Could the chylomicron marker apoB48 be of value in the diagnosis of chylous effusions?

• Published in: Clinica chimica acta 2023-01, Vol.539, p.184-190
• Main Authors: Lefrère, Bertrand, Sakka, Mehdi, Fourati, Salma, Levasseur, Antoine, Curis, Emmanuel, Cherfils, Corinne, Grès, Pierre, Guilbert, Zoé, Lacorte, Jean-Marc, Chenevière, Cristina, Bittar, Randa, Bonnefont-Rousselot, Dominique
• Format: Article
• Language: English
• Subjects: apoB48; Apolipoprotein B-48; Chylomicron; Chylomicrons; Chylothorax - diagnosis; Chylous effusion; Humans; Life Sciences; Lipoprotein gel electrophoresis; Pleural Effusion - diagnosis; Triglycerides
• ISSN: 0009-8981; 1873-3492
• DOI: 10.1016/j.cca.2022.11.022

•Triglyceride assay, indirect marker of the presence of chylomicrons, is the most common first-line biochemical test for determining the chylous nature of various effusion such as chylous ascite, chylothorax or chylopericardium.•apoB48 is a trafficking handle and a direct biomarker for chylomicrons.•Simple, rapid apoB48 immunoassay can be of value (relative to the gold-standard test, gel lipoprotein electrophoresis) in the diagnosis of chylous effusions of origin. Chylous effusions such as chylothorax, chylopericardium and chylous ascites are marked by the abnormal presence of chylomicrons in serous membranes. These relatively rare situations are associated with high morbidity and mortality rates. Given that a macroscopic assessment of the fluid is insufficient, the current gold standard method for chylous effusion is the electrophoretic separation of lipoproteins. Serous effusions are most frequently assayed for triglycerides, with a diagnostic threshold varying between studies. The present study is the first to assess the value of the apolipoprotein B48, specific of the chylomicron, in the diagnosis of chylous effusions. A chemiluminescent sandwich enzyme immunoassay was used to measure levels of apoB48 in remnant samples of effusion fluid sent to our laboratory for chylomicron detection and lipid assays. The diagnostic values of apoB48 and triglyceride assays were compared with that of the gold standard method. The triglyceride and apoB48 levels and the triglyceride/cholesterol ratio in the effusion fluid were significantly higher in patients with chylous effusion. The threshold values for apoB48 were respectively 2.45, 0.25 and 19.00 µg/mL for a maximal Youden index, a sensitivity > 95 %, and a specificity > 95 %. The apoB48 assay’s diagnostic value might be at least as high as that of a triglyceride assay (area under the receiver operating characteristic curve [95 % confidence interval]: 0.84 [0.72, 0.96]) and 0.80 [0.67, 0.94], respectively). ApoB48 appears to be a promising marker for the diagnosis of chylous effusions; the putative diagnostic improvement must be confirmed in larger studies.