Antinuclear Antibodies Staining Patterns and Titers in Juvenile Idiopathic Arthritis.

Abstract

Objective: The importance of antinuclear antibodies (ANA) patterns and titers in juvenile idiopathic arthritis (JIA) patients is not clearly determined in the literature. In our study, we evaluated the ANA staining patterns and titers in 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 titer of 1/100 or higher.

Results: Eight hundred-five patients with JIA were evaluated (oligoarticular JIA [OJIA, n=396], enthesitis-related arthritis [ERA, n=195], polyarticular JIA [PJIA, n=132], systemic JIA [SJIA, n=53], psoriatic arthritis [PsA, n=20], unclassified JIA [n=9]). Their median (min-max) age at diagnosis was 7.9 (4.6-12.1) years (F/M=1.2). 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 SJIA and unclassified JIA patients were ANA negative. The most frequently detected ANA titer in OJIA and ERA patients was 1/160 (p=0.026 and p=0.018, respectively), while in PsA patients, it was 1/320 (p<0.001). In addition, uveitis and inflammatory bowel disease, which were comorbidities associated with JIA, were most frequently associated with the nuclear AC-4/5 pattern and the cytoplasmic AC-19 pattern, as well as with an ANA titer of 1/160 (all p<0.001).

Conclusion: Our study showed that many JIA subtypes and JIA-related comorbidities were associated with the AC-4/5, AC-1, and AC-19 patterns of ANA. However, multicenter studies in larger cohorts are needed to generalize these results.