Abstract 3259: Leukocyte Subset Specific Gene Expression In Acute Stroke Patients
Background: Alterations in gene expression in the peripheral blood of patients with acute stroke have been demonstrated using microarray technology. Whole blood and peripheral blood mononuclear cells (PBMCs) were used in prior studies in which panels of genes diagnostic for stroke were developed. We aimed to determine the cellular sources of alterations in gene expression by studying individual leukocyte subsets.
Methods: The expression of four genes previously found to be upregulated in ischemic and hemorrhagic stroke (IL1R2, S100A9, ETS2 and F5) was measured in four leukocyte subsets: CD14+ monocytes, CD4+ T cell lymphocytes, CD20+ B cell lymphocytes and PBMCs. These four genes had been reported in at least two of the previously published stroke-related gene panels. Peripheral blood was obtained from six acute stroke patients (all <48 hours from symptom onset) and 6 age, race and sex matched control subjects. Leukocytes were separated from whole blood using density gradient centrifugation and column magnetic bead cell sorting. The purity of separated leukocyte subsets exceeded 90% and was verified with flow cytometry. Messenger RNA was isolated from each leukocyte subset and analyzed by two step RT PCR and qPCR. The expression of the four stroke-related genes was compared to the expression of a housekeeping gene (GAPDH). The relative expression of individual genes and of the 4 gene panel within cellular subsets was compared between stroke patients and control subjects.
Results: Individually, IL1R2 and S100A9 were significantly over-expressed in stroke patients with a 10 fold increase for IL1R2 in PBMCs (p<0.05) and a 3 fold increase for S100A9 in the CD4+ T and CD20+ B lymphocyte subsets (p<0.05). When analyzed as a panel of four genes the expression of IL1R2, S100A9, ETS2 and F5 was significantly higher in both the CD4+ T lymphocytes (p<0.05) and CD20+ B lymphocytes (p<0.05) of stroke patients but not in the monocytes or the PBMCs.
Conclusion: These results show the potential diagnostic value of selected genes from panels previously found in microarray studies in stroke patients. They also emphasize the value of panel analysis over that of single gene expression and the potential cellular specificity of alterations in gene expression. Analysis of whole blood and PBMCs alone may not reflect important dynamic changes in stroke-related gene expression.
- © 2012 by American Heart Association, Inc.