To assess the level of B-cell activating factor belonging to the tumor necrosis factor family (BAFF) also known as B-lymphocyte stimulator (BLyS) and A proliferation-inducing ligand (APRIL) in the serum of Juvenile idiopathic arthritis (JIA) patients and to detect their relation to the clinical manifestations and disease activity in the different subtypes of the disease.

Seventy-four consecutively recruited JIA patients were clinically examined, the Juvenile arthritis disease activity score in 27 joints (JADAS-27) calculated and Childhood Health Assessment Questionnaire (CHAQ) used to measure the functional status. Thirty-four healthy matched children served as controls. Routine laboratory examinations were recorded and serum BAFF and April were determined.

The JIA patients were 20 systemic-onset, 31 oligoarticular and 23 polyarticular. Serum BAFF and APRIL were elevated in JIA patients being higher in systemic onset and both significantly correlated. APRIL significantly correlated with both JADAS-27 and CHAQ scores while BAFF correlated only with JADAS-27. The APRIL serum levels were significantly associated with the presence of RF and ANA. The BAFF serum levels were significantly higher in oligoarticular onset JIA patients with uveitis compared to those without.

Our results suggest increased BAFF and APRIL serum levels in JIA patients denoting their possible role in the disease and calling for additional research to elucidate the intrinsic mechanisms explaining APRIL and BAFF over expression.