Possible clinical associations ِand prognostic role of antineutrophil cytoplasmic antibodies (ancas)‎ in early rheumatoid arthritis

الملخص EN

Objective: To study the frequency and distribution of antineutrophil cytoplasmic auto antibodies (ANCAs) among rheumatoid arthritis patients (RA), using different immunological methods.

Also to study the clinical associations and the possible prognostic role of ANCA in RA patients.

Methodology: Seventy-four serum samples were collected from rheumatoid arthritis patients (RA), 26 with early disease and 48 with long-standing disease (more than one year).

Twenty apparently healthy subjects served as a control group with matched age and sex.

All patients and controls were analyzed for ANCA with indirect immunofluorescence (IIF) and enzyme linked immunosorbant assay (ELISA) with four different neutrophil granule proteins as antigens (myeloperoxidase (MPO), proteinase 3 (PR3), lactoferrin, (LF) and elastase (ELS)), besides measuring the levels of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP).

IgM rheumatoid factor (RF) and antinuclear antibodies (ANA) were also performed.

Results: The prevalence of ANCA in the whole group of RA patients was 44.6% with IIF.

The provenances were 23 % and 56.3 % in patients with early and long-standing RA respectively.

The predominant staining pattern was p-ANCA, present in 85% of RA patients positive for ANCA.

In RA patients with vasculitis the incidence of ANCA positivity was 64.2% and the predominant pattern was p-ANCA (57.1%).

Overall, 39.2% of RA sera were positive with ELISA assays.

Antibodies directed against MPO occurred in 14.8%, antibodies against PR3, LF and ELS were found 2.7%, 12.1% and 9.4% respectively.

The corresponding figures for antibodies against MPO, PR3, LF, and ELS in long-standing RA were 27.1%, 4.1%, 16.7% and 2.1% respectively.

In early RA antibodies were detected only against MPO (11.5%) and LF (7.7%).

MPO was the antigenic specificity of ANCA most frequently found in patients with early RA and long-standing RA, whereas LF predominated in those with RA-associated vasculitis.

In those with early RA, positivity for ANCA was correlated with IgM RF levels.

On the other hand, ANCA in patients with long-standing RA were significantly correlated with clinical and laboratory findings indicating severe disease and increased inflammatory activity.

Conclusion: ANCAs are often found in RA patients, primarily among those with long standing disease.

ANCAs may serve as a valuable serologic marker in RA patients and be helpful in selecting those patients already in early RA who will benefit mostly from aggressive treatment.

Immunofluorescence technique is a good screening method; ELISA should be performed on positive cases and also on negative cases with clinical suggestive finding.