Current Status of Molecular Diagnosis of Hereditary Hemolytic Anemia in Korea.

Hereditary hemolytic anemia (HHA) is considered a group of rare hematological diseases in Korea, primarily because of its unique ethnic characteristics and diagnostic challenges. Recently, the prevalence of HHA has increased in Korea, reflecting the increasing number of international marriages and increased awareness of the disease. In particular, the diagnosis of red blood cell (RBC) enzymopathy experienced a resurgence, given the advances in diagnostic techniques. In 2007, the RBC Disorder Working Party of the Korean Society of Hematology developed the Korean Standard Operating Procedure for the Diagnosis of Hereditary Hemolytic Anemia, which has been continuously updated since then. The latest Korean clinical practice guidelines for diagnosing HHA recommends performing next-generation sequencing as a preliminary step before analyzing RBC membrane proteins and enzymes. Recent breakthroughs in molecular genetic testing methods, particularly next-generation sequencing, are proving critical in identifying and providing insight into cases of HHA with previously unknown diagnoses. These innovative molecular genetic testing methods have now become important tools for the management and care planning of patients with HHA. This review aims to provide a comprehensive overview of recent advances in molecular genetic testing for the diagnosis of HHA, with particular emphasis on the Korean context.

In vitro Evaluation of DINCH-Plasticized Blood Bags for Red Blood Cell Storage with CPDA-1 Anticoagulant.

Introduction: Di(2-ethylhexyl) phthalate (DEHP) is a plasticizer commonly used in blood bags. Despite its protective effects on red blood cell (RBC) storage, concerns about its reproductive toxicity exist. This study investigated the in vitro quality of RBC concentrates stored in bags using di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH) as an alternative plasticizer. Methods: Using a pool-and-split study design, we produced 20 matched homogenous quintets of RBC concentrates in two DINCH bags and three DEHP bags with citrate phosphate dextrose adenine (CPDA-1) anticoagulant. RBC storage quality was assessed weekly for 35 days. Results: On day 35, the median hemolysis levels in the DINCH bags (0.297-0.342%) were marginally higher (p < 0.05) than the DEHP bags (0.204-0.240%). All DINCH bags showed <0.8% hemolysis. RBCs in the DINCH bags showed increased mean corpuscular volume and decreased eosin 5' maleimide binding than in the DEHP bags. Higher pO2 and lower pCO2 levels in the DINCH bags indicated better gas permeability than in DEHP bags. Other metabolic parameters were comparable in both bags. Compared to DEHP, DINCH exhibited considerably lower levels of plasticizer leaching into blood bags. Conclusion: The quality of RBC concentrates stored for 35 days in DINCH-plasticized blood bags with CDPA-1 is generally comparable to those in DEHP bags. Hence, DINCH can be a viable alternative to DEHP in blood bags for nonleukoreduced RBC storage even without the use of next-generation additive solutions to improve RBC preservation quality.

A plasticizer is a chemical substance added to plastic to increase its flexibility. DEHP is a plasticizer that has been widely used in many products including plastic tubing and bags of medical devices. However, concerns about DEHP-related toxicity have been debated for many years. DEHP has been replaced with other plasticizers in many products, but it is still being used in blood bags due to its protective effect on RBC preservation. DINCH is an alternative plasticizer with a low toxicology profile. This study investigated the quality of RBC concentrates stored in blood bags using DINCH. Twenty sets of five RBC concentrates were produced using two DINCH bags and three DEHP bags with CPDA-1 anticoagulant, and the storage quality was assessed weekly for 35 days. On day 35, the median hemolysis levels in the DINCH bags (0.297­0.342%) were slightly increased than the DEHP bags (0.204­0.240%). However, all DINCH bags showed hemolysis lower than the regulatory limit of 0.8%. DINCH bags exhibited better gas permeability than DEHP bags. Compared to DEHP, DINCH exhibited considerably lower levels of plasticizer leaching into blood bags. Most of the other metabolic parameters were comparable in both bags. The quality of nonleukocyte-reduced RBC concentrates stored for 35 days in DINCH-plasticized blood bags with CDPA-1 is generally comparable to those in DEHP bags. Hence, DINCH can be a viable alternative to DEHP in blood bags for RBC storage, even without the use of next-generation additive solutions to improve RBC preservation quality.

Genomic testing for germline predisposition to hematologic malignancies.

Germline predisposition (GPD) to hematological malignancies has gained interest because of the increased use of genetic testing in this field. Recent studies have suggested that GPD is underrecognized and requires appropriate genomic testing for an accurate diagnosis. Identification of GPD significantly affects patient management and has diverse implications for family members. This review discusses the reasons for testing GPD in hematologic malignancies and explores the considerations necessary for appropriate genomic testing. The aim is to provide insights into how these genetic insights can inform treatment strategies and genetic counseling, ultimately enhancing patient care.

Comparison of Measurable Residual Disease in Pediatric B-Lymphoblastic Leukemia Using Multiparametric Flow Cytometry and Next-Generation Sequencing.

Measurable residual disease (MRD) testing, a standard procedure in B-lymphoblastic leukemia (B-ALL) diagnostics, is assessed using multiparametric flow cytometry (MFC) and next-generation sequencing (NGS) analysis of immunoglobulin gene rearrangements. We evaluated the concordance between eight-color, two-tube MFC-MRD the LymphoTrack NGS-MRD assays using 139 follow-up samples from 54 pediatric patients with B-ALL. We also assessed the effect of hemodilution in MFC-MRD assays. The MRD-concordance rate was 79.9% (N=111), with 25 (18.0%) and 3 (2.2%) samples testing positive only by NGS-MRD (MFC-NGS+MRD) and MFC-MRD (MFC+NGS-MRD), respectively. We found a significant correlation in MRD values from total nucleated cells between the two methods (r=0.736 [0.647-0.806], P<0.001). The median MRD value of MFC-NGS+MRD samples was estimated to be 0.0012% (0.0001%-0.0263%) using the NGS-MRD assays. Notably, 14.3% of MFC-NGS+MRD samples showed NGS-MRD values below the limit of detection in the MFC-MRD assays. The percentages of hematogones detected in MFC-MRD assays significantly differed between the discordant and concordant cases (P<0.001). MFC and NGS-MRD assays showed relatively high concordance and correlation in MRD assessment, whereas the NGS-MRD assay detected MRD more frequently than the MFC-MRD assay in pediatric B-ALL. Evaluating the hematogone percentages can aid in assessing the impact of sample hemodilution.

Diagnostic Approaches to Investigate JAK2-Unmutated Erythrocytosis Based on a Single Tertiary Center Experience.

INTRODUCTION: Erythrocytosis is attributed to various clinical and molecular factors. Many cases of JAK2-unmutated erythrocytosis remain undiagnosed. We investigated the characteristics and causes of JAK2-unmutated erythrocytosis. METHODS: We assessed the clinical and laboratory results of patients with erythrocytosis without JAK2 mutations and performed targeted next-generation sequencing (NGS) panels for somatic and germline mutations. RESULTS: In total, 117 patients with JAK2-unmutated erythrocytosis were included. The median hemoglobin and hematocrit levels were 17.9 g/dL and 53.4%, respectively. Erythropoietin levels were not below the reference range. Thrombotic events were reported in 17 patients (14.5%). Among JAK2-unmutated patients, 44 had undergone targeted panel sequencing consisting of myeloid neoplasm-related genes, and 16 had one or more reportable variants in ASXL1 (5/44), TET2, CALR, FLT3, and SH2B3 (2/44). Additional testing for germline causes revealed eight variants in seven genes in eight patients, including NF1, BPGM, EPAS1, PIEZO1, RHAG, SH2B3, and VHL genes. One NF1 pathogenic, one BPGM likely pathogenic, and six variants of undetermined significance were detected. CONCLUSION: Somatic and germline mutations were identified in 36.4% and 33.3 % of the JAK2-unmutated group; most variants had unknown clinical significance. Not all genetic causes have been identified; comprehensive diagnostic approaches are crucial for identifying the cause of erythrocytosis.

Coagulation Testing in Real-World Setting: Insights From a Comprehensive Survey.

The objective of this survey was to gain a real-world perspective on coagulation testing by evaluating the availability of various coagulation laboratory tests, assessing specific analytic and postanalytic steps in clinical laboratories in Korea.Participants were surveyed using a 65-question questionnaire specifically focused on their coagulation testing practices related to prothrombin time (PT), activated partial thromboplastin time (aPTT), plasma-mixing studies, lupus anticoagulant (LA) tests, platelet function tests, coagulation factor assays, and the composition of hemostasis and thrombosis test panels. The survey was performed between July and September 2022.The survey achieved a 77.9% (81 of 104) response rate. PT or aPTT tests were performed directly at all participating institutions, followed by D-dimer and fibrinogen tests, platelet function test, and plasma-mixing studies in order of frequency. Variations existed in the performance of mixing test and LA assessment. Patterns of coagulating testing differed depending on the size of the hospital. The survey revealed that most laboratories conducted coagulation tests following the international guidelines such as Clinical Laboratory Standards Institute guidelines and the Korean Laboratory Certification system. However, some coagulation tests, including mixing test and LA tests, are yet to be standardized in Korea.Continuous education on coagulation test methods and internal and external quality control are required to encourage laboratories to enhance the performance of coagulation testing.