Effects of antibiotics on expression and function of Toll-like receptors 2 and 4 on mononuclear cells in patients with advanced cirrhosis.
OBJECTIVE
Toll-like receptors (TLRs) are critical to innate immune responses. TLR4 recognises Gram-negative bacteria, whilst TLR2 recognises Gram-positive. We examined TLR expression and function in cirrhosis, and whether this is affected by antibiotic therapy.


METHODS
Sixty-four subjects were included (23 controls and 41 Child-Pugh C cirrhotic patients). Thirty patients were taking norfloxacin or trimethoprim-sulfamethoxazole as prophylaxis against bacterial peritonitis and 11 were not. In a second study, 8 patients were examined before and after commencement of antibiotics. Monocyte expression of TLR2 and 4 was determined by flow cytometry. Monocytes from the patients with paired samples were stimulated using TLR ligands and TNF-alpha production measured.


RESULTS
Patients not taking antibiotics had significantly decreased TLR4 expression compared with controls (0.74 vs. 1.0, p=0.009) and patients receiving antibiotics (0.74 vs. 0.98, p=0.02). There were no differences with regard to TLR2. In the patients with paired samples, TLR4 expression increased (0.74-1.49, p=0.002) following antibiotic use, whilst again, there was no change in TLR2 expression (0.99 vs. 0.92, p=0.20). TLR4-dependent TNF-alpha production increased following antibiotic use (1077 vs. 3620pg/mL, p<0.05), whilst TLR2-dependent production was unchanged.


CONCLUSIONS
TLR4 expression is decreased in patients with Child-Pugh C cirrhosis, but is restored by antibiotics targeting enteric Gram-negative bacteria. TLR4-dependent cytokine production also increases significantly following antibiotic therapy. This suggests that the high incidence of Gram-negative infection in cirrhotic patients is in part due to down-regulation of the TLR4-dependant immune response and that the efficacy of antibiotic prophylaxis is contributed to by modulation of innate immunity.
Testro
Adam G
AG
Department of Medicine, The University of Melbourne, Austin Health, Vic., Australia. adam.testro@austin.org.au
Gow
Paul J
PJ
Angus
Peter W
PW
Wongseelashote
Sarah
S
Skinner
Narelle
N
Markovska
Vesna
V
Visvanathan
Kumar
K
D000328:Adult; D000368:Aged; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D016022:Case-Control Studies; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control; D006801:Humans; D007113:Immunity, Innate / Q000187:drug effects; D066298:In Vitro Techniques; D007963:Leukocytes, Mononuclear / Q000187:drug effects / Q000276:immunology; D008103:Liver Cirrhosis / Q000188:drug therapy* / Q000276:immunology*; D008297:Male; D008875:Middle Aged; D009643:Norfloxacin / Q000494:pharmacology; D010538:Peritonitis / Q000517:prevention & control; D051195:Toll-Like Receptor 2 / Q000378:metabolism*; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000096:biosynthesis
D000900:Anti-Bacterial Agents; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D009643:Norfloxacin