Up to now, the factors that cause JIA and its pathogenesis
still remain explored mystery. Juvenile idiopathic
arthritis has clinical features which greatly differ from
those of RA.
15,16 It is also generally thought to be a
heterogeneous disease that has close correlations with
genetic predisposition, immunologic derangement,
and environmental factors. Based on differences in onset features, clinical manifestations, disease courses,
and outcomes, JIA can be classified into different
subtypes such as systemic JIA, polyarticular JIA, and
oligoarticular JIA.
17 Juvenile idiopathic arthritis is an
autoimmune disease which can lead to a high disability
rate among children; therefore, early diagnosis and
treatment are vital for the improvement of joint lesions
and the prognosis of the patients.
However, since a highly specific and sensitive
laboratory marker of JIA has not yet been found,
diagnosis mainly depends on the clinical manifestations.
Although RF has a high sensitivity in the diagnosis of
RA (but with a low specificity), it has a low sensitivity in
the diagnosis of JIA.18 Anti-cyclic citrillunated peptide
antibodies have only been recently reported to have
specific antibodies which reveal a diagnostic value for
the diagnosis of RA.19 In the current study, the positive
anti-CCP antibody rate in the JIA group was 12.5%,
which is basically consistent with a previous report by
van Rossum et al.,10 and the rate of the control group
was 0%. These results suggest that anti-CCP antibodies
have a high specificity in the diagnosis of JIA (100%).
Among 65 patients with RA, 48 had positive anti-CCP
antibodies, and the rate was 73.8%, which falls between
the previously reported rates of 40% and 85% seen in
the literature.7,8,20 These results show that anti-CCP
antibodies have a lower sensitivity to JIA than RA.
Significant differences in distribution among patients
with different subtypes of JIA have been determined
via anti-CCP antibodies. In our study, the positive anti-
CCP antibody rates of the polyarticular, oligoarticular,
and systemic JIA groups were 45.5%, 17.4% and 0%,
respectively. This suggests that they are of certain
directive significance in JIA clinical typing.
In addition, in order to make sure that the results
obtained from our experiment were stable, parallel
detections were performed using three different types
of kits, and no significant differences were detected
among the positive rates of the experimental subjects.
This suggests that ELISA is a stable and reliable method
for serum anti-CCP antibody detection.
Furthermore, we also analyzed radiological data in
our study, and the results showed that joint destruction
in the positive anti-CCP antibody JIA group was more
severe than that in the negative anti-CCP antibody
JIA group. This suggests that anti-CCP antibody
detection has an important role in the evaluation of
the severity of joint destruction in patients with JIA
and in the prognosis of the patients. In addition, the
RF positive rate of the positive anti-CCP antibody group was noticeably higher than that of the negative
group, suggesting that the combined detection of anti-
CCP antibodies and RF is helpful for increasing the
sensitivity and specificity in the diagnosis of JIA. These
results are consistent with previous studies,21-23 and
their simultaneous presence may be an indication for
earlier immunosuppressive treatment.24
No significant difference in disease course was
found between the positive and negative anti-CCP
patients in either the polyarticular group or the
oligoarticular group, which seems to indicate that anti-
CCP antibodies cannot serve as a reliable serological
marker in the early diagnosis of JIA. However, our
study showed that positive anti-CCP antibodies were
primarily found in children with polyarticular and
oligoarticular JIA, which conveys the idea that anti-CCP
antibody detection might be of clinical significance in
JIA typing and the prognostic evaluation of patients.
Declaration of conflicting interests
The authors declared no conflicts of interest with
respect to the authorship and/or publication of this
article.
Funding
This study was supported by the 11th Five-Year Plan of
China (2008BAI59B02).
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