Handheld x-ray fluorescence spectroscopy evaluation of leather chromium and cobalt

We present a 29-year-old non-atopic male apprentice power lineman and recreational cowboy with a case of allergic contact dermatitis due to both occupational and recreational exposure. He presented with a 4-month history of a pruritic, steroid-responsive, intermittent hand, foot and leg dermatitis. Patch testing was positive for chromium, cobalt and a piece of leather from his cowboy boots. His leather work gloves, inner lining of work harness, work boots and cowboy boots were assessed for chromium and cobalt content with handheld fluorescence x-ray spectrometry. Upon replacement of all leather items including the items tested and his leather cowboy saddle, the rash resolved. This case demonstrates the clinical relevance of using a handheld fluorescence x-ray spectrometer to assess for chromium and leather content.

Biomarkers of Checkpoint Inhibitor Induced Immune-Related Adverse Events-A Comprehensive Review

Immune checkpoint inhibitors (ICIs) have substantially improved the prognosis of patients with different types of cancer. Through blockade of cytotoxic T-lymphocyte antigen 4 (CTLA-4) and programmed cell death protein 1 (PD-1), negative feedback mechanisms of the immune system are inhibited, potentially resulting in very durable anti-tumor responses. Despite their promise, ICIs can also elicit auto-immune toxicities. These immune-related adverse events (irAEs) can be severe and sometimes even fatal. Therefore, being able to predict severe irAEs in patients would be of added value in clinical decision making. A search was performed using “adverse events”, “immune checkpoint inhibitor”, “biomarker”, and synonyms in PubMed, yielding 3580 search results. After screening title and abstract on the relevance to the review question, statistical significance of reported potential biomarkers, and evaluation of the remaining full papers, 35 articles were included. Five additional reports were obtained by means of citations and by using the similar article function on PubMed. The current knowledge is presented in comprehensive tables summarizing blood-based, immunogenetic and microbial biomarkers predicting irAEs prior to and during ICI therapy. Until now, no single biomarker has proven to be sufficiently predictive for irAE development. Recommendations for further research on this topic are presented.

The end of the laboratory developed test as we know it? Recommendations from a national multidisciplinary taskforce of laboratory specialists on the interpretation of the IVDR and its complications

The in vitro diagnostic medical devices regulation (IVDR) will take effect in May 2022. This regulation has a large impact on both the manufacturers of in vitro diagnostic medical devices (IVD) and clinical laboratories. For clinical laboratories, the IVDR poses restrictions on the use of laboratory developed tests (LDTs). To provide a uniform interpretation of the IVDR for colleagues in clinical practice, the IVDR Task Force was created by the scientific societies of laboratory specialties in the Netherlands. A guidance document with explanations and interpretations of relevant passages of the IVDR was drafted to help laboratories prepare for the impact of this new legislation. Feedback from interested parties and stakeholders was collected and used to further improve the document. Here we would like to present our approach to our European colleagues and inform them about the impact of the IVDR and, importantly we would like to present potentially useful approaches to fulfill the requirements of the IVDR for LDTs.

Mixed occupational and iatrogenic allergic contact dermatitis in a hairdresser

Allergic contact dermatitis (ACD) is a common occupational disease. Hairdressers and beauticians are at increased risk of occupational chronic hand eczema. We present a case of mixed occupational, non-occupational and iatrogenic ACD in a hairdresser which illustrates that delayed diagnosis can result in high morbidity, and unnecessary treatment and cost. A hairdresser with chronic hand and facial eczema failed medical management with topical steroids and dupilumab. Patch testing revealed contact allergy to multiple occupational exposures, home exposures and topical medicaments.

Frequencies and clinical associations of myositis-related antibodies in The Netherlands: A one-year survey of all Dutch patients

Idiopathic inflammatory myopathies (IIM) are a heterogeneous group of connective tissue diseases, collectively known as myositis. Diagnosis of IIM is challenging while timely recognition of an IIM is of utter importance considering treatment options and otherwise irreversible (severe) long-term clinical complications. With the EULAR/ACR classification criteria (2017) considerable advancement has been made in the diagnostic workup of IIM. While these criteria take into account clinical parameters as well as presence of one autoantibody, anti-Jo-1, several autoantibodies are associated with IIM and are currently evaluated to be incorporated into classification criteria. As individual antibodies occur at low frequency, the development of line blots allowing multiplex antibody analysis has improved laboratory diagnostics for IIM. The Euroline myositis line-blot assay (Euroimmun) allows screening and semi-quantitative measurement for 15 autoantibodies, i.e. myositis specific antibodies (MSA) to SRP, EJ, OJ, Mi-2α, Mi-2β, TIF1-γ, MDA5, NXP2, SAE1, PL-12, PL-7, Jo-1 and myositis associated antibodies (MAA) to Ku, PM/Scl-75 and PM/Scl-100. To evaluate the clinical significance of detection and levels of these autoantibodies in the Netherlands, a retrospective analysis of all Dutch requests for extended myositis screening within a 1 year period was performed. A total of 187 IIM patients and 632 non-IIM patients were included. We conclude that frequencies of MSA and MAA observed in IIM patients in a routine diagnostic setting are comparable to cohort-based studies. Weak positive antibody levels show less diagnostic accuracy compared to positive antibody levels, except for anti-NXP2. Known associations between antibodies and skin involvement (anti-MDA5, anti-TIF1-γ), lung involvement (anti-Jo-1), and malignancy (anti-TIF1-γ) were confirmed in our IIM study population. The availability of multiplex antibody analyses will facilitate inclusion of additional autoantibodies in clinical myositis guidelines and help to accelerate diagnosing IMM with rare but specific antibodies.

The clinical spectrum and incidence of anti-MOG-associated acquired demyelinating syndromes in children and adults

Objectives:

The aim of this study was to assess the Dutch nationwide incidence of myelin oligodendrocyte glycoprotein (MOG)-IgG-associated acquired demyelinating syndromes (ADS) and to describe the clinical and serological characteristics of these patients.

Methods:

All serum samples for routine diagnostics from February 2014 to December 2017 were sent to the single central reference laboratory for the full-length MOG-IgG cell-based assay (CBA) in the Netherlands. Clinical data from patients known in our National ADS centre were available.

Results:

A total of 1414 samples of 1277 patients were received; of these, 92 patients (7%) were MOG-IgG-seropositive. The mean incidence was 0.16/100,000 people, with higher seropositivity in children (0.31/100,000) than in adults (0.13/100,000). In MOG-IgG-positive patients at the National ADS centre (61/92, 66%), the most common presenting phenotype is acute disseminated encephalomyelitis (ADEM, 56%) in children and optic neuritis (ON, 44%) in adults. Relapsing disease occurred in 9/34 (26%) children and 11/27 (41%) adults during median follow-up of 27.5 months. Patients were tested MOG-IgG-positive >200 months after the initial attack, suggesting an extended time to first relapse (TTFR). Longitudinal analysis of MOG-IgG (25/61, 41%) showed that 67% of the monophasic patients remain seropositive and 60% in relapsing patients. Majority of seronegative patients had no relapses (89%).

Conclusion:

This nationwide study shows that the overall incidence of MOG-IgG-seropositive disorders is 0.16 per 100,000 people. The distribution over the clinical phenotypes differs between adults and children. Seropositivity can be maintained over years even without clinical activity, while seronegative patients generally had no relapses.

High voltage fragmentation of composites from secondary raw materials - Potential and limitations

The comminution of composites for liberation of valuable components is a costly and energy-intensive process within the recycling of spent products. It therefore is continuously studied and optimized. In addition to conventional mechanical comminution innovative new principles for size reduction have been developed. One is the use of high voltage (HV) pulses, which is known to be a technology selectively liberating along phase boundaries. This technology offers the advantage of targeted liberation, preventing overgrinding of the material and thus improving the overall processing as well as product quality. In this study, the high voltage fragmentation of three different non-brittle composites (galvanized plastics, carbon fibre composites, electrode foils from Li-ion batteries) was investigated. The influence of pulse rate, number of pulses and filling level on the liberation and efficiency of comminution is discussed. Using the guideline VDI 2225 HV, fragmentation is compared to conventional mechanical comminution with respect to numerous criteria such as cost, throughput, energy consumption, availability and scalability. It was found that at current state of development, HV fragmentation cannot compete with mechanical comminution beyond laboratory scale.

Clinically relevant discrepancies between different rheumatoid factor assays

Background:

Accurate measurements of rheumatoid factors (RFs), autoantibodies binding IgG, are important for diagnosing rheumatoid arthritis (RA) and for predicting disease course. Worldwide, various RF assays are being used that differ in technique and target antigens. We studied whether assay choice leads to clinically important discrepancies in RF status and level.

Methods:

RF measurements using four commercial RF assays were compared in 32 RF+ samples. Using enzyme-linked immunosorbent assays (ELISAs), the influence of the target antigen source – human IgG (hIgG) versus rabbit IgG (rIgG) – on measured RF levels was investigated in arthralgia patients and RA patients.

Results:

Substantial discrepancies were found between RF levels measured in the four commercial assays. Six samples (19%) with RF levels below or slightly above the cutoff in the rIgG-based Phadia assay were RF+ in three assays using hIgG as the target antigen, some with very high levels. Direct ELISA comparisons of RF reactivity against hIgG and rIgG estimated that among 173 ACPA+ arthralgia patients, originally RF negative in rIgG-based assays, up to 10% were single positive against hIgG. Monoclonal RFs binding to hIgG and rIgG or hIgG only supported these findings. In a cohort of 69 early RA patients, virtually all RF responses reacted with both targets, although levels were still variable.

Conclusions:

The use of RF assays that differ in technique and target antigen, together with the different specificities of RF responses, leads to discrepancies in RF status and levels. This has important consequences for patient care if RA diagnosis and disease progression assessments are based on RF test results.

Comprehensive approach to study complement C4 in systemic lupus erythematosus: Gene polymorphisms, protein levels and functional activity

Genetic variation of the genes encoding complement component C4 is strongly associated with systemic lupus erythematosus (SLE), a chronic multi-organ auto-immune disease. This study examined C4 and its isotypes on a genetic, protein, and functional level in 140 SLE patients and 104 healthy controls. Gene copy number (GCN) variation, silencing CT-insertion, and the retroviral HERV-K(C4) insertion) were analyzed with multiplex ligation-dependent probe amplification. Increased susceptibility to SLE was found for low GCN (≪2) of C4A. Serositis was the only clinical manifestation associated with low C4A GCN. One additional novel silencing mutation in the C4A gene was found by Sanger sequencing. This mutation causes a premature stop codon in exon 11. Protein concentrations of C4 isoforms C4A and C4B were determined with ELISA and were significantly lower in SLE patients compared to healthy controls. To study C4 isotypes on a functional level, a new C4 assay was developed, which distinguishes C4A from C4B by its binding capacity to amino or hydroxyl groups, respectively. This assay showed high correlation with ELISA and detected crossing over of Rodgers and Chido antigens in 3.2% (8/244) of individuals. The binding capacity of available C4 to its substrates was unaffected in SLE. Our study provides, for the first time, a complete overview of C4 in SLE from genetic variation to binding capacity using a novel test. As this test detects crossing over of Rodgers and Chido antigens, it will allow for more accurate measurement of C4 in future studies.

Therapeutic drug monitoring of infliximab: performance evaluation of three commercial ELISA kits

BACKGROUND

Therapeutic drug monitoring (TDM) of infliximab (IFX, Remicade®) can aid to optimize therapy efficacy. Many assays are available for this purpose. However, a reference standard is lacking. Therefore, we evaluated the analytical performance, agreement and clinically relevant differences of three commercially available IFX ELISA kits on an automated processing system.

METHODS

The kits of Theradiag (Lisa Tracker Infliximab), Progenika (Promonitor IFX) and apDia (Infliximab ELISA) were implemented on an automated processing system. Imprecision was determined by triplicate measurements of patient samples on five days. Agreement was evaluated by analysis of 30 patient samples and four spiked samples by the selected ELISA kits and the in-house IFX ELISA of Sanquin Diagnostics (Amsterdam, The Netherlands). Therapeutic consequences were evaluated by dividing patients into four treatment groups using cut-off levels of 1, 3 and 7 μg/mL and determining assay concordance.

RESULTS

Within-run and between-run imprecision were acceptable (≤12% and ≤17%, respectively) within the quantification range of the selected ELISA kits. The apDia assay had the best precision and agreement to target values. Statistically significant differences were found between all assays except between Sanquin Diagnostics and the Lisa Tracker assay. The Promonitor assay measured the lowest IFX concentrations, the apDia assay the highest. When patients were classified in four treatment categories, 70% concordance was achieved.

CONCLUSIONS

Although all assays are suitable for TDM, significant differences were observed in both imprecision and agreement. Therapeutic consequences were acceptable when patients were divided in treatment categories, but this could be improved by assay standardization.

Comparisons of Serum Infliximab and Antibodies-to-Infliximab Tests Used in Inflammatory Bowel Disease Clinical Trials of Remicade®

Monitoring infliximab (IFX) concentrations and antibodies-to-IFX (ATI) titers during inflammatory bowel disease treatment may allow more informed decisions in assessing exposure/response and determining appropriate dosing. To aid in interpreting results from different commercial tests in the context of Janssen's published Remicade® results, the reliability of Janssen's IFX and ATI assays was compared with commercial assays from KU Leuven, Sanquin, Dynacare, and LabCorp. Test results were independently reported to Janssen. All assays were tested for specificity, selectivity, and precision. ATI assays were evaluated for sensitivity, drug interference, and potential interference of tumor necrosis factor-alpha (TNF-α). IFX assays were specific, accurate, and reproducible. Intra-class correlation of Janssen IFX assay results with those from KU Leuven, Sanquin, Dynacare, and LabCorp were 0.960, 0.895, 0.931, and 0.971, respectively. ATI titers >10 interfered with IFX assessment in all IFX assays, whereas TNF-α (≤50 ng/mL) did not interfere with IFX detection in any assay. ATI assays specifically and reproducibly detected ATI. Janssen, Sanquin, and LabCorp ATI methods were more resistant to IFX interference than Dynacare and KU Leuven, which were affected by IFX concentrations at ≥2 μg/mL. TNF-α (<5 ng/mL) did not interfere with ATI detection. Strong agreement was observed between Janssen's IFX and ATI assays and the diagnostic service provider assays. Our study results indicate that all four commercially available assays are suitable for therapeutic drug monitoring of IFX. The substantial agreement reported here between the comparator assays and the Janssen drug-tolerant assay provides support to clinicians in their use of these commercial assays, and for understanding their patients' IFX and ATI results relative to published data from clinical studies of Remicade.

Multicentre comparison of a diagnostic assay: aquaporin-4 antibodies in neuromyelitis optica

OBJECTIVE

Antibodies to cell surface central nervous system proteins help to diagnose conditions which often respond to immunotherapies. The assessment of antibody assays needs to reflect their clinical utility. We report the results of a multicentre study of aquaporin (AQP) 4 antibody (AQP4-Ab) assays in neuromyelitis optica spectrum disorders (NMOSD).

METHODS

Coded samples from patients with neuromyelitis optica (NMO) or NMOSD (101) and controls (92) were tested at 15 European diagnostic centres using 21 assays including live (n=3) or fixed cell-based assays (n=10), flow cytometry (n=4), immunohistochemistry (n=3) and ELISA (n=1).

RESULTS

Results of tests on 92 controls identified 12assays as highly specific (0-1 false-positive results). 32 samples from 50 (64%) NMO sera and 34 from 51 (67%) NMOSD sera were positive on at least two of the 12 highly specific assays, leaving 35 patients with seronegative NMO/spectrum disorder (SD). On the basis of a combination of clinical phenotype and the highly specific assays, 66 AQP4-Ab seropositive samples were used to establish the sensitivities (51.5-100%) of all 21 assays. The specificities (85.8-100%) were based on 92 control samples and 35 seronegative NMO/SD patient samples.

CONCLUSIONS

The cell-based assays were most sensitive and specific overall, but immunohistochemistry or flow cytometry could be equally accurate in specialist centres. Since patients with AQP4-Ab negative NMO/SD require different management, the use of both appropriate control samples and defined seronegative NMOSD samples is essential to evaluate these assays in a clinically meaningful way. The process described here can be applied to the evaluation of other antibody assays in the newly evolving field of autoimmune neurology.

Incidence of AQP4-IgG seropositive neuromyelitis optica spectrum disorders in the Netherlands: About one in a million

Neuromyelitis optica (NMO) is a rare autoimmune disease affecting the optic nerves and spinal cord. In the majority of NMO patients anti-aquaporin-4 antibodies (AQP4-IgG) are detected. Here we assessed a nationwide incidence of AQP4-IgG-seropositive NMO spectrum disorders (NMOSD) in the Netherlands based on results of one central laboratory. Data were collected since the introduction of the highly sensitive cell-based assay for six consecutive years. Samples from 2795 individual patients have been received; of them 94 (3.4%) were seropositive. Based on the Dutch population with 16.6 million inhabitants, the mean incidence of AQP4-IgG-seropositive NMOSD was calculated at 0.09 per 100,000 people.

Neuromyelitis optica spectrum disorders: comparison of clinical and magnetic resonance imaging characteristics of AQP4-IgG versus MOG-IgG seropositive cases in the Netherlands

BACKGROUND AND PURPOSE

Neuromyelitis optica spectrum disorders (NMOSDs) are a group of rare inflammatory demyelinating disorders of the central nervous system. The identification of specific antibodies directed to aquaporin 4 (AQP4-IgG) led to the distinction from multiple sclerosis. However, up to 25% of the clinically diagnosed NMO patients are seronegative for AQP4-IgG. A subgroup of these patients might be identified by antibodies directed to myelin oligodendrocyte glycoprotein (MOG-IgG). Our objective was to investigate whether the clinical characteristics of these patients differ.

METHODS

Using a cell-based assay, samples of 61 AQP4-IgG seronegative patients and 41 AQP4-IgG seropositive patients with clinically NMOSD were analysed for the presence of MOG-IgG. Clinical characteristics of the AQP4-IgG, MOG-IgG seropositive and double seronegative NMOSD patients were compared.

RESULTS

Twenty of the 61 AQP4-IgG seronegative patients tested MOG-IgG seropositive (33%). MOG-IgG seropositive patients were more frequently males in contrast to AQP4-IgG seropositive patients (55% vs. 15%, P < 0.01) and Caucasians (90% vs. 63%, P = 0.03). They more frequently presented with coincident optic neuritis and transverse myelitis (40% vs. 12%, P = 0.02) and had a monophasic disease course (70% vs. 29%, P < 0.01). AQP4-IgG seropositive patients were 2.4 times more likely to suffer from relapses compared with MOG-IgG seropositive patients (relative risk 2.4, 95% confidence interval 1.2-4.7). AQP4-IgG seropositive patients had higher Expanded Disability Status Scale levels at last follow-up (P < 0.01).

CONCLUSION

Antibodies directed to MOG identify a subgroup of AQP4-IgG seronegative NMO patients with generally a favourable monophasic disease course.

Anti-MOG antibodies plead against MS diagnosis in an Acquired Demyelinating Syndromes cohort

BACKGROUND

Acquired demyelinating syndromes (ADS) in children are a group of distinct first immune-mediated demyelinating events of the central nervous system (CNS). Predictive biomarkers for future diagnosis are lacking. A putative target antigen is myelin oligodendrocyte glycoprotein (MOG). We analyzed the presence of MOG antibodies in a cohort of ADS patients in The Netherlands.

METHODS

Using a cell-based assay, we analyzed 117 children with ADS from a nationwide cohort, whom were divided into five groups: optic neuritis (ON; n = 20), transverse myelitis (TM; n = 7), other monofocal ADS (n = 22), polyfocal ADS without encephalopathy (n = 44) and polyfocal ADS with encephalopathy (n = 24). Additionally, we tested children with other neurological diseases (OND; n = 13), healthy children (n = 31) and adult polyfocal ADS plus encephalopathy (ADEM) patients (n = 29).

RESULTS

We found that 21 of the 117 children with ADS tested anti-MOG seropositive (18%). The group of patients with ADEM had the highest prevalence of anti-MOG seropositivity (42% versus 18% in the non-encephalopathic polyfocal ADS patients). Although 47 ADS children had a final diagnosis of multiple sclerosis (MS), in only one of them were MOG antibodies detected (2%), with only borderline positivity. Only 1 out of the 29 adult ADEM patients tested anti-MOG seropositive.

CONCLUSIONS

MOG antibodies are strongly skewed towards ADS children that present with an ADEM-like disease onset. The presence of such antibodies pleads against a future diagnosis of MS.

Anti-SSA antibodies are present in immunoglobulin preparations

BACKGROUND

Anti-SSA autoantibodies are among the most frequently detected autoantibodies and have traditionally been associated with Sjögren's syndrome (SjS) and systemic lupus erythematosus. The unexpected finding of anti-SSA antibodies in a patient with common variable immunodeficiency disorder (CVID) treated with intravenous immunoglobulin (IVIG), who developed discoid lupus erythematosus, prompted us to investigate the presence of anti-SSA antibodies in IVIG preparations. Since anti-SSA antibodies may be present in apparently healthy individuals without overt autoimmune features, IVIG preparations may also contain anti-SSA antibodies.

STUDY DESIGN AND METHODS

IVIG consists of polyclonal immunoglobulin G isolated from the plasma of more than 1000 blood donors. Several IVIG batches from different suppliers and serum samples of patients receiving these IVIG products were tested for the presence of anti-nuclear antibodies (ANAs) and extractable nuclear antibodies (ENAs). In addition, we tested several plasma pools for the presence of anti-SSA and subsequent serum samples of individual donors.

RESULTS

Several CVID-patients receiving IVIG tested positive for ANA and anti-SSA. The IVIG products administered also contained clearly detectable concentrations of these antibodies. The frequency of apparently healthy blood donors with anti-SSA positivity was 0.69% and one of 1894 donors (0.05%) showed a very high titer of anti-SSA of more than 10,000 U/mL.

CONCLUSION

Anti-SSA is present in IVIG products and in blood donors without clinical symptoms. IVIG replacement can interfere with ANA and ENA serology by passive transfer of autoantibodies. We hypothesize that such autoantibodies may be causally related to disease manifestations in some recipients.

Rising incidence and prevalence of primary biliary cirrhosis: a large population-based study

BACKGROUND & AIMS

Large population-based studies are much needed to accurately establish the epidemiology of primary biliary cirrhosis (PBC). We aimed to collect all PBC patients in a geographically defined area to evaluate the epidemiology of PBC and examine the possible association of PBC with smoking, age at menarche, age at first pregnancy and number of pregnancies.

METHODS

All PBC patients between 2000 and 2008 were identified in a geographically defined area of the Netherlands, comprising 50% of the Dutch population. Four independent hospital databases were searched in 44 hospitals. Medical records were reviewed on site verifying diagnosis and for collection of clinical data. Age- and gender matched controls were recruited from the outpatient clinics of four participating hospitals. Patients and controls were asked to fill out a questionnaire regarding family history, previous and current smoking behaviour and fertility status.

RESULTS

Nine hundred and ninety-two PBC patients fulfilled all inclusion criteria, resulting in a mean incidence of 1.1 per 100 000; 0.3 in men and 1.9 in women. On January 1st 2008 the point prevalence was 13.2 per 100 000 inhabitants. Incidence and prevalence rates were increasing over time (P < 0.001). No geographical differences in disease distribution were observed. Smoking behaviour, age at menarche, age at first pregnancy, gravidity and number of children were not significantly different between cases and controls.

CONCLUSION

Incidence and prevalence rates of PBC are increasing over time. PBC was not found to be associated with smoking, age at menarche, age at first pregnancy or number of pregnancies.

Anti-carbamylated protein (anti-CarP) antibodies precede the onset of rheumatoid arthritis

OBJECTIVE

The presence of anti-citrullinated protein antibodies (ACPA) and IgM-rheumatoid factor (IgM-RF) years before the clinical diagnosis of rheumatoid arthritis (RA) suggests they are possibly involved in the pathogenic process underlying RA. In this study, we analysed whether anti-carbamylated protein (anti-CarP) antibodies, a novel autoantibody system against carbamylated proteins, can also be detected in healthy individuals before they developed RA.

METHODS

Multiple sera from asymptomatic blood donors prior to the onset of their RA symptoms and sera from age-matched and sex-matched controls were tested for the presence of antibodies directed against carbamylated-fetal calf serum (Ca-FCS), carbamylated-fibrinogen (Ca-Fib), cyclic citrullinated-peptide 2 and IgM-RF.

RESULTS

Anti-Ca-FCS and anti-Ca-Fib antibodies were each present in 27% and 38% of the last serum samples of blood donors prior to the diagnosis of RA. Both anti-Ca-FCS and anti-Ca-Fib antibodies could be detected many years before the onset of RA. Anti-CarP antibodies as well as ACPA are, on average, detected earlier than IgM-RF.

CONCLUSIONS

In addition to ACPA and IgM-RF, also the newly identified anti-CarP antibodies appear many years before the diagnosis of RA.

Monoclonal anti-citrullinated protein antibodies selected on citrullinated fibrinogen have distinct targets with different cross-reactivity patterns

OBJECTIVE

ACPAs are thought to play a pathogenic role in RA. Because of their polyclonal nature it is difficult to study characteristics of ACPAs such as cross-reactivity or affinity. This study aimed to analyse the ACPA response at clonal level.

METHODS

Citrullinated fibrinogen-specific B cells were isolated from blood derived from an RA patient by fluorescent automated cell sorting (FACS). Antigen specificity was verified by ELISA of culture supernatant. RNA of antigen-specific B cells was isolated and VH and VL chains were cloned and subsequently expressed as IgG1 antibodies.

RESULTS

Two human recombinant antibodies were obtained that bind to citrullinated fibrinogen peptide (cFib). Both monoclonal antibodies originate from different naive B cells, undergo extensive somatic hypermutation and bind to cFib (but not to Fib) with moderate avidity. Furthermore, they show distinct cross-reactivity patterns towards other citrullinated peptides, suggesting that both antibodies have different primary targets.

CONCLUSION

Together these data suggest that ACPAs are formed by antigen-driven maturation, and that multiple citrullinated antigens are involved in activating the B-cell response.

Maggot excretions affect the human complement system

The complement system plays an important role in the activation of the inflammatory response to injury, although inappropriate complement activation (CA) can lead to severe tissue damage. Maggot therapy is successfully used to treat infected wounds. In this study, we hypothesized that maggot excretions/secretions influence CA in order to modulate the host's inflammatory response. Therefore, the effect of maggot excretions on CA was investigated in preoperatively and postoperatively obtained sera from patients. Our results show that maggot excretions reduce CA in healthy and postoperatively immune-activated human sera up to 99.9%, via all pathways. Maggot excretions do not specifically initiate or inhibit CA, but break down complement proteins C3 and C4 in a cation-independent manner and this effect proves to be temperature tolerant. This study indicates a CA-reducing substrate that is already successfully used in clinical practice and may explain part of the improved wound healing caused by maggot therapy. Furthermore, the complement activation-reducing substance present in maggot excretions could provide a novel treatment modality for several diseases, resulting from an (over)active complement system.

Service Desk Calls in a Home-based Clinical Informatics Study: Supporting End Users in the Field

Home-based clinical informatics technologies are being developed to facilitate health care provision and management. Given the novelty of these technologies, end users such as patients and their formal and informal caregivers may require support during use. This paper presents a case study within the United States of the service desk calls generated over a 31-month period by patients enrolled in a large randomized field experiment, HeartCare II. This case study provides future deployers of home-based clinical information technologies with an understanding of the types of support that may be required during use. Our analysis reveals that calls to the service desk originated as a result of user problems, hardware problems, software problems, and internal communication problems among individuals involved in the delivery and use of the technology. Implications of these needs for support during use are also discussed.

Antibodies against aquaporin-4 in neuromyelitis optica: distinction between recurrent and monophasic patients

The detection of antibodies against aquaporin-4 (AQP4) has improved the diagnosis of neuromyelitis optica (NMO). We evaluated a recently established cell-based anti-AQP4 assay in 273 patients with inflammatory CNS demyelination. The assay had a specificity of 99% and a sensitivity of 56% to detect all NMO patients and of 74% to detect the recurrent NMO patients, similar to the initial studies reported. AQP4 antibodies were absent in monophasic NMO patients, while samples in recurrent cases remained positive during follow-up. We conclude that the pathogenesis of monophasic NMO may be different from that of relapsing NMO.

The extent of the anti-citrullinated protein antibody repertoire is associated with arthritis development in patients with seropositive arthralgia

OBJECTIVES

To determine the fine specificity of anti-citrullinated protein antibodies (ACPA) in the early phase of arthritis development, the ACPA repertoire in arthralgia patients and the association with arthritis development were studied.

METHODS

A total of 244 patients with arthralgia positive for anti-cyclic citrullinated peptide antibodies (aCCPs) and/or IgM rheumatoid factor (IgM-RF), without arthritis were included. Development of arthritis was defined as presence of one or more swollen joints at clinical examination during follow-up. Sera were tested at baseline for reactivity to five citrullinated peptides derived from fibrinogen (three), vimentin (one) and α-enolase (one) and five corresponding arginine peptides in an ELISA.

RESULTS

In all, 69 patients (28%) developed arthritis in a median of 3 joints after a median follow-up of 11 (IQR 5-20) months. Reactivity to each peptide was significantly associated with arthritis development (p<0.001). The ACPA repertoire did not differ between patients who did or did not develop arthritis. Among aCCP-positive patients, patients recognising two or more additional citrullinated peptides developed arthritis more often (p=0.04). The number of recognised peptides was positively associated with the aCCP level (p<0.001). Crossreactivity between different peptides was minimal.

CONCLUSIONS

Arthritis development is not associated with recognition of a specific citrullinated peptide once joint complaints are present. The ACPA repertoire in some patients with arthralgia is expanded. High aCCP levels are associated with a qualitatively broad ACPA repertoire. Patients with an extended ACPA repertoire have a higher risk of developing arthritis.

Autoantibody standardization in The Netherlands

Several initiatives have been undertaken, independent of the European Autoantibody Standardization Initiative (EASI), to standardize autoantibodies in The Netherlands. The Dutch EASI team has made an inventory of which initiatives on autoantibody standardization are already available and what future plans for autoantibody standardization exist. This inventory will subsequently be used to define what may be addressed by the Dutch EASI team. The Diagnostic Compass, initiated by the association of Dutch health insurance companies, describes methods and relevance of laboratory tests, including autoantibody tests. Recently, this initiative has been taken over by an independent publisher. There is also a national organization involved in developing guidelines in medicine, including guidelines for autoantibody testing. In addition, there is a national foundation for quality assessment in clinical laboratories (SKML). The quality assessment includes a wide array of autoantibodies. Samples are collected and thoroughly investigated by reference laboratories. Interpretation of results and advice to clinicians are part of the program. Feedback on the results of this proficiency testing is given in reports and during meetings to discuss trends, technical issues, and new developments. The last initiative that we discuss is the foundation Referentie Laboratorium Reuma Serologie (RELARES), which was founded to standardize serology in rheumatic diseases by preparing standard sera. Recently, RELARES has been combined with SKML. A new SKML working group, Standardization Autoimmune Serology, has been initiated to continue the work of RELARES. When comparing the already available Dutch initiatives to the international EASI goals, there appears to be a lack of harmonization in testing algorithms, and this issue is the most important topic to be addressed in the near future.

Preferential decrease in IgG4 anti-citrullinated protein antibodies during treatment with tumour necrosis factor blocking agents in patients with rheumatoid arthritis

Objective:

To investigate the dynamics of IgG1 and IgG4 anti-citrullinated protein antibody (ACPA) subclasses during anti-tumour necrosis factor (TNF) treatment in patients with rheumatoid arthritis (RA).

Methods:

IgG, IgG1 and IgG4 ACPA levels were determined by ELISA on anti-citrullinated fibrinogen (ACF) and IgG1 : IgG4 ACPA ratios were calculated. A pilot study was performed in 28 ACF-positive patients treated with infliximab for one year. Confirmation of the results was obtained using a cohort of 180 consecutive patients treated with adalimumab for 28 weeks.

Results:

The median reduction in ACF levels was 31% for total IgG, 29% for IgG1, 40% for IgG4 and 22% for the IgG4 : IgG1 ACF ratio in the infliximab cohort. In adalimumab-treated patients, ACF levels declined 14% for total IgG and IgG1, and 36% for IgG4 ACF; the IgG4 : IgG1 ratio was reduced by 24% (all percentage values p<0.05). The decrease in antibody levels was correlated with the clinical response; European League Against Rheumatism good responders had the greatest decline in antibody levels and this effect was most pronounced for IgG4 (48% reduction). The IgG4 : IgG1 ACF ratio preferentially decreased in patients with adequate therapeutic adalimumab levels.

Conclusion:

ACPA subclass distribution is modulated by effective anti-inflammatory treatment. The preferential decline of IgG4 ACPA, reflected by the decreased IgG4 : IgG1 ratio, suggests a beneficial effect of anti-TNF treatment on chronic antigenic stimulation by citrullinated proteins. This effect may be directly anti-TNF mediated or the result of effective dampening of the inflammation in the rheumatoid joint.

IgM-rheumatoid factor, anti-cyclic citrullinated peptide, and anti-citrullinated human fibrinogen antibodies decrease during treatment with the tumor necrosis factor blocker infliximab in patients with rheumatoid arthritis

OBJECTIVE

To investigate the effect of treatment with infliximab on serum levels of rheumatoid factor (IgM-RF), antibodies against cyclic citrullinated peptide (anti-CCP), and antibodies against deiminated human fibrinogen, a specific citrullinated peptide (ACF), and their association with disease activity and disease duration in patients with rheumatoid arthritis (RA).

METHODS

The study sample included 62 consecutive patients who were treated with infliximab for at least one year. IgM-RF, anti-CCP, and ACF were measured at 0, 14, 30, and 46 weeks.

RESULTS

Patients had a mean age of 54 years and median disease duration of 10 years and were predominantly female (81%). At baseline 63%, 77%, and 82% of patients were positive for IgM-RF, anti-CCP, and ACF, respectively. In terms of percentages, the levels of IgM-RF were reduced by 64% at 46 weeks, while anti-CCP and ACF levels were reduced by roughly 25%. The decrease in serum levels of these autoantibodies was not associated with the decrease in disease activity. The change in ACF was significantly related to disease duration, while the changes in IgM-RF or anti-CCP were not.

CONCLUSION

In a cohort of patients with RA who responded to infliximab therapy, all autoantibodies decreased significantly, but IgM-RF showed a larger decrease than anti-CCP or ACF. These changes in levels of autoantibodies are not directly related to the change in disease activity. Early in the disease, ACF levels were best influenced by treatment with infliximab.

High incidence of type 1 diabetes mellitus during or shortly after treatment with pegylated interferon alpha for chronic hepatitis C virus infection

BACKGROUND

Development of diabetes mellitus (DM) during or shortly after treatment with interferon alpha (IFN-alpha) in patients with chronic hepatitis C virus (HCV) infection has been reported sporadically. We prospectively screened for DM during and after IFN-alpha therapy for chronic HCV infection.

METHODS

Blood glucose levels of patients with chronic HCV infection were routinely assessed at all outpatient visits during and after treatment with pegylated-IFN-alpha (Peg-IFN-alpha) and ribavirin (Riba).

RESULTS

Between December 2002 and October 2005, 189 non-diabetic patients were treated with Peg-IFN-alpha/Riba, of whom five developed type 1 DM (2.6%), three type 2 DM (1.6%) and one an indeterminate type of DM. Classical symptoms of DM were present in three patients who developed DM shortly after cessation of Peg-IFN-alpha/Riba. In the other patients, symptoms of DM were either indistinguishable from side effects caused by Peg-IFN-alpha/Riba or absent.

CONCLUSION

Our study showed a high incidence of type 1 DM during Peg-IFN-alpha/Riba therapy for chronic HCV infection. Symptoms of DM may be absent or mistaken for Peg-IFN-alpha/Riba-associated side effects. To diagnose DM without delay, we propose routine assessment of blood glucose at all outpatient visits during and after Peg-IFN-alpha/Riba treatment in chronic HCV patients.

Tailored release of TGF-β1 from porous scaffolds for cartilage tissue engineering

In view of cartilage tissue engineering, the possibility to prepare porous scaffolds releasing transforming growth factor-beta(1) (TGF-beta(1)) in a well controlled fashion was investigated by means of an emulsion-coating method. Poly(ether-ester) multiblock copolymers were used to prepare emulsions containing TGF-beta(1) which were subsequently applied onto prefabricated scaffolds. This approach resulted in defined porous structures (66%) with interconnected porosity, suitable to allow tissue ingrowth. The scaffolds were effectively associated with TGF-beta(1) and allowed to tailor precisely the release of the growth factor from 12 days to more than 50 days by varying the copolymer composition of the coating. An incomplete release was measured by ELISA, possibly linked to the rapid concentration decrease of the protein in solution. The released growth factor retained its biological activity as was assessed by a cell proliferation assay and by the ability of the released protein to induce chondrogenic differentiation of bone marrow-derived mesenchymal stem cells. However, exact bioactivity quantification was rendered difficult by the protein concentration decrease during storage. Therefore, this study confirms the interest of poly(ether-ester) multiblock copolymers for controlled release of growth factors, and indicates that emulsion-coated scaffolds are promising candidates for cartilage tissue engineering applications requiring precise TGF-beta(1) release rates.

Deficiency of functional mannose-binding lectin is not associated with infections in patients with systemic lupus erythematosus

Infection imposes a serious burden on patients with systemic lupus erythematosus (SLE). The increased infection rate in SLE patients has been attributed in part to defects of immune defence. Recently, the lectin pathway of complement activation has also been suggested to play a role in the occurrence of infections in SLE. In previous studies, SLE patients homozygous for mannose-binding lectin (MBL) variant alleles were at an increased risk of acquiring serious infections in comparison with patients who were heterozygous or homozygous for the normal allele. This association suggests a correlation between functional MBL level and occurrence of infections in SLE patients. We therefore investigated the biological activity of MBL and its relationship with the occurrence of infections in patients with SLE. Demographic and clinical data were collected in 103 patients with SLE. Functional MBL serum levels and MBL-induced C4 deposition were measured by enzyme-linked immunosorbent assay using mannan as coat and an MBL- or C4b-specific monoclonal antibody. The complete MBL-dependent pathway activity was determined by using an assay that measures the complete MBL pathway activity in serum, starting with binding of MBL to mannan, and was detected with a specific monoclonal antibody against C5b-9. Charts were systematically reviewed to obtain information on documented infections since diagnosis of SLE. Major infections were defined as infections requiring hospital admission and intravenous administration of antibiotics. In total, 115 infections since diagnosis of lupus, including 42 major infections, were documented in the 103 SLE patients (mean age 41 ± 13 years, mean disease duration 7 ± 4 years). The percentage of SLE patients with severe MBL deficiency was similar to that in 100 healthy controls: 13% versus 14%, respectively. Although deposition of C4 to mannan and MBL pathway activity were reduced in 21% and 43% of 103 SLE patients, respectively, neither functional MBL serum levels nor MBL pathway activity was associated with infections or major infections in regression analyses. In conclusion, SLE patients frequently suffer from infections, but deficiency of functional MBL does not confer additional risk.