Serum sCTLA-4 levels and clinical manifestations in ankylosing spondylitis patients.

Objective: T cell abnormal activation is thought to have a main role in the etiology of ankylosing spondylitis (AS). While cytotoxic T lymphocyte-associated molecule-4 (CTLA-4) is suppressing the immune system, in previous studies serum soluble CTLA-4 (sCTLA-4) was detected at high amounts in autoimmune disorders. We sought to evaluate the association between soluble CTLA-4 in serum and disease activity in AS patients.

Methods: Thirty-eight patients with AS, 28 rheumatoid arthritis (RA) patients, and 27 disease-free controls were enrolled to the study. The levels of sCTLA-4 were determined for each participant using an enzyme-linked immunosorbent assay. The erythrocyte sedimentation rate (ESR), C-reactive peptide, and demographic characteristics were documented. The data were analyzed by using relevant statistical methods.

Results: In comparison with RA patients and controls, patients with AS showed high sCTLA-4 levels (p<0.001). The sCTLA-4 levels did not correlate with the severity of the disease in AS patients (p=0.370). The ESR levels and Bath Ankylosing Spondylitis Disease Activity Index were correlated in AS patients (p=0.012).

Conclusion: We evaluated the association between the disease severity of AS and sCTLA-4. Although, the correlation was not shown, sCTLA-4 was highest in the AS group. Further studies with larger samples should be completed to attain a better understanding of the AS etiology.