APP and arthritic joint disease: APP acute phase proteins, JADAS27 Juvenile Arthritis Disease Activity Score (0–57), CRP C-reactive protein, ESR erythrocyte sedimentation rate, Hp haptoglobin, Hp(WB) haptoglobin by Western blot, Hp(IT) haptoglobin by immunoturbidimetry, SAA serum amyloid A