Table 2 The preliminary criteria of the main JIA disorders proposed by the Pediatric Rheumatology International Trials Organization (PRINTO) Consensus. The PRINTO classification proposed systemic JIA (sJIA), rheumatoid factor–positive JIA (RF+ JIA), enthesitis/spondylitis-related JIA and early-onset antinuclear antibody–positive (early-onset ANA+) JIA. ANA – antinuclear antibodies, AOSD - adult-onset Still’s disease, Anti-CCP – Anti-Cyclic Citrullinated Peptide, HLA - human leukocyte antigen system, RA – rheumatoid arthritis, RF – rheumatoid factor, y.o. – years old

Clinical criteria

• Arthritis for ≥6 weeks, and

• Early-onset (≤ 6 y.o.)

• Arthritis for ≥6 weeks

• Peripheral arthritis and enthesitis, or

• Arthritis or enthesitis, +

≥ 3 months of sacroiliitis, or

• Arthritis or enthesitis + 2 of the following:

- sacroiliac joint tenderness

- inflammatory back pain

- acute anterior uveitis

- history of a SpA in relative

• Fever with exclusion of infectious, neoplastic, autoimmune, or monogenic autoinflammatory diseases, for at least 3 days and reoccurring over 2 weeks

+  2 major criteria or 1 major criterion and 2 minor criteria

Major criteria:

• evanescent erythematous rash

• arthritis

Minor criteria:

- generalized lymphadenopathy and/or hepatomegaly and/or splenomegaly

- serositis

- arthralgia lasting more than 2 weeks

Laboratory criteria

• 2 “+” ANA tests with a titer ≥1/160 at least 3 months apart

• 2 positive tests for RF at least 3 months apart or

• 1 positive test for anti-CCP

- presence of HLA-B27 antigen

- leukocytosis (≥ 15,000/mm3) with neutrophilia

Adult equivalent

–

RF-positive RA

Spondyloarthritis

AOSD