Common polymorphisms and alternative splicing in the ILT3 gene are not associated with atopy

Recently, a linkage of the chromosomal region 19q13.4 with bronchial asthma has been demonstrated. This region harbours the so-called leucocyte recept or cluster with the gene for immunoglobuiin-like-transcript 3 (ILT3) as a m ember. ILT3 represents an inhibitory receptor bearing three immunoreceptor tyrosine inhibitory motifs (ITIM). The protein mediates downregulation of c ell activation through recruitment of different SH2-containing protein tyro sine phosphatases. With regard to the negative immunoregulatory function pa rticularly on B-cells, ILT3 represents a candidate gene for atopy and asthm a. The aim of this study was to screen for common polymorphisms in the gene coding for ILT3 and to test for association with the atopic phenotype. Usi ng single-stranded conformal polymorphism-analysis and direct genomic seque ncing seven polymorphisms, three mutations, a common deletion of 7 bp in th e third intron and evidence for further alternative splicing of the ILT3 ge ne were found. Although no association was found with atopy phenotypes, it might prove useful to test for association with bronchial asthma.