Figure 2.

Natural killer T (NKT) cells recognize glycolipids presented by CD1d molecules and are capable of producing large amounts of IFN-γ and IL-4. They are considered to have immunoregulatory effects. The reduced levels and/or dysfunctional NKT cells that have been described in sarcoidosis (12–14) may lead to a loss of control of the activated Th1 proinflammatory cells in sarcoidosis, theoretically through reduced NKT cell production of IL-4 (42), which has down-regulatory effects on Th1 cells. HLA = human leukocyte antigen.