Since neutrophils and monocytes are predominant IFN-λ2-expressing cells in blood of HC, the decreased expression of IFN-λ2 in these 2 cell types could contribute to diminished level of IFN-λ2 in the plasma of asthma, even though IFN-λ2 expression appeared to be upregulated in blood cytotoxic T cells and eosinophils in asthma as cytotoxic T cells only weakly express and eosinophils do not express IFN-λ2 in HC. Here, IFNL2 is linked to asthma.