Role of serum vascular endothelial growth factor D in discrimination of patients with polycystic lung diseases.

INTRODUCTION Polycystic lung diseases (PLDs) include numerous rare diseases including lymphangioleiomyomatosis (LAM), pulmonary Langerhans cell histiocytosis (PLCH), and lymphocytic interstitial pneumonia. In these cases, diagnosis is based on a histological examination of open lung biopsy samples; however, it is not always possible to perform this procedure. Serum markers characteristic for a given entity are still being sought. OBJECTIVES The aim of the study was to determine the usefulness of assessing serum vascular endothelial growth factor D (VEGF‑D) concentration in the differential diagnosis of LAM and other PLDs (OPLDs). PATIENTS AND METHODS Serum VEGF‑D levels were measured by an enzyme‑linked immunosorbent assay in 75 patients with PLDs including 29 women with LAM and 46 patients with OPLDs (28 women and 18 men). RESULTS Serum VEGF‑D levels were significantly higher in patients with LAM (median, 1557 pg/ml; interquartile range [IQR], 636-2593 pg/ml) than in all patients with OPLDs (median, 292 pg/ml; IQR, 233-405 pg/ml, P <0.0001) or than in women with OPLDs (median, 344 pg/ml; IQR, 243-452 pg/ml, P <0.0001). The serum VEGF‑D level exceeding 468 pg/ml identified LAM patients with the specificity of 90% and sensitivity of 87% (area under the curve of 0.908; 95% confidence interval, 0.820-0.996). In none of the patients with OPLDs serum VEGF‑D concentrations exceeded 800 pg/ml. CONCLUSIONS An increased serum VEGF‑D level is a highly specific biomarker useful in a differential diagnosis of LAM and OPLDs.