Critical cytokine pathways to cardiac inflammation

Area of Science:

• Immunology
• Infectious Diseases
• Cardiology

Background:

• Autoimmune diseases can follow infections in susceptible individuals.
• Mechanisms linking infection to autoimmunity are not fully understood.
• Coxsackievirus B3 infection can trigger autoimmune myocarditis.

Purpose of the Study:

• To elucidate cytokine pathways involved in infection-induced autoimmune myocarditis.
• To identify specific cytokines necessary and sufficient for disease development.
• To understand how cytokine profiles influence disease severity and progression.

Main Methods:

• Development of a mouse model for Coxsackievirus B3-induced autoimmune myocarditis.
• Analysis of early innate immune responses and subsequent autoimmune development.
• Quantification of various T helper (Th) cell cytokine profiles (Th1, Th2, Th17).

Main Results:

• Elevated interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α) during early infection are necessary and sufficient for autoimmune myocarditis.
• Disease severity correlates with specific T helper 1 (Th1) and T helper 2 (Th2) cytokine profiles.
• Th2 responses and eosinophil presence are prominent in severe myocarditis.
• Interferon-gamma (IFN-γ) can dampen Th1-mediated cardiac infiltration.
• Interleukin-17A (IL-17A) is not required for initial cardiac inflammation but is crucial for dilated cardiomyopathy progression.

Conclusions:

• Early innate immune cytokine production is critical for initiating autoimmune myocarditis after viral infection.
• Distinct Th1, Th2, and Th17 cytokine profiles modulate the severity and specific cardiac outcomes of autoimmune disease.
• Findings suggest potential biomarkers for identifying individuals at risk for post-infectious autoimmunity and inform early therapeutic strategies.