What is the Best Method in Measuring Rheumatoid Factors? / 대한류마티스학회지

OBJECTIVE: Rheumatoid factor (RF) is used as one of the criteria for the diagnosis of rheumatoid arthritis (RA). Nephelometers are widely used in laboratories to quantitatively measure RF. In nephelometric ways of measurement, there are endpoint nephelometry and rate nephelometry. BN II System (BN II) (Dade Behring Marburg GmbH, USA) is a well known endpoint nephelometer while IMMAGE System (IMMAGE) (Beckman Coulter, USA) is a well known rate nephelometer. We compared these two automatic nephelometric analyzers to evaluate which method shows the best results. METHODS: We measured RF (n=195) using the two machines. We evaluated the correlation between BN II and IMMAGE. We compared the results of BN II with those of IMMAGE in terms of interference and clinical usefulness. RESULTS: The correlation coefficient (r) of RF was 0.9310 (p<0.0001). We could not find any significant interference for BN II with high concentration of triglyceride or bilirubin, but IMMAGE showed significant interferences with high concentrations of triglyceride and bilirubin. The sensitivity and specificity of BN II for the diagnosis of RA were 90.3% and 82.4%. Those of IMMAGE were 86.1% and 74.5%. CONCLUSION: BN II was enough to satisfy the analytical features and it showed better results than IMMAGE. We expect BN II, the endpoint nephelometer, to be the best equipment in measuring RF for diagnosis of RA.

The Clinical Significance of Shared Epitope in Rheumatoid Arthritis / 대한류마티스학회지

OBJECTIVE: The application of DNA sequencing and molecular-based typing to detect HLA-DRB1 alleles showed that those associated with rheumatoid arthritis (RA)shared a consensus amino acid sequence (QKRAA or QRRAA)at positions 70-74 of the third hypervariable region of the HLA-DRB1 chain.This is defined as the so-called 'shared epitope'. Many studies reported that shared epitope was associated with RA susceptibility and disease severity.Also,DRB1*0401 and DRB1*0404 alleles confer genetic predisposition to RA in Caucasian.We studied the frequency of shared epitope,DRB1*04,DRB1*0401,and DRB1*0404 in Korean RA patients using monoclonal antibodies.We also tried to investigate the influence of these factors on susceptibility and severity in RA patients and to evaluate the method. METHODS: RA patients were 32 persons with classical or definite RA who attended the Hospital for Rheumatic Diseases,Hanyang University Hospital,Seoul,Korea.We separated lymphocytes from whole blood and used indirect immunofluorescence staining method using four monoclonal antibodies (Terra Nova,Canada). RESULTS: The frequency of DRB1*04 and shared epitope were 56%and 56%, respectively.That of DRB1*0401 and DRB1*0404 were positive in 19%and 9%of all patients,respectively.There were no association between share epitope and disease severity. CONCLUSION: The shared epitope is expressed with high frequency,as many as DR4 frequency in Korean RA patients.But the frequency of DRB1*0401 and DRB1*0404 is low different from Caucasian.The used method is simple and easy to screen shared epitope.

Measurement of urinary microalbumin using enzyme-linked immunosorbent assay and latex agglutination method / 대한임상병리학회지

BACKGROUND: Microabluminuria is defined as the amount of albumin in urine that is excreted above the normal but cannot be detected by the standard clinical dipstick test, and is used as a predictor for clinical diabetic nephropathy. It is therefore important to diagnose microalbuminuria with a sensitive, rapid and simple method. We developed a home-made ELISA for measuring microalbumin and a home-made latex agglutination method for diagnosing microalbuminuria. The aim of this study is to evaluate these methods and to evaluate the possibility of application for clinical uses. METHODS: We collected 24 hour urine samples from 86 patients at Hanyang University Kuri Hospital from January 1999 to April 1999. The principle of the ELISA is a double antibody sandwich technique. The latex agglutination method used rabbit anti-human albumin and latex bead. RESULTS: Within-run precisions of ELISA were 8.3% in low concentrations and 7.7% in high concentrations. Between-run precisions were 8.7% and 7.8%, respectively. The correlation coefficient between ELISA and RIA in samples from 80 patients was 9.4(P < 0.01). The sensitivity and specificity of the latex method were 90% and 97%, respectively. CONCLUSIONS: The home-made ELISA was a sensitive and relatively simple method for quantitation of microalbumin and correlated highly with the RIA. Therefore, this ELISA may replace RIA and can be used in other clinical uses. The latex agglutination method is simple, rapid, inexpensive and sensitive and correlated highly with the RIA. Clinically, this method may help patients and physicians in screening microalbuminuria.

A case of microgranular variant of acute promyelocytic leukemia with strong positive reaction in nonspecific esterase stain / 대한임상병리학회지

We report a case of microgranular variant of acute promyelocytic leukemia with strong positivity in nonspecific esterase stain (inhibited by sodium fluoride) in a 21-onth-ld girl who had complained of intermittent fever and severe vomiting. At admission, she showed marked leukocytosis in the peripheral blood. The majority of leukocytes were immature cells which exhibited marked nuclear irregularity and had sparse dust-ike granules in their cytoplasm. In immunophenotyping, these cells showed CD13 and CD33 positivity and in cytogenetic study, they showed t(15;17) abnormality. The patient died at the 6th hospital day because of pulmonary and intracranial hemorrhage.

A case of microgranular variant of acute promyelocytic leukemia with strong positive reaction in nonspecific esterase stain / 대한임상병리학회지

We report a case of microgranular variant of acute promyelocytic leukemia with strong positivity in nonspecific esterase stain (inhibited by sodium fluoride) in a 21-onth-ld girl who had complained of intermittent fever and severe vomiting. At admission, she showed marked leukocytosis in the peripheral blood. The majority of leukocytes were immature cells which exhibited marked nuclear irregularity and had sparse dust-ike granules in their cytoplasm. In immunophenotyping, these cells showed CD13 and CD33 positivity and in cytogenetic study, they showed t(15;17) abnormality. The patient died at the 6th hospital day because of pulmonary and intracranial hemorrhage.

Epidemiologic study of viral respiratory infection in children and comparison between the direct and indirect immunofluorescent assay / 대한임상병리학회지

BACKGROUND: Studies on the incidence and seasonality of respiratory viruses that are the main cause of lower respiratory tract disease in children are insufficient in Korea. In the present study, the epidemiology of respiratory viruses in children was studied during the last 2 years and, the indirect immunofluorescent (IF) method was compared with the direct IF method. METHODS: A total of 814 pediatric inpatients hospitalized for lower respiratory tract infection at Hanyang University Hospital were studied from April, 1996 to July, 1998. Nasopharyngeal aspirates were obtained from these patients and indirect IF (Respiratory Panel I Viral Screening & Identification Kit, Light Diagnostics, Chemicon, Temecula, CA, USA) was performed for the following viruses : respiratory syncytial virus (RSV), parainfluenza virus type I, II and III, influenza virus A, B, and adenovirus. Sixty-nine of these samples were tested by direct IF (IMAGENTM, DAKO, UK) and indirect IF, simultaneously. RESULTS: 1) Viral pathogens were detected in 30.5% of nasopharyngeal aspirates. Among the positive cases, RSV was 60.6%, influenza A 35.3%, adenovirus 5.2%, influenza B 4.0%, and parainfluenza II 0.8%. 2) The occurrence rate of RSV in spring, summer, fall and winter was 7.3%, 13.6%, 31.45%, 33.45%, respectively, and showed a unique pattern in that the incidence rate in the summer of 1997 was 22.2%. A unique pattern was also observed for influenza A, which was continuously detected from December 1997 to July 1998. 3) The positive rate of indirect IF was statistically higher than that of direct IF. Excluding the results of the influenza A, there was no statistically significant difference between the two methods. CONCLUSION: RSV was the most frequently detected virus in viral respiratory infections in children. Infection usually began in the fall and most frequently detected in the winter and lasted until spring. High incidence of RSV in summer 1997 and continuous detection of influenza A till summer 1997 suggest some change of epidemic pattern. The discordance between direct and indirect IF was probably due to the difference in quality of the anti-influenza A reagent rather than a real difference in the two methods.