Increase in IgE may be due to viral infections, which is the commonest cause of exacerbation of symptoms in asthma or may simply represent a generalized up-regulation of IgE production.[10] Systemic IgE have been found to increase following infection with Epstein Barr virus (EBV),[11] Cytomegalo virus (CMV), Measles virus,[12] vaccination with whole virion influenza vaccine[13] and Rhinovirus.[14]. This evidence concerns the gene IGHE and infection.