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

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.

Characteristics of anti-IL-17/23 biologics-induced interstitial pneumonia in patients with psoriasis

Objectives

Anti-IL-17/23 biologics are increasingly used to treat psoriasis. We aimed to elucidate characteristics of drug-induced interstitial pneumonia (DIIP) caused by anti-IL-17/23 biologics.

Methods

We retrospectively analyzed the clinical data of psoriasis patients treated with anti-IL-17/23 biologics. Chest CT was performed to evaluate DIIP. Serum KL-6 levels were measured before treatment (baseline) and during treatment.

Results

A total of 603 psoriasis patients were treated with anti-IL-17/23 biologics with mean follow-up of 21.1 months. Six patients developed DIIP at mean 14 months after initiation of the therapy. Older age, higher baseline KL-6 value and more frequent pre-existing IPs were associated with development of DIIP by univariate analysis. At the onset of DIIP, elevated serum KL-6 levels with concomitantly increased ground glass opacity (GGO) in Chest CT were demonstrated. DIIP was improved by only cessation of causative agents in five patients but steroid therapy was needed in one patient.

Conclusions

DIIP is a plausible complication of anti-IL-17/23 biologics. Age, baseline KL-6 level and underlying IP could be the risk factors for DIIP development. Serum KL-6 levels and chest CT are useful for not only predicting but also detecting DIIP caused by anti-IL-17/23 biologics.

A Patient with KL-6 Elevation with Anti-TNFα Who Could Receive Long-Term Use without Interstitial Pneumonia after Class Switch of Anti-TNFα

A 40-year-old man with refractory ulcerative colitis (UC) was treated with tumor necrosis factor α inhibitor (anti-TNFα), infliximab. One month later, the chest computed tomography and laboratory test showed noninfectious interstitial lung disease (ILD) and elevation of serum Krebs von den Lungen-6 (KL-6). Fortunately, ILD disappeared after the discontinuation with anti-TNFα. Two and a half years after his first UC treatment, he was treated again with another anti-TNFα, adalimumab, for relapse and he had a second ILD. This course suggested anti-TNFα induced ILD. The characteristics of anti-TNFα-induced ILD in inflammatory bowel disease (IBD) are not well understood. We summarized and investigated the characteristics of such patients based on a literature review including 15 cases. It suggested that anti-TNFα-induced ILD in IBD might be rare and tends to have a better outcome compared with ILD in rheumatoid arthritis.

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.