Abstract:
Introduction: Platelet activating factor (PAF) is an important mediator of vascular
leak in acute dengue. Phospholipase A2s (PLA2) are inflammatory lipid enzymes
that generate and regulate PAF and other mediators associated with mast cells. We
sought to investigate if mast cell activation and increases in secretory sPLA2s are
associated with an increase in PAF and occurrence of dengue haemorrhagic fever
(DHF).
Methods: The changes in the levels of mast cell tryptase, PAF and the activity of
sPLA2 were determined throughout the course of illness in 13 adult patients with
DHF, and 30 patients with dengue fever (DF).
Results: We found that sPLA2 activity was significantly higher in patients with
DHF when compared to those with DF, during the first 120 h of clinical illness.
sPLA2 activity was significantly associated with PAF levels, which were also
significantly higher in patients with DHF. Although levels of mast cell tryptase were
higher in patients with DHF, the difference was not significant, and the levels were
not above the reference ranges. sPLA2 activity significantly correlated with the
degree of viraemia in patients with DHF but not in those with DF.
Conclusion: sPLA2 appears to play an important role in the pathogenesis of
dengue. Since its activity is significantly increased during the early phase of
infection in patients with DHF, this suggests that understanding the underlying
mechanisms may provide opportunities for early intervention.
