TABLE 3.

Alterations in serum cytokine levels during infectious mononucleosis

Cytokine	Status during infectious mononucleosis	Possible impact on clinical pathogenesis (in terms of known function)	Reference(s)
IFN-γ	Elevated	Type II interferon, produced by NK cells and Th1 and CD8 T cells; broad immunostimulatory effects; important for control of chronic infection; likely inhibits viral replication and reactivation	24, 39, 91, 125, 180, 216
Neopterin	Elevated	A pteridine compound released from macrophages/monocytes stimulated by IFN-γ	24, 125, 180
IFN-α	Not reproducibly detected	Type I interferon, produced by monocytes and plasmacytoid dendritic cells; broad antiviral and immunostimulatory effects; important for control of acute infection	91, 125, 159, 216
IL-6	Elevated	Inflammatory cytokine produced by T cells and macrophages; mediator of fever and acute-phase response; promotes B-cell maturation	91, 125, 180, 218
TNF-α	Elevated	Inflammatory cytokine produced mainly by macrophages; activates macrophages, stimulates acute-phase response, and can cause liver dysfunction and fever	24, 218
IL-12	Elevated	Cytokine produced by dendritic cells; promotes differentiation of Th1 CD4 and CD8 T cells; enhances NK and CTL cytotoxicity	39, 216
IL-2	Occasionally elevated	Produced by activated T cells; growth factor for regulatory T cells	24, 39, 91, 216, 218
IL-10	Elevated	Immunosuppressive cytokine produced by monocytes and T cells; in combination with viral IL-10, it may suppress T-cell production of other cytokines (IFN-γ, TNF-α) and enable systemic spread of virus	197, 217, 218
TGF-β	Elevated	Immunosuppressive cytokine with pleiotropic effects	217