CCL19 and CCL21 levels in serum and ligament tissue (LT). (A) Serum CCL19/CCL21 levels in AS (n = 42), OA (n = 29), and healthy controls (HC, n = 16). The CCL19 level in the AS group was clearly higher than that in the OA and HC groups (AS vs OA, P = 0.011 and AS vs HC, P = 0.003). The CCL21 level displayed a similar distribution (AS vs OA, P = 0.039 and AS vs HC, P = 0.0075). (B) The levels of CCL19/CCL21 in AS (n = 27) and OA (n = 12) ligament tissue. The CCL19 level was significantly increased in AS ligament tissue compared to OA LT (AS vs OA, P = 0.024), and CCL21 level displayed a similar difference (AS vs OA, P = 0.041).*P < 0.05; **P < 0.01.