Background: Toll-like receptors (TLRs) act as mediators of an innate immune response to
infectious agents. The risk for chronic infection and the development of cancer can be potentially influenced
by the genetic variations in the TLR genes. TLR3 and TLR7 genes have been associated with
susceptibility to several infections and immune diseases. Human populations are very diverse. There
are significant variations in the TLR3 and TLR7 polymorphisms among ethnic groups. Variations within
the population are associated with the disease outcome. Hence, we aimed to compare the occurrence
of TLR3 (rs5743312 C/T, rs3775296 C/A, and rs3775291 C/T) and TLR7 (rs179009 and
rs179008) polymorphisms among healthy individuals of various populations.
Methods: Genotyping of TLR3 (rs5743312 C/T, rs3775296 C/A, and rs3775291 C/T) and TLR7
(rs179009 and rs179008) polymorphisms were done in 158 healthy controls from the Western India by
utilization of PCR-RFLP.
Results: In our study population, the prevalence of TLR3 rs5743312 CC, CT, and TT genotypes were
found to be 67.1%, 31.0%, and 1.9%, respectively, whereas genotype distribution of rs3775296 C/A
polymorphism was 65.2%, 31.6%, and 3.2%, respectively and rs3775291C/T was 59.5%, 32.3% and
8.2%, respectively. The occurrence of TLR7 rs179008AA, rs179008AT, rs179008TT genotypes and
rs179008A, rs179008T alleles in the healthy individuals was found to be 81.0%, 16.5%, 2.5% and
89.24%, 10.75%, respectively. The prevalence of TLR7 rs179009AA, rs179009AG, rs179009GG genotypes
and rs179009A, rs179009G alleles in healthy individuals was 63.3%, 29.1%, 7.6% and 63.3%,
36.7%, respectively. The frequency of TLR7 polymorphism was compared with Italian, Asian, European,
African, German and France populations. The frequency of TLR3 polymorphism was compared
with Asians, Caucasians, Taiwanese, Caucasians and Saudi Arabians, Poland, Taiwanese, Italy, Taiwan,
Estonia, Asia and Caucasus. The inter-population differences were observed in the distribution of
TLR3 and TLR7 polymorphisms.
Conclusion: The prevalence of TLR3 and TLR7 polymorphisms suggested that genotype-phenotype studies
should be conducted among populations to address the innate immune responses against pathogens.