Deep immunophenotyping in aneurysmal subarachnoid hemorrhage: a prospective and controlled clinical study

Area of Science:

• Neuroscience
• Immunology
• Cerebrovascular Disease

Background:

• Aneurysmal subarachnoid hemorrhage (aSAH) is a severe cerebrovascular event with high mortality.
• Inflammation significantly impacts post-hemorrhage complications, but immune cell dynamics are unclear.
• This study investigates monocyte and T cell polarization in aSAH patients.

Purpose of the Study:

• To analyze immune cell subpopulation shifts in aSAH patients.
• To correlate these immune changes with angiographic cerebral vasospasm and delayed cerebral ischemia (DCI).
• To explore the potential of immune profiling in aSAH management.

Main Methods:

• Prospective observational cohort study with 75 aSAH patients and 20 controls.
• Blood samples analyzed via flow cytometry for monocyte (M1, M2) and T cell (Th1, Th2, Th17, Treg) polarization.
• Complications monitored: vasospasm, DCI, and 6-month clinical outcome (mRS).

Main Results:

• aSAH patients showed decreased anti-inflammatory monocytes and Th2 cells, with increased pro-inflammatory Th17 cells compared to controls.
• Loss of anti-inflammatory monocytes preceded vasospasm and DCI onset.
• No significant correlation found between immune cell profiles and long-term outcomes.

Conclusions:

• aSAH induces a pro-inflammatory immune shift, characterized by a loss of anti-inflammatory monocytes.
• This monocyte loss is a potential early indicator for vasospasm and DCI.
• Immune subpopulation profiling could be a valuable tool for diagnosing and potentially treating aSAH complications.