Antinuclear antibodies staining patterns and titres in juvenile idiopathic arthritis

ABSTRACT Objectives In our study, we evaluated the antinuclear antibodies (ANA) staining patterns and titres in juvenile idiopathic arthritis (JIA) patients. Methods JIA patients were retrospectively assessed. ANA was identified by using indirect immunofluorescence assay on HEp-2 cells, with a positivity threshold set at a titre of ≥1/100. Results Eight hundred-five patients were evaluated [oligoarticular JIA (n = 396), enthesitis-related arthritis (n = 195), polyarticular JIA (n = 132), systemic JIA (n = 53), psoriatic arthritis (n = 20), and unclassified JIA (n = 9)]. The most frequently observed ANA nuclear staining patterns were AC-4/5 (fine or large speckled) in 29.7% of patients and AC-1 (homogeneous) in 25.9%. The most common ANA cytoplasmic staining pattern was AC-19 (dense, fine speckled) (17.6%). Most systemic and unclassified JIA patients were ANA negative. The most frequently detected ANA titre in oligoarticular JIA and enthesitis-related arthritis patients was 1/160 (P = .026 and P = .018, respectively), while in psoriatic arthritis patients, it was 1/320 (P < .001). In addition, uveitis and inflammatory bowel disease were most frequently associated with AC-4/5 & AC-19 patterns and an ANA titre of 1/160 (all P < .001). Conclusions Our study showed that many JIA subtypes and JIA-related comorbidities were associated with the AC-4/5, AC-1, and AC-19 ANA patterns. However, multicentre studies in larger cohorts are needed to generalize these results.