The revised Immunoscan RA
Rheumatoid Arthritis(RA)is a common systemic autoimmune disease with a prevalence
of about 0.5-1.0% worldwide. Atypical feature of the disease is a chronic inflammation
of the joints leading to progressive joint destruction. Although the aetiology of RAis still
unknown, several riskfactors have been identified. Likein most autoimmune diseases, RA
occurs more frequently in women than in men (3:1 ratio), suggesting a role for sex hormones.
There is evidence that environmental factors, such as infectious agents, oral contraceptives and
smoking, may playa role. Severalstudies have shown that genetic factors are also involved.
An early diagnosis and insertion of proper treatment is of uppermost importance in order to
limit progression of the disease.
fb Immunoscan RA(anti-CCP)
( RA-96RT ) Immunoscan RA (anti-CCP)
Quantitative kit (96 wells).
The Immunoscan RA(anti-CCP) assay makes
use of (patented) citrullinated cyclic peptides.
Patient sera show different patterns of
reactivity with the citrullinated peptide
variants (which reflects the heterogeneous
nature of the autoimmune response in RA).
For this reason the use of citrullinated
peptides increases the sensitivity of the assay. These peptides do not share homology with
any known synovial proteins, but have been
selected on the basis of their excellent
recognition by RA patients. The peptides are
not recognized when the citrulline residue is
replaced by an arginine. Cyclisation has been
performed to force the peptide into a more
stringent structure in which the citrulline side
chain is optimally exposed for antibody
binding.
This approach has resulted in a significantly
increase of the sensitivity of the assay.
The cyclic citrullinated peptides are coated
on microtitre plates.
The major advantages of the Immunoscan RAassay are:
Excellent specificity: the
anti-CCP test is extremely
specific(-98%) compared
with other RA serological
tests such as RF. In combination with a
sensitivity of more than
75% the test differentiates
RA from other rheumatic
diseases. before the actual onset of
the disease. Early treatment
is important to prevent
future joint damage.
Earlydetection: anti-CCP
can be detected very early in RA, although with a somewhat lower sensitivity (40-60%). Analyses of blood donor samples has shown that
anti-CCP antibodies can
even be detected years before the actual onset of
the disease. Earlytreatment
is important to prevent
future joint damage.
Prognostic value: anti-CCP
appears to be a good
prognostic marker and has
a high discriminating
power between erosive
and non-erosive RA.
Patients positive for anti-
CCP develop significantly
more radiological damage
than anti-CCP-negative
patients. |
