Effects of leukotriene D4 on adenoidal T cells in children with obstructive sleep apnea syndrome.

PURPOSE: This study aims to determine whether leukotriene D4 (LTD4) can promote T cell proliferation in adenoid tissues via activation of CysLT1 receptors in children with OSAS.

METHODS: CD4(+) and CD8(+) T cell proliferation was assessed by flow cytometry in adenoid mononuclear cells (AdMCs) stimulated with LTD4 from children with OSAS. The activation of mitogen-activated protein kinase pathways and their effects on the proliferation of CD4(+) and CD8(+) T cells in AdMCs were observed by western blotting.

RESULTS: LTD4 increased the proliferation rates of both phytohemagglutinin (PHA)-stimulated CD4(+) T cells (15.5±8.4% in the PHA group vs. 24.8±6.3% in the PHA+LTD4 group; n=27; P<0.001) and CD8(+) T cells (17.2±5.9% in the PHA group vs. 23.5±5.2% in the PHA+LTD4 group; n=27; P<0.05) in AdMCs. LTD4 (10(-4) mmol) significantly increased the phosphorylation of extracellular signal-regulated kinase (ERK1/2) and p38, but not c-Jun N-terminal kinases (JNK). The ERK1/2 inhibitor PD98059 significantly inhibited the proliferation of CD4(+) and CD8(+) T cells in LTD4-stimulated AdMCs.

CONCLUSION: LTD4 regulates the proliferation of CD4(+) and CD8(+) T cells in PHA-stimulated AdMCs via upregulation of the ERK1/2 pathway. This finding indicates that CysLT1 receptors play a regulatory role in the pathogenesis of OSAS in children.