OBJECTIVETo explore the role of CD4(+)CD25(+) regulatory T cells (Treg) in the occurrence of spontaneous subarachnoid hemorrhage (SAH).

METHODSFifteen patients with spontaneous SAH, 15 with traumatic SAH, and 15 with headache without organic pathologies as confirmed by lumbar puncture (control group) were examined with flow cytometry for Treg in the peripheral blood and cerebrospinal fluid and intracellular cytokine interleukin-10 (IL-10) and transforming growth factor beta1 (TGF-β1) levels. The Glasgow score (GCS), neurological deficit score (NIHSS), headache, visual analog scale (VAS) and hospitalization time were compared between the two SAH groups.

RESULTSSpontaneous SAH patients showed significantly lowered peripheral blood Treg, IL-10, and TGF-β1 in the cerebrospinal fluid compared with the patients with traumatic SAH and the control group (P<0.05), and the 3 measurements were comparable between the latter two groups (P>0.05). After administration of treatment, of Treg content in spontaneous SAH patients increased progressively and became comparable with those in the other two groups at the third and fourth lumbar punctures. Spontaneous SAH patients showed significantly lower GCS, NIHSS, and VAS with shorter hospital stay than the traumatic SAH patients. Correlation analysis showed that Treg, IL-10 and TGF-β1 were all inversely correlated with NIHSS, VAS, and duration of hospitalization but positively correlated with GCS (the absolute r values were all greater than 0.6, P<0.05).

CONCLUSIONTreg deficiency can be an important mechanism for the occurrence of spontaneous SAH, and a higher level of Treg indicates a better outcome of the patients.