Anti- CCP (Cyclic Citrullinated Peptid)
Anti-CCP, is an immune protein of IgG type, formed against a circular peptide, containing a non-standard aminoacid named citruline that does not exist in peptides or proteins normally. Citruline is a middele product that occurs as an amino group leaves the arginin aminoacid that is one of the standards in the body. Anti-CCP is used for diagnosis of rhomatoid arthritis.
Anti-CCP becomes detectable mostly in the blood of rhomatoid artritli patients in the early periods of the disease. The patients with a detectable anti-CCP in the blood is 90-95% of that disease. Anti-CCP is fairly useful in patients with unexplained articular inflamation and negative conventional blood test for especially Rhomatoid Factor. Furthermore, since anti-CCP is related to the increase in tendency towards the destructive forms of rhomatoid arhritisis, it has a prognostical value.
Citrulined proteins are detected in the joints of rhomatoid arthritis patients, hovewer thay are not present in other joint diseases. Those proteins probably have a role in the development of rhomatoid arthritis.
Antibodies against citruline may be detected in the blood of patients with a tendecy to rhomatoid arthritis far before – as long as 3 years – the clinical symptoms of this diseases begin, and its titration increases by time. It is far more specific than the rhomatoid factor. The specifity of anti-CCP for RA is 98%. It becomes positive earlier in RA patients than RF and it is less positive in diseases of autoimmune connecting tissue like SLE. It is rarely positive in infectious diseases and normal elderly population in contrast to RF. Anti-CCP may be positive in some RF negative RA patients.
Anti-CCP positiveness is found as follows in rhomatoid arthritis patients:
PERIOD |
|
SENSITIVITY |
More than 1,5 years before the symptoms begin |
|
% 25 (15,1-37) |
Less than 1,5 yeas before the symptoms begin |
|
% 52 (33,8-68,9) |
In symptomatic patients |
|
% 80 |
RA is one of the most frequent autoimmune diseases in the world with a frequency of 1%. It is a severe and chronical inflamatory joint disease. It is seen 3 fold more in women. Usually it begins in the middle ages, hovewer it may be seen in children or young adults. Since an irreversible joint damage may occur in the early periods of the disease, early diagnosis is very important. Thus, anti-CCP should be preferred as a diagnostik test for diagnosis and treatment.
|
