Background: The human leukocyte antigen B27 (HLA-B27) gene is strongly associated with seronegative spondylarthritis (SpA), particularly ankylosing spondylitis (AS). There is currently no data on the frequency of HLA-B27 in the SpA subtypes in Morocco. This study is the first to determine the distribution of the HLA-B27 gene among Moroccan patients with SpA and to investigate its correlation with inflammatory markers and clinical data.

Methods: From February 2009 to March 2023, we retrospectively analyzed 205 SpA patients at a private rheumatology clinic in Casablanca, Morocco. The medical records included demographic data, clinical features, and laboratory parameters. HLA-B27 was genotyped using quantitative polymerase chain reaction (qPCR) with high-resolution melting (HRM). Statistical analyses were performed using SPSS software (version 25.0).

Results: HLA-B27 was detected in 33 patients (15.1%). HLA-B27 prevalence was significantly higher in men (p<0.05) and showed a strong association with AS (p<0.000). A positive correlation was found between HLA-B27 positivity and elevated erythrocyte sedimentation rate (ESR) (r = 0.18) and C-reactive protein (CRP) levels (r = 0.16), suggesting a link with increased inflammation.

Conclusion: Our findings confirm a strong association between HLA-B27 and AS, with a higher prevalence among men. The correlation observed between HLA-B27 positivity and inflammatory markers supports its role as a potential biomarker for disease severity. Our data aligns with studies from the MENA region. Further research is needed to explore the genetic contributions to SpA susceptibility and progression.