In conclusion, this study showed for the first time that tSNPs of CLEC5A are not associated with susceptibility to KD, CAL formation, and IVIG treatment response in a Taiwanese population. A Non-VH1-69 Heterosubtypic Neutralizing Human Monoclonal Antibody Protects Mice against H1N1 and H5N1 Viruses Influenza viruses are among the most important human pathogens and are responsible for annual epidemics and sporadic, potentially devastating pandemics. The humoral immune response plays an important role in the defense against these viruses, providing protection mainly by producing antibodies directed against the hemagglutinin (HA) glycoprotein. However, their high genetic variability allows the virus to evade the host immune response and the potential protection offered by seasonal vaccines. The emergence of resistance to antiviral drugs in recent years further limits the options available for the control of influenza. The development of alternative strategies for influenza prophylaxis and therapy is therefore urgently needed. In this study, we describe a human monoclonal antibody (PN-SIA49) that recognizes a highly conserved epitope located on the stem region of the HA and able to neutralize a broad spectrum of influenza viruses belonging to different subtypes (H1, H2 and H5). Furthermore, we describe its protective activity in mice after lethal challenge with H1N1 and H5N1 viruses suggesting a potential application in the treatment of influenza virus infections. Seasonal influenza causes up to 500,000 deaths worldwide each year [1] . Infants, immunocompromised individuals and the elderly are particularly susceptible, with 90% of deaths occurring in the latter group [2] . Influenza viruses can also cause pandemics that, although rare, are recurrent events historically associated with high levels of morbidity and mortality [3, 4, 5, 6] . Preventive vaccination has historically been the most efficient measure of influenza control, but this approach presents important limitations due to the accumulation of antigenic mutations in the virus, known as antigenic drift. Vaccines typically elicit a potent neutralizing antibody response limited to the specific viral strains included in the preparation and to closely related viruses [2] . For this reason, seasonal vaccines need to be annually reformulated based upon the forecasting of viral strains that will circulate in the coming influenza season. Furthermore, influenza vaccines have suboptimal immunogenicity and efficacy in the groups at highest risk of severe disease [7] . Moreover in the case of a pandemic, the use of vaccine is limited by the time required for its development and deployment [8] .