TNFAIP3 Gene Polymorphisms Are Associated with Response to TNF Blockade in Psoriasis

The TNFAIP3 gene has been associated with psoriasis, rheumatoid arthritis, type 1 diabetes mellitus, systemic lupus erythematosus and celiac disease. TNFAIP3 encodes A20, a TNF-α-inducible zinc finger protein thought to limit NF-κB mediated immune responses. In this study we report association of response of psoriasis to TNF blockers with two TNFAIP3 SNPs (rs2230926 in exon 3 and rs610604 in intron 6) and their haplotypes. Treatment response was self-evaluated using a 0–5 visual analog scale in 433 psoriasis patients who received TNF blockers. Confirmation was sought in 199 psoriasis and psoriatic arthritis patients from Toronto who were followed prospectively. Response variables were dichotomized separately in the two cohorts, yielding similar proportions of good responses. While significant associations were observed only for the Michigan cohort, fixed-effects meta-analysis retained significant association between dosage of the G allele of rs610604 and good combined response to all TNF blockers (OR = 1.50, p(corr) = 0.050) and etanercept (OR = 1.64, p(corr) = 0.016). The rs2230926 T–rs610604 G haplotype was similarly associated. By demonstrating an association with therapeutic response, these results provide a clinically relevant functional correlate to the recently described genetic association between psoriasis and TNFAIP3.