Increment of interleukin 6, tumour necrosis factor alpha, nitric oxide, C-reactive protein and apoptosis in dengue

This study evaluated the levels of TNFalpha, IL-6, IL-1beta, nitric oxide (NO), CRP, C3 and apoptosis in 36 patients with dengue fever (DF), 34 patients with dengue haemorrhagic fever (DHF) and in virus-infected monocyte cultures. IL-6, TNFalpha, NO (nitrites) and CRP levels were increased and C3 diminished in patients with DF and DHF. IL-6, TNFalpha, CPR and C3 values were associated with disease severity (DHF). Nitrite content was incremented in DF patients. TNFalpha, NO and CRP levels were associated with secondary infection. IL-6 and CRP levels were associated with dengue virus type 4 (DENV-4) and DENV-2, respectively. Low levels of C3 were associated with DENV-2 and DENV-4 infections. Similarly, increased content of TNFalpha, IL-6 and nitrites were observed in supernatants from infected monocyte cultures. IL-6 was associated with DENV-4 infection. The different virus serotypes induced apoptosis in monocyte cultures. Dengue infection did not induce elevated IL-1beta production, either in patients or in infected cultures. These results suggest that TNFalpha, IL-6, NO and CRP are involved in dengue infection and that monocytes could be an important source of cytokine and NO production.