Expression of TLR-4 and -2 in peripheral mononuclear cells in renal transplant patients with TLR-4 gene polymorphism.
BACKGROUND
TLR-4 has also been identified as a receptor for endogenous alarmins, which are increased post transplantation. TLR-4 has also been associated with a polymorphism that could impact graft outcome.


OBJECTIVE
To assess the expression of TLR-4 in kidney transplant patients carrying or not a polymorphism.


METHODS
TLR-4 polymorphism (A299G/T399I) was studied in 200 renal transplant patients. Healthy volunteers were also enrolled as control group. The polymorphism analysis was performed using restriction enzymes technique (RFLP). Functionality of TLR-4 polymorphism was assessed in samples from controls by quantification of TNF-α after LPS stimulus. TLR-4 and -2 expressions were also analyzed by flow cytometry.


RESULTS
TLR-4 polymorphism was present in 8.5% of renal transplant patients. This polymorphism was associated with impairment in TNF-α secretion. In general, in renal transplant patients, TLR-4 expression in monocytes and in neutrophils was lower than in health volunteers. TLR-2 and TLR-4 expressions in healthy volunteers with A299G/T399I TLR-4 polymorphism was higher than in wild-type genotype healthy volunteers (p<0.01 and p<0.05, respectively), and also higher than A299G/T399I TLR-4 polymorphism renal transplant patients (p<0.05). TLR-2 expression on neutrophils in wild-type genotype renal transplant patients was higher compared to wild-type genotype healthy volunteers, and was also higher in relation to A299G/T399I kidney transplanted patients (p<0.01).


CONCLUSIONS
Stable renal transplant patients with TLR-4 polymorphism have a lower expression of TLR-4 and TLR-2 receptors in peripheral mononuclear cells, which ultimately indicate a less responsiveness for alarmins.
Laboratory of Clinical and Experimental Immunology, Nephrology Division, Federal University of São Paulo (UNIFESP), Brazil. enogueira@nefro.epm.br
Eliana
E
Nogueira
Reinaldo
R
Salomao
Milena Karina Colló
MK
Brunialti
Kikumi S
KS
Ozaki
Geórgia D M
GD
Marques
Marcos A
MA
Cenedeze
Niels Olsen Saraiva
NO
Câmara
Alvaro
A
Pacheco-Silva
D000328:Adult; D016022:Case-Control Studies; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D015870:Gene Expression; D005838:Genotype; D006084:Graft Rejection / Q000235:genetics / Q000276:immunology; D006801:Humans; D016030:Kidney Transplantation / Q000276:immunology*; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D012150:Polymorphism, Restriction Fragment Length; D051195:Toll-Like Receptor 2 / Q000235:genetics* / Q000276:immunology; D051197:Toll-Like Receptor 4 / Q000235:genetics* / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000097:blood / Q000276:immunology
D008070:Lipopolysaccharides; C495342:TLR2 protein, human; C495345:TLR4 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D014409:Tumor Necrosis Factor-alpha