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

AIMS

To investigate the association of IL10 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. IL10 polymorphisms (-1082 G/A, -819C/T and -592C/A IL10 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 IL10 SNPs did not differ between the CHC patients and controls. The first MDE was positive and independently associated with the IL10-1082*A, IL10-819*T and IL10-592*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 IL10 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 IL10 GCC high producer haplotype, demonstrating the functionality of the studied IL10 polymorphisms.

CONCLUSIONS

This is the first study to demonstrate that the IL10 low producer ATA haplotype is associated with the first MDE in patients with CHC.