Human Parvovirus B19 and Rheumatoid Arthritis in Korea / 대한류마티스학회지

BACKGROUND: The pathogenic human parvovirus B19 is the etiologic agent of erythema infectiosum and causes other events including aplastic crisis,hydrops fetalis and fetal loss.Recently,it has been reported in many articles that human parvovirus B19 infection is associated with rheumatoid arthritis (RA).In contrast to these reports from the United Kingdom,Germany,Japan and China,different results were reported that there is no association between human parvovirus B19 and the pathogenesis of RA in Northern Ireland,Finland and France.This study aimed to investigate the association between human parvovirus B19 and RA in Korea. METHODS: Sera from 104 patients with RA,40 with osteoarthritis (OA)and 32 with systemic lupus erythematosus (SLE)were tested for IgG and IgM of human parvovirus B19 by ELISA (Biotrin),respectively. RESULTS: There were no statistical differences among RA,OA and SLE patients in both anti-human parvovirus B19 IgG and IgM (p>0.05).Human parvovirus B19 IgM was positive in only four RA patients and negative in all SLE and OA patients. CONCLUSION: Human parvovirus B19 infection showed no association with RA in Korea,which is different from reports from other countries,especially Japan and China which are our neighbors.We thought that this result was due to the ethnic or national differences of baseline titer of anti-human parvovirus B19.Therefore anti-human parvovirus B19 test for RA patients is not necessary in Korea.In conclusion,we suggest that the indication and interpretation of anti-human parvovirus B19 testing in RA patients should be applied differently for each nation.

Does Human Parvovirus B19 have a Role in the Formation of the Anemia and the Disease Activity in Rheumatoid Arthritis? / 대한임상병리학회지

BACKGROUND: The pathogenic human parvovirus B19 replicates only in erythroid progenitor cells. The blood-group P antigen has been reported to be the cellular receptor of this virus. Human parvovirus B19 is known to be the etiologic agent of erythema infectiosum and causes a chronic anemia resulting from a persistent infection in immunocompromised patients. Recently, it has been re-ported to play a role in rheumatoid arthritis activity (RA). This study was aimed to determine whether human parvovirus B19 has a role to play in chronic anemia of RA which is the case in immunocompromised patients. We also investigated the association between the activity of the disease in RA and human parvovirus B19 infections. METHODS: Of 107 patients that had RA, 49 patients had anemia and 58 patients did not. We used ESR and CRP results to estimate the degree of disease activity. Thirty-eight patients having RA had a normal ESR and 69 patients had a high ESR. Sixty patients had normal CRP and 47 patients had high CRP. Sera of patients were tested for the presence of anti-human parvovirus B19 (IgG and IgM) using ELISA (Biotrin, Co. Dublin, Ireland). RESULTS: Of 107 patients who had RA, 79.4% (85/107) and 3.7% (4/107) were positive for IgG and IgM, respectively. There were no statistical differences between RA patients with anemia and those without anemia in the anti-human parvovirus B19 test (P>0.05). There were also no statistical differences between patients that had a normal or high ESR/CRP ratio (P>0.05). CONCLUSIONS: Human parvovirus B19 did not play a role in the formation of the chronic anemia of RA which is different from the cases of immunocompromised patients. Furthermore, we found no association between disease activity in RA and human parvovirus B19 infections.

Evaluation of Frozen Antibiotics for Antimicrobial Susceptibility Testing of Helicobacter Pylori / 대한임상미생물학회지

BACKGROUND: Antimicrobial susceptibility testing of Helicobacter pylori(H. pylori) is not yet standardized but broth dilution or agar dilution are considered as standard methods. In the broth microdilution method, antibiotic dilutions of different concentrations are made each time, but most of it is discarded because only small volumes of dilutions are used. To improve this tedious procedure and the waste of reagents, antibiotic solutions in 96-well microplates were frozen at -20 degrees C to evaluate their useful storage periods. METHODS: Various concentrations of metronidazole(MTZ) and clarithromycin(CLR) solutions were divided into ten plates of 96-well microplates, sealed and stored at -20 degrees C. The broth microdilution susceptibility test was done with fresh and preserved antibiotic dilutions each month on 5 occasions for 4 strains(initial minimum inhibitory concentration(MIC) for MTZ 1, 4, 16, 64 ug/mL, initial MIC for CLR <0.125, <0.125, <0.125, 32 ug/mL) of H. pylori. The difference of MIC values of more than +/-2 log2 diluti on was considered significant. RESULTS: For both MTZ and CLR, the difference of MIC values of fresh and frozen antibiotic solutions was within +/-1 log2 dilution and the results of susceptibility test were the same for 7 months. CONCLUSIONS: Various concentrations of frozen MTZ and CLR solutions could be used for at least 7 months for the antimicrobial susceptibility testing of H. pylori.

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.

Diagnostic Availability of the Soluble Transferrin Receptor in RA Patients / 대한임상병리학회지

BACKGROUND: The transferrin receptor (TfR) is expressed on almost all cellular surfaces and is shedded into the blood to form the soluble transferrin receptor (sTfR). The sTfR has been known to be a good marker to reflect cellular iron status and to differentiate between iron deficiency anemia (IDA) and anemia of chronic disease (ACD) without the need for a bone marrow aspiration in rheumatoid arthritis (RA) patients. So we aimed to evaluate the diagnostic availability of sTfR in patients with RA and degenerative joint disease (DJD). METHODS: Eighty-seven outpatients visiting the Department of Rheumatology at HYUH were studied and divided into anemic and non-anemic groups according to their Hb levels (female< 12 g/dL, male< 14 g/dL). The sTfR was measured by ELISA method (Quantikine IVDTM, R&D system). To differentiate whether the anemia was due to iron deficiency or other causes, we used the RBC parameters and a discriminant index which was calculated from serum iron, ferritin and TIBC instead of a bone marrow aspiration, an invasive procedure of which interpretation can be subjective. RESULTS: The median was higher (31.09 nM) than the normal reference values (9-28 nM) only in the anemic group of RA. The medians were within normal limit in all the other groups. sTfR levels were high in 15 of the 28 RA anemic patients which were composed of 10 patients with IDA, 4 with non-anemic RA and 1 with non-anemic RA & DJD. CONCLUSIONS: In the present study, sTfR was increased not only in IDA but also in ACD of RA patients and also in non-anemic patients, which showed that sTfR cannot be used to differentiate these two types of anemia by itself and the further tests are needed. We conclude that the expression of TfR in RA patients was dependent not only on iron deficiency but also on the disease itself.