Monocyte subsets and monocyte-related chemokines in Takayasu arteritis

The pathogenesis of Takayasu arteritis (TAK) is poorly understood and no previous studies have analyzed monocytes in TAK. This study evaluated monocyte subsets and monocyte-related chemokines in the peripheral blood of TAK patients and healthy controls (HC). Monocyte subsets were identified as classical (CD14(+)CD16(−)), intermediate (CD14(+)CD16(dim)), and non-classical (CD14(dim)CD16(high)) in the peripheral blood. The chemokines CCL (C–C chemokine ligand)2, CCL3, CCL4, CCL5, CCL7, CXCL (C-X-C motif ligand)10, and CX3CL (C-X3-C motif ligand)1 were measured in the sera. Thirty-two TAK patients and 30 HC were evaluated. Intermediate monocytes were higher in TAK than HC [25.0 cells ×10(6)/L (16.7–52.0) vs. 17.2 cells ×10(6)/L (9.2–25.3); p = 0.014]. Active disease was associated with monocytosis (p = 0.004), increased classical (p = 0.003), and intermediate (p < 0.001) subsets than HC. Prednisone reduced the percentage of non-classical monocytes (p = 0.011). TAK patients had lower CCL3 (p = 0.033) and CCL4 (p = 0.023) levels than HC, whereas CCL22 levels were higher in active TAK compared to the remission state (p = 0.008). Glucocorticoids were associated with lower CXCL10 levels (p = 0.012). In TAK, CCL4 correlated with total (Rho = 0.489; p = 0.005), classical and intermediate monocytes (Rho = 0.448; p = 0.010 and Rho = 0.412; p = 0.019). In conclusion, TAK is associated with altered counts of monocyte subsets in the peripheral blood compared to HC and CCL22 is the chemokine with the strongest association with active disease in TAK.