LAUSR

BACKGROUND The strong association between HLA-B27 and spondyloarthritis (SpA) has demonstrated that typing the HLA-B27 antigen is a crucial step in diagnosis and aids in defining the progression and severity of disease. OBJECTIVE To describe the frequency of HLA-B27 in Colombian individuals with clinical manifestations associated with SpA. MATERIALS AND METHODOLOGY We retrospectively analyzed 4109 HLA-B27 typing requests to the Hospital Militar Central and the Instituto de Referencia Andino from Colombian individuals with clinical signs suggestive of SpA between 2009 and 2012. We used basic digital cytometry followed by Polymerase Chain Reaction with sequence specific primers when confirmation was needed. We determined the frequency of HLA-B27 in the population and levels of association of HLA-B27 with SpA. RESULTS Our population included 1585 men (36.8%) and 2524 women (61.4%). The predominant age range was between 19 and 45 years (49.9%). The majority (95.4%) of the study population came from the Andean region and eastern plains. The most frequent clinical manifestations were peripheral. Only a small fraction (12.1%) of the 4109 subjects was HLA-B27 positive. Of those, 56.9% were male, and 54.7% were between 19 and 45 years old. In contrast, when rheumatologists referred the HLA B27, 64% were found to be positive. CONCLUSION The frequency of the HLA-B27 allele in individuals with clinical signs suggestive of SpA was low, in accordance with the lower prevalence found in Colombian patients diagnosed with SpA compared to American and European population.