Association of dengue virus type-specific IgG on platelets is specific for the acute phase in an imported Japanese patient with secondary dengue 2 virus infection

The mechanism of thrombocytopenia in dengue virus infection remains unknown. We report herein an imported case of a 21-year-old male Japanese with dengue fever caused by secondary dengue 2 virus infection. The thrombocytopenia detected around the day of defervescence was associated with an increased level of plateletassociated IgG (PAIgG). The eluate from the platelets during the acute phase of this case contained an increased activity of anti-dengue virus 2 IgG, while the eluate from platelets during the convalescent phase contained a low level of anti-dengue 2 IgG. These findings suggest the transient formation of PAIgG involving anti-dengue 2 virus IgG during the acute phase of secondary dengue 2 virus infection