Chronic periaortitis and HLA–DRB1*03: Another clue to an autoimmune origin

Abstract Objective Patients with chronic periaortitis (CP) often show clinical and laboratory findings of a systemic autoimmune disorder. The aim of the present study was to investigate the role of the HLA system in CP. Methods Low-resolution genotyping for HLA–A, HLA–B, and HLA–DRB1 loci and genotyping of TNFA(-238)A/G and TNFA(-308)A/G single nucleotide polymorphisms were performed in 35 consecutive patients with CP and 350 healthy controls. Results The HLA–DRB1*03 allele frequency was strikingly higher in patients with CP than in controls (24.28% versus 9.14%; χ2 = 15.50, P = 0.000084, corrected P [Pcorr] = 0.0012, odds ratio [OR] 3.187, 95% confidence interval [95% CI] 1.74–5.83); the HLA–B*08 allele frequency was also higher in patients than in controls (17.14% versus 6.28%; χ2=11.12, P = 0.0008, Pcorr = 0.0269, OR 3.085, 95% CI 1.54–6.16). The A*01 allele frequency was significantly different (P = 0.0463), but the statistical significance was lost after correction for multiple testing (Pcorr = 0.5088). TNFA(-238)A allele and TNFA(-308)A allele frequencies were not significantly different (P = 0.512 and P = 0.445, respectively). Comparison of the main clinical and laboratory findings suggestive of a systemic autoimmune disease (e.g., acute-phase reactants, constitutional symptoms, other autoimmune diseases associated with CP) between the HLA–DRB1*03–positive and the HLA–DRB1*03–negative patients showed that the former group had significantly higher levels of C-reactive protein (P = 0.045) at disease onset, although this difference was not statistically significant after correction for multiple tests (Pcorr = 0.369). Conclusion The HLA system plays a role in susceptibility to CP. The strong association between CP and HLA–DRB1*03, an allele linked to a wide range of autoimmune conditions, further supports the view that CP may represent a clinical manifestation of an autoimmune disease.