||Aim: To assess the potential usefulness ,of measurements of serum levels of cartilage
oligomeric matrix protein (COMP) and YKL-40 in patients with knee osteoarthritis (OA)
as biochemical markers of osteoarthritic status.
Methods: 40 patients having symptomatic knee OA and meeting the ACR criteria for
idiopathic knee OA and 15 healthy subjects matched with age and sex as controls were
included in this study. Serum COMP and YKL-40 levels were measured by ELISA tech
nique. The levels of these markers were compared according to the changes in joint
space width (JSW), Kellgren Lawrence (K-L) grade, age, disease duration, gender, body
mass index (BMI) and western Ontario MacMaster (WOMAC) index in our OA patients.
Results: There were significant elevations of the serum COMP and YKL-40 in OA pa
tients in comparison to the control group (P<0.001), more in hilateral than unilateral cases.
There were highly significant positive correlations of both parameters with K-L radiological
severity of the disease, but an inverse significant correlation with JSW (P<0.001). As regard
• synovitis, there was significant increase of serum YKL-40 (P<0.05) while serum COMP
level showed a slight but insignificant increase. There were highly significant positive cor
relations of serum COMP and YKL-40 levels with WOMAC index and age (P<0.001)
while there were no significant correlations with disease duration and body mass index
(BMI) (P>0.05). C-reactive protein (CRP) was significantly higher in OA patients than in
controls and showed positive significant correlation with serum level of YKL-40 (P<0.001).
There was a positive highly significant correlation between both parameters (P<0.05).
Conclusion: From these results we concluded that, the raised levels of serum COMP
and YKL-40 can reflect disease severity and multiple joint involvement. YKL-40 may be
a useful marker of synovitis in OA. The combined use of both markers can help in early
diagnosis and improve prediction of disease status.
Amal F. Soliman, Refaat Mostafa AI-Tanawy, Noha M. Abd-Alnaser,
Yasser M. *Ismail and **NaglaaIbrahem Azab.
Departments of Rheumatology & Rehabilitation, *CIinical Pathology,
**Biochemistry,Benha Faculty of Medicine, Egypt
VALUE OF CARTILAGE OLIGOMERIC MATRIX PROTEIN AND
YKL-40 AS BIOCHEMICAL MARKERS IN PATIENTS
WITH KNEE OSTEOARTHRITIS
The Egyptian Rheumatologist, Vol. 29, No. 2, 2007: P. 105^ 113 : i.:
The combined use of several markers in OA
patients seems to be necessary to improve pre
diction of disease severity (Jung et al., 2006).
AIM of the WORK:
To assess the potential usefulness of meas
urements of serum levels of COMP and YKL-
40 in patients with knee OA as biochemical
markers of osteoarthritic status
PATIENTS and METHODS:
This study is carried out on 40 patients hav
ing symptomatic knee OA and 15 healthy sub
jects matched for age and sex as controls. All
patients fulfilled the criteria of the American
College of Rheumatology (ACR) classification
criteria for idiopathic OA of the knee (Altaian
et al., 1986). They were selected from the out
patient clinic of the rheumatology and rehabili
tation of Benha University Hospitals.
We excluded the following cases:
•Secondary OA as joint injury, developmental
deformities, osteonecrosis, RA, gout and seronegative
•Patients who had a history of malignancy,
myocardial infarction or elevated liver en
•Patients who received intra-articular injection
(steroids, chondroitin polysulphate or hyaluronic
acid) for at least one month before
All our patients were subjected to the fol
•Full history taking with particular attention to
onset, course, disease duration, pain, articu
lar gelling, locking and instability.
Osteoarthritis is a multifactorial, structural
ly complex condition affecting the entire joint.
At the molecular level, osteoarthritis (OA) is
characterized by an imbalance between the
synthesis of cytokines, metalloproteinases, and
their natural inhibitors. These changes finally
lead to articular cartilage destruction, and
changes in the subchondral bone and synovial
membrane (Iannone and Lapadula, 2003).
The cartilage oligomeric matrix protein
(COMP) is a non collagenous protein, the
function of which is to bind to type II collagen
fibers and stabilize the collagen fiber network
in articular cartilage. The amount of this pro
tein increases under the influence of cytokines
and growth factors. As a result of various dis
eases that cause damage to cartilage, fragment
of matrix protein are released into synovial
fluid and then into blood (Wislowska and Jablonska,
YKL-40, also known as human cartilage
glycoprotein 39 (HC gp-39) and chondrex, is
produced by degenerated articular cartilage, in
flamed or hyperplastic synovium, activated
macrophages, neutrophilis (Kirkpatrick et al.,
1997). Several studies have suggested that
YKL-40 might be a useful new marker for pa
tients with OA and rheumatoid arthritis (RA)
(Johansen et al., 2001).
The diagnosis of OA is generally based on
clinical and radiographic changes, which occur
fairly late during disease progression and have
poor sensitivity for monitoring disease pro
gression, so measuring of these markers would
seem a promising approach to improve the pre
diction of disease progression at the individual
level (Taka hashi et al., 2004).