Evaluation of a novel particle-based multi-analyte technology for the detection of anti-fibrillarin antibodies

Systemic sclerosis (SSc) is a heterogeneous autoimmune disease associated with several anti-nuclear antibodies (ANA), including those in the classification criteria (anti-centromere, anti-topoisomerase I (Scl-70), anti-RNA Pol III). However, the presence of less common antibodies such as anti-fibrillarin (U3-RNP) that generate a clumpy nucleolar pattern by HEp-2 indirect immunofluorescence assay (IFA, ICAP AC-9) are considered disease specific and are with clinical subsets of SSc, therefore playing a role in diagnosis and prognosis. A specific and sensitive anti-fibrillarin assay would be an important addition to serological diagnosis and evaluation of SSc. The goal of this study was to evaluate a new particle-based multi-analyte technology (PMAT) for the measurement of anti-fibrillarin antibodies. A total of 149 patient samples were collected including 47 samples from France (Lyon and Paris, n = 32) and Italy (Careggi Hospital, Florence, n = 15) selected based on AC-9 HEp-2 IFA staining (> 1:640, clumpy nucleolar pattern) and 102 non-SSc controls (inflammatory bowel disease (IBD) n = 20, Sjögren's syndrome (SjS) n = 20, infectious disease (ID) n = 7, systemic lupus erythematosus (SLE) n = 17, rheumatoid arthritis (RA) n = 17, and healthy individuals (HI) n = 21). All samples were tested on the anti-fibrillarin PMAT assay (research use only, Inova Diagnostics, USA). Additionally, the 47 anti-fibrillarin positive samples were also tested on PMAT assays for detecting other autoantibodies in ANA-associated rheumatic diseases (AARD). Anti-fibrillarin antibody data performed by fluorescence enzyme immunoassay (FEIA, Thermo Fisher, Germany) was available for 34 samples. The anti-fibrillarin PMAT assay was positive in 31/32 (96.9%, France) and 12/15 (80.0%, Italy) of samples preselected based on the AC-9 IIF pattern (difference p = 0.09). Collectively, the PMAT assay showed 91.5% (95% confidence interval (CI): 80.1-96.6%) sensitivity with 100.0% (95% CI: 96.4-100.0%) specificity in non-SSc controls. Strong agreement was found between PMAT and FEIA with 100.0% positive qualitative agreement (34/34) and quantitative agreement (Spearman's rho = 0.89, 95% CI: 0.77.9-0.95%, p < 0.0001). Although most anti-fibrillarin positive samples were mono-specific (69.8%), some expressed additional antibodies (namely Scl-70, centromere, dsDNA, Ro52, Ro60, SS-B, Ribo-P, DFS70, and EJ). In conclusion, this first study on anti-fibrillarin antibodies measured using a novel PMAT assay shows promising results where the new PMAT assay had high level of agreement to FEIA for the detection of anti-fibrillarin antibodies. The availability of novel AFA assays such as PMAT might facilitate the clinical deployment, additional studies, standardization efforts, and potentially consideration of AFA for next generations of the classification criteria.

Ganglion Cell Assessment in Rodents with Retinal Degeneration

Analysis of how retinal ganglion cells change in retinal degeneration is critical for evaluating the potential of photoreceptor restorative therapies. Immunocytochemistry in combination with image analysis provides a way for quantifying not only the density of ganglion cells during disease, but also information about their morphology and an evaluation of excitatory and inhibitory synaptic inputs. Here, we describe how indirect immunofluorescence can be used in retinal whole mounts to obtain information about ganglion cells in retinal degeneration.

Medical Devices; Immunology and Microbiology Devices; Classification of the Automated Indirect Immunofluorescence Microscope and Software-Assisted System. Final order

The Food and Drug Administration (FDA or we) is classifying the automated indirect immunofluorescence microscope and software-assisted system into class II (special controls). The special controls that apply to the device type are identified in this order and will be part of the codified language for the automated indirect immunofluorescence microscope and software-assisted system's classification. We are taking this action because we have determined that classifying the device into class II (special controls) will provide a reasonable assurance of safety and effectiveness of the device. We believe this action will also enhance patients' access to beneficial innovative devices, in part by reducing regulatory burdens.

[Automation of the Examination for Autoantibodies]

Antinuclear antibody (ANA) testing is indispensable for diagnosing and estimating clinical conditions of autoimmune diseases. This literature explains the usability and problem points regarding routine laboratory tests with examples of our own experiments regarding ANA diagnostics with some new technologies. The indirect immunofluorescence assay (IFA) is the gold standard for ANA screening, and it can detect more than 100 different antibodies, including the anti-proliferating cell nuclear antigen as well as anti- cytoplasmic antibodies. However, complicated procedures of conventional IFA and visual interpretation require highly skilled laboratory staff. The EUROPattern Cosmic IFA System (EUROIMMUN, Cosmic Corporation) and HELIOS* (Aesku Diag- nostics, MBL), which are computer-aided microscope systems for ANA testing, showed concordance of the positivity rate as high as 93.3 and 91.9%, respectively, and concordance of the antibody titer as high as 94.0 and 98.8%, respectively (within +/-1 titer) compared with the conventional method, on the measurement of different populations for each system. Although the computer-aided microscope system is not considered a complete system and laboratory staff should verify each result, it is a useful system for routine ANA analysis because it contributes to ANA stand- ardization and an efficient workflow. In our previous study, we demonstrated that BioPlex2200 (Bio-Rad), a fully automated immunoassay ana- lyzer using suspension bead array technology, was useful for the clinical diagnosis of autoimmune diseases. As an ANA screening test, the positive rate was low (7.2%) in healthy subjects, and comparable with that of IFA ( X160). The prevalence of disease-specific ANA in connective tissue disease patients was comparable with the general occurrence rate except for anti-dsDNA antibody in SLE. In accordance with the results of double immunodiffusion and Western blotting with the conventional method, the concordance rate between BioPlex2200 and conventional methods was high (95.0-100%) except for anti-dsDNA antibody. To provide high-quality and prompt clinical tests while considering the efficiency of working and cost reduc- tion, each laboratory should actively innovate and operate these advanced inspection technologies. [Review].

Evaluation of five commercial assays for the detection of anti-dsDNA antibodies: three Crithidia luciliae indirect immunofluorescence test kits and two enzyme immunoassay kits

OBJECTIVE

There are various methods for anti-dsDNA detection. Crithidia luciliae indirect immunofluorescence test (CLIFT) and enzyme immunoassay (EIA) are the most commonly used at present. A number of CLIFT and EIA kits are commercially available. The objective of the present study was to evaluate the diagnostic performance of three commercial CLIFT kits, two commercial EIA kits, and their combinations for anti-dsDNA detection.

MATERIAL AND METHOD

One hundred thirty nine sera sent for anti-dsDNA testing were investigated. Three commercial CLIFT kits (kit C1, C2, and C3) and two commercial EIA kits (kit E1 and E2) were evaluated. Sensitivities and specificities were calculated. The gold standard methods were the consensus results of all five kits, together with the clinical diagnosis when the results of five kits were discrepant.

RESULTS

Of 139 sera investigated, 94 (67.6%) sera showed concordant results for all five kits and 45 (32.4%) sera showed discordant results. Thirty-five of those 45 patients (77.7%) were diagnosed as SLE. Sensitivities and specificities of the kits were as follows, Cl 82.1% and 94%, C2 46.4% and 100%, C3 78.6% and 98.8%, E1 71.4% and 94%, and E2 75% and 93.8%, respectively. Kit C3 yielded the maximum sum of sensitivity and specificity (177.4%). Sensitivities and specificities of the combinations of CLIFT and EIA kits were as follows, C1 + E1 89.3% and 90.4%, C1 + E2 98.2% and 87.9%, C2 + E1 73.2% and 94%, C2 + E2 82.1% and 92.8%, C3 + E1 85.7% and 94%, and C3 + E2 94.6% and 91.6%, respectively. The combination of kit C3 and E2 yielded the maximum sum of sensitivity and specificity (186.2%).

CONCLUSION

Kit C3 was the assay of choice for anti-dsDNA detection. EIA kits yielded lower sensitivities and specificities than two of three CLIFT kits. Therefore, they should not be used as the first assay for anti-dsDNA screening. When CLIFT and EIA assays were combined, sensitivities were increased Kit E2 helped CLIFT kits to detect more SLE cases than E1.

Enhanced microfiltration devices configured with hydrodynamic trapping and a rain drop bypass filtering architecture for microbial cells detection

Ultra-fine (<1 microm) microfilters are required to effectively trap microbial cells. We designed microfilters featuring a rain drop bypass architecture, which significantly reduces the likelihood of clogging at the cost of limited cell loss. The new rain drop bypass architecture configuration has a substantially lower pressure drop and allows a better efficiency in trapping protozoan cells (Cryptosporidium parvum and Giardia lamblia) in comparison to our previous generation of a microfilter device. A modified version displaying sub-micron filter gaps was adapted to trap and detect bacterial cells (Escherichia coli), through a method of cells labeling, which aims to amplify the fluorescence signal emission and therefore the sensitivity of detection.

Comparison of desmoglein ELISA and indirect immunofluorescence using two substrates (monkey oesophagus and normal human skin) in the diagnosis of pemphigus

A prospective study was performed to assess the usefulness of desmoglein enzyme-linked immunosorbent assay testing compared with indirect immunofluorescence in the diagnosis of new cases of pemphigus, as well as to compare the relative sensitivities of monkey oesophagus and normal human skin as substrates for indirect immunofluorescence. These tests were performed on the sera of 29 consecutive new cases of pemphigus diagnosed over a 2-year period based on clinical, histological and direct immunofluorescence findings. Desmoglein enzyme-linked immunosorbent assay was positive in all patients whereas indirect immunofluorescence was positive in only 25 of 29 patients. All four patients with negative indirect immunofluorescence had positive antinuclear antibodies or cytoplasmic fluorescence that could have masked the anti-intercellular antibodies. Desmoglein enzyme-linked immunosorbent assay appeared to reflect the disease activity better than indirect immunofluorescence in a few patients who had active disease of recent onset. Monkey oesophagus was found to be superior or equal to human skin as a substrate for indirect immunofluorescence in both pemphigus vulgaris and foliaceus.

Automated detection of immunofluorescently labeled cytomegalovirus-infected cells in isolated peripheral blood leukocytes using decision tree analysis

BACKGROUND

Cytomegalovirus (CMV) infection continues to be a major problem for immunocompromised patients. Detection of viral antigens in leukocytes (antigenemia assay) is widely used for the diagnosis of CMV infection and for guiding antiviral therapy. The antigenemia technique, contingent upon the manual microscopic analysis of rare cells, is a laborious task that is subject to human error. In this study, we combine automated microscopy with artificial intelligence for reliable detection of fluorescently labeled CMV-infected cells.

METHODS

Cytospin preparations of peripheral blood leukocytes were immunofluorescently labeled for the CMV lower matrix phosphoprotein (pp65) and scanned in the Rare Event Imaging System (REIS), a fully automated image cytometer. The REIS detected potential positive objects and digitally recorded 49 measured cellular features for each identified case. The measurement data of these objects were analyzed by the See5 decision tree (DT) algorithm to ascertain whether they were true-positive detections.

RESULTS

The DT was built from the measurement data of 2,047 true- and 2,028 false-positive detections, collected from 32 patient samples. By designating misclassifications of false-negatives three times more costly, the 10-fold cross-validation sensitivity, specificity, and misclassification error of the assay was 94.3%, 56.2%, and 25%, respectively. The method was also validated using an independent test set of 21 patient samples, in which similar results were obtained.

CONCLUSIONS

To our knowledge, this study represents the first attempt to improve the accuracy of rare event image cytometry through the implementation of artificial intelligence methodology. Results suggest that cost-sensitive decision tree analysis of digitally measured cellular features vastly improves the performance of rare event image cytometry.

Methods in virus diagnosis: immunofluorescence revisited

BACKGROUND

Immunofluorescence (IF) has been used in many laboratories for virus diagnosis but has begun to fall inappropriately out of favour as a diagnostic method as pressure on budgets and for objective quality control increases.

OBJECTIVES

To review the status, value and benefits of IF.

CONCLUSIONS

IF has, we believe, still a valuable role to play in routine virus diagnosis because it is rapid, accurate (with properly validated reagents), flexible and, by giving feedback on the quality of the specimens collected, promotes dialogue with the customer clinicians to their benefit and to that of the diagnostic laboratory. These benefits are not easily duplicated by other methods or techniques. While such rapid diagnosis primarily benefits the individual patient, providing results within a clinically relevant time has a secondary effect of increasing use of the service. It is our experience that the availability of rapid IF diagnosis (as opposed to culture or serology) for respiratory viral infections leads to a substantial increase in its use, thereby enhancing the amount and breadth of the resultant epidemiological data.

Comparison of ANA endpoint dilution using the PolyTiter immunofluorescent titration system and conventional serial dilution

The PolyTiter immunofluorescent titration system (PolyTiter system), an attachment for conventional fluorescent microscopes, facilitates immunofluorescent antinuclear antibody (IFA-ANA) testing by using calibrated light attenuation to determine the semiquantitative endpoint dilution or titer of ANA-positive specimens. The objective of this study was to compare the determination of ANA titer using the PolyTiter system to that of the conventional serial dilution method. A total of 172 consecutive ANA-IFA positive serum specimens, including the four most common pattern types, were evaluated in parallel by two readers to determine the dilution endpoint. The two methods produced equal dilution endpoints in 78 specimens (45%), within 1-dilution endpoint in 121 specimens (70%), and within 2-dilutions endpoint in 158 specimens (92%). The conventional method consistently produced a more conservative dilution endpoint than the PolyTiter system for three of the four patterns evaluated (i.e., centromere, nucleolar, and speckled vs. homogeneous). The PolyTiter system demonstrated satisfactory performance in comparison to the current standard for determining ANA dilution endpoints, while significantly reducing operator labor, time, and materials usage.

Evaluation of the automatic fluorescent image analyzer, Image Titer, for quantitative analysis of antinuclear antibodies

By making comparisons with the usual manual method, we evaluated an automatic fluorescent image analyzer (Image Titer, Tripath Imaging, Burlington NC), the software for which was developed to simplify measuring indirect immunofluorescent antinuclear antibodies (FANAs). In this new system, images of the stained sample are displayed, and it measures the FANA titer and staining pattern using only 1 slide per subject and does not required the staining of a series of diluted samples as does the manual method. This system showed good reproducibility and linearity for 4 types of control serum samples (with homogeneous, speckled, discrete speckled, and nucleolar staining patterns). In 132 serum samples, consistency between the methods was 100% for the FANA staining pattern and 93.9% for the FANA titer. The Image Titer system detected each pattern in samples with 2 mixed patterns. This system should partly reduce labor and lead to results with minimum differences among individuals, including newly trained persons.

Evaluation of total PSA assay on vitros ECi and correlation with Kryptor-PSA assay

BACKGROUND

An increasing number of multiparametric immuno-analysers for PSA assays are available. As different immuno-assays may vary in their analytical quality and their accuracy for the follow-up of patients, expertise is necessary for each new assay.

METHODS

The PSA assay on the Vitros-ECi analyser has been evaluated and compared with the PSA assay from the Kryptor analyser.

RESULTS

Variation coefficients were 0.91 to 1.98% for within-run assays, and 4.2% to 5.4% for interassay (PSA levels = 0.8 microgram/L to 33.6 micrograms/L). Dilution tests showed 93 to 136% recovery until 70 micrograms/L PSA. Functional sensitivity was estimated at 0.03 microgram/L. Equimolarity of the test was confirmed. Correlation of PSA levels measured with Vitros-ECi and Kryptor analysers displayed a correlation coefficient r2 of 0.9716. The half-lives and doubling times of PSA were similar using both methods.

CONCLUSION

Vitros-ECi PSA assay meets the major criteria for the management of prostate cancer patients.

96-Well plates providing high optical resolution for high-throughput, immunofluorescence-based screening of monoclonal antibodies against Toxoplasma gondii

We have developed a method for high resolution, high magnification immunofluorescence-based screening in a multi-well format, using a recently introduced 96-well plate specifically developed for fluorescence microscopy. We report here on the use of these plates to screen hybridoma supernatants for reactivity with specific subcellular compartments of the protozoan parasite Toxoplasma gondii. This has proven to be a powerful screening strategy, particularly when combined with high-throughput immunoblotting, and has enabled us to generate nine different monoclonal antibodies (MAbs) against either the periphery or structures within the apical end of T. gondii. The availability of a disposable, inexpensive, 96-well plate with optical properties suitable for high magnification imaging could lead to applications in a variety of fluorescence-based screening protocols.