Association of interleukin 4 (-590 T/C) and interleukin 4 receptor (Q551R A/G) gene polymorphisms with acne vulgaris

BACKGROUND AND OBJECTIVES: Acne vulgaris is a common skin disorder. The complete etiology of this disease remains to be identified; however, it seems that aberrant expression of cytokine genes might be a contributing factor. This study aimed to investigate the association of genetic polymorphisms related to interleukin 4 (IL-4) promotor and receptor (IL-4R) genes as inflammatory modulators with acne vulgaris. DESIGN AND SETTING: A case-control study 95 acne patients recruited from outpatient dermatology clinics affiliated with Qassim University, Qassim, Saudi Arabia. PATIENTS AND METHODS: Acne patient data were compared with 87 normal healthy unrelated controls from the same locality. The genomic DNA was extracted and processed using the real-time polymerase chain reaction amplification for characterization of polymorphisms related to IL-4 (-590 T/C) and IL-4R (Q551R A/G) genes. RESULTS: Acne patients compared to controls showed no significant difference in the frequencies of IL-4 (-590 T/C) polymorphic genotypes (P=.8), yet had a highly significant difference in IL-4R (Q551R A/G) genotypes (P<.001). The frequencies of the mutant genotype IL-4R GG as well as the allele IL-4R G were significantly higher in cases of acne than in controls. Furthermore, acne cases showed higher frequencies of combined genotypes IL-4R_GG with IL-4_CC, CT, or TT. However, no significant difference was noted on comparing subgroups related to disease severity or response to treatment (P>.05). CONCLUSIONS: This study provides evidence for a significant association of IL-4R (Q551R A/G) genetic polymorphisms with the susceptibility rather than the severity of acne vulgaris.