Impact of HLA -B*27 subtypes with increased susceptibility to seronegative spondyloarthropathies in Vojvodina population

Abstract

The aim of this study is to investigate which subtype of HLA-B*27 was associated with susceptibility of seronegative spondyloarthropathies (SpA) in Vojvodina patients. The dataset of the current study is composed of 172 SpA patients, among which there were 72 HLA-B*27+ (positive) and 100 HLA-B*27Ø (negative) patients. HLA-B*27 allele genotyping was carried out by Polymerase Chain Reaction-Sequence Specific Primer (PCR-SSP) method and low and high resolution tests, respectively. The association of HLA-B*27 subtypes with SpA was determined by the calculation of Relative Risk (RR) and Etiological Fraction (EF), while the allelic distribution between two group of patients was assessed by chi-square test. In HLA-B*27+ patients with SpA, the most common were patients with Reactive Arthritis (ReA) (41/72 or 56,94%) and Ankylosing Spondylitis (AS) (17/72 or 23,61%). Statistically significant difference was found in HLA-B*27+ and HLA-B*27Ø patients among SpA subgroups studied: Arthritis Psoriatica (PsA), Ankylosing Spondylitis (AS), Undifferentiated Spondyloarthritis (uSpA), Inflamatory Bowel Disease (IBD), Juvenilis Idiopathic Arthritis (JIA) and Reactive Arthritis (ReA). Two HLA-B*27 allele subtypes were found in SpA patients in Vojvodina: B*27:02 and B*27:05. Both HLA-B*27:02 and HLA-B*27:05 alleles have shown positive association with Ankylosing Spondylitis (RR=9.458 for B*27:02 and RR=6.585 for B*27:05), but significant Etiological Fraction (EF) or population attributive risk with value of 0.281 was found only for HLA-B*27:05 subtype. In this study we have showed, for the first time in Vojvodina population, that HLA-B*27:05 subtype have strong positive or susceptible association with Ankylosing Spondylitis.