T-cell immunophenotype correlations with cortical thickness and white matter microstructure in bipolar disorder

Area of Science:

• Neuroscience
• Immunology
• Psychiatry

Background:

• Inflammation and immune alterations, including T-cell and cytokine changes, are implicated in bipolar disorder (BD).
• Evidence suggests links between immune changes and brain structural alterations (cortical thickness, gray matter, white matter) in BD.
• The relationship between specific peripheral T-cell subsets and neuroimaging findings in BD is under-investigated.

Purpose of the Study:

• To investigate the association between T-cell immunophenotype and neuroimaging findings in individuals with bipolar disorder.

Main Methods:

• Studied 43 type I BD patients (22 depressive, 21 manic) and 26 healthy controls (HC).
• Analyzed T lymphocyte immunophenotype.
• Assessed brain structure using neuroimaging: cortical thickness (CT) for gray matter and fractional anisotropy (FA) for white matter microstructure.

Main Results:

• BD patients had higher CD4+ and CD4+ central memory (TCM) T-cells, but lower CD8+ effector memory (TEM) and terminal effector memory (TTEM) T-cells.
• Reduced CT was observed in multiple brain regions in BD patients.
• Significant negative correlations were found between CD4+ TCM levels and CT in the precuneus and fusiform gyrus.
• Widespread white matter microstructure alterations were detected in BD patients, with correlations between FA/radial diffusivity (RD) and CD4+ TCM, CD8+ TEM, and CD8+ TTEM subsets.

Conclusions:

• Distinct T-lymphocyte alterations and brain structure changes are present in bipolar disorder.
• Findings suggest potential immune-brain interactions in BD.
• Further research into these immune-brain interactions may reveal new therapeutic targets for BD.