A (G→C) transversion in the 3′ UTR of the human ECP (eosinophil cationic protein) gene correlates to the cellular content of ECP

Abstract

Eosinophil cationic protein (ECP) is a cytotoxic protein produced by and secreted from human eosinophil granulocytes. ECP may be involved in the injury of epithelial cells in allergic diseases such as asthma. The objectives were to determine the prevalence of the ECP gene polymorphism 562(G > C) in apparently healthy subjects and subjects with allergy and relate the prevalence to clinical disease and to serum and cellular levels of ECP. The 562(G > C) ECP gene polymorphism was determined by gene sequencing of the ECP gene from DNA prepared from 163 apparently healthy subjects and 151 subjects with allergic and nonallergic asthma or other diseases. ECP was measured by a sensitive radioimmunoassay. A polymorphism was detected at position 562, which mapped to the 3' untranslated region (UTR) of the gene encoding the ECP (RNase 3). Sixty-nine percent of the population had the 562GG genotype and 4%, the 562CC genotype. The cellular content of ECP in peripheral blood eosinophil granulocytes was significantly lower in cells from subjects with the 562GC (4.6+/-1.5 microg/10(6) eosinophils) and 562CC (3.2+/-0.7 microg/10(6) eosinophils) genotypes as compared with those with the 562GG genotype (6.0+/-1.9 microg/10(6) eosinophils; P < 0.001). A close link was found to the 434(G > C) ECP gene polymorphism. Associations between the 562(G > C) polymorphism or haplotypes of the two polymorphisms to allergy were not found. The 562(G > C) polymorphism in the 3'-end of the UTR of the ECP gene may determine the ECP content in human eosinophils, but unlike the 434(G > C) polymorphism, the 562(G > C) polymorphism is not related to allergy.