High Accuracy and Significant Savings Using Tag-SNP Genotyping to DetermineHLA-B*27Status

The treatment journey for patients with axial spondyloarthritis in North Africa and the Middle East: From diagnosis to management

The management of axial spondyloarthritis (axSpA) is challenging worldwide, and the particular challenges shared by North Africa and the Middle East are mainly related to early diagnosis and standardized management. We believe there are several reasons for these challenges, including: (a) limited awareness of the disease manifestations and prevalence in the region among physicians; (b) the concept of nonradiographic axSpA, while accepted with some difficulty by the rheumatology community, may not be well understood by the referring primary care physicians; (c) access to, and training in magnetic resonance imaging varies greatly between countries in the North Africa and Middle East region, and this may have a large impact on early diagnosis; (d) country‐specific treatment guidelines are unavailable; and (e) economic and cultural factors influence patients’ attempts to seek and continue treatment. In this review, we will discuss the prevalence of axSpA in North Africa and the Middle East, as well as the challenges to diagnose and treat patients in this region. As rheumatologists practicing in North Africa and the Middle East, we also provide suggestions to assist physicians, other healthcare professionals, and researchers in facilitating early, accurate diagnosis and treatment of axSpA.

High accuracy of HLA-B*27 genotyping by allele-specific real-time polymerase chain reaction in a heterogeneous population compared to flow cytometry and single nucleotide polymorphism detection assays

HLA-B27 is a risk marker for ankylosing spondylitis and other associated seronegative spondyloarthropathies. We compared three methods of HLA-B*27 typing in a New South Wales (NSW) population: flow cytometry, rs4349859 single nucleotide polymorphism (SNP) detection assay, and allele-specific real-time polymerase chain reaction (RT-PCR) analysis of exons 2 and 3. Over a 5-month period, 543 samples underwent flow cytometric testing and RT-PCR high-resolution melt analysis of rs4349859 SNP and of exon 2 (5' fragment) and exon 3. In the third method, positive samples were further analysed with fluorescent resonance emission transfer (FRET) RT-PCR of exon 2 fragments, 2a and 2b. HLA-B*27 and other genotypes were confirmed by Sanger sequencing of a 600 base pair fragment of exons 2 and 3. In our cohort, the rs4349859 SNP method had 78.6% sensitivity and 98.7% specificity. Screening with exon 2 (5' fragment) and exon 3 RT-PCR provided 100% sensitivity. Further testing with exon 2a and 2b FRET RT-PCR produced 100% specificity. This cascade approach with allele-specific RT-PCR assays was able to differentiate all samples into HLA-B*27 subtypes. HLA-B*27 genotyping with allele-specific RT-PCR assays, to screen for and confirm HLA-B27 positive samples, was more sensitive and specific than flow cytometry and rs4349859 SNP assays. It is a potentially cost-effective method for differentiating HLA-B27 subtypes. Our cascade genetic testing approach is suitable for replacing the current flow cytometric HLA-B27 assay for the heterogeneous NSW population.