Synovitis score: discrimination between chronic low-grade and high-grade synovitis

AIMS: To standardize the histopathological assessment of synovial membrane specimens in order to contribute to the diagnostics of rheumatic and non-rheumatic joint diseases. METHODS AND RESULTS: Three features of chronic synovitis (enlargement of lining cell layer, cellular density of synovial stroma, leukocytic infiltrate) were semiquantitatively evaluated (from 0, absent to 3, strong) and each feature was graded separately. The sum provided the synovitis score, which was interpreted as follows: 0-1, no synovitis; 2-4, low-grade synovitis; 5-9, high-grade synovitis. Five hundred and fifty-nine synovectomy specimens were graded by two independent observers. Clinical diagnoses were osteoarthrosis (n=212), post-traumatic arthritis (n=21), rheumatoid arthritis (n=246), psoriatic arthritis (n=22), reactive arthritis (n=9), as well as controls (n=49) from autopsies of patients without joint damage. Median synovitis scores when correlated with clinical diagnoses were: controls 1.0, osteoarthritis 2.0, post-traumatic arthritis 2.0, psoriatic arthritis 3.5, reactive arthritis 5.0 and rheumatoid arthritis 5.0. The scores differed significantly between most disease groups, especially between degenerative and rheumatic diseases. A high-grade synovitis was strongly associated with rheumatic joint diseases (P<0.001, sensitivity 61.7%, specificity 96.1%). The correlation between the two observers was high (r=0.941). CONCLUSION: The proposed synovitis score is based on well-defined, reproducible histopathological criteria and may contribute to diagnosis in rheumatic and non-rheumatic joint diseases.     

Synovial fibroblasts and synovial macrophages from patients with rheumatoid arthritis and other inflammatory joint diseases show chromosomal aberrations

Chromosomal aberrations were investigated in nuclei extracted from synovial tissue and first-passage synovial fibroblasts (P-1 SFB, 98% enrichment) or macrophages (P-1 Mphi) from patients with rheumatoid arthritis (n=10). The findings were compared with those in other rheumatic diseases (osteoarthritis, n=14; reactive arthritis, n=1), as well as with those in chronic obstructive pulmonary disease (n=8). Controls were paired peripheral blood lymphocytes from arthritic patients, synovial tissue or SFB/Mphi from joint trauma/normals (n=9), and peripheral blood monocytes from normal donors (n=10). GTG banding of metaphase chromosomes and interphase fluorescence in situ hybridization with centromere-specific probes were used. Comparable chromosomal aberrations were observed in synovial tissue and P-1 SFB of patients with rheumatoid arthritis, osteoarthritis, and reactive arthritis (polysomy 7 and aneusomies of chromosomes 4, 8, 9, 12, and 18). Notably, aneusomies of chromosomes 4, 6, 7, 8, 9, 11, 12, and/or X were also detected in P-1 synovial Mphi from rheumatoid arthritis (90% of the cases), osteoarthritis (93%), and reactive arthritis (1/1), as well as bronchial Mphi from chronic obstructive pulmonary disease (25%). No aberrations were detected in paired peripheral blood lymphocytes (except for one osteoarthritis case with a karyotype 45,X[10]/46,XX[17]), or in peripheral blood monocytes and synovial tissue of normals/joint trauma. Because Mphi aberrations were common to chronic joint and pulmonary disease, chronic inflammatory stress may induce chromosomal aberrations with potential functional relevance in local mesenchymal cells and infiltrating leukocytes in an organ-independent fashion.     

关节镜在不同膝关节滑膜病变中的诊疗分析

目的观察关节镜在不同膝关节滑膜病变中的诊断、治疗作用,分析不同病变的临床疗效。方法选取50例关节镜下诊断、治疗的膝关节滑膜病变患者为研究对象,术前拟诊为类风湿性关节炎10例,色素沉着绒毛结节性滑膜炎11例,膝关节慢性感染5例,慢性非特异性滑膜炎12例,膝关节滑膜结核5例,半月板损伤4例,不明原因3例,记录关节镜对膝关节滑膜病变的诊治效果。结果关节镜结合病理检查结果,术后10例患者更正临床诊断,所有伤口均一期愈合,无严重并发症发生。出院后所有患者均获得随访,6例色素沉着绒毛结节性滑膜炎,2例类风湿性关节炎,1例滑膜结核,1例慢性非特异性滑膜炎术后复发,其余患者术后膝关节功能均获得显著改善,总有效率80.0%。结论关节镜检查有利于明确诊断,而且微创可彻底切除病变的滑膜组织,耐受性好。     

Computer-assisted validation of the synovitis score

Histopathological examination of synovial specimens can contribute to the diagnosis of chronic joint diseases. A so-called synovitis score has been introduced as a standardised grading system, based on the semi-quantitative evaluation of the three determining features of chronic synovitis: enlargement of synovial lining, density of synovial stroma and inflammatory infiltrate, giving a score between 0 and 9. The present study examines the reliability of this procedure by comparison with exact measurements using computer-assisted image analysis (CAIA). Seventy-one synovial specimens from patients with osteoarthritis (OA, n = 22), psoriatic arthritis (PsA, n = 7), rheumatoid arthritis (RA, n = 35) and from a control group (Co, n = 7) were evaluated using both the synovitis score and CAIA. The measurements were transformed to semi-quantitative values analogous to the synovitis score. The differences between the transformed CAIA scores and the pathologist's scores were 0 or +/-1 in 40 cases, whereas in 31 cases the difference was greater than 1 (correlation coefficient r = 0.725). The CAIA scores differed significantly between Co and RA cases (p = 0.000) as well as between OA and RA (p = 0.000). We conclude that the synovitis score was validated by CAIA and can be regarded a reliable grading system that contributes to the diagnostic procedure of chronic joint inflammation.     

Mycoplasma fermentans,but not M penetrans,detected by PCR assays in synovium from patients with rheumatoid arthritis and other rheumatic disorders.

AIM/BACKGROUND: Mycoplasmas, especially Mycoplasma fermentans, were suggested more than 20 years ago as a possible cause of rheumatoid arthritis but this hypothesis was never substantiated. In view of the superior sensitivity of the polymerase chain reaction (PCR) assay over culture, the aim was to use this method to seek M fermentans and M penetrans in synovial samples from patients with various arthritides. METHODS: Synovial fluid samples (n = 154) and synovial biopsy specimens (n = 20) from 133 patients with various rheumatic disorders were stored at -80 degrees C for between one and 40 months. Aliquots (500 microliters) of the synovial fluid samples were centrifuged and the deposit, and also the synovial biopsy specimens (approximately 1 g) were placed in lysis buffer with proteinase K for DNA extraction. The DNA was tested by using a semi-nested PCR assay for M fermentans and a single-round PCR for M penetrans. RESULTS: M fermentans was detected in the joints of eight (21%) of 38 patients with rheumatoid arthritis, two (20%) of 10 patients with spondyloarthropathy with peripheral arthritis, one (20%) of five patients with psoriatic arthritis, and four (13%) of 31 patients with unclassified arthritis. M fermentans was not found in the joints of the seven patients with reactive arthritis, the 29 with osteoarthritis or post-traumatic hydrarthrosis, the nine with gouty arthritis, nor the four with chronic juvenile arthritis. M penetrans was not detected in any sample. CONCLUSIONS: These findings show that the presence of M fermentans in the joint is associated with inflammatory rheumatic disorders of unknown cause, including rheumatoid arthritis. However, whether this organism triggers or perpetuates disease of behaves as a passenger remains conjectural.     

Expression of Integrin αvβ3 in Gliomas Correlates with Tumor Grade and Is not Restricted to Tumor Vasculature

In malignant gliomas, the integrin adhesion receptors seem to play a key role for invasive growth and angiogenesis. However, there is still a controversy about the expression and the distribution of α_vβ₃ integrin caused by malignancy. The aim of our study was to assess the extent and pattern of α_vβ₃ integrin expression within primary glioblastomas (GBMs) compared with low-grade gliomas (LGGs). Tumor samples were immunostained for the detection of α_vβ₃ integrin and quantified by an imaging software. The expression of α_vβ₃ was found to be significantly higher in GBMs than in LGGs, whereby focal strong reactivity was restricted to GBMs only. Subsequent analysis revealed that not only endothelial cells but also, to a large extent, glial tumor cells contribute to the overall amount of α_vβ₃ integrin in the tumors. To further analyze the integrin subunits, Western blots from histologic sections were performed, which demonstrated a significant difference in the expression of the β₃ integrin subunit between GBMs and LGGs. The presented data lead to new insights in the pattern of α_vβ₃ integrin in gliomas and are of relevance for the inhibition of α_vβ₃ integrin with specific RGD peptides and interfering drugs to reduce angiogenesis and tumor growth.     

Interaction and localization of Necl-5 and PDGF receptor beta at the leading edges of moving NIH3T3 cells: Implications for directional cell movement

It was previously shown that platelet-derived growth factor (PDGF) receptor physically and functionally interacts with integrin α_vβ₃, effectively inducing cell movement. We previously showed that Necl-5, originally identified as a poliovirus receptor, interacts with integrin α_vβ₃ and enhances its clustering and the formation of focal complexes at the leading edges of moving cells, resulting in an enhancement of cell movement. We showed here that Necl-5 additionally interacts with PDGF receptor in NIH3T3 cells and regulates the interaction between PDGF receptor and integrin α_vβ₃, effectively inducing directional cell movement. PDGF receptor co-localized with Necl-5 and integrin α_vβ₃ at peripheral ruffles over lamellipodia, which were formed at the leading edges of moving cells in response to PDGF, but not at the focal complexes under these ruffles, whereas Necl-5 and integrin α_vβ₃ co-localized at these focal complexes. The clustering of these three molecules at peripheral ruffles required the activation of integrin α_vβ₃ by vitronectin and the PDGF-induced activation of the small G protein Rac and subsequent re-organization of the actin cytoskeleton. These results indicate a key role of Necl-5 in directional cell movement by physically and functionally interacting with both integrin α_vβ₃ and PDGF receptor.     

Cytokines and the chronic inflammation of rheumatic disease. II. The presence of interleukin-2 in synovial fluids.

Sera and synovial fluids from patients with a variety of rheumatic diseases were assayed for interleukin-2 (IL-2) activity in a system utilizing the proliferative response of cultured human phytohaemagglutinin (PHA) T cell blasts. The synovial fluids from 14 rheumatoid arthritis, eight ankylosing spondylitis, three psoriatic arthritis and 11 osteoarthritis patients, all showed IL-2 activity. The amounts of IL-2 present in the fluids from different diseases were compared and ranged from 4.2 to 140.0 units/ml.     

Cell Specific Synovial Expression of Nicotinic Alpha 7 Acetylcholine Receptor in Rheumatoid Arthritis and Psoriatic Arthritis

Neuroimmune interactions are known to influence several chronic inflammatory and rheumatic diseases, but the underlying mechanisms have been insufficiently elucidated. The cholinergic anti-inflammatory pathway is characterized by neural regulation of systemic inflammation, mediated by the vagus nerve and specific cholinergic stimulation of the nicotinic α-7 acetylcholine receptor (α7nAChR) on immune cells. Moreover, α7nAChR has been shown important for immune regulation also in the absence of nerves, but little is known about these mechanisms in chronic joint inflammation. The expression and localization of α7nAChR in synovial biopsies from patients with rheumatoid arthritis and psoriatic arthritis was investigated by immunohistochemistry using monoclonal antibody against α7nAChR. Surface staining of α7nAChR was observed in synovial tissue of all arthritis patients investigated and could also to a lesser extent be detected in the synovium of healthy individuals. α7nAChR positive cells were detected in mainly synovial lining cells and vessels. The α7nAChR positively stained cells were by double immunofluorescence identified as primarily macrophages and fibroblasts, with the majority of these cells expressing the receptor. These results indicate the importance of α7nAChR and cholinergic mechanisms in arthritis pathogenesis and implicate specific cholinergic modulation as a potential anti-inflammatory therapeutic strategy in joint inflammation.     

Characteristics of mononuclear cell populations in chronically inflamed synovial membranes.

Mononuclear cells infiltrating synovial membranes in chronic synovitis were characterised both in situ and in cell suspensions by surface markers and histochemical techniques. T-lymphocytes were the predominant infiltrating cell in rheumatoid arthritis as well as in other forms of chronic arthritis, including ankylosing spondylitis and arthritis associated with Crohn's disease. B-lymphocytes were found exclusively in rheumatoid synovial membranes. These cells were demonstrable both in true germinal centres and, focally and diffusely, in nodular mononuclear infiltrates lacking the histochemical characteristics of germinal centres. The synovial lining cells, unlike mononuclear phagocytes, had no demonstrable receptors for C3 and Fc.     

Induction of autologous lymphocyte transformation by synovial fluids from patients with rheumatoid arthritis

Appropriately diluted synovial fluids from thirteen of eighteen patients with rheumatoid arthritis induced in vitro transformation of autologous peripheral blood lymphocytes. By contrast, no significant transformation of autologous lymphocytes was induced by ten of eleven synovial fluids from patients without rheumatoid arthritis. These studies suggest that a similar blastogenic response in vivo may perpetuate subsynovial lymphoid hyperplasia and chronic synovitis in patients with rheumatoid arthritis.     

Immunopathological changes in rheumatoid arthritis and other joint diseases.

A comparative study of the distribution of immunoglobulins G, M, and A and C3 in the synovium and inside synovial fluid leucocytes and of the relative levels of IgG, IgM, AND C3 in paired samples of serum and synovial fluid from both seropositive and seronegative patients with rheumatoid arthritis and other types of non-infective synovitis shows that although there is no distinctive immunopathological feature of rheumatoid arthritis, the incidence of immune complexes containing IgG and IgM with and without detectable C3 in the affected synovium or inside synovial fluid granulocytes is higher in rheumatoid arthritis and especially so in seropositive cases. The mean level of C3 in synovial fluid from patients with rheumatoid arthritis is lower than that from the group without rheumatoid arthritis. In contrast to previous reports, extracellular clumps of IgA could be detected in the affected synovium of a number of affected patients. Aggretated human IgG could be bound by some of the synovial biopsies and synovial fluid leucocytes from both seropositive and seronegative rheumatoid arthritis patients. Antinuclear factor and rheumatoid factor could be detected in the synovial fluid but not in the serum of several patients suggesting either selective sequestration or local synthesis of antinuclear and rheumatoid factors in the affected joints.     

Elevated angiogenin levels in synovial fluid from patients with inflammatory arthritis and secretion of angiogenin by cultured synovial fibroblasts

Angiogenesis is a key process in the pathogenesis of inflammatory arthritis. Angiogenin is one of the most potent inducers of neovascularization in experimental models in vivo. To look for evidence that angiogenin is involved in inflammatory joint disease, we examined plasma and synovial fluid (SF) samples from rheumatology patients and synovial fibroblast cell culture supernatants. Angiogenin levels were determined by radioimmunoassay and ELISA. Plasma angiogenin concentrations ranged from 96 to 478 ng/ml, with no significant difference between patients and normal controls. In SF, angiogenin concentrations were significantly higher in patients with acute or chronic synovitis (rheumatoid arthritis (RA): median, 104 ng/ml; range 13-748, n = 14; crystal-induced arthritis (CIA): median, 149 ng/ml; range, 37-616, n = 14, and other chronic inflammatory arthritis: median, 42 ng/ml; range, 15-205; n = 9) than in the 18 patients with osteoarthritis (OA) (median, 20 ng/ml; range 8-116) (P < 0.0001, anova). Angiogenin levels in SF from RA patients in remission with secondary OA were similar to those achieved in primary OA, and decreased in parallel with the resolution of acute gout. Angiogenin protein was released by cultured synovial fibroblasts from OA and RA patients, and reached 1.18 ng/106 cells/day. These data suggest that angiogenin may mediate local inflammation in arthritis via effects on angiogenesis and leucocyte regulation.     

Detection of parvovirus B19 capsid proteins in lymphocytic cells in synovial tissue of autoimmune chronic arthritis.

The pathogenic influence of viral agents in chronic inflammatory joint diseases like rheumatoid arthritis has been discussed for many years. More recently, DNA of several viruses, among them parvovirus B19 (B19), was traceable by PCR analysis in synovial fluid and synovial tissue. To investigate the potential role of parvovirus B19 in rheumatoid arthritis, we analyzed the expression of B19 VP1/VP2 proteins by immunohistochemistry in paraffin sections of 63 synovial specimens in rheumatoid arthritis (RA; n = 29), psoriatic arthritis (PSA; n = 6), nonspecific arthritis or synovitis (n = 26), and normal synovia (n = 2). Thereby we could demonstrate replicative virus infection in a variable number of cells in about 90% of rheumatoid specimens and in four of six (66%) cases of psoriatic arthritis, but only in 38% of cases with chronic reactive inflammation and one case of normal synovia. In virus-positive rheumatoid specimens, moreover, the average number of affected cells was significantly higher than in virus-expressing synovia of nonspecific reactive inflammation. These findings support the importance of B19-viral infection in the pathogenesis of chronic arthritis. B19-positive cells in the synovia could be ascribed to CD20- or CD3-positive B- or T-lymphocytes by double immunostaining. Based on these results, B19 infection of lymphocytic cells also seems possible.     

Ultrastructural study of human synovial membrane with immunoperoxidase.

An ultrastructural immunoperoxidase study of human synovial membrane biopsies performed in 16 patients with rheumatoid synovitis and in 14 control patients showed that: (1) plasma immunoglobulins have an intercellular distribution and seem to diffuse mainly by an intercellular rather than by a transcellular pathway; and (2) there is a difference in the distribution of plasma IgG and IgM. IgG was found in intravascular and extravascular spaces in all biopsies. IgM was found only in intravascular spaces in control biopsies, but in rheumatoid synovitis it was present in both intravascular and extravascular spaces. This difference in distribution may be due to increased vascular permeability in inflammatory synovitis.     

Presence of HLA-DR antigen on synovial type A and B cells: an immunoelectron microscopic study in rheumatoid arthritis, osteoarthritis and normal traumatic joints

The HLA-DR antigen was investigated in synovial epithelia of rheumatoid arthritis, osteoarthritis and normal traumatic joints, using monoclonal anti-human HLA-DR antibody and horseradish peroxidase-conjugated antibody. The HLA-DR staining was observed in an electron microscope. HLA-DR antigen was observed to be present on the surface of both macrophage-like (type A) and fibroblast-like (type B) cells in synovial epithelia in all rheumatoid arthritis, osteoarthritis and normal joints. Since type A and B cells are ultrastructurally considered to be of synovial origin, the findings suggest that the expression of HLA-DR antigen on the surface is one of the common attributes of type A and B cells in synovial epithelia, even before cellular infiltration of chronic inflammation in rheumatoid arthritis. These cells may play an important role in the initiation of rheumatoid inflammation, since HLA-DR antigen is considered equivalent to murine Ia antigen.     

Site‐specific absence of microfibrillar‐associated protein 4 (MFAP4) from the internal elastic membrane of arterioles in the rheumatoid arthritis synovial membrane: an immunohistochemical study in patients with advanced rheumatoid arthritis versus osteoarthritis

Microfibrillar‐associated protein 4 (MFAP4) is a non‐structural matrix protein with cell regulatory activities and a potential as seromarker for fibrosis. We aimed to study the occurrence of MFAP4 in the synovial membrane from patients with rheumatoid arthritis (RA) vs osteoarthritis (OA). Formaldehyde‐fixed synovial tissue sections, from patients with RA (N = 6) and OA (N = 6) undergoing total hip arthroplasty, were deparaffinized and immunostained with monoclonal antibodies against MFAP4. Elastin was detected using ElastiKit. MFAP4 in serum (sMFAP4) and synovial fluid was measured by an immunoassay. MFAP4 was present in synovial biopsies from both RA and OA patients, particularly prominent in deep arterioles where it colocalized with elastin. Notably however, MFAP4 was absent from the internal elastic lamina in RA arterioles irrespective of disease duration and synovitis activity, while present although with irregular staining patterns in OA specimens. sMFAP4 was increased in RA and OA serum vs healthy controls: median (interquartile range) 29.8 (25.3–39.1) and 25.5 U/L (18.1–43.3) vs 17.7 U/L (13.7–21.2), p = 0.006 and p = 0.02, respectively The concentration of synovial fluid was lower than in serum in both RA and OA. These findings may suggest that MFAP4 is involved in adaptive vessel wall remodeling associated with chronic joint disease.