Impact of anti‐tumor necrosis factor‐α agents on serum levels of KL‐6 and surfactant protein‐D in patients with psoriasis

We longitudinally examined the influence of anti‐tumor necrosis factor (TNF)‐α treatment on serum levels of KL‐6 and surfactant protein‐D (SP‐D). The study group comprised 22 patients with psoriasis treated with infliximab or adalimumab and with no history of interstitial lung disease (ILD). KL‐6 and SP‐D levels were measured in serum samples. Twelve of the 22 patients (55%) showed at least a 20% increase in KL‐6 levels compared with baseline. Of these 12 patients, none exhibited any signs of ILD on chest computed tomography and nine who showed an increase in KL‐6 levels (75%) showed at least a 20% increase in SP‐D levels. Some patients showed simultaneous increases in KL‐6 and SP‐D levels after treatment with anti‐TNF‐α agents. Although these patients may have undetectable or subtle alveolar damage, careful observation is needed.