Low density neutrophils in patients with juvenile idiopathic arthritis

(1) To study the correlation among conventional clinical and laboratory parameters and the relation between the number of lymphocytes and neutrophils (L/N) in cell suspensions from peripheral blood of patients with juvenile idiopathic arthritis (JIA). (2) To evaluate the L/N relation of JIA patients after an 8 year follow-up period.

Fifty-one JIA patients (25 female, disease course: 19 systemic, 15 polyarticular, 17 pauciarticular) were enrolled in the study. To measure the L/N relation, we used Boyum's method: The leucocyte separation was done by centrifugation of peripheral blood on Ficoll-Hypaque (FH) gradient, and the number of lymphocytes, monocytes, and neutrophils in 500 cells was determined. The following clinical and laboratory parameters were evaluated: disease activity, number of active and limited joints, functional capacity, erythrocyte sedimentation rate (ESR), and C reactive protein (CRP). Twenty-four healthy children were used as controls. We also studied 13/51 patients from our Pediatric Rheumatology Unit who had been evaluated by the same method 8 years before.

We observed the lowest L/N relation in patients with active disease, especially those with polyarticular course. A statistical correlation was also observed with the acute-phase reactants (ESR and CRP, p < 0.05). The majority of patients who had presented a low L/N relation at the first evaluation (8 years before) had a worse outcome.

The measure of L/N relation from peripheral blood could be used as an auxiliary tool in the assessment of the activity and outcome of JIA patients, especially at disease onset.