Infliximab regulates monocytes and regulatory T cells in Kawasaki disease

Background

The effect of infliximab (IFX ) on immune cells has not been fully reported in Kawasaki disease (KD ). To investigate the mechanism of IFX in KD , we examined changes in the abundance of CD 14⁺CD 16⁺ activated monocytes, regulatory T cells (T_reg) cells, and T‐helper type 17 (Th17) cells following treatment with IFX .

Methods

We collected peripheral blood from patients with i.v. immunoglobulin (IVIG )‐resistant KD and analyzed absolute CD 14⁺CD 16⁺ monocyte, T_reg (CD 4⁺CD 25⁺FOXP 3⁺) and Th17 cell (CD 4⁺IL ‐17A⁺) counts on flow cytometry. We also measured changes in serum soluble interleukin (IL )‐2 receptor (IL ‐2R), IL ‐6, and tumor necrosis factor (TNF )‐α on enzyme‐linked immunosorbent assay.

Results

T_reg cells and Th17 cells significantly increased after IFX treatment compared with baseline (126 ± 85 cells/μL vs 62 ± 53 cells/μL, P < 0.01; 100 ± 111 cells/μL vs 28 ± 27 cells/μL, P < 0.05, respectively). In contrast, in a subgroup of patients with CD 14⁺CD 16⁺ monocytes above the normal range before IFX , the CD 14⁺CD 16⁺ monocytes significantly decreased following IFX treatment (72 ± 51 cells/μL vs 242 ± 156 cells/μL, P < 0.05).. Serum TNF ‐α did not change, but soluble IL ‐2R and IL ‐6 decreased after IFX treatment.

Conclusion

IFX could downregulate activated monocytes and upregulate T_reg cells towards the normal range. IFX treatment thus contributes to the process of attenuating inflammation in KD .