Diagnostic value of antibodies to citrulline containing peptides in patients with rheumatoid arthritis in southern Iraq

Abstract EN

A serological study has been done in Al-Nassiriyha, southern Iraq, from December 2006 to August 2007 designed to determine the frequency of anti-cyclic citrullinated peptide antibody (anti-CCP) in a group of patients with rheumatoid arthritis for specific period of time compared with other rheumatic diseases and healthy controls.

Also to show the diagnostic value of anti-CCP antibody in relation to other markers [rheumatoid factor (RF), antinuclear factor (ANF), C-reactive protein (CRP) and cytokines such as interleukin–6 (IL-6), tumor necrosis factor–? (TNF-α)] to discriminate between those patients with and without RA. Blood samples were taken from 121 patients with rheumatoid arthritis, 88 patients of other rheumatic diseases from AL-Hussein Teaching Hospital in AL-Nassiriyah and 120 healthy controls from medical personnel and school students who were healthy.

All the information was taken from the patients and controls. An Enzyme-linked immunosorbent assay was used for estimation of anti-CCP, IL-6, TNF-α and slide agglutination test for the estimation of RF, CRP and ANF.

The seropositivity to anti-CCP in RA patients group was 61.2% among them 23% with low levels of anti-CCP, 25% with moderate levels and 51.3% with high levels (> 60 units /ml.).The high levels of anti-CCP persist for long durations up to 10 years (54.7%).

However, anti-CCP was rarely detected among non- RA rheumatic diseases and healthy controls (2.3% and 2.5% respectively).

Anti-CCP showed the greater specificity (97.6%) and sensitivity (61.2%) compared to the other marker used in this study.

The overall agreement between the tested parameters in their ability to detect RA patient was higher for anti-CCP combined to IL-6 (91.7%) in comparison to the effect of other markers combination.

Although anti-CCP was more common in RA patient with 2-10 years duration of illness, anti-CCP, IL-6 and TNF-α positivity as estimated by ELISA were persistently with high titers regardless the duration of illness.

The majority of RA patients with high anti-CCP levels were among stage three of clinical RA.

Smoking has a positive relation to the increased levels of all tested parameters compared to the non-smokers.