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Natural killer cells and immune surveillance.

OBJECTIVES
To analyze the importance of natural killer cells, their killer immunoglobulin-like receptors (KIR) and genes in autoimmunity and in the immune surveillance against infectious agents and stem cells transplantation. The characteristics and polymorphisms of the KIR genes and receptors in the Brazilian population is described.


SOURCES
Textbooks, review articles and recent scientific articles are cited and listed in the references.


SUMMARY OF THE FINDINGS
KIR genes and haplotypes within a Brazilian Caucasian population were surveyed and analyzed to assess the future relationship of this system with diseases. Of 116 voluntary bone marrow donors, we identified 32 genotypes with frequencies of A and B haplotypes of 51 and 49%, respectively. A comparative analysis was performed between these genotypes and those from other populations.


CONCLUSIONS
Innate immunity is an important anti-infectious barrier in newborns. It is independent of both cellular and humoral immunity, can be faster and confers great advantage in early age. At the same time, it stimulates CD8 T lymphocytes to act and amplify the immunological protection network. Nevertheless, as in the majority of situations in which immunity is activated, it can also be harmful, damaging the body through autoimmune mechanisms or even, through its absence, creating space for infectious agents to act free. Our study of a control group for KIR genotype and haplotypes in Brazilian Caucasoids could be used in future analyse of diseases related to these genes.