Modulation of the Immunological Milieu in Acute Aneurysmal Subarachnoid Hemorrhage: The Potential Role of Monocytes Through CXCL10 Secretion

Introduction Emerging evidence indicates that aneurysmal subarachnoid hemorrhage (aSAH) elicits a response from both innate and adaptive immune systems. An upregulation of CD8 + CD161 + cells has been observed after aSAH, yet the precise role of these cells in the context of aSAH is yet to be elucidated. Methods CSF samples from patients aSAH and non-aneurysmal SAH (naSAH) were analyzed. Single-cell RNA sequencing (scRNAseq) was performed on CD8 + CD161 + sorted samples from aSAH patients. Cell populations were identified using “clustering”. Gene expression levels of ten previously described genes involved in inflammation were quantified from aSAH and naSAH samples using RT-qPCR. The study focused on the following genes: CCL5, CCL7, APOE, SPP1, CXCL8, CXCL10, HMOX1, LTB, MAL, and HLA-DRB1. Results Genes clustering analysis revealed that monocytes, NK cells, and T cells expressed CD8 + CD161 + in the CSF of patients with aSAH. In comparison to naSAH samples, aSAH samples exhibited higher mRNA levels of CXCL10 (median, IQR = 90, 16–149 vs 0.5, 0-6.75, p = 0.02). A trend towards higher HMOX1 levels was also observed in aSAH (median, IQR = 12.6, 9-17.6 vs 2.55, 1.68–5.7, p = 0.076). Specifically, CXCL10 and HMOX1 were expressed by the monocyte subpopulation. conclusion Monocytes, NK cells and T cells can potentially expressed CD8 + CD161 + in patients with aSAH. Notably, monocytes show high levels CXCL10. The elevated expression of CXCL10 in aSAH compared to non-aneurysmal SAH naSAH indicates its potential significance as a target for future studies.