Flow cytometric measurement of intracellular bilirubin in human peripheral blood mononuclear cells exposed to unconjugated bilirubin

✍ Scribed by Yoshio Haga; H. David Kay; Margaret A. Tempero; Rowen K. Zetterman

• Publisher: Elsevier Science
• Year: 1992
• Tongue: English
• Weight: 747 KB
• Volume: 25
• Category: Article
• ISSN: 0009-9120
• DOI: 10.1016/0009-9120(92)80033-d

✦ Synopsis

Human peripheral blood mononuclear cells were incubated at 37 °C with bilirubin in bovine albumin solution. Histological analysis of bilirubin-treated cells demonstrated a prominent brown pigment deposited in the cytoplasm. Homogenates of these cells in chloroform-methanol solution showed an identical absorption spectrum with pure bilirubin dissolved in the same solution. When bilirubin-treated cells were excited at 488 nm, a significant autofluorescence was detected by flow cytometry at 585 nm in a dose-dependent manner, which had a significant correlation with the amount of bilirubin chemically extracted from the cells (r = 0.963, n = 34, p < 0.001). Intraassay and interassay variability of the autofluorescence by flow cytometric analysis was small (both <5%). When bilirubin-treated cells were stained with fluorescein-labeled anti-CD14 antibody, the CD14 positive cell population can be fractionated without interference of autofluorescence derived from intracellular bilirubin. These results suggest that flow cytometric analysis of bilirubin-treated cells can quantitate intracellular bilirubin, and that bilirubin does not interfere with analysis of surface antigens.