AB1112 Autoantibodies in children with juvenile arthritis on biological therapy
Authors: O.A. Oshlyanska
Journal: Annals of the Rheumatic Diseases (2018)

<h3>Background</h3> Antinuclear antibodies (ANA) are described as initial serological findings in juvenile idiopathic arthritis (JIA). SLE-like syndromes with ANA seroconversion have been described in the patients on biological therapy, including JIA children. Biologics have been used in Ukraine since 2011. In 459 of 2,542 JIA cases registered in 2016, patients were on biologics. According to the data of the Ukrainian Registry of Patients Receiving Biologics, autoimmune diseases as complications of biological therapy have not been registered in Ukraine so far. <h3>Objectives</h3> To study the ANA dynamics in JIA children on biologics. <h3>Methods</h3> There was conducted a retrospective observational study which involved 138 JIA patients, including 44 children with the biologics as follows: TOZ 12, ADA 29, ETA 3. JIA markers (HLA B27 (PCR), RF (ELISA), aCCP (immunosorption), ANA (IFT and ELISA (10 subtypes) were determined in patients at the disease onset and after 1, 2, 5 years of biologics medication. <h3>Results</h3> Among all JIA patients, ANA were detected in 54% of oJIA, 47% of pJIA, 7% of all spondyloarthropathy (spA) cases. At the beginning of biologics, only 22% children were ANA-positive, 66% of them being female, mean age at the disease debut was 6.9±3.81 y. The median of the time from the disease onset to the initiation of biologics was 4.2±3.2 y. The mean age at biologic therapy start was 10.3±4.18 y. At the time of the examination, the mean duration of biologics was 2.4±1.46 y. In pJIA onset ANA were detected in 62% of patients, in oJIA with uveitis in 75%, in spA in 14.2%; in sJIA ANA were not identified. RF and aCCP were found in 2 pJIA children; HLA B27 was detected in 1 child with uveitis and in 64.2% of patients with spA. The data obtained showed that ANA were found more often in patients on biologics than in general JIA population (pJIA, p=0.04, oJIA, p=0.02), RF was lower (4.5%) (p=0.001). The relationship with the sex was not seen (r=0.19). 21.4% of patients had been ANA positive before ADA therapy initiation. Reverse seroconversion was seen in most patients after a year of ADA therapy (3.5% remained ANA+, reduced ANA titer). After 2 year medication, ANA were detected by IFT in 3 seronegative at the disease debut patients (7.1%). They had negative antibodies to histones and aDNAII (ELISA). After 5 y, 2 patients on ADA remained ANA+. Among patients on ADA, who had ANA as a new phenomenon there were 2 female and 1 male teens in disease remission. They had no clinical manifestations of secondary autoimmune pathology. All the patients continued methotrexate, corticosteroids were discontinued in 2 of them. All patients were on isoniazid medication for over a year. In RF +patients on ADA, the RF was not detected a year later, after 2 y it was revealed in 1 pJIA patient who was RF-neg (aCCP neg). There was 1 RF +case at pJIA debut with TOZ, after the therapy it was not detected. Two paediatric patients on TOZ (16.6%) were ANA +at the debut, but the subsequent dynamics studies did not detect ANA (TOZ vs ADA, p=0.04). Patients treated with ETA were observed for less than 1 year. <h3>Conclusions</h3> ANA types which are detected at JIA debut and after initiation of biologic treatment may differ. It is suggestive of the biologics potential to modify the immune response, thus increasing the risk of overlap-syndromes. Therefore, it is advisable to monitor autoantibody titers in JIA children on biologic treatment. <h3>Disclosure of Interest</h3> None declared