Sistemas histo-sanguíneos ABO, Secretor e Lewis como fatores de risco para a espondilite anquilosante

Abstract

The spondyloarthritis encomprises a group of diseases strongly associated with HLA-B*27 gene. It has been proposed that genes not belonging to the major histocompatibility complex human influence the genesis of these diseases especially in patients HLA-B*27 negative. Objectives. The aim of this study was to test the hypothesis that the antigens of the ABO, Secretor and Lewis histo-blood systems are associated with spondyloarthritis, especially ankylosing spondylitis (AS). Material and methods. Three hundred and ninety-four patients with clinical suspicion of spondyloarthritis sent for identification of HLA-B*27 gene were analyzed. One hundred and nineteen (30.2%) had confirmed the diagnosis of spondyloarthritis according to the ASAS criteria. The remaining 275 (69.8%) were used as controls. The identification of HLA-B*27 gene was performed using the PCR-SSOP method. The identification of the antigens of the ABO, Secretor and Lewis histo-blood systems was performed using hemagglutination and PCR-RFLP methods. The exact Fisher's test, the chi-square, and the values of Odds Ratio (OR) and Confidence Interval set at 95% were calculated using the GraphPad INSTAT software, accepting the error of 5%. Results. No statistically significant differences were observed in the frequency of antigenic profiles of ABO (χ2:1.152; p = 0.764; GL: 3), Secreto (χ2: 0.779; p = 0.377; GL: 1) and Lewis (χ2: 1.853; p= 0.396; GL: 2) histo-blood groups between patients and controls. The Lea antigen was more frequent in patients with AS compared to controls (OR: 1.833; 95% CI: 1025-3284, p = 0.053). This antigen was strongly associated with AS in HLA-B*27 negative patients compared to controls (OR: 4.469; 95% CI: 1931-10342; p = 0.0007). This association remained only in males in the absence of HLA-B*27 gene (OR: 6.880; 95% CI: 1852-25564; p = 0.004). Conclusions. AS is associated to the Lea antigen in HLAB* 27 negative male patients.