Ultrasound imaging in crystal arthropathies: a pictorial review.

OBJECTIVE: The prevalence of crystal arthropathies in the general population is rising. The purpose of this pictorial study is to describe the sonographic elements of the most prevalent crystal arthropathies by emphasizing particular sonographic findings using illustrative images and cases while considering technical details and common pitfalls. METHODS: Using established recommendations, specialists in the fields of sonography and crystal arthropathies agreed by consensus on the unique ultrasound signs associated with each of the conditions. RESULTS: Gout, calcium pyrophosphate deposition arthropathy, and hydroxyapatite arthropathy are the three most prevalent crystal arthropathies. Today's high-resolution sonography enables reliable evaluation of the underlying crystal deposits, post-inflammatory changes, and a precise description of joint inflammation. CONCLUSIONS: High-prevalence crystal arthropathies are reliably detectable by ultrasound with current ultrasound equipment. It is necessary to have extensive ultrasound training, know specific sonographic findings, and understand all possible differential diagnoses for disorders affecting the musculoskeletal system.

Increased radiographic progression of distal hand osteoarthritis occurring during biologic DMARD monotherapy for concomitant rheumatoid arthritis.

OBJECTIVES: A considerable proportion of patients with rheumatoid arthritis (RA) also suffer from hand osteoarthritis (OA). We here assess the association between conventional synthetic (cs) and biological (b) disease-modifying antirheumatic drugs (DMARDs) and radiographic distal interphalangeal-(DIP) OA in patients with RA. METHODS: Adult RA patients from a longitudinal Swiss registry of rheumatic diseases who had ≥ 2 hand radiographs were included at the first radiograph and followed until the outcome or the last radiograph. Patients were grouped into two cohorts based on whether DIP OA was present or absent at cohort entry (cohorts 1 and 2, respectively). Modified Kellgren-Lawrence scores (KLS) were obtained by evaluating DIP joints for the severity of osteophytes, joint space narrowing, subchondral sclerosis, and erosions. KLS ≥ 2 in ≥ 1 DIP joint indicated incident or existing OA, and increase of ≥ 1 in KLS in ≥ 1 DIP joint indicated progression in existing DIP OA. Time-varying Cox regression and generalized estimating equation (GEE) analyses were performed. We estimated hazard ratios (HRs) and odds ratios (ORs) with 95% confidence intervals (CI) of DIP OA incidence (cohort 2), or progression (cohort 1), in bDMARD monotherapy, bDMARD/csDMARD combination therapy, and past or never DMARD use, when compared to csDMARD use. In post hoc analyses, we descriptively and analytically assessed the individual KLS features in cohort 1. RESULTS: Among 2234 RA patients with 5928 radiographs, 1340 patients had DIP OA at baseline (cohort 1). Radiographic progression of DIP OA was characterized by new or progressive osteophyte formation (666, 52.4%), joint space narrowing (379, 27.5%), subchondral sclerosis (238, 17.8%), or erosions (62, 4.3%). bDMARD monotherapy had an increased risk of radiographic DIP OA progression compared to csDMARD monotherapy (adjusted HR 1.34 [95% CI 1.07-1.69]). The risk was not significant in csDMARD/bDMARD combination users (HR 1.12 [95% CI 0.96-1.31]), absent in past DMARD users (HR 0.96 [95% CI 0.66-1.41]), and significantly lower among never DMARD users (HR 0.54 [95% CI 0.33-0.90]). Osteophyte progression (HR 1.74 [95% CI 1.11-2.74]) was the most significantly increased OA feature with bDMARD use compared to csDMARD use. In 894 patients without initial DIP OA (cohort 2), the risk of incident OA did not differ between the treatment groups. The results from GEE analyses corroborated all findings. CONCLUSIONS: These real-world RA cohort data indicate that monotherapy with bDMARDs is associated with increased radiographic progression of existing DIP OA, but not with incident DIP OA.

Constraints on Elastic Neutrino Nucleus Scattering in the Fully Coherent Regime from the CONUS Experiment.

We report the best limit on coherent elastic scattering of electron antineutrinos emitted from a nuclear reactor off germanium nuclei. The measurement was performed with the CONUS detectors positioned at 17.1 m from the 3.9 GW_{th} reactor core of the nuclear power plant in Brokdorf, Germany. The antineutrino energies of less than 10 MeV assure interactions in the fully coherent regime. The analyzed dataset includes 248.7 kg d with the reactor turned on and background data of 58.8 kg d with the reactor off. With a quenching parameter of k=0.18 for germanium, we determined an upper limit on the number of neutrino events of 85 in the region of interest at 90% confidence level. This new CONUS dataset disfavors quenching parameters above k=0.27, under the assumption of standard-model-like coherent scattering of the reactor antineutrinos.

Diagnostic guidelines for the histological particle algorithm in the periprosthetic neo-synovial tissue.

BACKGROUND: The identification of implant wear particles and non-implant related particles and the characterization of the inflammatory responses in the periprosthetic neo-synovial membrane, bone, and the synovial-like interface membrane (SLIM) play an important role for the evaluation of clinical outcome, correlation with radiological and implant retrieval studies, and understanding of the biological pathways contributing to implant failures in joint arthroplasty. The purpose of this study is to present a comprehensive histological particle algorithm (HPA) as a practical guide to particle identification at routine light microscopy examination. METHODS: The cases used for particle analysis were selected retrospectively from the archives of two institutions and were representative of the implant wear and non-implant related particle spectrum. All particle categories were described according to their size, shape, colour and properties observed at light microscopy, under polarized light, and after histochemical stains when necessary. A unified range of particle size, defined as a measure of length only, is proposed for the wear particles with five classes for polyethylene (PE) particles and four classes for conventional and corrosion metallic particles and ceramic particles. RESULTS: All implant wear and non-implant related particles were described and illustrated in detail by category. A particle scoring system for the periprosthetic tissue/SLIM is proposed as follows: 1) Wear particle identification at light microscopy with a two-step analysis at low (× 25, × 40, and × 100) and high magnification (× 200 and × 400); 2) Identification of the predominant wear particle type with size determination; 3) The presence of non-implant related endogenous and/or foreign particles. A guide for a comprehensive pathology report is also provided with sections for macroscopic and microscopic description, and diagnosis. CONCLUSIONS: The HPA should be considered a standard for the histological analysis of periprosthetic neo-synovial membrane, bone, and SLIM. It provides a basic, standardized tool for the identification of implant wear and non-implant related particles at routine light microscopy examination and aims at reducing intra-observer and inter-observer variability to provide a common platform for multicentric implant retrieval/radiological/histological studies and valuable data for the risk assessment of implant performance for regional and national implant registries and government agencies.

Calcium pyrophosphate deposition disease: a frequent finding in patients with long-standing erosive gout.

OBJECTIVE: To characterize patients with both monosodium urate (MSU) and calcium pyrophosphate (CPP) crystals in their synovial fluid (SF). METHOD: Forty-nine gout patients with acute arthritis were included. Those patients with MSU crystals only in their SF were compared to those patients with both MSU and CPP crystals in their SF. RESULTS: A total of 36 out of 49 patients (73.5%) had only MSU crystals, whereas 13 out of 49 (26.5%) had both MSU and CPP crystals in their SF. Co-deposition of CPP crystals was associated with long-standing gout disease (p = 0.022), kidney dysfunction (p = 0.024), and erosive arthritis (p = 0.049), but not with age. CONCLUSION: Long-standing gout may be a risk factor for CPP deposition disease, and the frequency of CPP co-deposition may be higher than expected.

15 years of the histopathological synovitis score, further development and review: A diagnostic score for rheumatology and orthopaedics.

The histopathological synovitis score evaluates the immunological and inflammatory changes of synovitis in a graduated manner generally customary for diagnostic histopathological scores. The score results from semiquantitative evaluation of the width of the synovial surface cell layer, the cell density of the stroma and the density of the inflammatory infiltration into 4 semiquantitative levels (normal 0, mild 1, moderate 2, severe 3). The addition of these values results in a final score of 0-9 out of 9. On the basis of this summation the condition is divided into low-grade synovitis and high-grade synovitis: A synovitis score of 1 to≤4 is called low-grade synovitis (arthrosis-associated/OA synovitis, posttraumatic synovitis, meniscopathy-associated synovitis and synovitis with haemochromatosis). A synovitis score of≥5 to 9 is called high-grade synovitis (rheumatoid arthritis, psoriatic arthritis, Lyme arthritis, postinfection/reactive arthritis and peripheral arthritis with Bechterew's disease). By means of the synovitis score it is therefore possible to distinguish between degenerative/posttraumatic diseases (low-grade synovitis) and inflammatory rheumatic diseases (high-grade synovitis) with a sensitivity of 61.7% and a specificity of 96.1%. The diagnostic accuracy according to ROC analysis (AUC: 0.8-0.9) is good. Since the first publication (2002) and an associated subsequent publication (2006), the synovitis score has nationally and internationally been accepted for histopathological assessment of the synovitis. In a PubMed data analysis (status: 14.02.2017), the following citation rates according to Cited by PubMed Central articles resulted for the two synovitis score publications: For DOI: 10.1078/0344-0338-5710261 there were 29 Cited by PubMed Central articles and for the second extended publication DOI:10.1111/j.1365-2559.2006.02508 there were 44 Cited by PubMed Central articles. Therefore a total of 73 PubMed citations are observed over a period of 15 years, which demonstrates an international acceptance of the score. This synovitis score provides for the first time a diagnostic, standardised and reproducible histopathological evaluation method enabling a contribution to the differential diagnosis of chronic inflammatory general joint diseases. This is particularly the case by incorporation into the joint pathology algorithm. To specify the synovitis score an immunohistochemical determination of various inflammation-relevant CD antigens is proposed to enable a risk stratification of high-grade synovitis (e.g.: progression risk and sensitivity for biologicals).

[Fifteen years of the histopathological synovitis score : Review and further developments of a diagnostic score]. / 15 Jahre histopathologischer Synovialitis-Score : Rückblick und Weiterentwicklung eines diagnostischen Scores.

The histopathological synovitis score evaluates in a graded approach, as is largely usual for diagnostic histopathological scores, the immunological and inflammatory changes caused by synovitis. A synovitis score of between 1 and ≤ 4 is classified as low-grade (osteoarthritis-related synovitis, post-traumatic synovitis, meniscopathy-related synovitis and synovitis in hemochromatosis). Synovitis scores of between ≥ 5 and 9 are classified as high-grade synovitis (rheumatoid arthritis, psoriatic arthritis, Lyme's arthritis, post-infection/reactive arthritis and peripheral arthritis in Bechterew disease); sensitivity is 61.7% and sensitivity 96.1%. According to receiver operating characteristic (ROC) analysis (AUC: 0.8-0.9), diagnostic value is good. National and international acceptance of the synovitis score has grown since the first publication in 2002 and a related follow-up publication in 2006. PubMed data analysis (as of 11.01.2017) yielded the following citation values according to "cited by PubMed Central articles" for two publications relating to the synovitis score: there were 29 cited-by-PubMed articles for DOI: 10.1078/0344-0338-5710261 , and 44 cited-in-PubMed articles for the second publication, DOI: 10.1111/j.1365-2559.2006.02508 . This makes a total of 73 PubMed citations over a period of 15 years, thereby evidencing the score's international acceptance. Immunohistochemical determination of a number of CD antigens relevant to inflammation has been proposed to further specify the synovitis score for the purposes of risk stratification of high-grade synovitis (e.g., risk of progression and sensitivity to biological agents).

Hyperlipidaemia and incident osteoarthritis of the hand: a population-based case-control study.

OBJECTIVE: Preclinical evidence suggests that increased cholesterol levels might be involved in the pathophysiology of osteoarthritis of the hand (HOA), but evidence from observational studies remains scarce. We aimed to analyse the association between hyperlipidaemia and incident HOA. DESIGN: We conducted a matched (1:1) case-control study using the UK-based Clinical Practice Research Datalink (CPRD). Cases were patients aged 30-89 years with an incident diagnosis of HOA between 1995 and 2014. In multivariable conditional logistic regression analyses, we calculated odds ratios (OR) for incident HOA in patients with hyperlipidaemia, categorized by gender, age, previous duration of hyperlipidaemia, and recent statin treatment. RESULTS: Among 19,590 cases and 19,590 controls, we observed an increased risk of HOA in patients with hyperlipidaemia (OR 1.37, 95% confidence intervals (CI) 1.28-1.47), when compared to patients without hyperlipidaemia. Thus, of all HOA cases in our study population, 3.6% may have been attributable to the presence of hyperlipidaemia (population attributable risk). Most patients with HOA were elderly, but the strength of the association between HOA and hyperlipidaemia inversely correlated with increasing age, with the highest OR of 1.72 (95% CI 1.24-2.38) in patients aged 29-49 years. Categorization by previous hyperlipidaemia duration, as well as sub-classification of patients with hyperlipidaemia into those with and without recent statin use did not meaningfully change the effect estimate. CONCLUSIONS: Our results suggest that hyperlipidaemia may be an independent risk factor for new onset HOA.

Type II diabetes mellitus and incident osteoarthritis of the hand: a population-based case-control analysis.

OBJECTIVES: Emerging evidence suggests that diabetes may be a risk factor for osteoarthritis (OA). However, previous results on the association between diabetes and all OA were conflicting. We aimed to comprehensively analyse the association between type II diabetes mellitus (T2DM) and osteoarthritis of the hand (HOA) specifically. METHODS: We conducted a matched (1:1) case-control study using the UK-based Clinical Practice Research Datalink (CPRD) of cases aged 30-90 years with an incident diagnosis of HOA from 1995 to 2013. In multivariable conditional logistic regression analyses, we calculated odds ratios (OR) for incident HOA in patients with T2DM, categorized by T2DM severity (HbA1C), duration, and pharmacological treatment. We further performed sensitivity analyses in patients with and without other metabolic diseases (hypertension (HT), hyperlipidaemia (HL), obesity). RESULTS: Among 13,500 cases and 13,500 controls, we observed no statistically significant association between T2DM and HOA (OR 0.95, 95% confidence interval (CI) 0.87-1.04), regardless of T2DM severity, duration, or pharmacological treatment. Having HT did not change the OR. Although we observed slightly increased ORs in overweight T2DM patients with co-occurring HL with or without coexisting HT, none of these ORs were statistically significant. CONCLUSIONS: Our results provide evidence that T2DM is not an independent risk factor for HOA. Concurrence of T2DM with HT, HL, and/or obesity did not change this association significantly.

[Histopathological diagnostic work-up of joint endoprosthesis-associated pathologies]. / Histopathologische Diagnostik von Gelenkendoprothesen-assoziierten Erkrankungen.

Increasing classes of joint implants and the combination of materials results in increased and wear-associated pathologies. According to the revised consensus classification, the following types can be recognized at conventional histological examination: Type I, particle-induced type; Type II, infection type; Type III, combination type; Type IV, indifferent type; Type V arthrofibrotic type; Type VI, allergic/immunological/toxic adverse reactions and Type VII, bone pathologies. Wear particles are histopathologically characterized according to the Krenn particle algorithm which focuses on a descriptive identification of wear particles and the differentiation of other nonwear-related particles. Type VII is considered histologically when there is evidence of a perivascular/interstitial lymphocytic CD20- and CD3-positive infiltrate, presence of mast cells and eosinophils, and tissue necrosis/infarction associated with implant wear material. Since wear particle-induced toxicity cannot be differentiated with certainty from hypersensitivity/allergic reaction on histological examination, immunological-allergological and clinical data should be used as supplementary criteria for the differential diagnosis. Tissue sampling should be performed from periprosthetic soft tissue with location mapping and when feasible also from bone tissue. Additional information regarding the type of implant and clinical, radiological, immunological, and microbiology data should be available to the pathologist. Further immunohistochemical studies are recommended in the following settings: infection (CD15, CD20, CD68); prosthesis-associated arthrofibrosis (ß­catenin); allergic/immunologic/toxic adverse reactions (CD20, CD3, CD4, CD8, CD117 and for T­cell characterization T­bet, GATA-3, and FOXP3).

[Supramacroparticulate polyethylene in inflammation of synovial-like interface membranes: Characterization and suggested nomenclature]. / Supramakropartikuläres Polyethylen bei Entzündungen periprothetischer Membranen: Charakterisierung und Nomenklaturvorschlag.

BACKGROUND: The identification of particles of prosthesis material components in the histopathological diagnosis of synovialitis is of great importance in the evaluation of implant failure. MATERIALS AND METHODS: In histopathological particle algorithms, polyethylene (PE) particles with a maximum length of less than 100 µm are designated with the term macroparticles; however, a systematic investigation and characterization are lacking. RESULTS: In SLIM knee specimens (n = 24) a minimum value of 210 µm and a maximum value of 2100 µm were measured; the mathematical mean length varied between 235 µm and 1416 µm. In SLIM hip specimens (n = 11) the minimum value was 290 µm and the maximum value was 1806 µm; the mean length varied between 353 and 1726 µm. Because of this conspicuous size, and to distinguish from PE macroparticles, the designation PE supra-macroparticulate is suggested. This new terminology acknowledges the fact that these PE particles are visible under magnification (e.g., × 12.5) and also macroscopically. The particles were also indirectly proven as there were completely separate and optically clear, column-shaped cavities corresponding to the shape of the PE particles (PE vacuoles). The life of the prosthesis is highly variable at between 12 and 300 months. In all cases loosening of the prosthesis, misalignment of the PE components, and/or damage to the PE inlay occurred. CONCLUSION: The cause and existence of these supra-macroparticulate PE particles (more than 100 µm) is still unclear. A mechanical malfunction seems probable and should be discussed. In prostheses with short lives the proof of supra-macroparticulate PE in SLIM could be a sign of an early mechanical problem. In the wider histopathological particle algorithm supra-macroparticulate PE was considered to fall in the category of macroparticles and should be considered in the histopathological diagnosis of implant failure.

Multicolor flow cytometry-based cellular phenotyping identifies osteoprogenitors and inflammatory cells in the osteoarthritic subchondral bone marrow compartment.

PURPOSE: The cellular component of subchondral bone is thought to be responsible for aberrant bone remodeling in osteoarthritis (OA). Direct phenotypical analysis of the cellular compartment is critical to better understand the OA disease process. This study provides proof-of-principle for flow cytometry-based phenotyping of isolated subchondral trabecular bone (STB) marrow cells without prior use of cell culture techniques. METHODS: Tibial plateaus were obtained from OA patients undergoing total knee arthroplasty. Subchondral bone chips were digested with collagenase IA and single cell suspensions were directly phenotyped using flow cytometry. Cells were analyzed for the expression of alkaline phosphatase (ALP) as osteoblast/osteoprogenitor marker and monocyte/macrophage markers (CD14, CD68, HLA-DR, CD115). RESULTS: MTT staining revealed abundant viable cells in the bone marrow compartment of STB prior to digestion, which were efficiently released by collagenase. Within the CD45-negative cell fraction, approximately 20% of the cells were positive for the early osteoblast/osteoprogenitor marker ALP. Within the CD45+ hematopoietic cell fraction, the majority of cells were of monocytic origin (>80%) displaying strong surface expression of CD14. Discreet macrophage populations (CD14+/HLA-DR+/CD68+) and putative osteoclast progenitors (CD45+/HLA-DR-/CD115+) were unequivocally identified. Osteoblast, macrophage and osteoclast progenitor presence in the subchondral bone unit (SBU) was confirmed by (immuno)histochemical staining for osteocalcin, CD68 and tartrate-resistant acid phosphatase, respectively. CONCLUSIONS: Flow cytometric analysis is a valuable methodology to study the cellular compartment of STB marrow. This method provides a proof of principle that the whole resident cell population can be directly phenotypically characterized without the prior use of cell culture techniques.

Autologous hematopoietic stem cell transplantation reverses skin fibrosis but does not change skin vessel density in patients with systemic sclerosis.

Hematopoetic stem cell transplantation (HSCT) improves survival in patients with severe systemic sclerosis (SSc) by resetting the immune system. We studied how HSCT acts on the key SSc skin pathology findings (fibrosis and vascularization). In mean, 3 skin punch biopsies per patient (range 2-6) were analyzed from 13 patients (5 females) with severe diffuse SSc before and up to 96 months after HSCT. Fibrosis of the four skin layers was graded semi-quantitatively and an overall fibrosis score was then calculated. Vessel numbers and calibers were assessed in the superficial and deeper dermis after immune-staining for endothelial antigens (CD31, VE-cadherin and vWF). The median age of patients at HSCT was 47 (24-64) years. The overall median modified Rodnan skin score decreased from 24 to 10 (P=0.003) at first follow-up within a median of 9 (6-36) months after HSCT as did the histological skin score (P=0.03). The modified Rodnan skin score and the fibrosis score correlated positively (r=0.589, P<0.001). The vessels density did not significantly change after HSCT nor did the expression of the tested endothelial markers. Although improving skin fibrosis in patients with SSc, HSCT does not alter vessel density within skin biopsies.

The potential use of microcalorimetry in rapid differentiation between septic arthritis and other causes of arthritis.

Current diagnostic methods in differentiating septic from non-septic arthritis are time-consuming (culture) or have limited sensitivity (Gram stain). Microcalorimetry is a novel method that can rapidly detect microorganisms by their heat production. We investigated the accuracy and time to detection of septic arthritis by using microcalorimetry. Patients older than 18 years of age with acute arthritis of native joints were prospectively included. Synovial fluid was aspirated and investigated by Gram stain, culture and microcalorimetry. The diagnosis of septic arthritis and non-septic arthritis were made by experienced rheumatologists or orthopaedic surgeons. Septic arthritis was diagnosed by considering the finding of acute arthritis together with findings such as positive Gram stain or positive culture of synovial fluid or positive blood culture. The sensitivity and specificity for diagnosing septic arthritis and the time to positivity of microcalorimetry were determined. Of 90 patients (mean age 64 years), nine had septic arthritis, of whom four (44 %) had positive Gram stain, six (67 %) positive synovial fluid culture and four (44 %) had positive blood culture. The sensitivity of microcalorimetry was 89 %, the specificity was 99 % and the mean detection time was 5.0 h (range, 2.2-8.0 h). Microcalorimetry is an accurate and rapid method for the diagnosis of septic arthritis. It has potential to be used in clinical practice in diagnosing septic arthritis.

Allogeneic hematopoietic SCT for patients with autoimmune diseases.

Allogeneic hematopoietic SCT (HSCT) has been used as treatment for single patients with autoimmune diseases (AD). To summarise currently available information, we analyzed all patients who underwent allogeneic HSCT for AD and who reported to the European Group for Blood and Marrow Transplantation (EBMT) database. Thirty-five patients receiving 38 allogeneic transplantations for various hematological and non-hematological AD were identified. Four patients had had an allogeneic HSCT for a conventional hematological indication in the past. Fifty-five per cent of the transplantation procedures led to a complete clinical response of the refractory AD and 23% to at least a partial response. The median duration of response at the last follow-up was 70.7 (15.2-130) months. Three patients relapsed at a median of 12.3 months after HSCT. Treatment-related mortality at 2 years was 22.1% (95% CI: 7.3-36.9%). Two deaths were caused by progression of AD. The probability of survival at 2 years was 70%. No single factor predicting the outcome could be identified. The retrospective nature of this study and the heterogeneous, partly incomplete data are its limitations. However, allogeneic HSCT can induce remission in patients suffering from refractory AD. These data provide the basis for carefully conducted prospective trials.

Sclerosing skin disorders in association with multiple sclerosis. Coincidence, underlying autoimmune pathology or interferon induced?

OBJECTIVES: To describe and analyse the manifestation of sclerosing skin disorders in patients with multiple sclerosis (MS). CASE REPORTS: We describe three patients with relapsing-remitting MS who developed skin sclerosis while receiving interferon (IFN)-beta treatment and review nine further cases of systemic sclerosis (SSc) in MS from the literature. Of all 12 patients reported, eight had limited cutaneous SSc, three had diffuse cutaneous SSc and one patient had an antisynthetase syndrome. Localised scleroderma such as morphoea was not described. The mean age at diagnosis was 25.2 years for MS (range 12 to 51) and 38.3 years for SSc (range 16 to 66). Eleven patients developed SSc after the onset of MS and manifested with skin sclerosis after a mean of 14.9 years (range 1 to 45). In five patients IFN-beta was commenced before the development of skin sclerosis (mean 4.6 years, range 1 to 8 years). There was no relationship between the onset of skin sclerosis and MS activity. With the exception of one individual, all patients had antinuclear antibodies. CONCLUSIONS: Sclerosing skin disorders may develop in the course of MS. The relatively early age of SSc onset in patients with MS suggests a genetic predisposition and/or an IFN-associated trigger.

Serum procalcitonin for discrimination between septic and non-septic arthritis.

BACKGROUND: Early differentiation between septic and non-septic arthritis is difficult. A previous study showed promising diagnostic accuracy of serum Procalcitonin (PCT) in septic arthritis, limited by a low sensitive PCT test kit. OBJECTIVE: To investigate the diagnostic value of PCT in patients with septic and non-septic arthritis using a novel test with low detection limit. METHODS: Forty-two patients, 28 with non-septic and 14 with septic arthritis were prospectively included. For each patient, gram stain, culture and polarization microscopy of synovial fluid was done and PCT, C-reactive protein (CRP), white blood cell count, uric acid and blood cultures were taken. Patients with septic arthritis, patients with non-septic arthritis with and without concomitant infection were compared. RESULTS: Patients with septic arthritis had a significant higher PCT concentration than patients with non-septic arthritis (p<0.0001). At a cut-off of 0.1 (0.25) ng/ml, sensitivity for septic arthritis was 100(93)% and specificity 46(75)%. Specificity rose to 93% after exclusion of patients with non-septic arthritis and concomitant infection. Both sensitivity and specificity for the diagnosis of septic arthritis were higher for PCT than CRP. CONCLUSIONS: Our data suggest that PCT seems to be a highly sensitive and specific marker for septic arthritis, depending on the clinical setting. Further studies are warranted.

[Progressive multifocal leukoencephalopathy in a non-AIDS patient: high efficiency of combined cytarabine and cidofovir]. / Leucoencéphalite multifocale progressive en dehors du sida: efficacité de l'association cytarabine-cidofovir.

INTRODUCTION: Progressive multifocal leukoencephalopathy (PML) is an opportunistic infection of the central nervous system, occurring in immunocompromised patients. Treatment, not codified to date, is more often inefficient with a rapid and fatal deterioration. CASE RECORD: A 48-year-old woman, treated with immunosuppressant agents for systemic lupus, presented with PML mimicking neurolupus flare. A complete remission was obtained with cytarabine and cidofovir. CONCLUSION: Combined cytarabine and cidofovir appears a promising therapeutic option in PML associated with autoimmune systemic disorders.

Determinants for membrane association of the hepatitis C virus RNA-dependent RNA polymerase.

The hepatitis C virus (HCV) RNA-dependent RNA polymerase (RdRp), represented by nonstructural protein 5B (NS5B), is believed to form a membrane-associated RNA replication complex together with other nonstructural proteins and as yet unidentified host components. However, the determinants for membrane association of this essential viral enzyme have not been defined. By double label immunofluorescence analyses, NS5B was found in the endoplasmic reticulum (ER) or an ER-like modified compartment both when expressed alone or in the context of the entire HCV polyprotein. The carboxyl-terminal 21 amino acid residues were necessary and sufficient to target NS5B or a heterologous protein to the cytosolic side of the ER membrane. This hydrophobic domain is highly conserved among 269 HCV isolates analyzed and predicted to form a transmembrane alpha-helix. Association of NS5B with the ER membrane occurred by a posttranslational mechanism that was ATP-independent. These features define the HCV RdRp as a new member of the tail-anchored protein family, a class of integral membrane proteins that are membrane-targeted posttranslationally via a carboxyl-terminal insertion sequence. Formation of the HCV replication complex, therefore, involves specific determinants for membrane association that represent potential targets for antiviral intervention.

The hepatitis C virus nonstructural protein 4B is an integral endoplasmic reticulum membrane protein.

The hepatitis C virus (HCV) nonstructural protein 4B (NS4B) is a relatively hydrophobic 27-kDa protein of unknown function. A tetracycline-regulated gene expression system, a novel monoclonal antibody, and in vitro transcription-translation were employed to investigate the subcellular localization and to characterize the membrane association of this viral protein. When expressed individually or in the context of the entire HCV polyprotein, NS4B was localized in the endoplasmic reticulum (ER), as shown by subcellular fractionation, immunofluorescence analyses, and double-label confocal laser scanning microscopy. In this compartment NS4B colocalized with the other HCV nonstructural proteins. Association of NS4B with the ER membrane occurred cotranslationally, presumably via engagement of the signal recognition particle by an internal signal sequence. In membrane extraction and proteinase protection assays NS4B displayed properties of a cytoplasmically oriented integral membrane protein. Taken together, our findings suggest that NS4B is a component of a membrane-associated cytoplasmic HCV replication complex. An efficient replication system will be essential to further define the role of NS4B in the viral life cycle.