inhibitory killer cell immunoglobulin-like receptor kir3dl1 in combination with hla-b bw4iso protect against ankylosing spondylitis

background: the hla class i molecules serve as ligands for both t cell receptors and killer cell immunoglobulin-like receptors (kirs). objective: we investigated the hlac and hla-bw4 alleles as well as kirs expression on cd56 positive lymphocytes to evaluate whether these genes and molecules could influence ankylosing spondylitis (as) susceptibility, alone or in combination. methods: we typed 40 as patients and 40 normal controls for hla-c asn80 (group 1) and hla-c lys80 (group 2), hla-b bw4thero, hla-b bw4iso and hla-a bw4 alleles by pcr-ssp method. we also assessed the expression of kir2dl1/2ds1, kir2dl2/2dl3, kir3dl1 and kir2ds4 by flow cytometry. the pearson chi-square or fisher exact test was performed for statistical analysis. results: the frequency of hla-b bw4iso but not hla-b bw4thero and hla-a bw4, ligand for the inhibitory kir3dl1, was significantly reduced in as patients as compared with controls (p