Expression of TLR4 in peripheral blood mononuclear cells and plasma concentrations of TNF-αin patients with HIV/MTB co-infection

Objective To investigate the expression of TLR 4 and its downstream factor TNF-αin the patients with human immunodeficiency virus and Mycobacterium tuberculosis （ HIV/MTB） co-infection. Methods A total of 119 subjects including 32 patients with HIV infection （HIV group）, 30 patients with HIV/MTB co-infection （HIV/MTB group）, 28 patients with MTB infection （MTB group） and 29 healthy subjects （ control group ） were recruited continuously from the Fourth People′s Hospital of Nanning City , Guangxi.The expression of TLR4 in peripheral blood mononuclear cells （PBMCs） from the patients was de-termined by flow cytometry .ELISA was performed to detect TNF-αin plasma samples .The HIV-1 viral load was determined by standard method .Results The mean fluorescence intensity （ MFI） for TLR4 expression in PBMCs from HIV, HIV/MTB, MTB and control groups were 21.62±4.67, 18.29±3.87, 16.79±4.45, and 22.85±5.80, respectively, showing significant differences among four groups （F=8.105, P〈0.01）. The TLR4 levels in MTB and HIV/MTB groups were significantly lower than those in control group （ both P〈0.01） and HIV group （P〈0.01, P=0.014）.The plasma concentrations of TNF-αin HIV, HIV/MTB, MTB and control groups were 15.892 （10.494-21.646） pg/ml, 13.142 （8.014-22.038） pg/ml, 16.284 （11.916-24.005） pg/ml, and 26.657 （16.321-34.541） pg/ml, respectively, that were significantly dif-ferent from each other （F=4.350, P=0.006）.The levels of TNF-αin plasma from patients with HIV and＆amp;nbsp;HIV/MTB infection were significantly lower than those of healthy subjects （P=0.009 and P=0.001）.The viral load in patients from HIV/MTB group （5.113 ±1.018 copies/ml） was significantly higher than that from HIV group （4.416±1.020 copies/ml） （t=3.449, P=0.001）.Conclusion MTB infection might promote HIV replication by inhibiting the expression of TLR 4.HIV infection might increase host′s suscepti-bility to MTB infection by reducing the production of TNF-α.Suppressed expression of TLR and TNF-αpro-duction could contribute to the occurrence of HIV /MTB co-infection . Key words: MTB; HIV; Co-infection; Signaling pathway