Clinical research
Interleukin-1β gene polymorphism is associated with skin photosensitivity

Introduction: Ultraviolet radiation (UVR) exerts both beneficial and harmful effects on humans. Scarce data indicate that cytokine gene polymorphism might determine personal response to UVR. The aim of the study was to analyze the association between polymorphisms in the IL-1β gene and individual photosensitivity in healthy volunteers to ultraviolet B radiation.

Material and methods: The study group consisted of 234 healthy Caucasian volunteers (119 F, 115 M) with either II or III skin phototype. In each volunteer phototesting was undertaken and then 24 h later minimal erythema dose (MED) was determined. Three known dimorphic sites within the IL-1β gene were analyzed using RFLP-PCR technique: T→C (promoter region) at position-511 (rs16944), G®A (intron 4) known in literature as 5810 (rs1143633) and C→T (exon 5) known in literature as +3953 or 5887 (rs1143634).

Results: The mean value of MED in 234 volunteers was 0.156 J/cm². A statistically significant difference was found between MED in subjects with skin phototype II and skin type III: 0.13 vs. 0.17 J/cm², P<10–5. A significant association between phototypes and the 5887 (rs1143634) polymorphism was found. Phototype III occurred significantly more often among carriers of the CC genotype; OR (95% CI) = 2.1 (1.2-3.9). Moreover, carriers of the T allele had lower MED as compared to the CC genotype; 0.15 vs. 0.17 J/cm², P=0.016.

Conclusions: The obtained results demonstrate the role of genetic factors in skin phototype and individual photosensitivity. It indicates that individual susceptibility to UVB radiation needs to be considered when studying the effects of UVB in humans.