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Background: Liver damage is commonly seen in dengue infection, which can sometimes lead to acute liver failure. Although the
exact causes of liver injury is unknown, direct viral injury, hypoxic
injury due to vascular leakage and immune mediated liver damage
are thought to contribute to liver involvement in dengue. Therefore, we proceeded to investigate the patterns of liver injury and
the possible contributing factors in acute dengue infection.
Methods & Materials: 55 adult patients with confirmed acute
dengue infection were recruited during day 3 -5 of the illness and
serial recordings of liver function tests, viral loads, serum IL10 and
IL17 levels and the extent of fluid leakage were measureddaily until
discharge from hospital. According to the 2011 WHO guidelines,
19 of these patients were classified as dengue haemorrhagic fever
(DHF) and 36 were classified as dengue fever (DF).
Results: Serum alanine transaminase (ALT), aspartate transaminase (AST), conjugated and unconjugated bilirubin, gamma
glutamyl transaminase and alkaline phosphatase levels were highest on day 7 of illness in patients with DHF and DF. Serum albumin
levels were only lower in patients with DHF. The peak in liver
enzymes occurred 2 days after the peak of viraemia in patients with
DHF and DF. The extent of the rise in liver enzymes did not correlate with the extent of vascular leak and there were no significant
differences in any of the liver enzymes between patients with DF
or DHF. In contrast, IL-17 levels were significantly associated with
ALT levels (p = 0.02, Spearmans r = 0.17). IL-17 levels were significantly higher (p = 0.008) on day 5 of illness in patients with ALT
levels > 4 times the upper limit of normal (mean 38.2 SE ± 10.1),
when compared to those with lesser degree of liver involvement
(10.3, SE ± 10.2). Although IL-10 were higher in patients with higher
AST levels, this was not significant.
Conclusion: Dengue associated liver injury appears to peak at
day 7 of illness and appears to associate with serum IL-17 levels
but not with the degree of fluid leakage or viraemia. Since IL17
was also shown to cause liver injury in dengue mice models, the
mechanisms by which this occurs needs to be further investigated.
