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Early Treatment and IL1RN Single‐Nucleotide Polymorphisms Affect Response to Anakinra in Systemic Juvenile Idiopathic Arthritis
Author(s) -
Pardeo Manuela,
Rossi Marianicoletta,
Pires Marafon Denise,
Sacco Emanuela,
Bracaglia Claudia,
Passarelli Chiara,
Caiello Ivan,
Marucci Giulia,
Insalaco Antonella,
Perrone Chiara,
Tulone Anna,
Prencipe Giusi,
De Benedetti Fabrizio
Publication year - 2021
Publication title -
arthritis and rheumatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.106
H-Index - 314
eISSN - 2326-5205
pISSN - 2326-5191
DOI - 10.1002/art.41612
Subject(s) - anakinra , single nucleotide polymorphism , medicine , haplotype , arthritis , immunology , disease , genotype , biology , genetics , gene
Objective To evaluate the impact of early treatment and IL1RN genetic variants on the response to anakinra in systemic juvenile idiopathic arthritis (JIA). Methods Response to anakinra was defined as achievement of clinically inactive disease (CID) at 6 months without glucocorticoid treatment. Demographic, clinical, and laboratory characteristics of 56 patients were evaluated in univariate and multivariate analyses as predictors of response to treatment. Six single‐nucleotide polymorphisms (SNPs) in the IL1RN gene, previously demonstrated to be associated with a poor response to anakinra, were genotyped by quantitative polymerase chain reaction (qPCR) or Sanger sequencing. Haplotype mapping was performed with Haploview software. IL1RN messenger RNA (mRNA) expression in whole blood from patients, prior to anakinra treatment initiation, was assessed by qPCR. Results After 6 months of anakinra treatment, 73.2% of patients met the criteria for CID without receiving glucocorticoids. In the univariate analysis, the variable most strongly related to the response was disease duration from onset to initiation of anakinra treatment, with an optimal cutoff at 3 months (area under the curve 84.1%). Patients who started anakinra treatment ≥3 months after disease onset had an 8‐fold higher risk of nonresponse at 6 months of treatment. We confirmed that the 6 IL1RN SNPs were inherited as a common haplotype. We found that homozygosity for ≥1 high‐expression SNP correlated with higher IL1RN mRNA levels and was associated with a 6‐fold higher risk of nonresponse, independent of disease duration. Conclusion Our findings on patients with systemic JIA confirm the important role of early interleukin‐1 inhibition and suggest that genetic IL1RN variants predict nonresponse to therapy with anakinra.