TNF and susceptibility to pneumonia measurement: Viruses are intracellular pathogens where a strong cellular immune response is needed, and in the case of both groups, we infer that an increase of proinflammatory cytokines TNFα and IL-6 and Th1 cytokines IFNγ and IL-2 took place between the time of entrance of the pathogen to the organism and the development of pneumonia, which is demonstrated by the lymphoproliferation detected at the moment of pneumonia and slight decrease at resolution when the blood draw was taken.