Dengue hemorrhagic fever (DHF) is a severe form of dengue fever (DF). Recent in vitro
studies indicate that complement reduces the infection-enhancing activity of dengue antibodies, suggesting
its in vivo role in controlling viremia levels and disease severity. In this study, the complement hemolytic
activity (CH50) and levels of complement components and related factors in dengue patients in Indonesia
were assessed. Based on the number of days since fever onset, DF patients were compared with
patients at the DHF pre-critical phase who showed deterioration within 2 days.