Inflammatory Markers and Disease Activity in Juvenile Idiopathic Arthritis

To evaluate the post treatment changes in disease activity and inflammatory markers over time in longitudinal follow-up involving different subtypes of juvenile idiopathic arthritis (JIA) patients.

This prospective longitudinal study, carried out over a period of 2 y, included JIA patients, both old and new, with high disease activity. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), ferritin, CHAQ (Childhood Health Assessment Questionnaire) score and JADAS27 (Juvenile Arthritis Disease Activity score with 27 active joint counts) were estimated at the initial visit, 6 mo, 12 mo and 18 mo of follow-up.

Out of 40 patients, 10 had persistent oligoarthritis, 11 had rheumatoid factor (RF) positive polyarthritis, 8 had RF negative polyarthritis and 11 had systemic JIA. Twenty-one of them were females. Serum ferritin was highly elevated in systemic JIA patients with a range of 750-7712 ng/ml at the initial visit. All three inflammatory markers with disease activity score decreased significantly over 18-mo-period in all four subtypes. At any visit, all these parameters had largest value in systemic arthritis and least in oligoarthritis variety. At 18 mo, all oligoarthritis and polyarthritis cases had low or inactive disease while none of the systemic JIA patients achieved inactive disease. Elevated ESR and serum ferritin was found in all at 18 mo. CRP normalized in some with low or moderate disease activity.

Inflammatory markers and disease activity decreased in all subtypes of JIA with treatment without biologics. Acute phase markers often remain elevated in inactive disease state. Similarly, normal level of an inflammatory marker does not necessarily indicate absence of active disease.