Interleukin-10 promoter gene polymorphisms are associated with the first major depressive episode in chronic hepatitis C patients

Summary Aims To investigate the association of IL 10 SNPs in chronic hepatitis C (CHC) patients with and without the first major depressive episode (MDE), as well as their association with plasma levels of target cytokines. Methods A hundred and thirty two CHC patients (32 with and 100 without first MDE) and 98 controls were prospectively enrolled in this cross-sectional study. MDE was diagnosed by a psychiatrist, using the Mini International Neuropsychiatric Interview Plus 5.0. IL 10 polymorphisms (−1082 G/A, −819C/T and −592C/A IL 10 SNPs) were evaluated by Taqman SNP genotyping assay. Plasma concentrations of IL-2, IL-6, IL-10, IFN-γ and TNF-α were determined using the Human Th1/Th2 Cytometric Bead Array kit. The associations were investigated by logistic models. Results The frequencies of the studied IL 10 SNPs did not differ between the CHC patients and controls. The first MDE was positive and independently associated with the IL 10-1082*A, IL 10-819*T and IL 10-592*A (ATA) low producer haplotype (OR = 1.50; 95% CI = 1.11–2.04; P  = 0.009) and current alcohol misuse (OR = 4.29; 95% CI = 1.22–15.05; P  = 0.02), and inversely associated with increasing age (OR = 0.94; 95% CI = 0.91–0.98; P  = 0.006). In addition, plasma level of TNF-α was significantly higher in the carriers than in the non-carriers of the IL 10 ATA haplotype in patients with the first MDE. The IL-10 and IL-2 plasma levels were significantly higher in the carriers than in non-carriers of the IL 10 GCC high producer haplotype, demonstrating the functionality of the studied IL 10 polymorphisms. Conclusions This is the first study to demonstrate that the IL 10 low producer ATA haplotype is associated with the first MDE in patients with CHC.