IL-10 promoter polymorphisms influence disease severity and course in psoriasis.

We analyzed three single-nucleotide polymorphisms (SNPs) at the interleukin-10 (IL-10) 5' flanking region (positions -1082 A/G, -819 C/T and -592 C/A) in an association case-control study involving 248 patients with plaque type of psoriasis and 148 unrelated healthy volunteers using ARMS (amplification refractory mutation system)-PCR (Polymerase Chain Reaction) method. No difference was found in the frequencies of haplotype distribution between healthy controls and patients with psoriasis. There were no significant differences in the IL-10 haplotype distribution depending on the age of onset and family history of psoriasis. However, the results of our study demonstrate that the IL-10 haplotype has a role in determining severity and course of plaque type of psoriasis. IL-10 ACC haplotype (P<0.05) is likely to be defining lower activity of disease (PASI</=20; extent</=10%) and ATA haplotype is likely to be associated with persistent eruption (P<0.01). As ACC haplotype is suggested to be associated with high IL-10 secretion and ATA is related to low IL-10 secretion, potential differences in the IL-10 secretion levels might contribute the differences in the clinical course of psoriasis.