Toll-like receptor 4 gene polymorphism 1196 C/T does not influence the risk of neuropsychiatric systemic lupus erythematosus in Polish population--a preliminary report

Objective: Recent data indicate that Toll-like receptors (TLRs) participate in various neuropathologic conditions, including ictogenesis, myelin disruptions associated with chronic alcohol abuse, behavioral and cognitive dysfunctions associated with alcohol-induced neuroinflammatory damage, and activation of microglia to reduce amyloid β deposits. As seizures and depression are well known neuropsychiatric syndromes in systemic lupus erythematosus (SLE) the aim of the study was to investigate whether TLR4 gene polymorphism 1196C/T (rs4986791, Thr399Ile) was a candidate for susceptibility of development of neuropsychiatric systemic lupus erythematosus (NPSLE).

Methods: The study covered 60 patients with SLE and 100 healthy individuals. TLR4 1196C/T genotyping was performed by real-time polymerase chain reaction with the SimpleProbe.

Results: The SLE group comprised 86.7% of patients with wild-type homozygotes CC and 13.3% heterozygotes CT and no homozygotes TT. The control group consisted of 85% wild-type homozygotes CC, 15% heterozygotes CT and no homozygotes TT. The frequencies of genotype and allele distribution in SLE patients did not differ significantly from those of the control subjects. The probability of describing the possible risk of SLE imputed to genotype did not significantly differ in comparison with the healthy individuals (p = 0.77, odds ratio = 0.87, 95% confidence interval 0.34-2.19). A significant genotype association of genotype CC with arthritis was found in SLE patients (p = 0.02). It was further confirmed by a significant association of a dominant allele C with arthritis (p = 0.02). No association between CC and CT genotypes of TLR4 1196C/T and NPSLE was found. Allele distribution of TLR4 1196C/T also was not associated with NPSLE. No other significant differences were found in genotype and allele frequencies regarding clinical manifestation of SLE patients.

Conclusion: In the Polish population of SLE patients, 1196C/T polymorphism of TLR4 gene does not increase the risk of development of NPSLE; however, genotype CC and a dominant allele C is associated with arthritis in the course of SLE.