Measuring soluble ICAM-1 in African populations

Abstract

The level of plasma soluble ICAM-1 (sICAM-1) has been associated with the pathogenesis of several diseases. Previously, a commercial antibody was reported not to recognize an ICAM-1 allele known as ICAM-1kilifi prevalent among African populations. However, that study was based on 19 samples from African Americans of whom 13 had the wild type allele, five heterozygotes and one homozygote. Here, we compare plasma sICAM-1 measures using three different commercial antibodies in samples from Kenyan children genotyped for ICAM-1kilifi allele. We show that two of these antibodies have some degree of deficiency in detecting the ICAM-1kilifi allele. Consideration of the antibody used to measure sICAM-1 is important as up to 30% of the populations in Africa harbour this allele.

Figure 1. Plasma sICAM-1 in relation to ICAM-1^kilifi genotypes.

A. Venn diagram showing the samples used in this study We measured sICAM-1 in 163, 150, and 58 samples using DY720, BMS201MST, and DCD540 ELISA kits. These samples were genotyped from ICAM-1^kilifi mutation. Of these, 145 samples have been measured with both BMS201MST and R&D DY720, 52 with R&D DY720 and R&D DCD540, 48 with BMS201MST and R&D DCD540, and 45 with all the three kits. B. Plasma sICAM1 obtained with three different kits relative to ICAM-1^kilifi genotypes C. Plasma sICAM-1 in a subset of 45 samples where a measure was obtained with each of the three antibodies used. Measures of plasma sICAM-1 obtained with the BMS201MST, R&D (DCD540) and R&D (DY720) antibodies are depicted in black, red and green triangles respectively. The horizontal bar indicates the median sICAM-1 value. P value was calculated using Cuzick’s test for trend.