Killer Cell Immunoglobulin-Like Receptor Genotype and HTLV-1 Associated Disease’s Susceptibilities.

[Introduction] Natural killer (NK) cells show cytotoxicity against virus-infected cells and some tumor cells. The highly polymorphic killer cell immunoglobulin-like receptors (KIRs) which recognize HLA class 1 molecules play a major role in these cytotoxic activities, and also express on some T-cells. Human T-lymphotrophic virus-1 (HTLV-1) is a caucassive agent for leukemia and some autoimmune diseases. We investigated the correlations between the KIR genotype and susceptibilities to HTLV-1 associated diseases i.e. adult T-cell leukemia (ATL) and HTLV-1 associated myelopathy (HAM).

[Materials and Methods] Fifty six HTLV-1 carriers, fifty one ATL patients and fifty seven HAM patients were recruited in this study. Genotyping of six KIR genes (3DL1, 2DL5, 2DS1, 2DS2, 2DS3 and 3DS1) was performed using PCR amplification with sequence specific primers (Martin et al. J Immunol 2002).

[Results and Conclusion] Frequencies of each KIR and genotype were analysed as described in Table. Genotype means the pattern of positive KIR combinations. Significant differences between carrier vs. HAM in genotype 2 (p=0.01), and ATL vs. HAM in genotype 4 (p=0.01) were observed. Increased frequencies of genotype 3 and 2DS3 allele in HAM compared to carrier were also observed although these tendencies were not statistically significant. These preliminary results suggest that KIR gene polymorphism may play a role in determining susceptibility to HTLV-1 associated diseases.