Elevated circulating interleukin-17 levels in systemic sclerosis: a meta-analysis

Area of Science:

• Immunology
• Rheumatology
• Biochemistry

Background:

• Systemic sclerosis (SSc) is a complex autoimmune disease characterized by fibrosis and vascular abnormalities.
• Interleukin-17 (IL-17) is a pro-inflammatory cytokine implicated in various autoimmune and inflammatory conditions.

Purpose of the Study:

• To conduct a meta-analysis evaluating the association between circulating interleukin-17 (IL-17) levels and systemic sclerosis (SSc).
• To compare IL-17 levels in SSc patients versus healthy controls and analyze specific IL-17 subtypes.

Main Methods:

• A systematic literature search was performed across MEDLINE, Embase, and Web of Science.
• Included 16 studies with 1,229 SSc patients and 839 controls, comparing serum/plasma levels of IL-17, IL-17A, IL-17B, IL-17E, and IL-17F.
• Subgroup analyses were conducted based on ethnicity and disease subtype.

Main Results:

• Overall circulating IL-17 levels showed no significant difference between SSc patients and controls (SMD=0.260, p=0.825).
• However, IL-17A, IL-17B, IL-17E, and IL-17F levels were significantly elevated in SSc patients (p<0.05 for all).
• IL-17A exhibited the most pronounced association (SMD=2.046, p=0.002). No significant difference in IL-17A was found between diffuse and limited SSc.

Conclusions:

• Specific IL-17 subtypes, particularly IL-17A, IL-17B, IL-17E, and IL-17F, are significantly elevated in systemic sclerosis.
• These findings suggest that IL-17 cytokines, especially IL-17A, play a crucial role in the pathogenesis of SSc.