Rituximab is a chimeric monoclonal anti-CD20 antibody that has been proposed as an effective therapy for neuromyelitis optica spectrum disorder (NMOSD). Previous data have been based mostly on small case series with short-term follow-up.^1-10 There has been concern about the variability of rituximab responses.^6,7 Previously, we reported the therapeutic efficacy of rituximab in 30 patients with NMOSD across a 5-year period and the depletion of memory B cells in peripheral blood was associated with a clinical response to rituximab.^3,5 However, not all patients respond to rituximab treatment and the durability of the memory B-cell depletion is variable.^3,5 The reason for this variability in rituximab response and the question of who will benefit from a lower and more cost-effective dose of rituximab is unresolved.

Background: Array comparative genomic hybridization (CGH) is currently the most powerful method for detecting chromosomal alterations in pre and postnatal clinical cases. In this study, we developed a BAC based array CGH analysis platform for detecting whole genome DNA copy number changes including specific micro deletion and duplication chromosomal disorders. Additionally, we report our experience with the clinical implementation of our array CGH analysis platform. Array CGH was performed on 5080 pre and postnatal clinical samples from patients referred with a variety of clinical phenotypes. Results: A total of 4073 prenatal cases (4033 amniotic fluid and 40 chorionic villi specimens) and 1007 postnatal cases (407 peripheral blood and 600 cord blood) were studied with complete concordance between array CGH, karyotype and fluorescence in situ hybridization results. Among 75 positive prenatal cases with DNA copy number variations, 60 had an aneuploidy, seven had a deletion, and eight had a duplication. Among 39 positive postnatal cases samples, five had an aneuploidy, 23 had a deletion, and 11 had a duplication. Conclusions: This study demonstrates the utility of using our newly developed whole-genome array CGH as first-tier test in 5080 pre and postnatal cases. Array CGH has increased the ability to detect segmental deletion and duplication in patients with variable clinical features and is becoming a more powerful tool in pre and postnatal diagnostics.

We evaluated a new immunochromatographic assay (ICA) using mouse monoclonal anti-MPT64 antibody for rapid discrimination between Mycobacterium tuberculosis and nontuberculous mycobacteria in clinical isolates. A study with mycobacteria and other organisms showed excellent sensitivity (≅99%) and specificity (100%) and an appropriate detection limit (10 ⁵ CFU/ml) when tested with M. tuberculosis H37Rv. This ICA can simplify the identification of M. tuberculosis in clinical laboratories.

Passive exposure to tobacco smoke significantly contributes to morbidity and mortality in children. Children, in particular, seem to be the most susceptible population to the harmful effects of environmental tobacco smoke (ETS). Paternal smoking inside the home leads to significant maternal and fetal exposure to ETS and may subsequently affect fetal health. ETS has been associated with adverse effects on pediatric health, including preterm birth, intrauterine growth retardation, perinatal mortality, respiratory illness, neurobehavioral problems, and decreased performance in school. A valid estimation of the risks associated with tobacco exposure depends on accurate measurement. Nicotine and its major metabolite, cotinine, are commonly used as smoking biomarkers, and their levels can be determined in various biological specimens such as blood, saliva, and urine. Recently, hair analysis was found to be a convenient, noninvasive technique for detecting the presence of nicotine exposure. Because nicotine/cotinine accumulates in hair during hair growth, it is a unique measure of long-term, cumulative exposure to tobacco smoke. Although smoking ban policies result in considerable reductions in ETS exposure, children are still exposed significantly to tobacco smoke not only in their homes but also in schools, restaurants, child-care settings, cars, buses, and other public places. Therefore, more effective strategies and public policies to protect preschool children from ETS should be consolidated.

Since vancomycin-intermediate Staphylococcus aureus (VISA) was first reported in Japan in 1997, there has been great concern that heterogeneous vancomycin-intermediate S. aureus (hetero-VISA) is the putative precursor of VISA. To investigate the prevalence, clinical significance, and molecular epidemiology of S. aureus with reduced susceptibility to vancomycin, all consecutive isolates of S. aureus isolated from clinical specimens from December 1998 to August 1999 at Asan Medical Center were screened for VISA and hetero-VISA by using brain heart infusion agar containing 4 μg of vancomycin/ml. Screen-positive isolates were confirmed by susceptibility testing and population analysis of subpopulations with reduced susceptibility to vancomycin. The isolates confirmed as hetero-VISA were typed by pulsed-field gel electrophoresis (PFGE). Medical records were reviewed to evaluate the clinical significance and risk factors for the acquisition of hetero-VISA. Of the 4,483 isolates that were tested, 53 were screen positive; no VISA was detected, but 24 isolates (0.54%) from 22 patients were hetero-VISA. All but two strains appeared to be clones of the Korean VISA strain, AMC11094, in the PFGE analysis. A total of 18 patients were in intensive care units, and 16 underwent major surgeries during the same admission. Only 10 of the 22 patients had previous methicillin-resistant S. aureus infections and 11 had previous vancomycin or teicoplanin therapy. Only 7 of the 22 patients from whom hetero-VISA strains were isolated were infected, and the remaining 15 patients were colonized. All seven infected patients were successfully treated with vancomycin. These results suggest that hetero-VISA can be treated with vancomycin, but the spread of hetero-VISA clonal to VISA is of concern, since many believe that VISA can arise from hetero-VISA, although this phenomenon was not observed in this study.

Background: Lung cancer is a leading cause of cancer deaths. Unfortunately, no effective early screening modality exists for lung cancer. We aimed to evaluate the prevalence of HOXA9 promoter methylation in tissue and induced sputum samples from Korean patients with lung cancer. Methods: Using pyrosequencing, HOXA9 methylation was analyzed for 40 pairs of primary lung cancer and normal tissues and 185 induced sputum specimens, including 76 patients with lung cancer. Results: The methylation of HOXA9 in lung cancer tissue was significantly higher compared with normal tissues (67.4%±17.6% vs. 23.6%±10.3%, respectively; p45.6% of HOXA9 gene methylation in tissues, the sensitivity was 90.5% and the specificity was 97.5%. In induced sputum specimens, the HOXA9 gene in lung cancer patients was significantly more hypermethylated compared with patients with benign lung diseases and the healthy group (23.4%±15.9%, 14.9%±7.9%, and 9.7%±5.0%, respectively; p<0.001). Conclusions: The HOXA9 gene was hypermethylated in 32 of 40 tumors (80%), especially in early stages of lung cancer. HOXA9 methylation could be a potential biomarker to aid early detection and prognosis.