The effect of season on cytokine expression in multiple sclerosis and healthy subjects

Area of Science:

• Immunology
• Neuroimmunology
• Seasonal biology

Background:

• Cytokine profiles in healthy individuals and those with multiple sclerosis (MS) can vary.
• Seasonal influences on immune responses are increasingly recognized.
• Interferon-beta is a common treatment for relapsing-remitting MS.

Purpose of the Study:

• To investigate seasonal variations in cytokine production in healthy individuals.
• To compare cytokine profiles in untreated MS patients versus healthy controls.
• To assess the impact of Interferon-beta treatment on cytokine levels and seasonal effects in MS.

Main Methods:

• Peripheral blood mononuclear cells (PBMC) were isolated from healthy donors and MS patients.
• PBMC were stimulated with mitogens to induce cytokine production.
• Levels of Interferon-gamma (IFNgamma), Tumor Necrosis Factor-alpha (TNFalpha), Interleukin-4 (Il-4), and Interleukin-10 (Il-10) were measured.
• Blood samples were collected during summer and winter to assess seasonal differences.

Main Results:

• Healthy individuals exhibited a summer excess of Il-4, Il-10, and TNFalpha, and a winter excess of IFNgamma.
• Untreated MS patients showed a summer excess of Il-10.
• MS patients treated with Interferon-beta had significantly lower levels of all measured cytokines compared to untreated patients and healthy controls.
• Interferon-beta treated MS patients displayed no discernible seasonal variation in cytokine production.

Conclusions:

• Seasonal variations in immune cell cytokine production are evident in healthy individuals.
• Multiple sclerosis patients exhibit altered cytokine profiles, with some seasonal influence in untreated cases.
• Interferon-beta treatment in MS normalizes cytokine levels and abrogates seasonal immune fluctuations, suggesting a broad immunomodulatory effect.