CD14 down-modulation as a real-time biomarker in Kawasaki disease

Abstract

Objectives: The objectives of this study were to investigate the pathophysiology of Kawasaki disease (KD) from immunological and oxidative stress perspectives, and to identify real-time biomarkers linked to innate immunity and oxidative stress in KD.

Methods: We prospectively enrolled 85 patients with KD and 135 patients with diverse conditions including immune, infectious and non-infectious diseases for this investigation. Flow cytometry was used to analyse the surface expression of CD14, CD38 and CD62L on monocytes, along with a quantitative assessment of CD14 down-modulation. Additionally, oxidative stress levels were evaluated using derivatives of reactive oxygen metabolites (d-ROMs) and antioxidant capacity measured by a free radical elective evaluator system.

Results: During the acute phase of KD, we observed a prominent CD14 down-modulation on monocytes, reflecting the indirect detection of circulating innate immune molecular patterns. Moreover, patients with KD showed a significantly higher CD14 down-modulation compared with infectious and non-infectious disease controls. Notably, the surface expression of CD14 on monocytes was restored concurrently with responses to intravenous immunoglobulin and infliximab treatment in KD. Furthermore, d-ROM levels in patients with KD were significantly elevated compared with patients with infectious and non-infectious diseases. Following intravenous immunoglobulin treatment, oxidative stress levels decreased in patients with KD.

Conclusion: Monitoring CD14 down-modulation on monocytes in real-time is a valuable strategy for assessing treatment response, distinguishing KD relapse from concomitant infections and selecting second-line therapy after IVIG treatment in KD patients. The interplay between inflammation and oxidative stress likely plays a crucial role in the development of KD.

Keywords: CD14; Kawasaki disease; innate immunity; oxidative stress.

Figure 1

CD14 down‐modulation in Kawasaki disease and various controls. CD14 down‐modulation of monocytes (CD14 B/A ratio) was compared among KD and various controls. Immune disorders A included active phase of innate immune disorders as positive controls 1 (PC1: n = 12), and immune disorders B: autoimmune diseases and inactive phase of innate immune disorders (n = 6). C: non‐COVID‐19‐associated FS as positive controls 2 (PC2: n = 16) and D: COVID‐19‐associated FS (n = 7). KD: n = 85, DC included infectious and other diseases: n = 94. Significant differences were determined by the Wilcoxon signed‐rank test. **P < 0.01, ***P < 0.001. COVID‐19, coronavirus disease 2019; DC, disease control; FS, febrile seizure; KD, Kawasaki disease; N.S., not significant; PC, positive controls.

Figure 2

Temporal dynamics of CD14 modulation in IVIG‐responsive and ‐resistant patients with Kawasaki disease. KD patients were divided into three groups: (a) initial IVIG‐responsive KD (n = 30), (b) IVIG‐resistant KD patients with recrudescent fever after the initial IVIG, who responded to the second IVIG (n = 4) and (c) IVIG‐resistant patients with persistent fever (n = 4). Three of the four responded to the second IVIG. In initial IVIG responders (n = 30), high CD14 down‐modulation (high B/A ratios) rapidly decreased after the first treatment with IVIG (P < 0.001). IVIG, intravenous immunoglobulin; KD, Kawasaki disease.

Figure 3

Oxidative stress index in patients with Kawasaki disease and disease controls. (a) OSI (d‐ROM/BAP) in patients with KD (n = 80) vs. DC (n = 38), as shown in Supplementary table 2b. (b) OSI in the acute phase of KD patients (pre‐IVIG: n = 80) and after treatment with IVIG (post‐IVIG: n = 20). OSI: 0.191 [0.147–0.240] vs. 0.147 [0.101–0.189], P = 0.004. (c) Comparison among the 4‐season groups. Significant differences were determined by the analysis of variance. **P < 0.01, ***P < 0.001. BAP, biological antioxidant potential; DC, disease control; d‐ROM, derivatives of reactive oxygen metabolites; IVIG, intravenous immunoglobulin; KD, Kawasaki disease; OSI, oxidative stress index.