After stratification by sex, it turned out that boys with JIA, who did not achieve clinical remission on medication with the methotrexate therapy, had a significantly increased proportion of the IL1B rs16944*T allele (41.86% vs. 22.00%, P = 0.025, pcor = 0.024, OR = 2.553, 95% CI 1.195–5.410, in comparison with those who achieved, respectively). Here, IL1B is linked to juvenile idiopathic arthritis.