Serum platelet-activating factor acetylhydrolase activity in dengue.

INTRODUCTION Severe dengue infection is characterized by enhanced vascular permeability produced by cytokines and biochemical mediators. One of these mediators is the platelet-activating factor. Degradation of platelet-activating factor is accomplished by its specific acetylhydrolase. Down or up regulation of this enzyme has been linked to several diseases. However, the role of this enzyme in dengue infection is unknown, a well as whether differential activity occurs by ethnic group. OBJECTIVE The activity of the platelet-activating factor-acetylhydrolase was compared in patients infected with dengue virus in two ethnic groups. MATERIAL AND METHODS A descriptive, prospective and longitudinal study was made in two states of Colombia (Antioquia and Chocó). Serum samples were taken from 43 mestizo patients and 33 patients of African descent, each taken during five consecutive days of the acute dengue phase. A second serum sample was taken during the convalescent phase. RESULTS The mestizo patients showed higher frequency of dengue hemorrhagic fever than the patients of African descent (23.3% vs. 12.1%, p=0.25). The serum activity of the platelet-activating factor acetylhydrolase was higher in African descendents than in mestizos (0.89, CI: 0.72-1.10 vs. 0.76 CI: 0-1.03, p<0.001). This relationship is maintained for occurence of dengue fever (0.89, CI: 0.73–1.10 vs. 0.73, CI: 0–1.05, p<0.001), but not significant for dengue hemorrhagic fever (0.88, CI: 0.69–1.12 vs. 0.83, CI: 0.71–1.08, p=0.89). CONCLUSION. An increased production of platelet-activating factor-acetylhydrolase occurs in the serum of dengue-infected African descendants. However, a study of the frequencies of polymorphisms for this enzyme will permit more conclusive support for these observations.