Serum Krebs von den Lungen-6 levels in psoriatic patients under treatment with biologics

Real-world blood examination screening data before initiation of biologics for psoriasis patients

Psoriasis is a chronic immune-mediated inflammatory skin disease characterized by hyperproliferation of epidermal keratinocytes. Biologics have been available for the treatment of patients with refractory psoriasis since 2010 in Japan, and as of December 2021, 10 biologics were available. The Biologics Review Committee of the Japanese Dermatological Association for Psoriasis recommends blood examination tests for antinuclear antibodies (ANA), Krebs von den Lugen (KL)-6, hepatitis B surface antigen (HBsAg), hepatitis B surface antibodies (HBsAb), hepatitis B core antibodies (HBcAb), hepatitis C virus (HCV) antibodies, HIV antibodies, human T-cell leukemia virus (HTLV)-1 antibodies, β-D-glucan, and the T-cell spot (T-SPOT) test before initiation of biologics at screening. In this study, we evaluated the use of biologics for 127 psoriasis patients and the blood examination screening data before initiation of biologics in the real-world setting. Tumor necrosis factor inhibitors, interleukin (IL)-17 inhibitors and IL-23 inhibitors were initiated for 54 (42.5%), 36 (28.3%), and 37 (29.1%) patients, respectively. The numbers of patients positive for ANA, HBsAg, HBsAb, HBcAb, HCV antibody, HIV antibody, HTLV-1 antibody, and T-SPOT were 27 (21.3%), 0 (0%), 22 (17.3%), 20 (15.7%), three (2.4%), zero (0%), one (0.8%), and 4 (3.1%), respectively. The numbers of patients whose KL-6 and β-D-glucan levels were higher than the reference values were seven (5.5%) and seven (5.5%), respectively. In the real-world setting, it is sometimes unavoidable to use biologics for those patients with abnormal data although careful monitoring is necessary.

Effect of anti-interleukin-17 biologics on Krebs von den Lungen-6 level in patients with psoriasis

Interleukin (IL)-17 plays critical roles in the pathogenesis of both psoriasis and interstitial pneumonia (IP). We hypothesized that anti-IL-17 biologics might suppress both clinically relevant and latent IP activity and decrease Krebs von den Lungen-6 (KL-6) level in psoriasis patients. We aimed to elucidate the effects of anti-IL-17 biologics on KL-6 levels. We retrospectively analyzed the clinical data of psoriasis patients treated with anti-IL-17 biologics. KL-6 levels were measured before treatment (baseline) and at 3 and 6 months after the initiation of the treatment, and ratios of KL-6 levels at each time point to the baseline levels were calculated. Chest computed tomography (CT) was performed on patients with coexisting IP. The clinical characteristics and radiographic findings were evaluated. A total of 294 psoriasis patients were treated with anti-IL-17 biologics. Baseline KL-6 levels were higher than 401 U/mL in 34 patients (high baseline KL-6 group). While anti-IL-17 biologics did not affect KL-6 levels and ratios of KL-6 to the baseline levels at any time point in the overall study population, they decreased both KL-6 levels and ratios at 6 months after the initiation of the treatment in the high baseline KL-6 group. A total of 10 patients with coexisting IP showed decreasing ratios of KL-6 to the baseline levels at 6 months without affecting coexisting IP in CT performed at 3-12 months. Anti-IL-17 biologics decreased KL-6 levels in the high baseline KL-6 group regardless of recognizable IP. A decrease in KL-6 levels was not associated with a radiographic improvement of IP, which should be examined in large numbers with long-term observations in future studies.