Single nucleotide polymorphisms of toll-like receptor-4 protect against acne conglobata.

BACKGROUND

Former studies have shown that Propionibacterium acnes may stimulate expression of toll-like receptor 4 (TLR4) in keratinocytes of patients with acne vulgaris.

OBJECTIVE

To investigate the impact of single nucleotide polumorphisms (SNPs) of the TLR4 gene in acne vulgaris.

METHODS

Genomic DNA was isolated from 191 patients with acne vulgaris and 75 healthy controls. Asp299Gly and Thr399Ile SNPs were defined after cutting of the PCR products by restriction enzymes. Sebum of lesions was cultured for P. acnes.

RESULTS

No differences in SNP allele frequencies were found between patients and healthy controls. 46.5% of carriers of wild-type alleles were suffering from acne conglobata compared with 28.6% of carriers of SNP alleles (P=0.040). After adjusting for gender, family history of acnes, intake of any therapy and skin isolation of P. acnes, carriage of TLR4 gene SNPs was the only independent variable linked with a protective role against acne conglobata (OR=0.269, P=0.014). No differences were found in the amount of pro-inflammatory cytokines released by peripheral blood mononuclear cells isolated from patients with acne conglobata carrying only wild-type alleles and SNP alleles.

CONCLUSIONS

Carriage of gene SNPs is protective against the development of acne conglobata even in the presence of P. acnes.