Can Polymerized C9 be a New Disease Activity Parameter in Rheumatoid Arthritis? / 대한류마티스학회지

OBJECTIVE: Rheumatoid arthritis (RA) is a chronic, recurrent, systemic inflammatory disease and results in major deformity or dysfunction of joints. A disease activity parameter has important clinical significance because it is a useful objective tool for assessing disease activity and planning individualized therapeutic program. However, in RA, only a few parameters have been available such as C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), or rheumatoid factor (RF). By using these parameters, it is difficult to recognize concomitant nephropathy in RA. Therefore, as a new disease activity parameter for RA and a marker for nephropathy, we evaluated polymerized C9 which is the neoantigen produced after in vitro activation of complement and is quantified by using an enzyme conjugated monoclonal antibody. METHODS: Polymerized C9 (CAE, INCSTAR-DiaSorin, Italy), CRP, ESR and RF testing on 86 patients diagnosed with RA were undertaken. According to clinical and laboratory review, we grouped the patients into three disease categories as active RA (symptomatic, n=43), inactive RA (asymptomatic, n=35), and RA with nephropathy (n=8) and compared the means between three groups. RESULTS: In comparing with each disease monitoring parameter between groups, polymerized C9, CRP, ESR, and RF discriminated active RA from inactive RA (p<0.05). The ROC performance test showed polymerized C9 and CRP are the two best parameters in discriminating disease activity of RA. Furthermore, only polymerized C9 accurately discriminated disease activity and also predicted nephropathy in RA patient (p<0.05). CONCLUSION: Like CRP, Polymerized C9 can be a useful disease activity parameter for RA and also a predictive parameter for RA nephropathy.

A Method for Measuring Uric Acid Accurately in Refrigerated Urine Specimens / 대한진단검사의학회지

BACKGROUND: There have been many reports about the decrease in uric acid concentration in refrigerated urine specimens as compared to fresh urine. In an effort to correct this problem, pre-treatment steps such as the pre-alkalinization of sample tubes or the pre-dilution of urine were recommended before the refrigeration. The authors sought to find a way to correct the decreased measurement of uric acid concentrations in the refrigerated urine samples. METHODS: The uric acid concentrations of 53 fresh urine samples were measured and all were refrigerated. After 24 hours of refrigeration, the samples were measured for their uric acid concentrations (the refrigerated samples). All samples were then mixed well with 1 M NaOH 20 microL/mL (the refrigerated-alkalinized samples) and they were again measured for their uric acid concentrations. The differences of uric acid concentrations between the fresh urine samples and the refrigerated samples and also between the fresh urine samples and the refrigerated-alkalinized samples were noted. RESULTS: In a precipitated group of 14 urine samples, the compared results between the fresh urine and the refrigerated urine showed a statistically significant difference (P<0.05). However, there were no significant differences between the fresh urine and the refrigerated-alkalinized urine (P=0.49). In a non-precipitated group, there were no significant differences between the fresh urine and the refrigerated urine, or between the fresh urine and the refrigerated-alkalinized urine (P=0.47, P=0.18). CONCLUSIONS: For 24 hour refrigerated urine samples, the addition of 1 M NaOH 20 microL/mL to the urine samples after refrigeration was recommended for accurate measurement of uric acid concentration.

Immunophenotyping Panels for the Diagnosis of Acute Promyelocytic Leukemia: Evolution and Diagnostic Capacity / 대한진단검사의학회지

BACKGROUND: Acute promyelocytic leukemia (APL) has two subtypes, a typical French-American-British (FAB)-M3 type and an atypical FAB-M3v type described as microgranular variant, and immunophenotyping is a rapid and accurate method for the diagnosis of APL. We tried to define immunological criteria for the diagnosis of APL in each different period from 1987 to 2003. The purpose of this study was to compare the discrimination capacity of several panels with FAB classification. METHODS: We applied immunophenotyping panel I, II, and III for the diagnosis of APL in each of the following three different periods: Panel I [HLA-DR(-), CD15(-)] (1987-1991); Panel II [HLA-DR(-), CD13(+), CD33(+), CD14(-)] (1992-1994); and Panel III [HLA- DR(-), CD34(-), CD13(+), CD33(+), CD14(-)] (1994-2003) with negative lymphoid markers in all panels. Standard FAB classification and direct immunofluorescence method were applied to diagnosis in 570 cases of acute leukemia. RESULTS: The immunophenotyping to identify FAB subtype AML-M3 and M3v was established as the panel of [HLA-DR (-), CD34 (-), CD13 and/or CD33 (+), CD14 (-)] with negative lymphoid markers (CD19, CD10, CD20, CD22, CD3, CD5, and CD7). The sensitivity and specificity of this panel for the diagnosis of APL was 100% and 99%, respectively. CONCLUSIONS: Our study demonstrates the evolution of immunophenotyping panel from a primitive to advanced design. This immunophenotyping panel can be a "quick reference" for the diagnosis of APL without extra effort.

A New Digital Image Processing Technique for Mixed Pattern Analysis of Anti-neutrophil Cytoplasmic Antibody Test / 대한류마티스학회지

OBJECTIVE: Anti-neutrophil cytoplasmic antibody (ANCA) is an important marker for the diagnosis and the classification of rheumatic diseases and systemic vasculitis. If the autoantibodies that can be stained in the nucleus of neutrophil used for substrate of ANCA test, there's a need for its differential diagnosis from real p-ANCA. This paper focuses on digital image processing technique for the differentiation of p-ANCA without performing additional tests. METHODS: Positive ANCA results which showed mixed fluorescent pattern were transformed into digital image. Using Matlab (MathWorks, U.S.A.), we developed 2D to 3D transformation method and virtual tomography for the interpretation of mixed fluorescent pattern, and compared these results with ANA and anti-DNA test by indirect immunofluorescence (IIF) method using IT-AIT, IT-ANCA, and IT-DNA kit (ImmunoThink, Korea). RESULTS: By applying the 3D transformation method and virtual tomography to the results of ANCA test where combined antibodies exist, we were able to separate each different fluorescent pattern that were difficult to separate by manual reading. CONCLUSION: The new digital image analysis methods developed in this study displace some of the disadvantages of IIF method. Therefore, these methods can easily be applied to complex samples, and can allow rapid and accurate tests for rheumatic diseases and other autoimmune diseases.

Can Polymerized C9 Predict and Differentiate Nephropathy in Various Renal and Rheumatic Diseases? / 대한류마티스학회지

OBJECTIVE: Various rheumatic diseases are often complicated by nephropathy and cases combined with nephropathy show a poorer prognosis. Traditional diagnostic tools for nephropathy are complement activity (CH50) or serum levels of C3 and C4. These tests are neither sensitive nor precise for clinical use because they have a wide reference range and a number of reagents that are difficult to standardize. Polymerized C9 testing is a novel approach for measurement of total classical complement activity. After in vitro activation of complement in a well of a microtiter plate, the neoantigen of terminal polymerized C9 is quantified by using an enzyme-conjugated monoclonal antibody. We evaluate clinical significance of polymerized C9 as a predictor and differential marker for nephropathy in various renal and rheumatic diseases. METHODS: Polymerized C9 testing (CAE, INCSTAR-DiaSorin, Italy) on 69 patients with various rheumatic or renal diseases and 13 normal controls was undertaken. According to the polymerized C9 levels, we grouped each disease into five categories and compared means between groups. RESULTS: The increased group included pyelonephritis and the normal group included CRF, normal control and nephrotic syndrome. The slightly decreased group included glomerulonephritis and SLE without nephritis. The moderately decreased group included RA with nephritis and the markedly decreased group included lupus nephritis. There were significant mean differences between each group (p<0.05). CONCLUSION: We conclude that polymerized C9 can be a useful reference in the initial differential diagnosis of nephropathy and in the appropriate approach for each rheumatic disease.

Is the LE Cell Test Necessary? / 대한임상병리학회지

BACKGROUND: Before the introduction of the antinuclear antibody test (ANA), the lupus erythematosus (LE) cell test was a useful diagnostic test for systemic lupus erythematosus(SLE) But, the ANA test has replaced the LE cell test in virtually all laboratories as the current routine test for SLE. However, because the LE cell test is still performed in some laboratories, the authors compared the LE cell test with the ANA test to reevaluate the LE cell test. METHODS: A total of 522 cases were evaluated from Aug. 1990 to Aug. 1994. In these cases, the LE cell test and the ANA test were performed simultaneously, and the results were compared. The authors defined the 'True LE Phenomenon' as only when the LE cell test results agreed with the anti-histone antibody pattern of the ANA test. RESULTS: Of the total 522 cases, 56 cases(10.7%) were SLE. The LE cell test was positive in 22 cases(39.3%) and the ANA test in 56 cases(100%). The LE cell test produced 6(27%) false positive cases and 3 (8.8%) false negative cases. Therefore, the sensitivity of the LE cell test that was verified by the ANA test was only 28.6%. On the other hand, the sensitivity of the ANA test was 100%. In 2 cases, the LE cell results were different in repetitive tests although the ANA results were the same. In 2 other cases, it was impossible to interprete the results of the LE cell test because of severe leukopenia. CONCLUSIONS: The authors concluded that the LE cell test showed markedly low sensitivity and a high false positive and false negative rates for SLE, and that the LE cell test was difficult to perform and interpret accurately due to numerous interfering factors. Therefore, for accurate diagnosis of SLE, the LE cell test must be replaced by more definitive and quantitative immunologic tests in all laboratories such as the ANA test.

Is the LE Cell Test Necessary? / 대한임상병리학회지

BACKGROUND: Before the introduction of the antinuclear antibody test (ANA), the lupus erythematosus (LE) cell test was a useful diagnostic test for systemic lupus erythematosus(SLE) But, the ANA test has replaced the LE cell test in virtually all laboratories as the current routine test for SLE. However, because the LE cell test is still performed in some laboratories, the authors compared the LE cell test with the ANA test to reevaluate the LE cell test. METHODS: A total of 522 cases were evaluated from Aug. 1990 to Aug. 1994. In these cases, the LE cell test and the ANA test were performed simultaneously, and the results were compared. The authors defined the 'True LE Phenomenon' as only when the LE cell test results agreed with the anti-histone antibody pattern of the ANA test. RESULTS: Of the total 522 cases, 56 cases(10.7%) were SLE. The LE cell test was positive in 22 cases(39.3%) and the ANA test in 56 cases(100%). The LE cell test produced 6(27%) false positive cases and 3 (8.8%) false negative cases. Therefore, the sensitivity of the LE cell test that was verified by the ANA test was only 28.6%. On the other hand, the sensitivity of the ANA test was 100%. In 2 cases, the LE cell results were different in repetitive tests although the ANA results were the same. In 2 other cases, it was impossible to interprete the results of the LE cell test because of severe leukopenia. CONCLUSIONS: The authors concluded that the LE cell test showed markedly low sensitivity and a high false positive and false negative rates for SLE, and that the LE cell test was difficult to perform and interpret accurately due to numerous interfering factors. Therefore, for accurate diagnosis of SLE, the LE cell test must be replaced by more definitive and quantitative immunologic tests in all laboratories such as the ANA test.