What Does Human Leukocyte Antigen B27 Have to Do with Spondyloarthritis?

Human leukocyte antigen (HLA) B27 is the key laboratory parameter for axial spondyloarthritis (axSpA). Its prevalence is variable across different geographic zones and ethnicities, and often mirrors the prevalence of axSpA. HLA-B27 plays a role in axSpA physiopathology. It is correlated with spondyloarthritis phenotype with a consistent positive association with family history, early disease onset, shorter diagnostic delay, hip involvement, and acute anterior uveitis. HLA-B27 has a pivotal role in many referral strategies. However, these strategies were developed in European populations and need to be evaluated in populations with lower HLA-B27 background prevalence, and where additional parameters might be needed.

Added Value of Anti-CD74 Autoantibodies in Axial SpondyloArthritis in a Population With Low HLA-B27 Prevalence.

Axial spondyloarthritis (axSpA) is often diagnosed late due to the non-specific nature of its main symptom [chronic back pain (CBP)] and to the paucity of diagnostic markers, particularly in regions with low HLA-B27 prevalence, such as the Middle-East. We tested the performance of IgG4 and IgA anti-CD74 antibodies as an early diagnostic marker for axSpA, compared with the performance of HLA-B27, in Lebanon. Sera of axSpA patients diagnosed by the rheumatologist and also fulfilling the imaging arm of the ASAS criteria (patients) and of blood donors (BD) (controls) were analyzed for HLA-B27, IgG4 and IgA anti-CD74, blinded to clinical characteristics. Receiver Operating Characteristic curves were constructed to identify an optimal cut-off point for anti-CD74 antibodies. Diagnostic properties were calculated (sensitivity, specificity, positive, and positive predictive values (PPV, NPV), Likelihood ratios) for each marker. Forty-nine axSpA patients and 102 BD were included in the final analysis. IgA anti-CD74 correlated poorly with axSpA (Area Under the Curve (AUC) 0.657), whereas IgG4 anti-CD74 had a good discriminative value (AUC 0.837). Respectively, for HLA-B27, IgG4 anti-CD74, and the combination of both, we found a sensitivity of 33-92-33%, specificity of 96-79-98%, PPV 80-68-89%, NPV 75-95-75%, and LR+ 8.2-4.4-16.5. IgG4 anti-CD 74 were positive in 88% of HLA-B27 negative axSpA patients, and correlated with BASDAI. In this first study in a population with low HLA-B27 prevalence, IgG4 anti-CD74 antibodies combined with HLA-B27 showed higher diagnostic value than HLA-B27 alone for early axSpA. IgG4 anti-CD74 should be considered for further evaluation as an early axSpA diagnostic marker in future dedicated research, particularly in patients with CBP.

Patient preferences for rheumatoid arthritis treatments: results from the national cross-sectional LERACS study.

INTRODUCTION: To investigate the treatment preferences of patients with rheumatoid arthritis (RA) and determine whether these preferences are related to specific disease characteristics. METHOD: A national survey was designed to collect demographic, disease, treatment, and preference data on RA patients enrolled in 7 private and university hospital clinics in Lebanon. Associations between patient factors and treatment preferences for RA were analyzed by χ2 or Mann-Whitney U test. RESULTS: A total of 693 patients (83% female; 67% aged 41-70 years) consulting 7 trained rheumatologists completed the survey. Most patients (80%) had established RA >24 months, and approximately one-third (34%) were in remission according to the disease activity score in 28 joints (DAS28). Most (87%) were receiving oral agents (60% oral only). Almost two-thirds of patients (64%) expressed a preference for oral treatments, and more than half (53%) ranked doctor's advice as the most influential factor when choosing treatment. In univariable analysis, health coverage, radiographic damage, disease duration, current therapy, and previous side effects were significantly associated with treatment preference. In multivariable analyses, only radiographic damage and current route of administration were independently associated with preference (both P<0.001), with patients with no radiographic damage and those on oral-only therapy being more likely to prefer oral agents. CONCLUSION: RA patients expressed a preference for oral rather than subcutaneous/intravenous-administered drugs. Understanding patients' preferences may help to inform policymaker decisions.