ABSTRACT
<p><b>OBJECTIVE</b>To study the significance of toll-like receptors (TLR) -7 and -8 in the pathogenesis of infection caused by Enterovirus type 71 (EV71) through measuring the expression of TLR7 and TLR8 in brain and lung tissues from the death cases caused by EV71 infection.</p><p><b>METHODS</b>Nine children who died of EV71 infection (EV71 group) were selected as study subjects, and 7 children who died of accidents or non-infectious diseases were used as the control group. Brain and lung tissues from the death cases in both groups at autopsy were collected, and immunohistochemistry was applied to detect the expression of TLR7 and TLR8 in lung and brain tissues in both groups. Integrated optical density (IOD) was applied for semi-quantitative analysis of the expression of TLR7 and TLR8.</p><p><b>RESULTS</b>Immunohistochemical results showed that the expression of TLR7 and TLR8 in lung and brain tissues was strongly positive in the EV71 group, and the IOD values in the EV71 group were also significantly higher than those in the control group (P<0.05). There was no significant difference in the expression of TLR7 and TLR8 between lung and brain tissues in the EV71 group (P>0.05).</p><p><b>CONCLUSIONS</b>TLR7 and TLR8 are highly expressed in lung and brain tissues from the patients who die of severe EV71 infection, suggesting that TLR7 and TLR8 may be involved in the pathogenesis of brain and lung damages caused by severe EV71 infection.</p>