Therefore, the aims of this study are to demonstrate the hematological changes especially the increment of Hct which indicate the vascular leakage, dengue viral infected monocytes, and the monocyte's markers of activation/exhaustion as shown by the proinflammatory and anti-inflammatory cytokines production including of TNF-α, IL-1β, and IL-10 especially intracellular cytokines in monocytes of patients infected with dengue virus in order to understand the cause and effect relationship which may lead to the severity of the diseases. The gene discussed is IL1B; the disease is dengue disease.