title: Flow cytometric assessment of LDL receptor activity in peripheral blood mononuclear cells compared to gene mutation detection in diagnosis of heterozygous familial hypercholesterolemia.
abstract: BACKGROUND
  Studies indicate that human peripheral blood mononuclear cells mirror low-density lipoprotein (LDL) receptor activity of other cells in the body. To measure LDL receptor activity in patients with heterozygous familial hypercholesterolemia (FH), we prepared peripheral blood mononuclear cells from individuals with molecularly verified LDL receptor defective (Trp66-Gly mutation, n = 18) or receptor negative (Trp23-stop mutation, n = 17) heterozygous FH and from healthy individuals (n = 24).
  
  
  METHODS
  The cells were stimulated to express maximum LDL receptor by preincubation in lipoprotein-free medium. They were then incubated at 4 degrees or 37 degrees C with fluorescently conjugated LDL (DiI-LDL). T-lymphocytes and monocytes were identified by fluorescently conjugated monoclonal antibodies. DiI-LDL bound (at 4 degrees C) or internalized (at 37 degrees C) by the cells was measured using flow cytometry. Knowing the LDL receptor gene mutation of the FH patients allowed us to compare the diagnostic capability of our functional assay with the DNA diagnosis.
  
  
  RESULTS
  The diagnostic accuracy did not allow our assay to be used for diagnosis of individual cases of heterozygous FH.
  
  
  CONCLUSIONS
  We suggest that our two-color fluorescence flow cytometry assay can be used to characterize functionally gene mutations causing LDL receptor dysfunction in patients with heterozygous FH.
authors.affiliation: Department of Internal Medicine and Cardiology, Aarhus Amtssygehus University Hospital, Denmark. rau@dadlnet.dk
authors.forename: B
authors.initials: B
authors.lastname: Raungaard
authors.forename: F
authors.initials: F
authors.lastname: Heath
authors.forename: J U
authors.initials: JU
authors.lastname: Brorholt-Petersen
authors.forename: H K
authors.initials: HK
authors.lastname: Jensen
authors.forename: O
authors.initials: O
authors.lastname: Faergeman
mesh_terms: D001161:Arteriosclerosis / Q000175:diagnosis / Q000235:genetics / Q000276:immunology; D004252:DNA Mutational Analysis; D005192:Family Health; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D006937:Hypercholesterolemia / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology; D009000:Monocytes / Q000737:chemistry* / Q000276:immunology; D017354:Point Mutation; D011973:Receptors, LDL / Q000032:analysis / Q000235:genetics*; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000737:chemistry* / Q000276:immunology
chemical_list: D011973:Receptors, LDL