Killer cell immunoglobulin-like receptor (KIR) gene diversity in a population naturally exposed to malaria in Porto Velho, Northern Brazil.

Killer cell immunoglobulin-like receptors (KIR) are expressed mainly in natural killer cells and specifically recognize human leukocyte antigen (HLA) class I molecules. The repertoire of KIR genes and KIR-HLA pairs is known to play a key role in the susceptibilities to and the outcomes of several diseases, including malaria. The aim of this study was to investigate the distribution of KIR genes, KIR genotypes and KIR-HLA pair combinations in a population naturally exposed to malaria from Brazilian Amazon. All 16 KIR genes investigated were present in the studied population. Overall, 46 KIR genotypes were defined. The two most common genotypes in the Porto Velho communities, genotypes 1 and 2, were present at similar frequencies as in the Americas. Principal component analysis based on the frequencies of the KIR genes placed the Porto Velho population closer to the Venezuela Mestizos, USA California hispanic and Brazil Paraná Mixed in terms of KIR gene frequencies. This analysis highlights the multi-ethnic profile of the Porto Velho population. Most of the individuals were found to have at least one inhibitory KIR-HLA pair. Seventy-five KIR-HLA pair combinations were identified. The KIR-2DL2/3_HLA-C1, KIR3DL1_HLA-Bw4 and KIR2DL1_HLA-C2 pairs were the most common. There was no association between KIR genes, KIR genotypes or KIR-HLA pair combinations and malaria susceptibility in the studied population. This is the first report on the distribution of KIR and known HLA ligands in the Porto Velho population. Taken together, these results should provide baseline information that will be relevant to population evolutionary history, malaria and other diseases studies in populations of the Brazilian Amazon.

In vitro radioautographic studies of the biodistribution of radiopharmaceuticals on blood elements

In the present study evaluated the binding of the radiopharmaceuticals sodium pertechnetate (Na (99m)TcO4), methylenediphosphonic acid (99m)Tc-MDP)) and glucoheptonate acid (99m)Tc-GHA)) to blood elements using centrifugation and radioautographic techniques. Heparinized blood was incubated with the labelled compounds for 0, 1, 2, 3, 4, 6 and 24 h. Plasma (P) and blood cells (BC) were isolated and precipitated with 5 percent trichloroacetic acid (TCA), and soluble (SF) and isoluble fractions (IF) were separated. Blood samples were prepared (0 and 24 h) and coated with LM-1 radioautographic emulsions and percent radioactivity (percent rad) in P and BC was determined. The binding of Na (99m)TcO4 (percentrad) to P was 61.2 percent (0 h) and 46.0 percent (24 h), and radioautography showed 63.7 percent (0 h) and 43.3 percent (24 h). The binding to BC was 38.8 percent (0 h) and 54.0 percent (24 h), and radioautography showed 36.3 percent (0h) and 56.7 percent (24 h), and radioautography showed 36.3 percent (0 h) and 56.7 percent (24 h). (99m) Tc-MDP study presented 91.1 percent (0 h) to P and 87.2 percent (24 h), and radioautography showed 67.9 percent (0 h) and 67.4 percent (24 h). The binding to BC was 8.9 percent (0 h) and 12.8 percent (24 h), and radioautography showed 32.1 percent (0 h) and 32.6 percent (24 h). (99m)Tc-GHA study was 90.1 percent (0 h) to P and 79.9 percent (24 h), and radioautography showed 67.2 percent (0 h) and 60.1 percent (24 h). The binding to BC was 9.9 percent (0 h) and 20.1 percent (24 h), and radioautography showed 32.8 percent (0 h) and 39.9 percent (24 h). The comparasion of the obtained results suggests that the binding to plasma and blood cells in the two techniques used (radioautography and centrifugation) qualitatively in accordance.