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A high sensitivity quantitative assay for hepatitis B virus (HBV) surface antigen (HBsAg-HQ assay) was recently developed and is useful for earlier detection of HBV reactivation. We created HBsAg-HQ assay operational proce- dures by the sample transport system and laboratory information system. In this study, we evaluated the perfor- mance and utility of the HBsAg-HQ assay based on our operational procedures using internal quality control (IQC) data and 13,762 samples routinely measured for 8 months. The IQC data of the HBsAg-HQ assay demonstrated good accuracy (CV: 1.6-2.7%). The difference in IQC data between two of the same analyzers or several reagent lots had no clinical significance. Of 13,762 samples, HBsAg titer was negative in 12,592(91.5%) and positive in 1,169(8.5%), and HBsAg negative samples were remarkably lower(0.001 IU/mL) than the cut-off value(0.005 IU/mL). Among 114 HBsAg weakly positive samples ranging from 0.005 to 1.000 IU/mL, false positive results occurred in 12 samples, which were converted into negative results after re-measurement. We could effectively perform carry-over prevention and dilution of high titer samples using our operational procedures. Furthermore, we performed inhibition test in 52 HBsAg weakly positive samples, and 20 samples, most of which were taken from patients with connective tissue disease or malignancy, were judged as non-specific reactivity. Taken together, our operational HBsAg-HQ assay procedures may contribute to efficient workflow for routine testing. Moreover, the HBsAg-HQ assay may be clinically useful for not only highly sensitive assays, but also for reducing false positives.

The fully automated HELIOS® system for antinuclear antibody (ANA) test is capable of automatically per- forming all IFA procedures. We evaluated the analytical performance, characteristics and utility of HELIOS system as ANA screening test. We compared HELIOS system and the conventional methods in sera from 161 connective tissue disease (CTD) patients and 250 healthy individuals. The presence and titer of ANA were automatically determined by performing HELIOS system at 1:80 dilution and the ANA titers were com- pensated by several dilution and visual determination in sera with a high ANA titer and ANA-positive sera combined with anti-cytoplasmic antibody. The ANA staining patterns were assessed by visual determination of the digital image on HELIOS system. The total concordance rate between the conventional method and HELIOS system was 94.4%. The concordance of ANA titer (within ± 1 tube difference) between the con- ventional method and automated or compensated evaluation of HELIOS system was 85.7% or 98.8%, respec- tively. The concordance rate of six nuclear staining patterns was from 81.4% to 100% and the discrepancies of granular staining pattern might be caused by the fixation of HEp-2 cells. The positive rates of ANA in CTD patients and healthy individuals were comparable with the conventional methods. Taken together, HELIOS system can appropriately perform the automated determination of ANA except in some cases and is useful as ANA screening test. Furthermore, this system can contribute not only an efficient IFA procedure but also the ANA standardization by IFA. [Original].

Antinuclear antibody (ANA) testing is indispensable for diagnosing and understanding clinical conditions of autoimmune diseases. The indirect immunofluorescence assay (IFA) is the gold standard for ANA screening, and it can detect more than 100 different antibodies, such as anti-PCNA as well as anti-cytoplasmic antibodies. However, complicated procedures of conventional IFA and visual interpretation require highly skilled laboratory staff. This study evaluates the capability, characteristics, and applicability of the recently developed ANA detection system (EUROPattern Cosmic IFA System, EPA) using HEp20-10 cells and the automated pattern recognition microscope. Findings using EPA and conventional methods were compared in 282 sera obtained from connective tissue disease patients and 250 sera from healthy individuals. The concordance of the positivity rate, antibody titer (within +/- 1 tube difference), and the accurate recognition rate of ANA patterns between the automated EPA method and the microscopic judgement of the EPA image by eye was 98.9, 97.4, and 55.3%, respectively. The EPA method showed concordance of the positivity rate as high as 93.3% and concordance of the antibody titer as high as 94.0% (within +/- 1 titer) compared with the conventional method. Regarding the four typical patterns of ANA (homogeneous, speckled, nucleolar, and centromere), large differences between the EPA and conventional methods were not observed, and the rate of concordance between the final EPA result and the conventional method was from 94.1 to 100%. The positivity rate of ANA using the EPA and conventional methods showed marked agreement among the six connective tissue diseases (SLE, MCTD, SSc, PM/DM, and SS) and healthy individuals. Although the EPA system is not considered a complete system and laboratory staff should verify the results, it is a useful system for routine ANA analysis because it contributes to ANA standardization and an efficient workflow.

Measurement of matrix metalloproteinase-3(MMP-3), a marker for rheumatoid arthritis, by means of latex agglutination turbidimetric immunoassay (LTIA), has come to replace ELISA kit, but pre-improvement LTIA kit S(Sekisui Medical) frequently shows false values resulting from non-specific reactions. We analyzed factors influencing the frequency of non-specific reactions for MMP-3 detection using various methods.Serum MMP-3 levels were measured in 1,214 routine samples or 57 panels with various immunoserological abnormalities by means of pre-improvement and improved kit S, LTIA kit E (Eiken Chemical) and ELISA kit. Non-specific reaction samples were selected either from the routine samples based on the results of correlativity tests between the kits and of dilution linearity tests, or from 57 panels with immunoserological abnormalities based on the results of recovery tests. To explore the factors causing non- specific reactions, titers of rheumatoid factor (RF), immunoglobulins and four heterophil antibodies were measured in these samples. In addition, changes in findings as a result of reduction treatment or IgM absorption were examined in selected samples to clarify the effect of heterophil antibodies.Samples which showed suspected false values probably due to non-specific reaction numbered 75, 15, 5 and 17 as measured with pre-improvement kit S, improved kit S, kit E and ELISA kit, respectively. Kit S also showed high rate of deviation in recovery tests on panels with immunoserological abnormalities. Rate of RF titer in samples with non-specific reactions was higher than that of other factors. Non-specific reaction could be inhibited in two samples as a result of reduction treatment or absorption of IgM subtype.Pre-improvement kit S showed a higher rate of non-specific reactions than other kits. The most common cause of non-specific reactions is thought to be high RF titer, but high levels of IgM, including heterophil antibodies, may also affect the values of MMP-3.

Connective tissue diseases are chronic inflammatory diseases that can affect multiple organs and, thus, have a broad spectrum of clinical presentations. Various autoantibodies are detected in patients with connective tissue diseases, represented by anti-nuclear antibody for systemic lupus erythematosus (SLE), systemic sclerosis (SSc), polymyositis/dermatomyositis (PM/DM), Sjögren's syndrome, and mixed connective tissue disease. Assessment of the autoantibody profile is fundamental for the clinical management of patients with connective tissue diseases, providing important data for the diagnosis, clinical characterization, and disease activity evaluation. Anti-ribosomal P antibody and anti-NMDA receptor antibody are associated with neuropsychiatric SLE. Anti-synthetase syndrome comprises the association of myositis (PM/DM), interstitial lung disease, fever, Raynaud's phenomenon, mechanic's hands, and anti-aminoacyl tRNA synthetase antibodies. Anti-MDA5 antibody is detected in patients with clinically amyopathic DM, often complicated by rapidly progressive interstitial lung disease. Between 50 and 75% of malignancy-associated DM patients are positive for anti-TIF1-γ antibody. Anti-RNA polymerase III antibody is associated with diffuse cutaneous SSc and renal crisis. This review focuses on the importance and usefulness of these autoantibodies for the diagnosis and management of patients with connective tissue diseases in clinical practice.

Anti-SS-A/Ro antibody is commonly found in the sera of patients with rheumatic disease. The antigenic components of SS-A/Ro are 60kD. and 52kD-Ro protein. Only anti-60kD SS-A/Ro antibody is detected by commonly used tests in clinical laboratories. "UniCAP EliA SS-A/Ro" is a new reagent using fluorescence enzyme immunoassay (FEIA) based on a mixture of both 60kD- and 52kD-Ro antigens. We evaluated the efficacy of detecting both anti-60kD and 52kD SS-A/Ro antibodies.We collected sera from 264 rheumatic disease patients and 106 healthy subjects. Anti-SS-A/Ro antibodies were measured by the new reagent along with conventional method. Anti-52kD and 60kD SS-A/Ro antibodies were measured by ELISA kit in rheumatic disease patients.Anti-SS-A/Ro antibody levels were higher in patients with Sjögren's syndrome than those with SLE or RA. The prevalence of anti-SS-A/Ro antibody in rheumatic disease patients and healthy subjects were comparable with the conventional method, and patients with Sjögren's syndrome had highest prevalence of anti-SS-A/Ro antibody. Concordance rate between EliA and conventional method, and EliA and DID, were 96.6% and 94.3%, respectively. ELISA analysis revealed that patients with Sjögren's syndrome had anti-52kD SS-A/Ro antibody at high rates, while anti-60kD SS-A/Ro antibody was widely found in rheumatic disease patients. Three patients were positive only for anti-52kD SS-A/Ro antibody.Taken together, "UniCAP EliA SS-A/Ro" is useful as a screening test for anti-SS-A/Ro antibodies.

Autoimmune diseases are complex diseases in which both genetic and environmental factors are involved. Excessive oxidative stress is thought to have an important role in the pathogenesis of autoimmune diseases by enhancing the inflammation, inducing apoptotic cell death, and breaking down the immunological tolerance. When the state of oxidative stress was investigated in patients with rheumatoid arthritis(RA), systemic lupus erythematosus(SLE), and Sjögren's syndrome(SS) by oxidative stress profile(OSP), most subjects were in excessive oxidative stress or in defective antioxidant potentials. The thioredoxin(TRX) level in peripheral blood was significantly higher in these patients than in healthy subjects. Urinary excretion of 8-hydroxy-guanosine was also significantly increased in these patients compared with healthy subjects. We have proven that oxidative stress as well as UV irradiation induced the expression of SS-A/Ro52 autoantigen on the cell surface of keratinocytes. Oxidative stress not only injures the cellular components but also induces cellular responses, including apoptosis and gene activation. We also identified that GSTM1 null genotype was a candidate gene for susceptibility to SS and was associated with SS-A/Ro autoantibody production. In the synovial fluid of RA patients, TRX was abundantly detected and was produced in the lining layer of synovial tissue, indicating that TRX might protect synovial tissue from oxidative stress. Infections, UV irradiation, coldness, and emotional stress have been clinically well known as developing and exacerbating factors for autoimmune diseases. These environmental factors are closely related to oxidative stress. It is very important to develop reliable test methods to detect the state of oxidative stress and antioxidants.