Association between TLR2 and TLR4 Expression and Response to Induction Therapy in Acute Myeloid Leukemia Patients

Toll-like receptors (TLRs) are a family of transmembrane pattern-recognition receptors that play a crucial role in the realization of innate and adaptive immune response. TLRs may play a role in tumor development and growth because of expression or up-regulation of functional TLRs in some tumors and tumor cell lines. The participation of TLRs in the pathogenesis of acute myeloid leukemia (AML) remains unspecified. This study aimed to investigate the effect of TLR2 and TLR4 expression in peripheral blood mononuclear cells of AML patients in response to induction chemotherapy. Eighty- five patients with newly diagnosed AML were evaluated. Using quantitative reverse transcriptase PCR, the mRNA expression of genes TLR2 and TLR4 was measured before starting and after induction chemotherapy. The differences in the mean expression levels of TLR2 and TLR4 before and after chemotherapy were compared using a paired t-test. The mean expression levels of TLR2 and TLR4 regarding laboratory data were analyzed by one-way ANOVA and Chi-square test. We found that the mRNA expression of TLR2 after induction chemotherapy was significantly lower as compared to before treatment (p=0.001). Also, we found a lower TLR4 gene expression level after chemotherapy as compared to before chemotherapy, albeit it was not statistically significant (p=0.21). Moreover, we observed significantly higher expression of TLR2 and TLR4 in AML-M3 cases compared to non-M3 AML patients. The decreased expression of TLR4 in leukemic samples after induction chemotherapy might indicate a novel potential prognostic role for this receptor, particularly in AML-M3 cases.