Increased pro-inflammatory cytokines (TNF-α and IL-6) and anti-inflammatory compounds (sTNFRp55 and sTNFRp75) in Brazilian patients during exanthematic dengue fever

Pro-inflammatory cytokines, tumor necrosis factor (TNF-alpha), interleukin-6 (IL-6) and interleukin-1 beta (IL-1 beta) as well as anti-inflammatory compounds, soluble TNF-Receptor p55 (sTNFRp55), sTNFRp75 and IL-1 receptor antagonist (sIL-1Ra), were investigated in 34 Brazilian cases of dengue fever (DF) originated from a study of exanthematic virosis. The presence of pro-inflammatory cytokines was detected in sera from these patients by ELISA. TNF-alpha and IL-6 levels were significantly higher than control subjects in 32% and 52% patients, respectively. To our knowledge this was the first time a receptor antagonist and soluble receptors for cytokines were detected in sera obtained during exanthematic DF without hemorrhagic manifestations. Both sTNFRp55 and sTNFRp 75 were consistently elevated in 42% and 84% patients, respectively. Most patients had IL-1 beta levels not different from those of normal subjects, except for one case. Only 16% patients had altered levels of IL-1Ra. Previous studies in dengue hemorrhagic fever patients demonstrated production of these soluble factors; here we observed that they are found in absence of hemorrhagic manifestations. The possible role of these anti-inflammatory compounds in immune cell activation and in regulating cytokine-mediated pathogenesis during dengue infection is discussed.