Table 1.

Inhibition of PMN Apoptosis during Viral Infections

	Respiratory Syncitial Virus (RSV)	Human Cytomegalovirus (HCMV)
Virus-induced Pathology	Lower respiratory tract disease in infants Associated with respiratory distress	Belong to the Herpes family: persistence of the virus in a latent state and repeated reactivation Subclinically in immunocompetent individuals but fatal disease for immunocompromized patients
Characteristics	Accumulation of PMN in lower airways PMN production of IL-9 which increases mucus production by Goblet cells	Presence of activated-PMN
Mechanisms	Presence of the anti-apoptotic cytokine IL-6 Interaction of ssRNA from RSV with TLR7/8 ? Activation of PI3K and NFκB signaling pathways Increased expression of the anti-apoptotic protein Mcl1	Interaction of the viral protein UL36 with apoptotic pathways Blockade of caspase 8 activation Inhibition of Fas ligand-mediated apoptosis
Consequences	Immune evasion	Exacerbation of inflammatory responses e.g. in intestinal tissue