Comparison of dengue virus antigens in sera and peripheral blood mononuclear cells from dengue infected patients.

The presence of dengue virus antigens in acute sera and peripheral blood mononuclear cells (PBMC) from dengue infected patients were determined by a biotin-streptavidin enzyme-linked immunosorbent assay (BS-ELISA). The frequency of the antigens detected in PBMC was higher than that in sera (53.8% vs 18.9%). In comparison with sera, the detection rate in PBMC was greater than six times: 7 cases were positive only in sera whereas 44 cases were positive only in PBMC, p < 0.001. The presence of the antigens in the sera did not depend on the severity of the disease, i.e. dengue fever, dengue hemorrhagic fever (grades I and II) or dengue shock syndrome (grades III and IV). In contrast, the presence of the antigens in PBMC increased from 36.8% to 100% when the infection was more severe. The dengue virus antigens could be detected in the samples collected between day 2 and day 7 after onset of the disease with the highest rate of detection (68.8%) in PBMC collected on day 4. The data suggest the use of PBMC with access to the appropriate acute-phase specimen for detection of dengue virus antigens.