IL15 and infection: However, interferon and IL-15 deficiency have been demonstrated in cultured cells retrieved from stable asthmatics at baseline following infection of these cells with a standardised quantity of rhinovirus ex vivo (Wark et al., 2005, Contoli et al., 2006, Edwards et al., 2013, Message et al., 2008, Sykes et al., 2012, Laza-Stanca et al., 2011).