Causes and predictors of death among Finnish patients with systemic sclerosis

OBJECTIVE

The aim of this study was to assess causes and predictors of death among Finnish patients with systemic sclerosis (SSc).

METHOD

Medical records of patients registered with the ICD-10 code M34 from 1996 to 2018 in two university hospitals were reviewed retrospectively. Clinical data were collected until the end of 2020. Death certificates were obtained from Statistics Finland up to August 2021. Using death certificates and patient records, the cause of death for each patient was determined. The mean age at death, median time from SSc diagnosis, and factors predicting death were analysed.

RESULTS

Among 313 SSc patients, 91 deaths occurred between April 2000 and September 2020. Overall 5 and 10 year survival rates were 88.4% and 80.2%, respectively. SSc was the most common primary cause of death (n = 35) and interstitial lung disease (ILD) was the most common SSc-related cause of death (n = 13). Moreover, 52% of the patients with diffuse SSc and 33% of those with limited cutaneous SSc died as a result of SSc itself. Patients who died because of SSc were significantly younger [mean ± sd age 65.6 ± 12.7 years, 95% confidence interval (CI) 61.2-70.1] than those who died from other causes (74.2 ± 9.6 years, 95% CI 71.5-76.9) (p = 0.0006). ILD, pulmonary arterial hypertension, gastrointestinal involvement, male gender, and older age at disease onset predicted death.

CONCLUSION

The disease itself was the major cause of death among Finnish SSc patients, in both diffuse and limited forms of SSc.

Systemic sclerosis: changes in the incidence rates in the Finnish population during the years 1999-2018

OBJECTIVE

The aim of our study was to examine changes in the incidence of systemic sclerosis (SSc) in Finland using two different classification criteria.

METHOD

Medical records of patients who had been registered with ICD-10 code M34 from 1999 to 2018 in two university hospitals were reviewed retrospectively. This period was divided into 5 year periods: 1999-2003, 2004-2008, 2009-2013, and 2014-2018. Using American College of Rheumatology (ACR)/European League Against Rheumatism (EULAR) 2013 criteria and clinical findings, we reclassified patients into four groups: diffuse SSc, limited SSc, sine SSc, or early SSc. In the same population, we also investigated whether the ACR 1980 criteria were fulfilled.

RESULTS

In 1999-2018, 246 new patients with SSc and 45 patients with early SSc were identified using ACR/EULAR 2013 criteria. Of these patients, 70 fulfilled the ACR 1980 criteria. Using ACR/EULAR 2013 criteria, the increase in new diagnoses was statistically significant when comparing the fourth period with the first period (p = 0.0012). The increase was due to a rise in limited SSc. Mean annual incidence rates in these groups were 0.9, 1.2, 1.9, and 2.8 per 100 000 inhabitants ≥ 16 years old. An increasing trend was also seen when using ACR 1980 criteria, but this was not statistically significant.

CONCLUSION

The incidence of SSc increased during the period between 1999-2003 and 2014-2018 using ACR/EULAR 2013, but not using ACR 1980 criteria. The increase was detected within a limited SSc subclass, owing to more sensitive classification criteria.

Differential diagnostics of polymyalgia rheumatica in a university hospital in Finland

OBJECTIVES

Diagnosing polymyalgia rheumatica (PMR) can be difficult as many conditions present with similar symptoms and findings. This study aimed to analyse how often the diagnosis of PMR changes during follow-up in a university hospital setting and to determine the most common clinical conditions initially misdiagnosed as PMR.

METHOD

All patients with a new primary diagnosis of PMR on at least one visit during the years 2016-2019 were identified from the hospital discharge register of Turku University Hospital, Finland. A diagnosis of PMR was confirmed if the patient met at least one of the five classification criteria, complete clinical follow-up (median 34 months) was compatible with PMR, and no other diagnosis better explained their condition.

RESULTS

Of the patients initially diagnosed with PMR, 65.5% were considered to have PMR after further evaluation and clinical follow-up. The most common conditions initially diagnosed as PMR were inflammatory arthritides (34.9%), degenerative or stress-related musculoskeletal disorders (13.2%), infection (9.3%), malignancy (9.3%), giant cell vasculitis (6.2%) and other vasculitis (6.2%), and a wide range of other less common diseases. The diagnosis of PMR remained in 81.3% of patients who fulfilled the 2012 American College of Rheumatology/European League Against Rheumatism PMR classification criteria and in 45.5% of patients who did not.

CONCLUSIONS

Diagnosing PMR is challenging, even in a university hospital. One-third of the initial diagnoses of PMR changed during further evaluation and follow-up. There is a substantial risk of misdiagnosis, especially in patients with atypical presentation, and the differential diagnoses of PMR must be considered carefully.

Real-world registry-based study on apremilast use in psoriasis and psoriatic arthritis in Finland

OBJECTIVES

This study assessed the position of apremilast in the treatment pathway of psoriasis (PsO) and psoriatic arthritis (PsA) in Finnish clinical practice, compared the characteristics of apremilast and biologic therapy users, evaluated persistence with apremilast and identified factors influencing treatment discontinuation.

METHOD

This retrospective study used data from Finnish national health registries. The target group was identified based on L40* diagnosis and medication records between 2015 and 2018. Treatment persistence was analysed using Kaplan-Meier curves and Cox regression.

RESULTS

Of eligible patients (PsO 31 202; PsA 12 386), 1% (n = 471) used apremilast and 10% (n = 4214) biologics, apremilast users being older (mean age 55.9 vs 52.4 years, p < 0.001) with a higher Charlson comorbidity score (0.71 vs 0.54, p < 0.001). Most patients switched to apremilast from conventional synthetic therapy (PsO 75%; PsA 76%); 47% of patients remained on apremilast during the observation period (PsO 58%; PsA 42%). Most patients discontinuing apremilast switched to biologics (PsO 51%; PsA 51%). Apremilast persistence increased with age (p = 0.042) and was higher in PsO than in PsA (median 14 vs 11 months; p = 0.005). Compared to prior conventional synthetic therapy, prior biologic therapy decreased persistence (hazard ratio for discontinuation 2.15, 95% confidence interval 1.42-3.25).

CONCLUSION

In Finnish clinical practice, apremilast is mainly used between conventional synthetic therapy and biologics, with at least as high treatment persistence as reported in previous studies. Apremilast users were older with higher comorbidity burden than biologics users.

The validity of rheumatoid arthritis diagnoses in Finnish biobanks

OBJECTIVE

The aim of this study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in Finnish biobanks.

METHOD

We reviewed the electronic medical records of 500 Finnish biobank participants: 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA, and 250 age- and gender-matched controls. The patients were chosen from five different biobank hospitals in Finland. A rheumatologist reviewed the medical records to assess whether each patients' diagnosis was correct. The diagnosis was compared with the diagnostic codes in the Finnish Care Register for Health Care (CRHC) and special reimbursement data of the Social Insurance Institution of Finland.

RESULTS

The positive predictive value (PPV) of CRHC diagnosis of RA (for seropositive and seronegative RA combined) was 0.82. For patients with a special reimbursement for anti-rheumatic medications for RA, the PPV was 0.89. The PPV was higher in patients with more than one visit. For one, two, five, and 10 visits, the PPV was 0.82, 0.85, 0.89, and 0.90, respectively, and for patients who also had the special reimbursement, the PPV was 0.89, 0.91, 0.93, and 0.94 for one, two, five, and 10 visits, respectively. In patients positive for anti-citrullinated protein antibodies, the PPV was 0.98.

CONCLUSION

These results demonstrate that the validity of RA diagnoses in Finnish biobanks was good and can be further improved by including data on special reimbursement for medication, number of visits, and serological data.

The validity of systemic sclerosis diagnoses in two university hospitals in Finland

OBJECTIVE

This study aimed to determine the validity of systemic sclerosis (SSc) diagnoses in Finnish university hospitals.

METHOD

Electronic medical records for 385 patients with a registered diagnosis of SSc (ICD-10 code M34) in two Finnish university hospitals from 2008 to 2018 were reviewed to assess whether each patient's diagnosis was correct.

RESULTS

The positive predictive value (PPV) of a diagnosis of SSc was 0.66 when fulfilment of the 2013 American College of Rheumatology/European League Against Rheumatism (ACR/EULAR) classification criteria for SSc was required; the PPV was 0.75 if patients meeting the 2001 LeRoy and Medsger classification criteria for early SSc were also included. When a diagnosis of SSc was made in a department of rheumatology, the PPV was 0.78, and 0.90 when including patients with early SSc. For the more specific diagnosis of limited cutaneous SSc (lcSSc), the PPV was 0.80, and 0.95 when including early SSc. For an lcSSc diagnosis made in rheumatology, the PPV was 0.81, and 0.97 with early SSc included.

CONCLUSION

These results demonstrate that in these two Finnish university hospitals, the diagnostic validity of a diagnosis of SSc was good if it was diagnosed in the department of rheumatology. For a more specific diagnosis of lcSSc, the most prevalent form of SSc in Finland, the validity was good even when registered in any department.

POS1383 DIFFERENTIAL DIAGNOSTICS OF POLYMYALGIA RHEUMATICA IN A UNIVERSITY HOSPITAL IN FINLAND

Background

Polymyalgia rheumatica (PMR) is an inflammatory disease that causes muscle pain and morning stiffness, especially in the shoulders and hips. Diagnosing PMR can be difficult, as the diagnosis is mainly clinical without a definitive diagnostic test, and many symptoms and findings of PMR may also be present in other conditions. There is little recent data on differential diagnostics of PMR.

Objectives

The aim of our study was to analyse patients diagnosed with polymyalgia rheumatica (PMR) in Turku University Hospital in Finland and determine how often a competing diagnosis better explaining the patients’ symptoms was found during further evaluation and clinical follow-up. We also aimed to find out what are the most common conditions initially misdiagnosed as PMR.

Methods

All patients with a new primary diagnosis of PMR (International Classification of Diseases – 10th revision [ICD-10] code M35.3) on at least one (in- or outpatient) visit during years 2016–2019 were identified from the hospital discharge register of Turku University hospital in Finland. We did a chart review of the patient charts including the full clinical follow-up period (median 34 months). We studied how often the primary diagnosis of PMR changed after further diagnostic evaluation or during follow-up.

Results

In 125 (32.7%) of the 382 patients, the initial diagnosis of PMR changed during further diagnostic evaluation or follow-up. Most common diagnoses initially misdiagnosed as PMR were inflammatory arthritides 36.0% (45/125), degenerative or stress-related musculoskeletal disorder 12.8% (16/125), infection 9.6% (12/125), malignancy 9.6% (12/125), giant cell vasculitis 6.4% (8/125) and other vasculitis 6.4% (8/125) (Table 1). Diagnosis changed in 19% (39/207) of patients fulfilling the 2012 ACR/EULAR PMR classification criteria and in 49% (86/175) of patients who did not.

Table 1.

Demographic and clinical characteristics of the study sample.

Number of patients382Female (%)218 (57.1%)Age at diagnosis in years [IQR]70.0 [64.0–77.8]Follow-up in months [IQR]34.0 [21.0–49.0]Diagnosed in rheumatology (%)299 (79%)Treated in rheumatology (%)310 (81%)Nr. of visits [IQR]6.5 [3.0–12.0]Diagnosis changed during follow-up (%)125 (32.7%)Final diagnosis in 125 patients whose initial diagnosis of PMR changedInflammatory arthritides (%)45 (36.0%)Degenerative or stress-related musculoskeletal disorder (%)16 (12.8%)Infection (%)12 (9.6%)Malignancy (%)12 (9.6%)Giant cell vasculitis (%)8 (6.4%)Other vasculitis (%)8 (6.4%)Other rheumatological disease (%)7 (5.6%)Fibromyalgia or other chronic pain syndrome (%)4 (3.2%)Gout or other crystal arthropathy (%)2 (1.6%)Endocrinological disease (%)2 (1.6%)Other or unknown (%)14 (11.2%)

Continuous variables are expressed as medians with interquartile ranges, and categorical variables are described as counts with percentages.

Conclusion

In a university hospital setting, a third of initial diagnoses of PMR were changed during further evaluation and follow-up. Our findings highlight that thorough consideration of differential diagnosis is always essential when diagnosing PMR. Especially in patients with atypical presentation, there is a substantial risk for misdiagnosis.

Disclosure of Interests

Johanna Paltta: None declared, Saara Suuronen: None declared, Laura Pirilä Consultant of: Has received consulting fees from Novartis, UCB, Pfizer, Lilly, Roche, Sanofi, Abbvie, Bristol-Myers-Squibb, Jansen-Cilag, Celgene and MSD, all unrelated to this work, Antti Palomäki Speakers bureau: Has received a lecture fee from Pfizer and Sanofi, all unrelated to this work, Consultant of: Has received consulting fees from Pfizer, Amgen and Abbvie, all unrelated to this work

Immunogenicity of subcutaneous TNF inhibitors and its clinical significance in real-life setting in patients with spondyloarthritis

Key messages

Considerable proportion of patients with SpA have been immunized to the subcutaneous anti-TNF drug they are using. Concomitant use of MTX protects from immunization, whereas SASP does not. Patients with SpA using subcutaneous anti-TNF drugs can benefit from monitoring of the drug trough levels.

Abstract

Immunization to biological drugs can lead to decreased efficacy and increased risk of adverse effects. The objective of this cross-sectional study was to assess the extent and significance of immunization to subcutaneous tumor necrosis factor (TNF) inhibitors in axial spondyloarthritis (axSpA) patients in real-life setting. A serum sample was taken 1–2 days before the next drug injection. Drug trough concentrations, anti-drug antibodies (ADAb) and TNF-blocking capacity were measured in 273 patients with axSpA using subcutaneous anti-TNF drugs. The clinical activity of SpA was assessed using the Bath AS Disease Activity Index (BASDAI) and the Maastricht AS Entheses Score (MASES). ADAb were found in 11% of the 273 patients: in 21/99 (21%) of patients who used adalimumab, in 0/83 (0%) of those who used etanercept, in 2/79 (3%) of those who used golimumab and in 6/12 (50%) of those who used certolizumab pegol. Use of methotrexate reduced the risk of formation of ADAb, whereas sulfasalazine did not. Presence of ADAb resulted in decreased drug concentration and reduced TNF-blocking capacity. However, low levels of ADAb had no effect on TNF-blocking capacity and did not correlate with disease activity. The drug trough levels were below the consensus target level in 36% of the patients. High BMI correlated with low drug trough concentration. Patients with low drug trough levels had higher disease activity. The presence of anti-drug antibodies was associated with reduced drug trough levels, and the patients with low drug trough levels had higher disease activity. The drug trough levels were below target level in significant proportion of patients and, thus, measuring the drug concentration and ADAb could help to optimize the treatment in SpA patients.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00296-021-04955-8.

THU0561 PREDICTING LIVER TOXICITY CAUSED BY CONVENTIONAL SYNTHETIC DISEASE-MODIFYING ANTIRHEUMATIC DRUGS

Background:

Routine laboratory testing is recommended for early identification of toxicity during conventional synthetic disease modifying antirheumatic drug (csDMARD) treatment. Based on expert consensus, testing is recommended every 2–4 weeks for the first 3 moths and quarterly thereafter (1).

Objectives:

In addition to evaluating the incidence of alanine transaminase (ALT) elevations in rheumatoid arthritis (RA) patients initiated on 1–2 csDMARDs, we aimed to distinguish patterns in ALT levels to develop a model for identifying patients at high risk for liver toxicity.

Methods:

We identified RA patients who were initiated a new csDMARD course at the rheumatology clinic of Turku University Hospital in 2013–2019. Baseline and follow-up safety monitoring results were drawn from the electronic health record (EHR) data. Data on diagnoses and csDMARD initiation/cessation dates were manually confirmed from the EHR.

As the primary endpoint, we used ALT-elevations of more than twice the upper limit of reference range (women ≥ 70 U/l, men ≥ 100 U/l) within 6 months after treatment initiation. Intergroup differences were tested using Mann-Whitney test for continuous variables and the chi-square test or Fisher’s exact test (n<5) for categorical variables. Associations between different characteristics and the primary endpoint were tested using Cox proportional hazards regression.

Results:

We identified 2851 RA patients of whom 1017 initiated a new csDMARD course requiring laboratory monitoring. Of these, 860 patients (58.9 years, 68% women, 65% seropositive) were included in the analyses after excluding patients with missing laboratory results (n=148) or elevated ALT at baseline (n=9). Of the 860 patients, 220 initiated two csDMARDs simultaneously [99% sulfasalazine (SSZ) and methotrexate (MTX)]. Primary endpoint was reached in 55 of 860 (6.4%) patients, including 10 who initiated two csDMARDS. Of these 55 patients, primary endpoint was reached in 40 of 55 (73%) patients during first three follow-up tests. In 31 of 55 (56%) patients, including 3 initiators of 2 csDMARDs, elevated ALT led to csDMARD cessation during the first 6 months. In Cox proportional hazards model with age, sex, seropositivity, baseline ALT, and csDMARDs as the explanatory variables, only baseline ALT level [hazard ratio 1.56 per 1 SD increase, 95% confidence interval (CI) 1.30–1.88, p<0.001] was associated with incident ALT-elevations. Survival according to normalized baseline ALT is shown in Figure, where normalized ALT value of 1.0 refers to the upper limit of reference range (women 35 U/l, men 50 U/l).

Table.

Multivariable Cox proportional hazards model including the results of the first follow-up laboratory test. Only values before occurrence of primary endpoint were used (n=843).

CharacteristicHazard ratio (95% CI)P ValueAge (per year)1.00 (0.98-1.02)0.78Sex (male)0.50 (0.21-1.15)0.10Seronegativity0.88 (0.44-1.75)0.71Baseline ALT*1.72 (1.32-2.25)<0.001ALT / t (per 1 SD increase / 30 days)§1.33 (1.17-1.52)<0.001Methotrexate0.58 (0.22-1.52)0.27Sulfasalazine0.95 (0.38-2.35)0.91Azathioprine2.30 (0.48-11.13)0.30Leflunomide1.08 (0.23-5.16)0.92

*Normalized ALT according to sex-specific reference range;§Rate of change from baseline to 1stfollow-up test

Conclusion:

Most incident ALT elevations can be predicted before the first csDMARD dose. Patients with elevated ALT at baseline or a rising trend at first follow-up are at high risk for liver toxicity and benefit from frequent testing.

References:

[1]Saag KG et al. American College of Rheumatology 2008 recommendations for the use of nonbiologic and biologic disease-modifying antirheumatic drugs in rheumatoid arthritis. Arthritis Rheum 2008;59:762-84.

Disclosure of Interests:

Laura Kuusalo Consultant of: Gilead, Pfizer Finland, Speakers bureau: Abbvie, Orion, Pfizer Finland, Novartis, Sanofi, Mikko Venäläinen: None declared, Sofia Saranpää: None declared, Heidi Kirjala: None declared, Laura Elo: None declared, Laura Pirilä Consultant of: Novartis, MSD Finland, Roche, Bristol-Myers-Squibb, Pfizer Finland, Sanofi, Abbvie, Eli Lilly Finland, UCB Pharma, Janssen-Cilag, Mylan, Sandoz, Boerhinger-Ingelheim, Paid instructor for: Boehringer-Ingelheim, MSD Finland, Speakers bureau: Boehringer-Ingelheim, Pfizer Finland

AB1251 VALIDITY OF RHEUMATOID ARTHRITIS DIAGNOSES IN FINNISH BIOBANK PATIENTS

Background:

Finnish healthcare registers are used in medical research, but there is little data about the validity of these registers in rheumatology.

Objectives:

The aim of our study was to determine the validity of rheumatoid arthritis (RA) diagnoses in patients participating in the Finnish Biobanks.

Methods:

We reviewed the electronic patient charts of 125 patients with at least one visit with a diagnosis of seropositive RA, 125 patients with at least one visit with a diagnosis of seronegative RA and 250 age-and-sex matched controls. Patients were randomly selected from Finnish biobank participants. We evaluated whether the patients’ diagnosis of RA recorded in the hospital discharge registry at the participating hospital was correct according to chart review and expert opinion. In the control group it was investigated whether the diagnosis of RA was written in the patients’ chart, but the diagnosis code was not recorded.

Results:

The positive predictive value (PPV) of a single hospital registry diagnosis of seropositive RA was 0.74 but rose to 0.98 in patients with a special reimbursement for seropositive RA and 0.98 in anti-citrullinated protein antibody positive patients. For seronegative RA, the PPV of a diagnosis was 0.72 and in patients with a special reimbursement for seronegative RA 0.89. The PPV was higher in patients with more than one visit with the diagnosis: 0.92 if the patients had at least 5 visits with seropositive RA and 0.88 with at least 5 visits with seronegative RA. Negative predictive value for RA diagnosis was 0.99.

Conclusion:

These results demonstrate that the validity of RA diagnoses in healthcare registers can be markedly improved with data about special reimbursement for medication, number of visits and serological data.

Disclosure of Interests:

Antti Palomäki Consultant of: Pfizer, Speakers bureau: Pfizer, Sanofi, MSD, Johanna Paltta Consultant of: Lilly, Abbvie, Laura Pirilä Consultant of: Novartis, MSD Finland, Roche, Bristol-Myers-Squibb, Pfizer, Sanofi, Abbvie, Oy Eli LIlly Finland Ab, UCB Pharma Oy Finland, Jansen-Cilag, Mylan, Sandoz, Boehringer-Ingelheim, Paid instructor for: Boehringer -Ingelheim, MSD Finland, Speakers bureau: Boehringer-Ingelheim, Pfizer Finland, Hanna-Kaisa Heikkilä: None declared, Pia Isomäki Consultant of: Abbvie, BMS, Eli Lilly, MSD, Novartis, Pfizer, Roche, Sanofi, Johanna Huhtakangas Consultant of: Boehringer Ingelheim, Tuulikki Sokka-Isler: None declared, Oili Kaipiainen-Seppänen Speakers bureau: Boehringer Ingelheim, Kari Eklund Consultant of: Celgene, Lilly, Speakers bureau: Pfizer, Roche

Measuring the economic value of morning stiffness: consistency over 1 year

OBJECTIVES

The aims of this study were to determine the within-patient variation in the duration of morning stiffness (MS) over 1 year and the corresponding monetary equivalents assigned to its changes using the willingness-to-pay (WTP) methodology.

METHOD

A sample of 100 patients with rheumatoid arthritis (RA) was drawn from the register of the Hospital District of Southwest Finland. Subjects were interviewed by telephone on recruitment and 1 year later, using the same structured questionnaire. The subjects were asked to estimate in minutes the typical duration of their MS during the previous week. Sociodemographic background data and subjects' WTP for a 25, 50, 75, and 100% reduction in MS duration were requested, and years with RA diagnosis and serological data were obtained from hospital records.

RESULTS

After 1 year, there was a reduction in average MS duration from 44.7 min to 39.0 min (ns); duration was reduced in 35% of patients, unchanged in 35%, and prolonged in 30%. Changes in MS duration were reflected by within-patient variation in WTP estimates. In linear regression models, change in duration of MS significantly (p < 0.03) explained the variation in change of WTP for symptom reduction.

CONCLUSIONS

WTP methodology produces consistent monetary values to assess the relative values patients with RA place on reduction in duration of MS.

Syndecan-1 expression is upregulated in degenerating articular cartilage in a transgenic mouse model for osteoarthritis

OBJECTIVE

Mice heterozygous for the Del1 transgene locus with a short deletion mutation in the type II collagen gene develop early-onset degenerative changes in the knee joints that progress to end-stage osteoarthritis by the age of 12-15 months. This study focuses on the expression and distribution of syndecan-1, a cell-surface heparan sulfate proteoglycan, during the development of osteoarthritic cartilage degeneration, to better understand its role in this disease.

METHODS

Northern analyses of total RNA extracted from knee joints of transgenic Del1 mice and their nontransgenic controls were used to monitor changes in syndecan-1 mRNA levels during development, growth, ageing, and cartilage degeneration. Immunohistochemistry was used to study the distribution of syndecan-1 in the knee joints at different stages of cartilage degeneration.

RESULTS

Syndecan-1 mRNA was present in knee joints throughout life, with the highest mRNA levels in ageing knee joints. In Del1 mice, a transient upregulation of syndecan-1 mRNA synthesis was observed at the age of 6 months coinciding with early stages of cartilage degeneration and a period of attempted repair. Immunostaining for syndecan-1 was most intense in chondrocytes of superficial and intermediate zones of articular cartilage adjacent to defect areas. Chondrocyte clusters also stained strongly for syndecan-1.

CONCLUSION

The present temporospatial expression data on upregulation of syndecan-1 in articular cartilage during early stages of cartilage degeneration suggest that this molecule is involved in the attempted repair of cartilage fibrillations. Combined with the known role of syndecan-1 during skeletal development and wound healing, this interesting finding warrants further validation.

Identification of alpha6beta1 integrin positive cells in synovial lining layer as type B synoviocytes

OBJECTIVE

In rheumatoid arthritis (RA) the synovial lining is responsible for cartilage destruction. Laminin is one of the major matrix molecules surrounding the lining cells. We investigated the laminin adhesion mechanism of synovial lining cells by analyzing the presence of its receptor, alpha6beta1 integrin, on type A and type B synoviocytes.

METHODS

The alpha6 integrin subunit and a macrophage marker were simultaneously localized by immunohistochemistry in 29 RA derived, 6 osteoarthritis derived, and 2 healthy synovial samples by light and electron microscopy. We also used enzyme treatments to release cells from synovial tissue samples and localized the same antigens on adherent cells.

RESULTS

The alpha6beta1 integrin positive cells were localized in basal areas of the lining layer and many of them were negative for the macrophage markers. By immunolabeling electron microscopy the alpha6 integrin positive cells were confirmed to represent the fibroblast-like type B cells. Further, in freshly isolated synoviocyte cultures the type B cells were positive for alpha6 integrin, whereas all other cell types were negative for this laminin receptor.

CONCLUSION

Integrin alpha6beta1 is known to be a laminin receptor of endothelial cells, adipocytes, and macrophages, not usually expressed on fibroblasts. However, in synovial lining layer it is expressed on fibroblastic type B cells, but the macrophage population is negative. The unique characteristics of synovial lining cells distinguish them from other connective tissue cells and must be taken into account in all considerations of the pathogenic mechanisms of rheumatoid disease.

Expression of vitronectin and its integrin receptors in the synovial membrane-like interface tissue from aseptic loosening of total hip replacement

OBJECTIVE

To investigate expression of vitronectin (VN) and its integrin (Int) receptors in synovial membrane-like interface tissue (SMLIT) in aseptic loosening of total hip replacement (THR), and the potential role of VN-Int interaction in production of collagenase-3.

METHODS

Avidin-biotin-peroxidase complex (ABC) staining was used to detect distribution of VN and Int alphaV, beta3, and beta5 subunits. Immunofluorescence labeling with FITC and TRITC conjugated IgG was used to localize Int beta3 subunit and matrix metalloproteinase (MMP-13) double positive cells in SMLIT.

RESULTS

Intensive VN immunoreactivity was found in the lining-like layers, sublining area, and endothelium of SMLIT. Statistical analysis of the VN staining score revealed a significant difference between SMLIT and control synovial membrane. All 3 Int subunits appeared in the lining-like layers and sublining area. The Int beta3 subunit was also detected in giant cells of SMLIT. Int beta5 subunit staining was relatively weak and rarely found in vascular endothelium. Immunofluorescence labeling showed many double positive cells in the lining-like layer and sublining area of SMLIT.

CONCLUSION

Expressions of VN and Int alphaVbeta3 and alphaVbeta5 are increased in SMLIT compared with that in OA synovial membrane. Int alphaVbeta3 engagement with VN might play a potential role in local MMP-13 production in SMLIT.

Expression of the myc-family proto-oncogenes and related genes max and mad in synovial tissue

OBJECTIVE

To examine the expression of myc proto-oncogenes; c-myc, L-myc, and N-myc, and their related genes max and mad, in the arthritic synovium.

METHODS

Using reverse transcription-polymerase chain reaction (RT-PCR), Northern and Southern hybridizations, the expression of these genes in the synovial tissue from rheumatoid arthritis (RA) and osteoarthritis (OA) was analyzed. Synovial specimens from cadavers without any joint disease and peripheral blood mononuclear cells (PBMC) from healthy individuals served as controls.

RESULTS

As a novel finding, synovial cells were observed to express L-myc, N-myc as well as their related genes max and mad, in addition to the previously described presence of c-myc proto-oncogene in synovium. c-myc, L-myc, N-myc, and mad were expressed in all patient samples studied, including the controls. Instead, max was detected in only 10/12 of RA patients, in 11/13 of OA patients, and in all controls (4/4 cadavers, 5/5 blood donors). Six patients with RA revealed positive signals for max only after hybridization. The same was also true of two patients with OA and of one healthy individual donating blood.

CONCLUSIONS

The L-myc, N-myc, max, and mad genes are expressed in synovial cells, in addition to c-myc proto-oncogene. However, expression of these genes is not disease-specific, since they were equally expressed in synovial samples from patients with RA or OA as well as from cadavers representing controls without any joint disease.

Expression of laminins and their integrin receptors in different conditions of synovial membrane and synovial membrane-like interface tissue

OBJECTIVE

To demonstrate the expression of laminins (Lns) and their integrin (Int) receptors in different synovial samples and synovial membrane-like interface tissues from well fixed and aseptically loosened total hip replacement (THR), and the potential role of Ln-Int interaction in the production of collagenases and cytokines.

METHODS

Immunohistochemical staining was done to detect the distribution of EHS Ln, Ln alpha2, alpha3, alpha5, beta1, beta2 chains and Int alpha1, alpha2, alpha3, alpha6, beta1, beta4 subunits in different samples. Double immunofluorescence labelling was used to find colocalisation of Int alpha6 subunit and collagenase-1/collagenase-3/TNFalpha/IL6.

RESULTS

General Ln immunoreactivity was detected in all specimens. Ln alpha5, beta1 and beta2, but not alpha2 and alpha3 chains were seen in the synovial lining and the basement membrane of blood vessels with the intensity/extent of labelling in the following rank order: rheumatoid arthritis (RA) loosened prostheses, osteoarthritis, well fixed prostheses, traumatic knees. Among Int subunits, staining for beta1 was usually the strongest, followed by staining for Int alpha6, alpha1, alpha3, and alpha2 subunits, with the same rank order for overall expression of Lns. Int beta4 subunit was not detectable in most of the specimens. Double labelling focused on Int alpha6 subunit disclosed its frequent colocalisation with collagenases 1 and 3 and with tumour necrosis factor alpha and interleukin 6 in synovial lining.

CONCLUSION

Synovial lining contains Ln-10, Ln-11, and Int alpha6beta1 and alpha1beta1 receptors. In aseptic loosening of THR, interface tissue has a similar Ln subtype and Int receptor composition as RA synovium, which confirms its "lining-like" phenotype. Synovial lining does not contain Ln-5 (alpha3beta3gamma2) or Int alpha6beta4, which are components of epithelial hemidesmosomes. The expression of Lns and their Int receptors is upregulated in inflammation. The close spatial relation between Ln and its Int receptors in synovial lining cells containing proteinases and cytokines suggests a potential role in joint destruction and prosthetic loosening.

H-ras oncogene point mutations in arthritic synovium

OBJECTIVE

To examine mutational activation of ras proto-oncogenes in synovial tissue from patients with rheumatoid arthritis (RA) compared with synovial specimens from patients with osteoarthritis (OA) or other arthropathies. Synovial samples from cadavers, without any signs of joint disease, were used as control material.

METHODS

Using a combination of polymerase chain reaction (PCR) and automated sequencing of the amplified PCR product, regions around codons 12, 13, and 61 of the H-, K-, and N-ras proto-oncogenes were analyzed. Confirmation of mutations was based on restriction fragment length polymorphism analysis and/or oligonucleotide hybridization.

RESULTS

Four (6%) of 72 patients with RA, 2 (13%) of 16 with OA, and 1 (8%) of 12 with other arthropathies harbored mutant H-ras proto-oncogenes, and were heterozygous at codon 13 for the GGT-->GAT (Gly-->Asp) change. An unexpected mutation was found in the H-ras gene, in which a heterozygous GTG-->ATG (Val-->Met) mutation was observed over codon 14. The incidence for this mutation was 39% (28 of 72) in RA patients, 94% (15 of 16) in OA patients, and 42% (5 of 12) in patients with other arthropathies. All samples carrying the codon 13 mutation of H-ras were also codon 14-mutated, i.e., double mutations existed. Identical point mutations were also detected in a few synovial specimens obtained from cadavers (n = 8), including a single case of double mutation. All specimens showed normal K- and N-ras loci.

CONCLUSION

Activation of proto-oncogene H-ras by point mutation in codons 13 and 14 occurred in the synovial tissue of patients with RA, OA, or other arthropathies, as well as, to some extent, in the control synovia, indicating that the phenomenon is not specific for RA. In codon 14, incidence of the H-ras point mutation was highest in OA tissue. The possible significance of this codon 14-mutated H-ras gene needs to be clarified.

Bone morphogenetic protein-2 is a regulator of cell adhesion

Bone morphogenetic proteins (BMPs) are a group of peptide growth factors closely related to transforming growth factors-beta. The BMPs are suggested to play an essential role in bone development and they are strong candidate molecules to be used clinically to improve fracture healing. BMPs are also involved in the differentiation of several other tissues during embryogenesis. Here, we show that human recombinant BMP-2 regulates cell-matrix interactions by modifying the expression of integrin-type receptors. The synthesis of alpha3 integrin was down-regulated by BMP-2 in two osteogenic sarcoma-derived cell lines, Saos-2 and HOS, and also in human fetal chondrocytes. BMP-2 had no effect on the expression of alpha1, alpha2, alpha5, alpha6, and alphaV integrins. BMP-2 reduced the expression of alpha3 integrin subunit at mRNA level. Laminin-5 was shown to be the ligand for alpha3beta1 integrin on Saos cells and BMP-2 decreased the ability of Saos cells to attach to it. These results suggest that BMP-2 has a specific effect on the alpha3beta1 integrin-mediated cell adhesion to laminin-5. Given the fact that BMP-2 is expressed in osteosarcomas, in addition to in bone, this mechanism is putatively important especially in bone development and tumors. We also studied the effect of BMP-2 on a human keratinocyte cell line, HaCaT. In HaCaT cells, the expression of alpha2 integrin was strongly down-regulated by BMP-2, whereas its effect on the expression of alpha3 integrin was smaller. We suggest that the effects of BMP-2 may be partially mediated by specifically altered cell adhesion.

Altered integrin expression in rheumatoid synovial lining type B cells: in vitro cytokine regulation of alpha 1 beta 1, alpha 6 beta 1, and alpha v beta 5 integrins

OBJECTIVE

We recently showed that in rheumatoid arthritis (RA) the extracellular matrix around the lining cells is similar to the matrix seen in osteoarthritis, whereas the cellular adhesion apparatus is very different. In hyperplastic synovial membrane there is very little of alpha 6, alpha v, and beta 5 integrin subunits, whereas in noninflammatory synovial membrane these integrins are well expressed. We studied how expression of these cell adhesion molecules is regulated in RA in vitro.

METHODS

The integrin expression in 6 different synovial fibroblast strains representing the type B cells and in THP-1 cell line was examined by immunoprecipitation, flow cytometry, and Northern hybridization.

RESULTS

Proinflammatory cytokines, especially interleukin 1 beta, increased the expression of alpha 1 integrin in synovial fibroblasts. When the monocyte-like THP-1 cells were induced to differentiate to adherent macrophages they started to express alpha 6 and beta 5 integrin subunits. In adherent THP-1 cells the expression of integrin alpha 6 subunit was strongly enhanced by transforming growth factor-beta and downregulated by the combination of tumor necrosis factor-alpha and interferon-gamma.

CONCLUSION

Cytokines regulate the cell adhesion molecules of synovial fibroblasts and mononuclear phagocytes in vitro causing alterations in integrin expression similar to the ones seen in rheumatoid synovium in vivo.

Oncoprotein expression in human synovial tissue: an immunohistochemical study of different types of arthritis

Based on the fact that synovial lining cells have some properties of transformed-appearing cells, we have examined the expression of Myc, Myb, Fos, Jun and Ras oncoproteins in synovial tissues from patients with different types of arthritis. Formalin-fixed and paraffin-embedded sections of synovial tissue from 12 patients with rheumatoid arthritis (RA), 14 with reactive arthritis (ReA), nine with other seronegative arthritis (OSA), seven with bacterial arthritis (BA), eight with probable bacterial arthritis (PBA) and eight with osteoarthritis (OA) were studied using the immunoperoxidase staining technique. The oncoproteins studied were expressed both in the synovial lining layer and in the sublining layer, consisting of lymphocytes, other inflammatory cells and blood vessels. Among the six disease entities, RA and OA appeared to be the most distinct, whereas the results obtained for ReA and OSA, and on the other hand for BA and PBA, closely resembled each other. The expression of Myc, Myb, Fos and Jun was significantly correlated both to the degree of synovial hypercellularity and the synovial lymphocytic infiltration. For Ras, such a correlation could not be seen. We conclude that we find no evidence of a cell lineage-specific or a disease-specific abnormality of proto-oncogene products in RA, and the expression of these oncoproteins is consistent with inflammation rather than with any primary abnormality of cell growth.

Effects of liposomal antisense oligonucleotides on mRNA and protein levels of the HPV 16 E7 oncogene

Despite the known association of human papillomavirus (HPV) infection with cervical cancer there is no specific antiviral treatment for HPV infection. Antisense oligode-oxynucleotides (AS-ODNs) may offer an effective way to treat HPV infections as the stability and delivery have been improved using modified ODNs or carrier systems. In this study we investigated the effects of liposomal AS-ODNs (0.1, 1 and 5 microM) on HPV 16 E7 mRNA and protein levels in CaSki cells. We used cationic liposomes (10 microM) containing dimethyldioctadecylammonium bromide (DDAB) or 2,3-dioleyloxy-N-[2(sperminecar-boxamido)ethyl]-N, N-dimethyl-1-propanaminium trifluoroacetate (DOSPA). Both these liposomes had dioleoylphosphatidyl-ethanolamine (DOPE) as a helper lipid. The target of the AS-ODNs was E7 protein because it is the one of the two oncoproteins of HPV 16. Only liposomal AS-ODNs which were targeted to the initiation codon of E7, had an effect on E7 mRNA expression; two shorter transcripts were detected, suggesting that RNase H degradation was activated. Liposomal random ODN or liposomal ODN targeted downstream from the initiation site of E7 did not affect the mRNA pattern. However, no change was found in the E7 protein levels detected by immunoprecipitation. Further studies showed that AS-ODNs inhibited the translation of E7 mRNA in a rabbit reticulocyte lysate assay. This data, together with the changes in mRNA levels, proved that the AS-ODNs reached the target mRNA. One possible explanation for the unchanged protein level of E7 in CaSki cells might be that immunoprecipitation is not sensitive enough to detect minor changes in protein levels. However, further progress is still needed in the field of carrier systems and modifications of AS-ODNs before non-sequence specific effects can be avoided.