Disease status of ankylosing spondylitis (AS) and percentages of CD8+ CD28- T cells. AS patients were subdivided into groups with low, medium and high grades of movement restriction by a metrology index which includes cervical rotation, chin-to-jugulum distance, thoracic Schober, chest expansion, and the fingers-to-floor distance. Whiskers boxblots show 50% of cases within the boxes and 80% between the endpoints of the whiskers (lines). The two-sided Pearson test (with subsequent Bonferroni adjustment due to multiple testing) was used to assess statistical significance. *P = 0.032.