Polarization of natural killer T cells towards an NKT2 subpopulation occurs after stimulation with alpha-galactosylceramide and rhG-CSF in aplastic anemia.

Natural killer T (NKT) cells play an important role in the regulation of immune responses in a broad range of diseases, including autoimmune disorders, infectious diseases and cancer. So far, few studies have evaluated the roles of NKT cells in the pathogenesis of aplastic anemia (AA), an autoimmune disease. In this study, we investigated the quantitative and qualitative changes in NKT cells in bone marrow (BM) mononuclear cells of AA patients in response to in vitro stimulation with alpha-galactosylceramide. Compared to healthy controls, BM from AA patients had reduced fraction of NKT cells, which possessed a decreased potential to expand in vitro in response to alpha-galactosylceramide stimulation, producing more IFNgamma+ NKT1 cells. In the presence of rhG-CSF, the expansion capacity of NKT cells stimulated by alpha-galactosylceramide was significantly reduced in both AA and control groups, with the majority of the activated NKT cells expressing intracellular IL-4, and the fractions of IFNgamma+ NKT cells were significantly reduced. In summary, our results indicate that polarization of NKT cells towards the NKT2 subpopulation occurs after co-stimulation with alpha-galactosylceramide and rhG-CSF in AA. 2008 S. Karger AG, Basel.