The study’s objective is to utilize single cell CyTOF (mass cytometry by time of flight mass spectrometry) to investigate serum inflammatory changes in transient ischemic attack (TIA) and minor stroke patients versus non-ischemic transient neurologic events (TNEs).

Clinically diagnosing TIAs remains challenging. An accurate serum marker to differentiate TIAs from TNEs would greatly improve treatment.

Patients presenting to the emergency department with transient neurologic symptoms or with minor strokes (NIHSS≤4) were prospectively enrolled. A blood sample was collected within 72 hours, on which CyTOF analysis was completed examining 11 inflammatory markers in 19 single cell populations. These populations also underwent stimulation from lipopolysaccharide (LPS). Mixed ANOVA analysis was performed to evaluate response to stimulation and its differences between the groups.

Patients with TIA/minor stroke (n=10) and TNEs (n=10) were enrolled.  The difference in CREB (cAMP response element binding protein) and NfKB (nuclear factor light chain enhancer of activated B Cells) levels before and after LPS stimulation were evaluated.  Interestingly in the classical monocyte cell population, the change of CREB  levels in response to LPS stimulation was increased in the TIA/minor stroke group compared to the TNE group  (1.64±0.13 versus 1.28±0.42 respectively, indicated by a significant interaction effect between change and group, p=0.020, with Partial Eta Squared η_p²=0.267 suggesting large effect).  NfKB also showed an increased change in response to LPS stimulation in the TIA/minor stroke patients compared to controls (0.88±0.11 versus 0.75±0.14 respectively, p=0.045, η_p²=0.205).  

In our hypothesis generating study, differences exist in inflammatory markers between TIA/minor strokes and TNE patients that can be measured via CyTOF. These findings suggest following an ischemic episode the immune system is more primed to respond to a stimulus. Promising prospects for future TIA serum biomarker studies include CREB and NfKB concentrations with LPS stimulation.