Killer cell immunoglobulin-like receptor gene diversity in a Caucasian population of southern Brazil.

Killer immunoglobulin-like receptors (KIR) regulate the activity of natural killer and T cells through an interaction with specific human leucocyte antigen (HLA) class I molecules on target cells. Diversity in KIR gene content, KIR allelic and haplotype polymorphism has been observed between different ethnic groups. However, most population studies on KIR variability have focused on Europe and Asia, while Americas, Oceania and Africa remain poorly studied. The aim of this study was to analyse the variability of KIR genes in 200 healthy nonrelated individuals from the Southern Brazilian population. KIR genes and HLA-A, -B and -Cw were genotyped using polymerase chain reaction-sequence-specific primers. Southern Brazilian population demonstrated several similarities to states that are closer geographically and distinct differences with Northern Brazil in the frequency of genes KIR2DS1, 2DS2, 2DS3, 2DS5, 3DL1, 3DS1, 2DL1 and 2DL2. The activating gene KIR2DS5 was the least frequent locus found in our group. Interaction of KIR/HLA was more common in the 2DS1-/2DL1+/C2+ association. This study demonstrated the diversity of KIR genes and of KIR/HLA association in a Caucasian group of Southern Brazil, establishing differences and similarities to other different populations.