The defined
antigen substrate sphere system is a simple method for detecting
antigen or antibody in the circulation. The technic is based on the coupling of
antigen or antibody with
Sepharose 4B beads that have been activated by
cyanogen bromide. In this study the activated beads were exposed to
dengue antigen in the serum from a patient with
dengue hemorrhagic fever and then stained with antidengue antibody conjugated with
horseradish peroxidase. The positive reaction showed brown beads by light microscopy, whereas the negative reaction gave colorless beads. The authors examined 134 specimens from 91 cases. The results were positive in 53.85%. The
dengue antigen appeared in the sera on the day before
shock or subsidence of
fever. The percentages of sera containing soluble
dengue antigen were greatest on the day of
shock or subsidence of
fever (33.33%) and on the fifth day of
fever (28.07%). The highest titers of soluble
dengue antigen (1:40 to 1:80) appeared in the sera of patients who had Grade III disease on the day of
shock. The
dengue antigen appeared most often in sera that had high titers of
dengue antibody. It is postulated that this detected
dengue antigen may be a part of soluble
immune complexes formed during the hyperimmune stage of the immune response, and plays a significant role in the pathogenesis of
dengue hemorrhagic fever and
shock syndrome.