Increment of Serum Free Light Chain Kappa/Lambda Ratio in Patients with Renal Dysfunction

BACKGROUND: Since free light chain (FLC) is metabolized in the kidney, serum FLC concentration and kappa/lambda ratio are increased in patients with decreased renal function, even in the absence of monoclonal protein. In this study, we measured serum FLC levels to investigate the change in kappa/lambda ratios in relation to the severity of renal dysfunction. METHODS: Serum FLC concentrations were measured in 92 archived serum samples from patients diagnosed with chronic kidney disease using the Freelite assay (The Binding Site Group Ltd., UK), and kappa/lambda ratios were calculated. Serum creatinine levels were assayed to calculate estimated glomerular filtration rate (eGFR), and patients were divided into subgroups according to Kidney Disease Improving Global Outcomes (KDIGO) guidelines. We analyzed the difference in serum FLC levels and kappa/lambda ratios between subgroups. RESULTS: Serum FLC levels and kappa/lambda ratios increased depending on the severity of renal dysfunction. When patients were classified by setting cut-off value of eGFR as 60 mL/min/1.73 m2 (group A: eGFR ≥60 mL/min/1.73 m2, group B: < 60 mL/min/1.73 m2), the kappa/lambda ratio of group B was significantly higher than that of group A (group B: 1.60±0.46 vs. group A: 1.35±0.27, P=0.018). Serum FLC kappa/lambda ratios were within the previously determined renal reference interval (0.37–3.1). CONCLUSIONS: When interpreting results of serum FLC kappa/lambda ratio, renal function status should be considered in addition to hematological findings. If renal function deteriorates, a wider renal reference interval is preferred instead of the usual reference interval.

Dose Estimation Curves Following In Vitro X-ray Irradiation Using Blood From Four Healthy Korean Individuals

Cytogenetic dosimetry is useful for evaluating the absorbed dose of ionizing radiation based on analysis of radiation-induced chromosomal aberrations. We created two types of in vitro dose-response calibration curves for dicentric chromosomes (DC) and translocations (TR) induced by X-ray irradiation, using an electron linear accelerator, which is the most frequently used medical device in radiotherapy. We irradiated samples from four healthy Korean individuals and compared the resultant curves between individuals. Aberration yields were studied in a total of 31,800 and 31,725 metaphases for DC and TR, respectively, obtained from 11 X-ray irradiation dose-points (0, 0.05, 0.1, 0.25, 0.5, 0.75, 1, 2, 3, 4, and 5 Gy). The dose-response relationship followed a linear-quadratic equation, Y=C+αD+βD², with the coefficients C=0.0011 for DC and 0.0015 for TR, α=0.0119 for DC and 0.0048 for TR, and β=0.0617 for DC and 0.0237 for TR. Correlation coefficients between irradiation doses and chromosomal aberrations were 0.971 for DC and 0.6 for TR, indicating a very strong and a moderate correlation, respectively. This is the first study implementing cytogenetic dosimetry following exposure to ionizing X-radiation.

Comparison of YD URiSCAN PluScope Urine Microscopic Analyzer and Sysmex UF-1000i Flow Cytometry Systems

BACKGROUND: Urinalysis is one of the most commonly performed tests in clinical laboratories. In this study, we compared YD URiSCAN PluScope (PluScope; YD Diagnostics Corp., Korea) and Sysmex UF-1000i (UF-1000i; Sysmex Corp., Japan) for urine microscopic sediment analysis. METHODS: A total of 404 fresh urine samples were collected and analyzed using PluScope, UF-1000i, and manual microscopy. Quantitative correlation analyses for red blood cells (RBCs), white blood cells (WBCs), epithelial cells (EC), and casts were performed using Spearman's correlation. We evaluated agreement among the three systems by using weighted Cohen's κ and calculating concordance rates within one grade of difference for semiquantitative and qualitative parameters. RESULTS: There were moderate-high correlations between PluScope and UF-1000i for RBCs, WBCs, and ECs (r=0.542, 0.714, and 0.571, respectively) but negligible correlation for casts (r=0.186). There were moderate-high correlations between manual microscopy and automated devices for RBCs, WBCs, and ECs (r=0.550–0.745) but negligible correlations for casts (PluScope: r=0.247; UF-1000i: r=0.223). The pairwise concordance rates within one grade difference among the three methods were good for RBCs, WBCs, and ECs (95.0%–99.0%, κ=0.41–0.74). For casts, the concordance rate between PluScope and manual microscopy was fair (96.8%, κ=0.25), but concordance rates between UF-1000i and manual microscopy and between the two automated devices were poor (81.2% and 81.7%; κ=0.04 and 0.06, respectively). CONCLUSIONS: The two automated urine sediment analyzers showed a moderate-high correlation and concordance rate. They showed good correlations and concordance rates for RBCs, WBCs, and ECs. However, manual microscopic examinations are still needed for reviewing and confirming the presence of pathologic particles in urine, such as casts and crystals.

Phosphorylated S6 Kinase-1 as Predictive Marker of Lapatinib Efficacy in Human Epidermal Growth Factor Receptor 2-Positive Metastatic Breast Cancer Patients

PURPOSE: The 40S ribosomal protein S6 kinase-1 (S6K1) is a crucial downstream effector of the PI3K/AKT/mTOR pathway. S6K1 overexpression is found in 10% to 30% of breast cancers and is associated with aggressive disease and poor prognosis. Herein, we investigated the relationship between the expression of phosphorylated S6K1 (p-S6K1) and efficacy of lapatinib in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer. METHODS: We retrospectively analyzed the data of 36 patients with HER2-positive metastatic breast cancer treated with lapatinib between January 2010 and September 2014. The p-S6K1 expression status of the primary tumor was assessed via immunohistochemistry using a mouse monoclonal antibody. RESULTS: Fourteen of the 36 patients (38.9%) had p-S6K1-positive tumors. The median progression-free survival (PFS) of patients with p-S6K1-positive tumors was significantly longer than that of patients with p-S6K1-negative tumors (13.4 months vs. 7.1 months, p=0.025). In multivariate analysis, p-S6K1 positivity remained an independent, favorable predictive factor for PFS (hazard ratio, 0.32; 95% confidence interval, 0.11–0.97; p=0.044). CONCLUSION: The high expression of p-S6K1 was significantly associated with prolonged PFS, suggesting that p-S6K1 can be a potential biomarker for predicting the efficacy of lapatinib in patients with HER2-positive metastatic breast cancer.

Usefulness of Serum Thymidine Kinase 1 as a Biomarker for Aggressive Clinical Behavior in B-cell Lymphoma

BACKGROUND: The cell cycle-dependent enzyme thymidine kinase 1 (TK1) is known to increase during cancer cell proliferation and has been reported as a prognostic marker for various hematologic malignancies and solid tumors. This study aimed to determine the reference interval in Korean healthy controls and to evaluate the usefulness of TK1 as a biomarker for aggressive clinical behavior in B-cell lymphoma patients. METHODS: We enrolled 72 previously untreated patients with B-cell lymphoma and 143 healthy controls. Serum TK1 levels were measured by chemiluminescence immunoassay (Liaison(R), DiaSorin, USA). We established the reference intervals in healthy controls. The diagnostic performance of serum TK1 was studied using receiver operating characteristic (ROC) analysis, and the correlation between the cutoff level for serum TK1 and clinical characteristics of B-cell lymphoma was evaluated. RESULTS: The reference range (95th percentile) of serum TK1 in healthy controls was 5.4-21.8 U/L. There was a clear difference in TK1 levels between patients with B-cell lymphoma and healthy controls (40.6+/-68.5 vs. 11.8+/-4.4 U/L, P or =15.2 U/L) correlated with the advanced clinical stage (P<0.001), bone marrow involvement (P=0.013), international prognostic index score (P=0.001), lactate dehydrogenase level (P=0.001), low Hb level (<12 g/dL) (P=0.028), and lymphocyte count (P=0.023). CONCLUSIONS: The serum TK1 level could serve as a useful biomarker for aggressive clinical behavior in B-cell lymphoma patients.

A Rare Case of Pediatric T Lymphoblastic Leukemia With t(11;17)(q23;q21) Involving Mixed-Lineage Leukemia Gene Rearrangement

No abstract available.

Serial Serum HER2 Measurements for the Detection of Breast Cancer Recurrence in HER2-Positive Patients / 한국유방암학회지

PURPOSE: The measurement of serum human epidermal growth factor receptor 2 (HER2) extracellular domain levels is a well-established method for evaluating whether a metastatic HER2-positive breast cancer patient will respond to HER2-targeted treatment. However, little is known about the value of serum HER2 for detecting disease relapse following curative surgical treatment in breast cancer patients. The purpose of this study was to evaluate the sensitivity of serum HER2, carcinoembryonic antigen (CEA), and carcinoma antigen 15-3 (CA 15-3) for the detection of disease recurrence in postoperative breast cancer patients with a primary HER2-positive tumor. METHODS: Serial measurements were taken of serum HER2, CEA, and CA 15-3 levels in patients with primary invasive HER2-positive breast cancer who underwent curative surgical treatment between January 2008 and December 2010. Following treatment, serum HER2 levels were monitored every 6 months using a chemiluminescence immunoassay. RESULTS: Overall, 264 patients were analyzed in this retrospective study. The median follow-up period was 27.7 months, and 24 patients relapsed during follow-up. The sensitivity of serum HER2, CEA, and CA 15-3 for the detection of disease recurrence was 37.5%, 25.1%, and 12.5%, respectively. Sensitivity increased to 45.8% when all three tumor markers were combined in the analysis. In a subgroup of patients without liver disease, the sensitivity of serum HER2, CEA, and CA 15-3 was 57.1%, 21.4%, and 14.3%, respectively. Of the 264 patients in this study, 80 patients had chronic hepatitis, liver cirrhosis, or abnormal aspartate aminotransferase or alanine aminotransferase levels during the follow-up period. Following the exclusion of these patients, the sensitivity of serum HER2 for the detection of disease recurrence increased to 57.1%. CONCLUSION: Serial serum HER2 measurement may be useful for the detection of disease relapse in patients with HER2-positive breast cancer. Abnormal liver function can result in elevated serum HER2 in the absence of disease recurrence.

Comparison of Serum Fibrin-Fibrinogen Degradation Products with Carcinoembryonic Antigen as Biomarkers for Colon Cancer / 임상검사와정도관리

BACKGROUND: Colon cancer is the second most common cancer in males and fourth most common in females in Korea. The levels of serum fibrin-fibrinogen degradation products (FDP) are elevated in many malignancies due to haemostatic alterations resulting from carcinogenesis. We compared serum FDP with carcinoembryonic antigen (CEA) to assess whether FDP has a diagnostic value for colon cancer. METHODS: A total of 177 serum samples from 95 colon cancer patients and 82 healthy controls were provided by the Korea Cancer Center Hospital biobank. Serum FDP levels were measured using the DR-70 detection kits (AMDL, USA) and the levels of serum CEA were measured using the Roche E170 Analytics (Roche Diagnostics, Germany). RESULTS: The mean serum FDP and serum CEA levels were significantly higher in the cancer patient group (FDP, 1.65+/-1.44 microg/mL; range, 0.36 to 9.48; CEA, 99.99+/-321.74 ng/mL; range, 1.46 to 2,170.00) than in the control group (FDP, 0.58+/-0.46 microg/mL; range, 0.02 to 3.27, P<0.05; CEA, 1.66+/-1.18 ng/mL; range, 0.20 to 6.38, P<0.05). The receiver operating characteristic curve for FDP showed 80% clinical sensitivity and 83% specificity with an optimal cut-off of 0.81 microg/mL, while that for CEA exhibited 84% sensitivity and 94% specificity with a cut-off of 3.51 ng/mL. The area under the curve was 0.87 and 0.96 for serum FDP and CEA, respectively. A combination of the two markers showed 90% clinical sensitivity and 92% specificity for colon cancer. CONCLUSIONS: The diagnostic sensitivity for colon cancer was increased by using a combination of FDP and CEA.

Utilization of Mean Peroxidase Index for Discrimination of Pseudoneutropenia

BACKGROUND: Autoanalyzer ADVIA2120 uses intracellular peroxidase concentration to perform white blood cell (WBC) differential. Therefore, in specimens containing neutrophils with low peroxidase concentration, neutrophils can be miscounted as monocytes or large unstained cells resulting in pseudoneutropenia. Myeloperoxidase deficiency can be detected by the mean peroxidase index (MPXI). The aims of this study are to establish the reference interval of MPXI and define a cut off value for manual slide review to discriminate pseudoneutropenia. METHODS: We calculated reference intervals as mean+/-2SD according to the indirect method of CLSI C28-A3 guideline from MPXI data of 5,802 individuals who took routine health checkup from April 2010 to June 2012. We performed manual slide review on specimens with low MPXI and compared neutrophil differential count of manual method with that of autoanalyzer. When neutrophil differential in manual slide review was >20%P higher than autoanalyzer result, it was regarded as a pseudoneutropenia. We performed ROC analysis using the MPXI results of samples with and without pseudoneutropenia to define a cutoff to discriminate pseudoneutropenia. RESULTS: The reference intervals of MPXI in total population, male, and female were -4.9 to 7.5, -5.5 to 7.3, and -4.5 to 7.5, respectively. The mean value of MPXI was significantly higher in female than in male and there was no difference by age. Twenty-two pseudoneutropenia samples from 7 patients were identified. ROC analysis yielded cutoff value of -20.7 with 94.9% of sensitivity and 77.3% of specificity. CONCLUSIONS: MPXI may be used in the manual slide review guideline for detecting pseudoneutropenia.

A Case of Hepatosplenic T-cell Lymphoma Diagnosed by Bone Marrow Examination

Hepatosplenic T-cell lymphoma (HSTL) is a condition in which lymphoma cells infiltrate the sinusoids of the liver, spleen, and bone marrow, without lymph node involvement. We encountered a case of hepatosplenic T-cell lymphoma in a Vietnamese woman. The patient was hospitalized with epigastric pain and nausea. Splenomegaly and multiple poorly defined, low-attenuating nodular lesions in the liver were visualized on computed tomography (CT), and thrombocytopenia was noted. The lymph nodes were not significantly enlarged. Splenic biopsy could not be performed because of severe thrombocytopenia. Neoplastic lymphoid cells were present in bone marrow aspirates. Bone marrow sections revealed infiltration of CD3(+) and CD20(-) neoplastic lymphoid cells in the sinusoids. A clonality assay (IdentiClone T-Cell Receptor Delta Gene Clonality Assay; Invivoscribe Technologies, USA) showed gene rearrangements in the T-cell receptor delta gene. Thus, we made a confirmatory diagnosis of HSTL. When splenic biopsy is not available, bone marrow aspirates and clonality assessment may become useful diagnostic tools.

Automated Quantification of Mitral Regurgitation by Three Dimensional Real Time Full Volume Color Doppler Transthoracic Echocardiography: A Validation with Cardiac Magnetic Resonance Imaging and Comparison with Two Dimensional Quantitative Methods

BACKGROUND: Accurate assessment of mitral regurgitation (MR) severity is crucial for clinical decision-making and optimizing patient outcomes. Recent advances in real-time three dimensional (3D) echocardiography provide the option of real-time full volume color Doppler echocardiography (FVCD) measurements. This makes it practical to quantify MR by subtracting aortic stroke volume from the volume of mitral inflow in an automated manner. METHODS: Thirty-two patients with more than a moderate degree of MR assessed by transthoracic echocardiography (TTE) were consecutively enrolled during this study. MR volume was measured by 1) two dimensional (2D) Doppler TTE, using the proximal isovelocity surface area (PISA) and the volumetric quantification methods (VM). Then, 2) real time 3D-FVCD was subsequently obtained, and dedicated software was used to quantify the MR volume. MR volume was also measured using 3) phase contrast cardiac magnetic resonance imaging (PC-CMR). In each patient, all these measurements were obtained within the same day. Automated MR quantification was feasible in 30 of 32 patients. RESULTS: The mean regurgitant volume quantified by 2D-PISA, 2D-VM, 3D-FVCD, and PC-CMR was 72.1 +/- 27.7, 79.9 +/- 36.9, 69.9 +/- 31.5, and 64.2 +/- 30.7 mL, respectively (p = 0.304). There was an excellent correlation between the MR volume measured by PC-CMR and 3D-FVCD (r = 0.85, 95% CI 0.70-0.93, p < 0.001). Compared with PC-CMR, Bland-Altman analysis for 3D-FVCD showed a good agreement (2 standard deviations: 34.3 mL) than did 2D-PISA or 2D-VM (60.0 and 62.8 mL, respectively). CONCLUSION: Automated quantification of MR with 3D-FVCD is feasible and accurate. It is a promising tool for the real-time 3D echocardiographic assessment of patients with MR.

A Case of Heterozygous alpha(+)-Thalassemia Diagnosed in a Korean Family by Using Multiplex Ligation-Dependent Probe Amplification / 임상검사와정도관리

Alpha-thalassemia (alpha-thalassemia), which is prevalent in the Mediterranean region, is caused by deficient synthesis of the alpha-globin chains. It is commonly caused by HBA1 and/or HBA2 gene deletion and is diagnosed by DNA sequence analysis. The proband was a 38-year-old woman who was found to have microcytic and hypochromic anemia on a routine health checkup. Results of the Hb electrophoresis (EP) and direct sequencing of the HBA1 and HBA2 genes were found to be normal. As multiplex ligation-dependent probe amplification (MLPA) for the HBA1 and HBA2 genes revealed heterozygous deletion, she was diagnosed with heterozygous alpha+-thalassemia. Although routine laboratory tests revealed similar findings in the proband's father, brother and niece, MLPA revealed heterozygous deletions of the HBA1 or HBA2 gene in her brother and niece. In summary, we report a case of heterozygous alpha+-thalassemia in a Korean family that was detected by MLPA. We recommend that patients with suspected hemoglobinopathies should be followed-up further with MLPA, especially when Hb EP shows a normal pattern.

Type Distribution of Unexpected Red Cell Antibodies in Patients with Malignancy / 대한수혈학회지

BACKGROUND: Performance of antibody screening and identification tests before blood transfusion is important because the unexpected presence of red cell antibodies may cause hemolytic transfusion reactions. Many patients with malignancy undergo transfusion in order to overcome pancytopenia due to disease itself or chemotherapy. We investigated the type distribution of unexpected red cell antibodies in cancer patients and compared our results with those of other institutions. METHODS: From January 2008 to June 2011, 30,989 serum samples were screened using a LISS/Coombs card and ID-DiaCell I, II (DiaMed AG, Morat, Switzerland). Data-Cyte Plus Reagent Red Blood Cells (Medion Diagnostics, Dudingen, Switzerland) were used in performance of antibody identification tests. RESULTS: Out of 30,989 serum samples, 180 cases (0.58%) showed screening-positive results, and unexpected antibodies were identified in 72 cases. The type of unexpected antibody observed most often in cancer patients was a member of the Rh antibody group, anti-E in 17 cases (29.8%), followed by anti-Lea in five cases (8.8%) and anti-e in three cases (5.3%). While Rh group antibodies were observed in the colon cancer group, non-Rh group antibodies were observed in the rectal cancer group. And, in the genitourinary cancer group, Lewis group antibodies were more frequently detected than others. CONCLUSION: Findings from our study demonstrated a type distribution of unexpected red cell antibodies that was similar to those reported in previous studies. Compared with non-cancerous patients, no difference in type distribution of unexpected red cell antibodies was observed in cancer patients. Some antibodies were frequently observed in certain cancer groups. Further comprehensive research on unexpected antibodies based on location or histologic type of cancer is needed.

Clinical Significance of Oligoclonal Bands in Patients with Multiple Myeloma after Autologous Stem Cell Transplantation

BACKGROUND: Oligoclonal bands or isotype switch detectable by serum immunofixation electrophoresis (IFE) has been reported following chemotherapy and stem cell transplantation in patients with multiple myeloma (MM). We studied the significance of oligoclonal bands appearing after chemotherapy and autologous stem cell transplantation (ASCT) in Korean MM patients, and its impact on relapse. And we investigated the serial serum free light chain (FLC) ratio to establish its possible relationship with the relapse of MM. METHODS: We conducted a retrospective analysis of the serial serum IFE and FLC ratio in 16 MM patients treated with chemotherapy and ASCT. RESULTS: Eleven out of 16 patients (68.8%) had oligoclonal bands with or without isotype switch after ASCT and the median interval from transplantation was 2.0 months. And relapse or persistence rate of monoclonal gammopathy was lower in patients with oligoclonal bands (27.3% vs. 60.0%), though without statistical significance (P=0.299). In eight patients who developed oligoclonal bands and did not relapse, the serial serum FLC ratio was normal in range. But one patient who developed oligoclonal bands and showed increase of plasma cells in bone marrow, the serial serum FLC ratio was abnormal in range. CONCLUSIONS: The occurrence of oligoclonal bands after chemotherapy and ASCT in Korean MM patients is not significantly associated with adverse consequence of relapse or persistence of monoclonal gammopathy. Therefore oligoclonal bands may be not bad prognostic criterion. And the measurement of serum FLC ratio may be a useful indicator to predict relapse in MM patients who developed oligoclonal bands.

Practical applications of cytogenetic biodosimetry in radiological emergencies / 대한혈액학회지

No abstract available.

A Case of a 63-bp Deletion in the mpt64 Gene of Mycobacterium tuberculosis Strains Which Showed False Negativity in the Immunochromatographic Assay / 대한임상미생물학회지

Mycobacterium tuberculosis complex (MTBC) is discriminated from non-tuberculous mycobacteria (NTM) via an immunochromatographic assay (ICA) which is based on the reactions of monoclonal antibodies against MPT64, one of the predominant proteins excreted by MTBC. Recently, the authors of the present study discovered SD TB-negative Mycobacterium tuberculosis strains. In addition, sequence analysis of the mpt64 genes in these strains was performed and showed a deletion of 63 bp from nucleotides 196 to 258. In cases of MPT64-negative mycobacterium, the authors recommend performing TB PCR for correct diagnosis.

Two Case of Erythroleukemia and Myelodysplastic Syndrome in a Non-Destructive Inspector / 대한산업의학회지

BACKGROUND: Ionizing radiation is a group 1 carcinogen according to the IARC(International Agency for Research on Cancer) classification. With the development of the radiation related industry, the number of radiation exposed workers has been increasing. There have been several reports on AML(Acute Myeloid Leukemia) on exposure to ionizing radiation; however, there are no reports of occupational malignant lymphohematopoietic disease related to non-destructive inspection. CASE REPORT 1: A 35-years-old male, who had worked for 10 years in non-destructive inspection, was diagnosed with myelodysplastic syndrome. He worked 8 hours a day, for three weeks per months, where he was exposed to 192Ir and 60Co radiation sources. Because he had not worn a film badge for monitoring his radiation exposure dose, the accurate exposure dose was not reported. The estimate exposure dose calculated via a chromosomal study was 1.20 Gy, which exceed the dose limits of Korean radiation dose standards, which are 50 and 100 mSv annually and quinquennially respectively. CASE REPORT 2: A 26-years-old male, who had worked for 2.5 years in the same company was also diagnosed with myelodysplastic syndrome. CONCLUSION: Non-destructive inspection is the main source of ionizing radiation in the workplace, which could be the cause of malignant lymphohematopoietic diseases. Therefore, more practical plans and guidelines are needed to prevent non-destructive inspectors from workplace radiation exposure.

Two Pediatric Osteosarcoma Cases with Delayed Methotrexate Excretion: Its Clinical Course and Management / Journal of the Korean Cancer Association, 대한암학회지

High-dose methotrexate (MTX) chemotherapy extends the duration of hospitalization and introduces the risks of serious complications related to delayed MTX excretion. The treatment of delayed MTX excretion is largely dependent on invasive measures such as hemodialysis because the clinical data regarding the efficacy or safety of carboxypetidase G2 is limited. We report here on the cases of two pediatric osteosarcoma patients with delayed MTX excretion and who were successfully managed using supportive measures. Potential life-threatening complications were prevented by administering high doses of leucovorin.

Development of Indicators to Assess the Stability of Remnant Blood Samples Stored in a Biobank: Experience at One Institution / 대한진단검사의학회지

BACKGROUND: One of the major concerns with biobanking is the absence of standard operating procedures to eliminate pre-analytical variation arising from sample collection, preparation, and storage. Currently, there is a lack of tools to carry out quality control procedures for stored blood samples. The aim of this study is to assess the quality of stored blood samples in our biobank and to suggest appropriate indicators for their quality control. METHODS: The stored blood samples that we tested have been registered into our biobank since 2003. These were transferred to our biobank after carrying out routine requested tests, because the samples would have otherwise been discarded. For the purpose of quality control, we analyzed the concentrations and the integrity of DNA and RNA extracted from the stored samples and tested the levels of several serum proteins; the results were compared with the corresponding pre-storage levels. RESULTS: A total of 19 samples were stored from 2006 to 2009. Of the 22 samples stored between 2003 and 2005, 50% showed complete DNA integrity. However, sufficient RNA integrity was noted in only 1 sample stored as recently as 2009. High blood urea nitrogen levels were also noted in the stored sera, but the increase did not correlate to the duration of storage. CONCLUSIONS: The amount and integrity of nucleic acids extracted from stored blood samples are potential indicators that can be used for quality control. A guideline for the quality assessment of stored blood samples in a biobank is urgently needed.

Late-onset Neutropenia Following Rituximab Therapy as a Treatment of Diffuse Large B-cell Lymphoma: A Single Institution Study / 대한진단검사의학회지

BACKGROUND: Late-onset neutropenia (LON) following rituximab therapy has been reported in recent years. However, its incidence has not been reported in Korea. The aim of this study is to investigate the incidence of LON after rituximab therapy in Korean patients with diffuse large B-cell lymphoma (DLBCL). METHODS: Ninety-eight cases of DLBCL treated with rituximab between 2004 and 2008 were evaluated. We identified LON as defined by the neutrophil count of <1.5x10(9)/L without apparent cause after the recovery of neutrophil count following rituximab therapy. Bone marrow aspiration and biopsy specimens at the time of neutropenia were available for retrospective review in only 5 of the patients. RESULTS: LON was observed in 15 (15.3%) of the 98 patients. In the bone marrow specimens of the 5 patients, promyelocytes were relatively increased and the maturation index of the granulopoiesis was 2:1-3:1, which reflects maturation arrest. CONCLUSIONS: The incidence of LON following rituximab therapy was 15.3% in Korean patients with DLBCL. Although there are several hypotheses about the causative mechanisms of LON, we suggest that maturation arrest at the promyelocyte stage of granulopoiesis may be one of the mechanisms involved in the development of LON.