Introduction: Ankylosing spondylitis (AS) is an autoimmune disease, which causes mild to severe clinical symptoms in patients. Several inherited and acquired factors are involved in the pathogenesis of the disease. Human leukocyte antigen B27 (HLA-B27) is one of the factors, whose expression affects patients’ susceptibility to AS.
Objectives: In this study, we evaluated HLA-B27 frequency in AS patients of Khuzestan province of Iran.
Patients and Methods: The study population (N=114) including patients with AS. Patients were examined and confirmed by a rheumatologist based on New York modified criteria. Clinical information was extracted from patients’ documents. Furthermore, general characteristics of the patients and several clinical variables (physio-pathological, self-report, and imaging) were taken into consideration.
Results: The results showed that 62.3% of the patients were HLA-B27 positive, while 37.7% of which were HLA-B27 negative. This difference was statistically significant (P <0.05). The disease duration was shown to be almost equal in both groups (i.e., HLA-B27 positive and HLA-B27 negative). According to the results, various clinical symptoms (like ocular complications and peripheral arthritis) were observed in patients, and the complications of which were higher in HLA-B27 negative patients compared to HLA-B27 positive ones (P <0.05). Besides, it was seen that the male patients have shown a higher physio-pathological (using polymerase chain reaction [PCR] technique) report for positive HLA-B27 and a higher magnetic resonance imaging involvement compared with females, whereas the women showed higher disease activity score i.e., higher mean Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) value.
Conclusion: For the AS patients, negative HLA-B27 cases show more progressive involvement sacroiliac joints compared with the positive HLA-B27 cases. More importantly, of hundred percent of patients who responded to anti-tumor necrosis factor (TNF) treatment, 52.6% were positive for the HLA-B27 antigen, and 47.4% were negative for the HLA-B27 antigen. Overall, it can be said that HLA-B27 lonely is not involved in the pathogenesis of AS and environmental factors should be investigated and involved in the disease development.