The IL-33/sST2 Axis in Thromboangiitis Obliterans

Area of Science:

• Immunology
• Rheumatology
• Vascular Medicine

Background:

• Thromboangiitis obliterans (TAO) classification remains debated, with uncertainty regarding its relation to systemic vasculitis.
• Elevated levels of Interleukin-33 (IL-33) and its decoy receptor sST2 are characteristic of the acute phase in systemic vasculitis.

Purpose of the Study:

• To investigate the serum levels of IL-33 and sST2 in patients with TAO.
• To compare these levels with those in healthy smokers and non-smokers.
• To explore the potential role of IL-33/sST2 in TAO pathogenesis and its distinction from autoimmune vasculitis.

Main Methods:

• Serum IL-33 and sST2 levels were measured in 50 TAO patients and 2 control groups (20 smokers, 19 non-smokers).
• Patients were categorized into active and quiescent disease phases, and by presence of gangrene or non-healing ulcers.
• Statistical analysis was performed to compare IL-33 and sST2 levels and the IL-33/sST2 ratio between groups.

Main Results:

• TAO patients exhibited significantly higher serum IL-33 levels compared to both control groups (p < 0.001).
• IL-33 levels were notably higher in the active phase of TAO and in patients with gangrene.
• The IL-33/sST2 ratio was significantly elevated in TAO patients across all disease phases compared to controls (p < 0.001).

Conclusions:

• The IL-33/sST2 regulation pattern in TAO differs from that observed in autoimmune vasculitis.
• These findings suggest that IL-33 may play a distinct role in the inflammatory processes underlying TAO.