Psoriasis is a chronic autoimmune skin diseasewith both environmental and genetic risk factors. Previousstudies of the association between psoriasis and PTPN22C1858T (rs2476601), a gain of function variant associatedwith a stronger inhibitory effect of T-lymphocytes, haveproduced inconsistent results. The purpose of the currentstudy is to evaluate the association between PTPN22C1858T and psoriasis using meta-analysis to: (1) have asufficient sample size for detecting a weak association; and(2) to explore the heterogeneity between studies. A meta-analysis based on random-effects model was performedwith ten studies (3,334 psoriasis cases and 5,753 controls)identified from a literature search. A non-significantlypositive association between psoriasis and the PTPN22T1858 was observed [summary allelic odds ratio(OR) = 1.15, 95 % confidence interval (CI): 1.00–1.33]and the association appears stronger among subjects withpsoriatic arthritis (summary allelic OR = 1.23, 95 % CI:1.00–1.52). A null association between PTPN22 T1858 andearly-onset psoriasis was observed (summary allelicOR = 1.08, 95 % CI: 0.92–1.28). The current analysisshowed a non-significantly positive association betweenpsoriasis and the PTPN22 T1858 allele, and the associationappeared stronger among subjects with psoriatic arthritis.Future studies of psoriasis should incorporate gene-envi-ronment interaction in the analysis and pay attention to theheterogeneity of psoriasis cases and bias associated withpopulation stratification.
