Clinical significance of serum lipids in idiopathic pulmonary alveolar proteinosis

We retrospectively reviewed 25 patients with idiopathic PAP(iPAP). The serum lipid levels of patients with idiopathic PAP were compared with those of the healthy volunteers. In patients and healthy subjects, the LDL-C/HDL-C ratios were 2.94 ± 1.21 and 1.60 ± 0.70, respectively (p < 0.001), HDL-C were 1.11 ± 0.27 and 1.71 ± 0.71 respectively (p < 0.001). The values of LDL-C correlated significantly with those of PaO2 and PA-aO2 (r = -0.685, p = 0.003, and r = 0.688, p = 0.003, respectively). The values of LDL-C/HDL-C ratios also correlated with PaO2 levels and PA-aO2 levels (r = -0.698, p = 0.003, and r = 0.653, p = 0.006, respectively). 11 and 13 patients experienced respectively a decline in TC and LDL-C levels following whole lung lavage(WLL), the median decline was 0.71 mmol/L(p < 0.009) and 0.47 mmol/L(p < 0.003), respectively.the serum lipid levels, especially the levels of LDL-C and LDL-C/HDL-C, may reflect the severity of the disease in PAP patients, and predict the therapeutic effect of WLL.Pulmonary alveolar proteinosis(PAP) is a rare disease characterized by the accumulation of lipoproteinaceous material in the alveoli[1]. Clinically, Three forms of PAP have been described: congenital, secondary, and idiopathic. More than 90% of patients are idiopathic PAP(iPAP), is specifically associated with the presence of granulocyte-macrophage colony stimulating factor(GM-CSF) autoantibodies that are thought to mediate pathogenesis by eliminating GM-CSF bioactivity, thereby this loss of functional GM-CSF results in a filling of the alveolar spaces of the lungs with the lipoproteinaceous material called pulmonary surfactant[2,3].Pulmonary surfactant is comprised of 90% lipid, 10% protein, and less than 1% carbohydrate. Cholesterol is the major neutral lipid (up to 90%) in pulmonary surfactant. At least 80% of the cholesterol present in the lung[4], and virtually all that in surfactant, is derived from circulating lipoproteins, with very low-density lipoprotein believe