Objective: To investigate the genetic contribution of cytokine gene polymorphisms (interleukin 1 (IL1) and tumour necrosis factor alpha (TNFalpha)) on disease phenotype and on response to TNF-blocking agents in a population of patients with juvenile idiopathic arthritis (JIA).
Methods: A cohort of 107 consecutive patients with JIA who were receiving treatment with anti-TNF agents was enrolled in this study. Analysis of genetic polymorphisms for IL1B +3954, IL1RA +2018, TNFalpha -238 and TNFalpha -308 was performed by enzyme-linked oligo sorbent assay, and compared with those obtained from 630 healthy Caucasians and 263 adult patients with rheumatoid arthritis. Relevant demographic, clinical and laboratory data were collected from clinical charts and entered into a customised database, and chi(2) analysis was performed to compare cytokine polymorphisms with disease type according to the International League of Associations for Rheumatology criteria, presence of uveitis, rheumatoid factor and anti-nuclear antibody positivity, erosive disease, frequency of adverse effects to anti-TNF and clinical response after 3 months.
Results: The T/T genotype of the IL1B +3954 polymorphism was absent in patients with JIA and present in 5% of controls (p = 0.015). No significant correlation was found between the studied polymorphisms and clinical or laboratory variables considered. Clinical response to TNF inhibitors at 3 months was not associated with the genetic polymorphisms considered.
Conclusion: In our cohort, the absence of the rare IL1B +3954 gene polymorphism was associated with JIA, but without specificity to particular disease phenotypes. The TNF and IL1 gene polymorphism studied did not seem to be associated with response to anti-TNF treatment.