Thus, more indepth multivariate and mechanistic clinical analyses were limited. Moreover, no recommendations for monitoring viral persistence were available; therefore, only a subset of severely ill patients admitted to the ICU was evaluated. Despite that, an important connection between clinical and GDC-0879 Raf inhibitor laboratory information was studied, revealing the continuous evolution of H1N1pdm HA sequences and the stability of the NA gene in severely ill patients. In conclusion, this study provides evidence that severe H1N1pdm infection is associated with significant morbidity and mortality in cancer patients. In these patients, viral persistence without the emergence of antiviral resistance may occur during the clinical course of the disease. This result has major implications for the clinical management of H1N1pdm infections and infection control strategies. Our study may provide insights into H1N1pdm shedding and might contribute to the development of new guidelines to manage cancer patients with H1N1pdm infection. Primates have been infected with retroviruses frequently throughout their evolution. Retroviral infections are believed to have driven the evolution of host factors such as the restriction factors TRIM5a and TRIMCyp. These restriction factors specifically inhibit retroviral replication, and bear the marks of previous evolutionary conflicts. TRIM5a and TRIMCyp are two of several alternatively spliced isoforms of the TRIM5 gene. This gene belongs to the tripartite motif gene family, of which several members in addition to TRIM5 have been implicated in immune responses to pathogens. TRIM proteins contain, in order, a RING domain, one or two B-Box domains, and a coiled coil domain. TRIM5a also has a Cterminal B30.2/SPRY domain, which recognizes and binds to the capsids of susceptible retroviruses, leading to post-entry restriction of infection. This restriction occurs in a two-stage process, with stages both before and after reverse transcription. Based on molecular evidence, the macaques are thought to have diverged from the papionin clade about 9–10 million ybp, although fossil and geological evidence indicates that this event could have occurred as recently as 6 million ybp. Molecular evidence suggests that the Asian macaques diverged from M. sylvanus approximately 5.5–6 million ybp, and diverged from each other about 5–6 million ybp. Based on these data and on our findings, we hypothesize that a retrovirus invaded the population of the Asian macaque progenitors approximately 5–6 million ybp, causing selection for a novel antiretroviral factor and leading to the evolution of TRIMCyp in this clade. This event could have occurred either in Asia or in Europe or Africa, before these species arrived in Asia.