CD44H and the isoforms CD44v5 and CD44v6 in the synovial fluid of the osteoarthritic human knee joint.
OBJECTIVE
To determine whether the concentrations of CD44H and v5 and v6 in the synovial fluid are correlated with the presence of accompanying synovitis in the osteoarthritic joint and with the grade of osteoarthritis.


METHODS
Using antero-posterior and lateral X-rays of the knee joint and patellar view of 46 patients were graded with the Kellgren & Lawrence scale. Synovial fluid from these patients with different grades of primary osteoarthritis of the knee joint with and without synovial inflammation (synovitis) was collected during surgical procedures. A horseradish peroxidase conjugated anti-CD44H-, anti-sCD44v5- or anti-sCD44v6-antibody was added and labeled with tetramethylbenzidine. The absorbance was measured at wavelengths of 450/620 nm. Regression analysis was performed and the statistical significance was assessed, using the Student t-test for unequal variance.


RESULTS
CD44H and v5 and v6 were detected in the synovial fluid of all 46 patients. Osteoarthritic patients with synovial inflammation showed significantly higher levels of CD44H and v6, but not v5, than osteoarthritic patients without synovial inflammation. With progression of osteoarthritis from Kellgren grade II to III, CD44v5 decreased significantly. All other isoform concentrations remained statistically unchanged.


CONCLUSIONS
CD44H and the isoforms v5 and v6 were present in the synovial fluid of osteoarthritic patients. Their concentrations do not reflect the osteoarthritic stage in the Kellgren grading scale. CD44H and CD44v6, but not CD44v5, are significantly up-regulated in osteoarthritic synovial inflammation.
Fuchs
S
S
Department of Orthopaedic Surgery, University of Muenster, Germany. fuchssu@uni-muenster.de
Rolauffs
B
B
Arndt
S
S
Tibesku
C O
CO
Prehm
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006023:Glycoproteins / Q000032:analysis; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications / Q000378:metabolism* / Q000473:pathology; D013582:Synovial Fluid / Q000378:metabolism*; D013585:Synovitis / Q000150:complications / Q000378:metabolism / Q000473:pathology
C113800:CD44v5 antigen; C112697:CD44v6 antigen; D006023:Glycoproteins; D018960:Hyaluronan Receptors