TNF and viral infectious disease: The semantic similarity analysis of the GO BP terms of the down-regulated PsO genes further highlighted the importance of the cell cycle and mitosis, in the skin biopsies derived from the PsO responders, in the response to anti-TNFα therapy; terms including chromosome segregation and nuclear division were abundant, along with skin-related terms (e.g., keratinization and skin developmen t), whilst immune-related pathways mainly referred to interferon signaling and response to viral infection, as shown in Figure 3b.