Evaluation of an automated commercial immunoluminometric assay for alpha-foetoprotein.

We evaluated a two-site immunoluminometric assay (AFP LIA-mat Byk Sangtec) for the determination of alpha-foetoprotein (AFP). The assay, involving two monoclonal antibodies which recognize two different alpha-foetoprotein epitopes, is rapid (4 h) with a wide working range (0-600 x 10(3) IU/l), a good lower limit of detection and good reproducibility (CV less than 10%). The regression equation for the AFP LIA-mat (y) and the immunoradiometric assay AFP Bridge Serono (x) was y = 1.175x - 2.27 (n = 95, r = 0.996) for serum and y = 1.16x + 479.2 for amniotic fluid. It did not display a hook effect, and when we assessed the linearity by assaying a high concentration of alpha-foetoprotein, it gave a linear response down to 3.1 x 10(3) IU/l. We also evaluated the clinical response of AFP LIA-mat in 278 patients with different diseases. Eighteen of the 19 patients with hepatocellular carcinoma had alpha-foetoprotein levels greater than 100 x 10(3) IU/l. In contrast, only 5 of the 47 patients with cirrhosis showed values above 50 x 10(3) IU/l, demonstrating that this assay discriminates fairly well between hepatocellular carcinoma and cirrhosis. Data in agreement with the literature were obtained for testicular tumours; all of seven seminomatous tumours presented values below 5 x 10(3) IU/l, whereas 50% of the non-seminomatous tumours (n = 8) presented values above 20 x 10(3) IU/l.

A method for the determination of the adherence of granulocytes to microtitre plates.

We report a new partially automated method for the measurement of the adherence of PMN in vitro. Adherence to a plastic surface was detected by measuring leukocyte alkaline phosphatase activity of the adherent cells, with a Titertek Multiscan system. Using three different cellular concentrations (1 X 10(6), 5 X 10(5), 2.5 X 10(5) PMN/ml) the response curve was linear to 45 min and adhesion was maximal by 30 min. The specificity of the reaction was acceptable as was the assay reproducibility (intra-assay coefficient of variation less than 8%; inter-assay coefficient of variation less than 11%).

Familial hypercholesterolemia and HLA antigens.

Hereditary factors play an important role in the etiology and progression of coronary heart disease (CHD), most probably by causing the appearance and the levels of its risk factors. To investigate if there is a correlation between familial hypercholesterolemia and HLA system antigens, 25 subjects of 7 families with familial hypercholesterolemia were compared with 14 normocholesterolemic related subjects. Compared to normocholesterolemic kindreds, the familial hypercholesterolemic subjects have a significant increased HLA-Bw35 antigen and a lack of HLA-A1. Therefore, the correlation found with some HLA system phenotypes improves our knowledge about familial hypercholesterolemia and aids in the identification of subjects affected with this disorder of lipid metabolism, which is one of the most important CHD risk factors.