A controlled study of ANA+ RF- arthritis

Area of Science:

• Rheumatology
• Immunology
• Clinical Medicine

Background:

• Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation.
• Serological markers like antinuclear antibodies (ANA) and rheumatoid factor (RF) are used in RA diagnosis and classification.
• The clinical significance of specific antibody profiles, such as ANA-positive, RF-negative (ANA+RF-) RA, requires further elucidation.

Purpose of the Study:

• To investigate the clinical, laboratory, and radiographic characteristics of adult rheumatoid arthritis patients who are antinuclear antibody positive (ANA+) and rheumatoid factor negative (RF-).
• To compare the disease profile of the ANA+RF- RA group with matched RA patient groups possessing different antibody profiles (ANA+RF+, ANA-RF+, ANA-RF-).

Main Methods:

• Retrospective analysis of 401 adult rheumatoid arthritis (RA) patients.
• Identification of patients with ANA+RF- profile (n=30).
• Comparison of clinical, laboratory, and radiographic parameters between the ANA+RF- group and 90 matched RA controls across different antibody profiles.

Main Results:

• Approximately 7.5% (30/401) of adult RA patients were ANA+RF-.
• The majority of ANA+RF- patients (15/16) maintained this serological status over a year.
• The ANA+RF- group demonstrated significantly fewer rheumatoid nodules and less destructive radiographic disease compared to ANA+RF+, ANA-RF+, and ANA-RF- groups.

Conclusions:

• The ANA+RF- serological profile in adult RA patients is relatively uncommon but stable over time.
• Patients with RA and an ANA+RF- profile tend to have a milder disease phenotype with less joint destruction and fewer nodules.
• This distinct serological subset may represent a specific clinical subtype of rheumatoid arthritis.