Reflections on the prevalence of human leukocyte antigen-B27 and human leukocyte antigen-B51 co-occurrence in patients with spondylarthritis

We performed a literature mini-review of the clinical profile of patients with spondylarthritis who are also human leukocyte antigen (HLA)-B51-positive. It seems to us that patients with HLA-B27 and HLA-B51 are more common in men, Asians and between the third and ninth decades of life. They are more likely to develop peripheral joint conditions, with cutaneous manifestations (e.g., oral ulcers) and uveitis. Therefore, more robust epidemiological studies with more accurate methodology and multicenter locations are needed to better map the role of the interaction between HLA-B51 in patients with spondylarthritis.