Associations between the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism and susceptibility to psoriasis and psoriatic arthritis: a meta-analysis.

The aim of this study was to assess whether the major histocompatibility complex class I chain-related gene A transmembrane (MICA-TM) polymorphism is associated with the susceptibility to psoriasis and psoriatic arthritis (PsA). A meta-analysis was conducted to establish the association between the MICA-TM A9 allele and psoriasis and PsA in the general population and each ethnic group. Ten studies (6 psoriasis, 4 PsA) involving 2,002 cases and 1,933 controls were included in this meta-analysis. The Asian controls showed the lowest A9 allele prevalence (16.6%), whereas the European controls had the highest allele prevalence (33.3%). Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population, which included the psoriasis and PsA cases (OR 1.703; 95% CI 1.301-2.229; p = 1.0 × 10(-5)). We further divided the entire study population into the psoriasis and PsA groups. Meta-analysis revealed a significant association between the MICA-TM A9 allele and the entire study population (OR 1.427, 95% CI 1.021-1.994; p = 0.037) and Asians (OR 1.264; 95% CI 1.014-1.576; p = 0.037). A significant association was found between the MICA-TM A9 allele and PsA (OR 2.227; 95% CI 1.462-3.393; p = 1.9 × 10(-5)) and Europeans (OR 2.039; 95% CI 1.285-3.235; p = 0.002). This meta-analysis showed that the MICA-TM A9 allele is associated with psoriasis susceptibility in Asian populations and that the MICA-TM A9 allele is associated with a PsA risk in Europeans.