Generation of IgM anti-platelet autoantibody in dengue patients

Dengue virus infection causes a wide range of diseases from dengue fever to life-threatening dengue hemorrhagic fever and dengue shock syndrome (DHF/D SS). The mechanisms involved in DHF/DSS pathogenesis remain unclear. Patien t sera collected from an outbreak in southern Taiwan from November 1998 to January 1999 were studied. The presence of antibodies which cross-reacted w ith platelets could be detected in patient sera, and the isotype of these a utoantibodies was IgM. The anti-platelet IgM levels were higher in DHF/DSS than in dengue fever patient sera in disease acute phase. These autoantibod ies were still detectable in convalescent stage (1-3 weeks after acute phas e) and even eight to nine months after illness. The platelet binding activi ty was not observed in other virus-infected patient sera tested. Further in vestigation showed that dengue patient sera caused platelet lysis in the pr esence of complement. The platelet cytotoxicity induced by DHF/DSS patient sera was higher than that by dengue fever sera. Dengue patient sera also in hibited platelet aggregation which, however, appeared to be not related to DHF/DSS development. (C) 2001 Wiley-Liss, Inc.