The synovitis of "non-inflammatory" orthopaedic arthropathies: a quantitative histological and immunohistochemical analysis.
OBJECTIVE
To quantify inflammatory changes in synovial membranes from orthopaedic "non-inflammatory" arthropathies (Orth. A).


METHODS
Synovial membranes from patients with femur fracture, avascular necrosis of the femur, plica syndrome, and meniscus and/or ligament injury (n = 23); rheumatoid arthritis (n = 28); osteoarthritis (OA; n = 25); and from normal controls (n = 10) were assessed by light microscopy, a histological synovitis score, immunostaining for CD3, CD20, CD38, CD68, Ki-67 and von Willebrand factor, and with an immunohistochemical inflammation score.


RESULTS
Orth. A histology varied between normal and markedly inflamed. Predominant abnormalities were mild lining hyperplasia, scattered inflammatory cells and small perivascular infiltrates. The synovitis score classified Orth. A as "mild synovitis". Inflammatory cells occurred frequently: CD68+ cells in 100% of Orth. A specimens; CD3+, 91%; CD38+, 70%; and CD20+, 39%. Orth. A had 36% greater lining thickness (p = 0.04), 40% higher vascular density (p = 0.009) and 51.3-fold higher CD38+ cell density (p = 0.02) than normal controls; and 60% fewer subintimal Ki-67+ cells (p = 0.003), 42% fewer CD68+ lining cells (p<0.01) and 40% fewer subintimal CD68+ cells (p<0.01) than OA. The immunohistochemical inflammation score was 2.2-fold higher in Orth. A than in controls (p = 0.048) and similar to OA, with three Orth. A specimens showing marked inflammation.


CONCLUSIONS
Synovial membranes from "non-inflammatory" arthropathies featured neovascularisation and inflammation intermediate between normal and OA synovium. These results expand previous findings that mechanical joint injury may lead to a mild-to-moderate synovitis.
Pessler
F
F
The Children's Hospital of Philadelphia, Division of Rheumatology, Philadelphia, USA. frank.pessler@uniklinikum-dresden.de
Dai
L
L
Diaz-Torne
C
C
Gomez-Vaquero
C
C
Paessler
M E
ME
Zheng
D-H
DH
Einhorn
E
E
Range
U
U
Scanzello
C
C
Schumacher
H R
HR
D051997:ADP-ribosyl Cyclase 1 / Q000032:analysis; D015703:Antigens, CD / Q000032:analysis; D018951:Antigens, CD20 / Q000032:analysis; D015214:Antigens, Differentiation, Myelomonocytic / Q000032:analysis; D001172:Arthritis, Rheumatoid / Q000276:immunology; D015415:Biomarkers / Q000032:analysis; D017252:CD3 Complex / Q000032:analysis; D016022:Case-Control Studies; D005264:Femoral Fractures / Q000150:complications / Q000276:immunology; D005269:Femur / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007596:Joints / Q000293:injuries*; D008022:Ligaments / Q000293:injuries; D009336:Necrosis; D010003:Osteoarthritis / Q000150:complications / Q000276:immunology; D018709:Statistics, Nonparametric; D013583:Synovial Membrane / Q000737:chemistry*; D013585:Synovitis / Q000209:etiology / Q000276:immunology*; D014841:von Willebrand Factor / Q000032:analysis; D000097382:CD68 Molecule
D051997:ADP-ribosyl Cyclase 1; D015703:Antigens, CD; D018951:Antigens, CD20; D015214:Antigens, Differentiation, Myelomonocytic; D015415:Biomarkers; D017252:CD3 Complex; D014841:von Willebrand Factor; C067980:CD68 antigen, human; D000097382:CD68 Molecule