ABSTRACT
One of the characteristics of rheumatoid arthritis [RA] is the presence of several autoantibodies in the serum of the patient. However, most of these antibodies have failed to demonstrate adequate diagnostic and prognostic value so far. There is growing evidence that therapeutic intervention early in the course of RA leads to earlier disease control less joint damage, and a better prognosis. A new serological test, the anti-cyclic citrollinated peptide [anti-CCP] was developed. Anti-CCP was reported to have a high specificity for the diagnosis of RA, especially in patients with early disease and its presence before disease presentation is suggestive of its role in disease pathogenesis .The aim of this study is to estimate the level of anti-CCP antibodies in the serum of RA patients and to correlate them with RF isotypes [IgG and IgM] and clinical findings as disease activity and severity. This study comprised 68 RA patients [64 female and 4 males] diagnosed according to the revised criteria described by ACR [1987], in addition to 15 healthy control subjects. Clinical assessment of RA disease activity and severity, radiological investigations, and laboratory investigations [complete blood picture, ESR, CRP, determination of anti-CCP, IgG-RF and IgM-RF antibodies by ELISA technique] were done for all subjects.Highly significant increase in the levels of anti-CCP, IgG-RF and IgM-RF antibodies were found in RA patients compared to control group [P<0.001 for each]. Anti-CCP antibodies showed the highest diagnostic specificity [100%] than both RF IgM and IgG [93.33% for each].The anti-CCP and IgG-RF tests had excellent sensitivity [95.59% and 98.53% respectively] while IgM-RF had relatively lower sensitivity than both tests [86.76%]. Anti-CCP level was significant positively correlated with duration of the disease [P=0.024].Also,there was positive correlation between anti-CCP levels and all disease activity parameters which include the number of active joints [P=0.007], duration of morning stiffness [P<0.001], ESR [P<0.001] and CRP values [P=0.024]. Anti-CCP test had the best correlation with disease activity grades .disease severity, and radiological score [P=<0.001, P=<0.001 and P=0.000 respectively]. The level of anti-CCP in patients receiving methotrexate either alone or with lefwnomide is lower than other patients receiving methotrexate with corticosteroids [56.5 +/- 41.33,112 +/- 95.04 lU/ml respectively]. In conclusion, anti-CCP antibodies could be regarded as a new diagnostic marker for RA as they have 100% specificity and 95.8% sensitivity and it could predict erosive development early in the disease, and it could be used in evaluation of disease activity, severity and therapeutic response