Toll-like receptor 9 negatively related to clinical outcome of AML patients.

Background: Acute myeloid leukemia (AML) can modulate toll-like receptor-9 (TLR9) expression and activation. This study was conducted to elucidate the expression of TLR9 in AML patients and its relation to the prognosis of the disease.

Results: The study included 40 newly diagnosed AML patients managed in the hospital in addition to 20 sex and age matched normal volunteers as control. TLR9 expression assay was conducted on peripheral blood samples of AML cases before the start of treatment as well as the controls by immunophenotyping. TLR9 expression was ranging from 0.10 to 2.40% in AML patients with higher expression among the control, ranging from 0.94 to 8.25%. The median TLR9 expression in AML patients was significantly lower with advanced cytogenetic risk score. It is not significantly differing in relation to patients' sex, age group, and FAB type of AML. However, significant lower median expression was found in relation to clinical outcome. TLR9 expression ≤ 1% showed lower median overall survival time when compared to those with > 1% expression.

Conclusion: This study concluded that AML patients express TLR9 in leukemic cells with very low percentage. This expression was negatively related to the clinical outcome.