HLA-B*27 – Frequency of clinical signs in Brazilian patients with spondyloarthritis

Spondyloarthritis presents clinical features, laboratory findings, and similar images, but their clinical manifestations reveal great heterogeneity in patients HLA-B*27 positive and negative. This study compared the frequencies of the clinical manifestations in the presence and absence of HLA-B*27. From the 156 patients with clinical suspicion of spondyloarthritis, 73 had a diagnosis of spondyloarthritis confirmed. The HLA-B*27 gene was identified by polymerase chain-reaction sequence-specific oligonucleotide probe (PCR-SSOP). The Student t test was used to calculate the values of mean and the Fisher's exact test was used to compare proportions. The values of odds ratio (OR) and confidence interval (CI) at 95% were also calculated (p < 0.05). The spondyloarthritis found were: ankylosing spondylitis (n = 47, 64.4%), psoriatic spondyloarthritis (n = 9, 12.3%), undifferentiated spondyloarthritis (n = 9, 12.3%), enteropathic spondyloarthritis (n = 6; 8.2%) and reactive spondyloarthritis (n = 2, 2.7%). Overall, 35 (47.9%) patients were HLA-B*27 positive and 38 (52.1%) were negative. This gene was associated with ankylosing spondylitis (OR: 5.37, 95% CI: 1.813–15.905, p = 0.003) but not with enteropathic spondyloarthritis (OR: 0.07, 95% CI: 0.003–1.301, p = 0.025). The sacroiliitis was associated with HLA-B*27 positive (OR: 10.552, 95% CI: 1.260–88.256, p = 0.014) and intestinal injury with HLA-B*27 negative (OR: 0.195, 95% CI: 0.038–0.978, p = 0.048). The image signals sacroiliitis were associated with the HLA-B*27 gene while intestinal involvement was not associated with this gene.