The prototypical example is biological agent-induced psoriasis, due to a TNF-α/type-1 IFN cytokine imbalance: TNF-inhibitors (TNFi) block TNF-α, which results in uncontrolled activation of plasmacytoid dendritic cells (pDCs), with surplus production of IFN-α. This evidence concerns the gene IFNA1 and psoriasis.