosis of early-phase or subclinical interstitial pneumonia was made in two patients, and their KL-6 level decreased after anti-TNF-α discontinuation. The rise in KL-6 in the other patient was attributed to methotrexate. We propose that serum KL-6 should be monitored routinely in patients treated with anti-TNF agents.