Loss of thymic function promotes EAE relapse in anti-CD52-treated mice

Area of Science:

• Immunology
• Neuroimmunology
• Autoimmune Diseases

Background:

• Anti-CD52 therapy reduces multiple sclerosis (MS) relapses by causing CD4 T cell lymphopenia.
• In mice, anti-CD52 therapy at disease onset suppresses experimental autoimmune encephalomyelitis (EAE) but results in rapid T cell repopulation.

Purpose of the Study:

• To investigate if prolonged T cell lymphopenia influences the effectiveness of anti-CD52 treatment.
• To determine the role of thymus function in modulating anti-CD52 therapy outcomes.

Main Methods:

• Mice underwent thymectomy before EAE induction and anti-CD52 treatment to reduce recent thymic emigrant T cells.
• CD4 T cell counts in peripheral blood were monitored.
• EAE relapse rates were compared between thymectomized and control mice (no surgery or sham surgery).

Main Results:

• Thymectomy led to a prolonged reduction in peripheral blood CD4 T cells.
• Two-thirds of thymectomized mice experienced an EAE relapse after anti-CD52 treatment.
• Control mice (no surgery or sham surgery) remained relapse-free.

Conclusions:

• Thymus function significantly alters the effectiveness of anti-CD52 treatment.
• Prolonged T cell lymphopenia, influenced by thymus function, may promote EAE relapses.
• Targeting thymus function could be a strategy to enhance anti-CD52 therapy for MS.