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