Clinical Features of ACPA-Negative and ACPA-Positive Variants of Rheumatoid Arthritis

Area of Science:

• Rheumatology
• Immunology
• Clinical Medicine

Background:

• Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by joint inflammation.
• Anti-citrullinated protein antibodies (ACPAs) are key biomarkers for RA diagnosis and prognosis.
• Understanding clinical differences between ACPA-negative and ACPA-positive RA is crucial for patient management.

Purpose of the Study:

• To investigate and compare the clinical features of ACPA-negative and ACPA-positive rheumatoid arthritis.
• To identify distinct patterns in disease onset, activity, and systemic involvement between the two RA subtypes.

Main Methods:

• A comparative study involving 158 rheumatoid arthritis patients diagnosed per ACR/EULAR 2010 criteria.
• Patients were categorized into ACPA-negative (n=79) and ACPA-positive (n=79) groups, matched for age, gender, disease duration, and therapy.
• Disease activity assessed using DAS28, SDAI, and CDAI indices; joint involvement and systemic manifestations were evaluated.

Main Results:

• ACPA-positive RA patients demonstrated significantly higher disease activity (DAS28, SDAI, CDAI), elevated C-reactive protein and ESR, and more painful/swollen joints (p < 0.05).
• Arthritis localization differed, with ACPA-positive patients more frequently showing involvement of proximal interphalangeal, metacarpal, wrist, and shoulder joints.
• Systemic manifestations, particularly rheumatoid nodules, were more prevalent in ACPA-positive RA (32.9%) compared to ACPA-negative RA (17.7%), though neuropathy and scleritis showed a trend in the ACPA-negative group.

Conclusions:

• ACPA-negative RA presents with less pronounced joint damage and inflammation compared to ACPA-positive RA.
• The less distinct clinical presentation and lack of specific biomarkers in ACPA-negative RA necessitate careful, long-term patient monitoring.
• Despite differences in objective markers, subjective disease severity and joint dysfunction do not significantly differ between ACPA-negative and ACPA-positive RA subtypes.