A rare, likely pathogenic GCK variant related to maturity-onset diabetes of the young type 2: A case report

Maturity-onset diabetes of the young (MODY) is caused by autosomal dominant pathogenic variants in one of 14 currently known monogenic genes. Characteristics of patients with MODY include early-onset clinical disease with a family history of diabetes and negative autoantibodies and may present with heterogeneous phenotypes according to the different subtypes. Here, we report a patient with early-onset diabetes who presented asymptomatic mild fasting hyperglycemia with the absence of autoantibodies. She was diagnosed with glucokinase (GCK)-MODY caused by a GCK variant, c.1289T>C (p.L430P), identified by targeted gene-panel testing, and the affected father had the same variant. We interpreted this rare missense variant as a likely pathogenic variant and then she stopped taking oral medication. This case highlights the usefulness of genepanel testing for accurate diagnosis and appropriate management of MODY. We also note the importance of familial genetic testing and genetic counseling for the proper interpretation of MODY variants.

Revision of Laboratory Testing Guidelines for Initial Diagnosis of Hematologic Neoplasms

Emergence of Monosomy 7 in Philadelphia-Negative Cells during MDS Development and not CML Diagnosis Proved by Serial Droplet Digital PCR

Emergence of new clonal chromosomal abnormality (CCA) has been reported in Philadelphia-negative cells in patients with chronic myeloid leukemia (CML) undergoing the tyrosine kinase inhibitor (TKI) treatment. However, the time of emergence and clinical significance of CCA remains to be elucidated. In this study, we report a CML patient undergoing TKI treatment who developed myelodysplastic syndrome (MDS) after 206 months since the diagnosis of CML. Results of droplet digital PCR performed with serial bone marrow samples revealed that monosomy 7 in Philadelphia-negative cells appeared at the time of MDS development that did not exist initially at the time of CML diagnosis.

Emergence of Monosomy 7 in Philadelphia-Negative Cells during MDS Development and not CML Diagnosis Proved by Serial Droplet Digital PCR

Emergence of new clonal chromosomal abnormality (CCA) has been reported in Philadelphia-negative cells in patients with chronic myeloid leukemia (CML) undergoing the tyrosine kinase inhibitor (TKI) treatment. However, the time of emergence and clinical significance of CCA remains to be elucidated. In this study, we report a CML patient undergoing TKI treatment who developed myelodysplastic syndrome (MDS) after 206 months since the diagnosis of CML. Results of droplet digital PCR performed with serial bone marrow samples revealed that monosomy 7 in Philadelphia-negative cells appeared at the time of MDS development that did not exist initially at the time of CML diagnosis.

Recommendation for the Peripheral Blood Cell Morphology Report

There is considerable heterogeneity in the peripheral blood smear reports across different diagnostic laboratories, despite following the guidelines published by the International Council for Standardization in Haematology (ICSH). As standardization of reports can facilitate communication and consequently the diagnostic efficiency in both laboratories and clinics, the standardization committee of the Korean Society for Laboratory Hematology aimed to establish a detailed guideline for the standardization of peripheral blood smear reports. Based on the ICSH guidelines, additional issues on describing and grading the peripheral blood smear findings were discussed. In this report, the proposed guideline is briefly described.

Effects of Pre-analytical Variables on Cell-free DNA Extraction for Liquid Biopsy

BACKGROUND: Extraction of cell-free DNA (cfDNA) is a key step for determining the quality of cfDNA-related molecular diagnostics. We evaluated the effect of sample containers and sample storage conditions on cfDNA extraction. METHODS: The cfDNA extraction using the MagMAX Cell-Free DNA Isolation Kit from five healthy controls and five lung cancer patients was evaluated according to the type of sample container and storage conditions: K2-EDTA container, <1, 6, 24, and 48 hr storage at 4℃ after immediate plasma separation; and Cell-Free DNA BCT container, <1, 3, 7, and 14 days stored at room temperature. Mutation analysis of EGFR exons 18–21 was performed. To assess the effect of a delay in centrifugation, EDTA whole blood samples from five healthy individuals were stored at 4℃ for 6, 12, and 24 hr before plasma separation. RESULTS: There was no significant difference in the amount and nucleic acid size of cfDNA in both controls and patients with cancer when EDTA plasma was stored at 4℃ up to 48 hr. The amount and size of cfDNA in the BCT container were not different up to 7 days; however, the 14-day sample showed an increase in cfDNA concentration due to genomic DNA contamination. EGFR mutations were detected on EDTA containers up to 48 hr and with BCT containers up to 14 days. When EDTA whole blood was stored at 4℃ and plasma separation was delayed, the cfDNA concentration increased from 24 hr. CONCLUSIONS: The cfDNA extraction was affected by the sample containers and storage conditions.

A Clue to Discovering Unstable Hemoglobin Variants via Abnormal WBC Differential Scattergrams Using the Sysmex Automated Hematology Analyzer

Incidentally, hemoglobin (Hb) variants can be detected using HbA1c tests in clinical laboratories. We found 38 patients with Hb variants after reviewing a total of 29,398 HbA1c test results from January 2017 to December 2017. While reviewing the complete blood count results of the patients (N=36) using the Sysmex XN-9000 analyzer (Sysmex, Japan), 35 patients were flagged as unremarkable with respect to differential white blood cell (WBC) counts. However, 1 patient with a normal WBC count did not obtain a differential WBC count while being flagged for an abnormal WBC scattergram in the white blood cell differential (WDF) channel. The WBC histogram showed an abnormally low fluorescent signal in the WDF channel; however, the differential WBC count was normal upon microscopic examination. After testing the patient's buffy coat suspended in normal saline and removing red blood cells (RBCs), the WBC scattergram and differential WBC count returned to normal. This finding suggests that the presence of a patient's RBCs may affect WBC scattergrams and Hb variants may interfere with the fluorescent dye in the differential WBC count. Therefore, when an abnormal WBC scattergram with an abnormally low fluorescent signal is encountered on the Sysmex XN-9000 analyzer, the presence of an Hb variant can be suspected.

Analytical Performance of INNOVANCE Free Protein S Antigen on Sysmex CS-5100

BACKGROUND: Protein S deficiency is a common cause of thrombophilia. Free protein S has been suggested as one of the best screening tests for this deficiency. We evaluated an immunoturbidimetric free protein S reagent, INNOVANCE Free Protein S Antigen (Free PS Ag; Siemens Healthcare Diagnostics, Germany), using a CS-5100 coagulation analyzer (Sysmex, Japan). METHODS: The performance of INNOVANCE Free PS Ag was evaluated according to the CLSI guidelines. Precision, linearity, and verification of reference intervals were examined. The INNOVANCE Free PS Ag was also compared by the STA-Liatest Free Protein S immunoturbidimetric assay (Diagnostica Stago, France). RESULTS: The repeatability and within-laboratory imprecision of INNOVANCE Free PS Ag were 0.8% CV and 2.0% CV at the normal level, and 1.3% CV and 2.3% CV at the abnormally low level, respectively. This assay showed linearity from 4.0% to 151.9% (correlation coefficient r=1, P < 0.0001). Reference intervals for males and females were verified as acceptable. INNOVANCE Free PS Ag was comparable with STA-Liatest Free Protein S with a very high correlation (r=0.935, P < 0.0001). The results for the INNOVANCE antigen were higher. CONCLUSIONS: The INNOVANCE Free PS Ag on a Sysmex CS-5100 coagulation analyzer has excellent analytical performance and is comparable with the STA-Liatest Free Protein S assay.

The 2016 WHO versus 2008 WHO Criteria for the Diagnosis of Chronic Myelomonocytic Leukemia

The 2016 WHO diagnostic criteria for chronic myelomonocytic leukemia (CMML) require both absolute and relative monocytosis (≥1×10⁹/L and ≥10% of white blood cell counts) in peripheral blood. Moreover, myeloproliferative neoplasm (MPN) features in bone marrow and/or MPN-associated mutations tend to support MPN with monocytosis rather than CMML. We assessed the impact of the 2016 WHO criteria on CMML diagnosis, compared with the 2008 WHO criteria, through a retrospective review of the medical records of 38 CMML patients diagnosed according to the 2008 WHO classification. Application of the 2016 WHO criteria resulted in the exclusion of three (8%) patients who did not fulfill the relative monocytosis criterion and eight (21%) patients with an MPN-associated mutation. These 11 patients formed the 2016 WHO others group; the remaining 27 formed the 2016 WHO CMML group. The significant difference in the platelet count and monocyte percentage between the two groups indicated that the 2016 WHO criteria lead to a more homogenous and improved definition of CMML compared with the 2008 WHO criteria, which may have led to over-diagnosis of CMML. More widespread use of molecular tests and more sophisticated clinical and morphological evaluations are necessary to diagnose CMML accurately.

GATA1 Expression in BCR/ABL1-negative Myeloproliferative Neoplasms

BACKGROUND: This study aimed to determine GATA1 expression levels to better characterize subgroups in BCR/ABL1-negative myeloproliferative neoplasms (MPNs). METHODS: This study enrolled 49 patients diagnosed as having BCR/ABL1-negative MPN on the basis of the 2016 World Health Organization classification : nine polycythemia vera (PV), 17 essential thrombocythemia (ET), 12 prefibrotic primary myelofibrosis (prePMF), and 11 overt primary myelofibrosis (PMF). Relevant clinical and laboratory data were retrieved from the medical records. The molecular analysis of CALR and MPL mutations and quantification of JAK2 V617F allele burden were performed. GATA1 expression was assessed by an immunohistochemical assay on bone marrow biopsy. GATA1 expression was analyzed serially in 18 patients. RESULTS: GATA1 expression decreased significantly in PMF compared with that in other subtypes, while no statistical difference was identified between ET and prePMF. GATA1 expression did not differ according to the mutation profiles or the allele burden of JAK2 V617F, but it decreased significantly in patients with overt fibrosis or leukemic transformation. CONCLUSIONS: Our results suggest that GATA1 expression is significantly low in PMF and decreases with progressive fibrosis and possibly with leukemic transformation, although our attempt to accurately distinguish between subgroups using GATA1 immunohistochemical approach did not achieve statistical significance. A large patient cohort with long term follow-up is required to evaluate the prognostic value of GATA1 expression.

Variable Natural Killer Cell Activity in Hematological Malignancies at Diagnosis

BACKGROUND: Natural killer (NK) cells play a key role in innate immune responses and are an important component of anti-cancer defenses. This study aimed to investigate the clinicopathological characteristics of NK cell activity (NKA) among various hematological malignancies at diagnosis and to evaluate their clinical value as a monitoring marker. METHODS: A total of 111 patients that were newly diagnosed with hematological malignancies were recruited, comprising 18 acute myeloid leukemia (AML), 31 multiple myeloma (MM), and 62 lymphoma. Twenty-three normal control subjects from our health examination center were recruited. NKA was measured using a commercially available enzyme-linked immunosorbent assay kit, which measures interferon-gamma secreted by ex vivo-stimulated NK cells in whole blood. RESULTS: The 111 patients had a median NKA of 202.80 pg/mL (range 40–2,000). NKA was significantly decreased in patients with AML (median 47.05 pg/mL, 40–2,000, P<0.0001), MM (275.00, 40–2,000, P<0.0001), and lymphoma (289.49, 40–2,000, P<0.0001) compared with that in normal controls (1,891, 412–2,000). There was a difference in NKA between AML and lymphoma (P=0.0499). Serial changes in NKA correlated with disease progression. NKA did not correlate with the NK cell count in any group of hematological malignancies. CONCLUSIONS: The measurement of NKA could be useful to evaluate the immunological status in hematological malignancies at diagnosis and during follow-up.

Anaplastic Large Cell Lymphoma with Massive Eosinophilia and Complex Karyotype Initially Misdiagnosed as Chronic Eosinophilic Leukemia

We report a patient with massive eosinophilia and a complex karyotype that was initially misdiagnosed as chronic eosinophilic leukemia (CEL), but later diagnosed as anaplastic large cell lymphoma (ALCL) masked by massive eosinophilia. The complex karyotype observed at initial diagnosis remained unchanged later, after the evidence of bone marrow involvement of ALCL was obtained. At diagnosis, genetic aberrations corresponding to metaphase cytogenetics were not identified by interphase fluorescence in situ hybridization, although abnormal results were noted at follow-up. Together, these observations indicate that the complex karyotype at initial work-up has been derived from a low proportion of lymphoma cells with high mitotic ability that were not identified by microscopy, rather than from massive eosinophils. These findings suggest that our patient had ALCL with secondary eosinophilia rather than CEL since initial diagnosis.

Clinicopathological Characteristics of Hyperdiploidy with High-Risk Cytogenetics in Multiple Myeloma

In multiple myeloma (MM), hyperdiploidy (HD) is known to impart longer overall survival. However, it is unclear whether coexistent HD ameliorates the adverse effects of known high-risk cytogenetics in MM patients. To address this issue, we investigated the clinicopathological characteristics of HD with high-risk cytogenetics in MM. Ninety-seven patients with MM were included in the study. For metaphase cytogenetics (MC), unstimulated cells from bone marrow aspirates were cultured for either 24 or 48 hours. To detect HD by interphase fluorescence in situ hybridization (iFISH), we assessed trisomies of chromosomes 5, 7, 9, 11, 15, and 17. Of the 97 MM patients, 40 showed HD. The frequency of co-occurrence of HD and high-risk cytogenetics was 14% (14/97). When the clinicopathological characteristics were compared between the two groups of HD with high-risk cytogenetics vs. non-HD (NHD) with high-risk cytogenetics, the level of beta 2 microglobulin and stage distribution significantly differed (P=0.020, P=0.032, respectively). This study shows that some of the clinicopathological characteristics of MM patients with high-risk cytogenetics differ according to HD or NHD status.

Neutrophilic Leukemoid Reaction Associated with Malignancy Initially Suspected as Chronic Neutrophilic Leukemia

Although neutrophilia can manifest from various causes, it is important to be able to distinguish chronic neutrophilic leukemia (CNL) from neutrophilic leukemoid reactions (NLR). In this paper, we describe four cases of leukocytosis with neutrophilia, including one case of CNL with a T618I mutation in colony stimulating factor 3 receptor (CSF3R) and three cases of NLR associated with malignancy or sepsis, which were initially suspected as CNL. Of the three NLR cases, one was associated with ovarian cancer, one with monoclonal gammopathy of undetermined significance and one with multiple myeloma with sepsis. This study demonstrated that confirming the clonality of myeloid cells with CSF3R T618I could contribute to making an accurate differential diagnosis between CNL and NLR in patients with solid cancers or plasma cell neoplasms caused by paraneoplastic syndromes and/or infection.

Test Guidelines for Initial Diagnosis of Hematologic Neoplasms

The standardization committee of the Korean Society for Laboratory Hematology sought to establish standardized testing guidelines for the diagnosis of hematologic malignancies. The guidelines were developed on the basis of survey results and international guidelines, including the National Comprehensive Cancer Network Guidelines and European LeukemiaNet recommendations. The committee expects that the diagnostic guidelines presented here will enhance diagnostic test standardization and clinical decision making and that the novel developments due to new molecular technologies will be integrated into the diagnostic algorithms through ongoing consensus initiatives.

Submicroscopic Deletions of Immunoglobulin Heavy Chain Gene (IGH) in Precursor B Lymphoblastic Leukemia with IGH Rearrangements

Translocations leading to fusions between the immunoglobulin heavy chain gene (IGH) and various partner genes have been reported in B-cell precursor acute lymphoblastic leukemia (B-ALL). However, submicroscopic deletions within IGH in B-ALL have not been rigorously assessed. In this study, we investigated characteristics of IGH submicroscopic deletions, by FISH, in B-ALL with IGH rearrangements. FISH was performed by using commercially available IGH dual-color break-apart rearrangement probes (Abbott/Vysis, Downers Grove, IL, USA; Kreatech, Amsterdam, Netherlands). The study group included seven B-ALL patients with IGH rearrangements, observed by FISH. Among them, two exhibited deletion of the 5' variable region of IGH by FISH. The B-ALL in these two patients included two kinds of abnormal cells; one had an IGH rearrangement without any IGH submicroscopic deletion, while the other had an IGH submicroscopic deletion, which showed that one normal fusion signal and one 3' IGH signal were detected. Thus, submicroscopic deletion of the IGH 5' variable region may have occurred in either the native or rearranged chromosome 14. These findings indicate that B-ALL with IGH rearrangements may be accompanied by submicroscopic deletions of the IGH 5' variable region, which can be detected by FISH. The clinical significance of such deletions is unclear, but the loss of part of the IGH gene in B-ALL warrants further study.

Clinical Usefulness of Bronchoalveolar Lavage Cellular Analysis and Lymphocyte Subsets in Diffuse Interstitial Lung Diseases

BACKGROUND: Diffuse interstitial lung diseases (DILDs) form a part of a heterogeneous group of respiratory diseases. Bronchoalveolar lavage (BAL) analysis has been used for differential diagnosis of DILDs, but their clinical usefulness is controversial. The aim of this study was to investigate the clinical usefulness of BAL cellular analysis with lymphocyte subsets for the differential diagnosis of DILDs. METHODS: A total of 69 patients diagnosed with DILDs were enrolled. Basic demographic data, BAL cellular analysis with lymphocyte subsets, histology, and high resolution computed tomogram (HRCT) findings were analyzed and compared as per disease subgroup. RESULTS: Significant differences were found between groups in the proportion of neutrophils (P=0.0178), eosinophils (P=0.0003), T cells (P=0.0305), CD4 cells (P=0.0002), CD8 cells (P<0.0001), and CD4/CD8 ratio (P<0.0001). These findings were characteristic features of eosinophilic pneumonia and sarcoidosis. Other parameters were not significantly different between groups. At the cut-off value of 2.16 for sarcoidosis, CD4/CD8 ratio showed sensitivity of 91.7% (95% CI, 61.5-98.6%) and specificity of 84.2% (95% CI, 72.1-92.5%). CONCLUSIONS: Routine analysis of BAL lymphocyte subset may not provide any additional benefit for differential diagnosis of DILDs, except for conditions where BAL is specifically indicated, such as eosinophilic pneumonia or sarcoidosis.

Chromothripsis Identified by Copy Number Profiling in a Case of Plasma Cell Leukaemia / 임상검사와정도관리

A genomic instability called chromothripsis occurs as a single catastrophic event, generating massive complex genomic rearrangement with a possible characteristic pattern of copy number oscillations. Here, we report a case of secondary plasma cell leukaemia (PCL) showing chromothripsis identified by single nucleotide polymorphism array (SNP-A)-based karyotyping. A 53-year-old male patient was diagnosed as having secondary PCL four years after he was diagnosed with multiple myeloma, and he died four days later due to intracerebral haemorrhage. Chromosomal analysis and fluorescence in situ hybridization (FISH) revealed the deletions of 13q and 17p and an insertion of 1q. Further, genomic aberrations that were not detected by chromosomal analysis and FISH were identified by SNP-A. In particular, SNP-A revealed numerous alternating copy number state switches involving one, two, or three copy number states on chromosome 7q, suggesting the presence of chromothripsis. The present case suggests that chromothripsis may occur in secondary PCL and can be inferred from genomic copy number profiles identified by SNP-A.

Systemic Epstein-Barr Virus-Positive T-cell Lymphoproliferative Disease of Childhood Presenting as Hemophagocytic Lymphohistiocytosis with Chromosomal Abnormalities / 임상검사와정도관리

Epstein-Barr virus (EBV)-positive T-cell lymphoproliferative disease (EBV+ T-cell LPD) is characterized by a clonal proliferation of T-cells, which may trigger hemophagocytic lymphohistiocytosis (HLH). Chromosomal abnormalities in patients with HLH are usually found in association with underlying malignancies. We report here a case of systemic EBV+ T-cell LPD of childhood initially presenting with HLH. A 19-year-old man was admitted to the hospital with a 2-week history of fever. Laboratory data revealed pancytopenia, hypertriglyceridemia, high ferritin levels, and abnormalities in liver function tests. EBV infection was confirmed by serologic tests and real-time polymerase chain reaction. Examination of the bone marrow showed histiocytic hyperplasia and hemophagocytosis. Further investigation revealed atypical lymphoid cells expressing EBV-encoded RNA, CD3, CD4, and CD8. A chromosomal analysis displayed a complex karyotype. Despite intensive treatment, the patient died 15 days after initial presentation. In conclusion, systemic EBV+ T-cell LPD of childhood presenting with HLH and chromosomal abnormalities may progress rapidly and be fatal. Therefore, a diagnostic workup for chromosomal aberration is essential.

An unrelated Clone of 20q Deletion Following Successful Treatment of Leukemia in Patients with t(8;21), t(15;17) or t(9;22) / 임상검사와정도관리

Cases of clonal cytogenetic abnormalities in Philadelphia-negative cells during the treatment of Philadelphia-positive CML have been previously reported. However, clonal abnormalities unrelated to the original t(8;21) or t(15;17) karyotype are not common. Deletion of 20q (del(20q)) is one of the most common recurrent cytogenetic abnormalities in myeloid neoplasms. Here we describe 3 patients with t(8;21), t(15;17), or t(9;22) who developed unrelated del(20q) after successful treatment of leukemia. We retrospectively reviewed the cytogenetic results of 23 AML patients with t(8;21)(q22;q22), 28 AML patients with t(15;17)(q22;q12), and 47 CML patients with t(9;22)(q34;q11.2). We identified 3 patients with del(20q) as the only clonal aberration unrelated to the primary karyotype when they achieved complete morphologic and cytogenetic remission. The latency period between diagnosis and emergence of del(20q) was 1, 114, and 35 months for the 3 patients, respectively. There was no evidence of therapy-related MDS/AML during the follow-up period. In 1 AML patient with t(8;21), relapse occurred in a t(8;21)(q22;q22) clone and the del(20q) clones were lost. The clinical significance of del(20q) as an unrelated clonal aberration is unknown, but our study suggests that del(20q) does not cause therapy-related MDS/AML or indicate disease progression.