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The following is a summary of “Evaluating the diagnostic and prognostic utility of serial KL-6 measurements in connective tissue disease patients at risk for interstitial lung disease: correlations with pulmonary function tests and high-resolution computed tomography,” published in the December 2024 issue of Pulmonology by Troncoso et al. 

Researchers conducted a retrospective study to assess the utility of serial Krebs von den Lungen-6 (KL-6) measurements in predicting disease activity and progression in patients with connective tissue disease-associated interstitial lung disease (CTD-ILD).  

They assessed 50 patients with CTD at risk of or diagnosed with ILD from a tertiary care center, KL-6 levels and pulmonary function tests (PFTs) were estimated at baseline, 6 months, and 12 months, along with high-resolution computed tomography (HRCT) scans.  

The results showed the initial KL-6 levels were inversely related to PFTs. Mean KL-6 levels started at 504.96 U/mL (SD ± 508.46) and increased to 739.42 U/mL (SD ± 612.75) at 6 months, reaching 1150.27 U/mL (SD ± 1106.70) by 12 months, indicating disease progression. Elevated KL-6 levels were associated with reduced Forced Vital Capacity (FVC) (P = 0.019) and Diffusing Capacity for Carbon Monoxide (DLCO) (P < 0.001). Radiologically, increased KL-6 was linked with subpleural thickening (P = 0.003), septal thickening (P = 0.036), ground-glass opacities (P = 0.018), and other signs of advanced ILD. The sensitivity and specificity of KL-6 for detecting ILD at a threshold of ≥400 U/mL were 86.7% and 71.4%, respectively, with higher thresholds improving diagnostic accuracy. Patients with elevated KL-6 levels exhibited more significant radiological and functional deterioration over time.  

Investigators concluded the KL-6 as a valuable biomarker for diagnosing, monitoring, and predicting disease activity and progression in CTD-ILD. 

Source: bmcpulmmed.biomedcentral.com/articles/10.1186/s12890-024-03264-7