IL28B Genetic Variations in Patients with Recurrent Herpes Simplex Keratitis

Abstract

Background and objectives: Recurrent herpes simplex keratitis (HSK) is the most common cause of corneal blindness in the developed world. A relationship between host gene polymorphisms and the recurrence of herpes simplex virus (HSV) infection has previously been proposed. Thus, the aim of this study was to investigate a potential association between the IL28B host genotype and recurrent HSK. Materials and Methods: Eighty patients older than 18 years of age of both genders with a history of recurrent herpes simplex labialis (HSL) were considered for inclusion. Seventy-five of these patients were found to be seropositive for HSV-1 and were subsequently enrolled in the study. Twenty-four of the enrolled patients also had a history of recurrent HSK associated with severe corneal scarring and visual acuity deterioration. Total DNA was isolated from whole blood samples. A single-nucleotide polymorphism (SNP) rs12979860 near the IL28B gene on chromosome 19 was genotyped. Results: A significant association was observed between recurrent HSK and two SNPs of the IL28B genotype (CCrs12979860 and CTrs12979860, p < 0.01). The variation CCrs12979860 showed a significantly greater association with HSK (16 out of 26 patients) compared with CTrs12979860 (8 out of 34 patients). Conclusion: Seropositive individuals with a history of recurrent HSK are likely to have the CC IL28B genotype. This genotype may be related to incomplete control of the infection and more frequent periodical viral shedding along the first nerve branch of the trigeminal ganglion, which clinically manifests as recurrent herpes keratitis. The clinical manifestation of recurrent HSV-1 infection seems to be influenced by polymorphism of the IL28B genotype.

Keywords: herpes simplex virus type 1 (HSV-1); keratitis; type III interferons (IL28B) genotype.

Figure 1

Polymorphism rs12979860—determination of genotypes (size of PCR product: 153 bp). Line 1, DNA ladder; lanes 2,3, TT homozygous; lanes 4,5, CC homozygous, Lines 6,7, CT heterozygous. Heterozygous samples resulted in the amplification of both bands, indicating the presence of the two alleles.

Figure 2

Distribution of the IL28B genotype rs12979860 in the study group as a whole. Percent distribution of the IL28B genotype rs12979860. CC: CCrs1279860, CT: CTrs1279860, TT: TTrs1279860.

Figure 3

IL28B genotype distribution according to the clinical manifestation of recurrent herpes simplex virus (HSV) infection. Patients with herpes simplex keratitis (HSK) are marked in blue, and patients without HSK are marked in orange.