YKL-40 and KL-6 Levels in Serum and Sputum of Patients Diagnosed With Hypersensitivity Pneumonitis

BACKGROUND

YKL-40 (chitinase 3-like-1) and Krebs von den Lungen-6 (KL-6) are 2 promising biomarkers that may have an important role in the management of interstitial lung diseases (ILD).

OBJECTIVE

The aim of this study was to investigate the values of KL-6 and YKL-40 as biomarkers in the diagnosis and prognosis of patients with hypersensitivity pneumonitis (HP).

METHODS

A cross-sectional study conducted in 49 patients diagnosed with HP due to exposure to birds (n = 32) or fungi (n = 17), 48 patients with other ILD, and 67 healthy volunteers. Patients with HP were divided into fibrotic and nonfibrotic. Serum and sputum YKL-40 and KL-6 levels were determined using commercial enzyme-linked immunosorbent assay kits. Receiver operating characteristic (ROC) curves were used to determine the sensitivity and specificity of both biomarkers for the diagnosis of HP. Pulmonary function tests were performed in patients during follow-up.

RESULTS

KL-6 and YKL-40 levels were significantly higher in serum of patients with HP exposed to birds with a fibrotic pattern than in controls (P < .0001 and .0055, respectively). Serum KL-6 levels were also significantly higher in patients with fibrotic HP exposed to fungi compared with the control group (P = .0001). In patients with HP exposed to fungi, sputum KL-6 and YKL-40 levels were higher in those with a fibrotic pattern (P = .0289 and .016, respectively). ROC analysis showed that the range between 55-121 ng/mL for serum YKL-40 levels and 346-1441 U/mL for serum KL-6 levels had the best sensitivity and specificity for discriminating between patients with HP, healthy controls, and patients with idiopathic pulmonary fibrosis (IPF). In patients with HP, serum KL-6 levels correlated negatively with total lung capacity (r = -0.485; P = .0103) and diffusing capacity of the lungs for carbon monoxide (r = -0.534; P = .0002) at 12 months.

CONCLUSIONS

Both KL-6 and YKL-40 proteins seem to be capable of distinguishing patients with HP from healthy individuals and from patients with IPF. Their sensitivity and specificity confirm their potential role as biomarkers. KL-6 may also be a predictor of disease progression.

Pilot Trial of Extended Hypothermic Lung Preservation to Analyze Ischemia-reperfusion Injury in Pigs

BACKGROUND

In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.

METHODS

Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.

RESULTS

We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.

CONCLUSIONS

We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.

Pilot Trial of Extended Hypothermic Lung Preservation to Analyze Ischemia-reperfusion Injury in Pigs

BACKGROUND

In lung transplantation (LT), the length of ischemia time is controversial as it was arbitrarily stablished. We ought to explore the impact of extended cold-ischemia time (CIT) on ischemia-reperfusion injury in an experimental model.

METHODS

Experimental, randomized pilot trial of parallel groups and final blind analysis using a swine model of LT. Donor animals (n=8) were submitted to organ procurement. Lungs were subjected to 6h (n=4) or 12h (n=4) aerobic hypothermic preservation. The left lung was transplanted and re-perfused for 4h. Lung biopsies were obtained at (i) the beginning of CIT, (ii) the end of CIT, (iii) 30min after reperfusion, and (iv) 4h after reperfusion. Lung-grafts were histologically assessed by microscopic lung injury score and wet-to-dry ratio. Inflammatory response was measured by determination of inflammatory cytokines. Caspase-3 activity was determined as apoptosis marker.

RESULTS

We observed no differences on lung injury score or wet-to-dry ratio any given time between lungs subjected to 6h-CIT or 12h-CIT. IL-1β and IL6 showed an upward trend during reperfusion in both groups. TNF-α was peaked within 30min of reperfusion. IFN-γ was hardly detected. Caspase-3 immunoexpression was graded semiquantitatively by the percentage of stained cells. Twenty percent of apoptotic cells were observed 30min after reperfusion.

CONCLUSIONS

We observed that 6 and 12h of CIT were equivalent in terms of microscopic lung injury, inflammatory profile and apoptosis in a LT swine model. The extent of lung injury measured by microscopic lung injury score, proinflammatory cytokines and caspase-3 determination was mild.