Kyung-Nam Koh

Central nervous system (CNS) involvement is a critical prognostic factor for hemophagocytic lymphohistiocytosis.

Background Hemophagocytic lymphohistiocytosis (HLH) is a rare multisystem disorder that frequently involves the central nervous system (CNS). We compared the clinical characteristics, treatment, and prognosis of patients with HLH according to the degree of CNS involvement. Methods The clinical manifestations, initial laboratory data, treatment, and outcomes for 50 patients diagnosed with HLH and treated at Asan Medical Center between January 1995 and August 2011 were retrospectively reviewed and analyzed. CNS involvement was defined as the presence of neurological symptoms or an elevated white blood cell (WBC) count in the cerebrospinal fluid (CSF). Results Among these 50 patients, 23 (46%) developed CNS disease. Among patients with CNS disease, 19 had neurological symptoms, including seizures, altered consciousness, facial palsy, dysarthria, and dysphagia. Four patients had elevated CSF WBC counts without neurological symptoms. Twelve patients had abnormal brain imaging results, including high signal intensity lesions on T2-weighted magnetic resonance imaging (MRI) findings, ventriculomegaly, hemorrhage, atrophy, and leptomeningeal enhancement. Patients with CNS disease had lower ferritin, aspartate aminotransferase (AST), and alanine aminotransferase (ALT) levels as well as reduced 5-year survival as compared to those without CNS disease. Conclusion CNS involvement is common among patients with HLH. Overall, patients with CNS disease achieve poorer outcomes than patients without CNS involvement. To improve outcomes, physicians must carefully monitor the neurological manifestations in patients with HLH and administer the appropriate course of intensified chemotherapy to patients with CNS disease.

Clinical features, genetics, and outcome of pediatric patients with hemophagocytic lymphohistiocytosis in Korea: report of a nationwide survey from Korea Histiocytosis Working Party

We analyzed a nationwide registry of pediatric patients with hemophagocytic lymphohistiocytosis (HLH) in Korea to assess the clinical and genetic features and treatment outcomes in pediatric HLH.

Founder effects in two predominant intronic mutations of UNC13D, c.118-308C>T and c.754-1G>C underlie the unusual predominance of type 3 familial hemophagocytic lymphohistiocytosis (FHL3) in Korea

Familial hemophagocytic lymphohistiocytosis (familial HLH or FHL) is a potentially fatal autosomal recessive disorder. Our previous study demonstrated that UNC13D mutations (FHL3) account for ∼90xa0% of FHL in Korea with recurrent splicing mutation c.754-1G>C (IVS9-1G>C). Notably, half of the FHL3 patients had a monoallelic mutation of UNC13D. Deep intronic mutations in UNC13D were recently reported in patients of European descent. In this study, we performed targeted mutation analyses for deep intronic mutations and investigated on the founder effect in FHL3 in Korean patients. The study patients were 72 children with HLH including those with FHL3 previously reported to have a monoallelic UNC13D mutation. All patients were recruited from the Korean Registry of Hemophagocytic Lymphohistiocytosis. In addition to conventional sequencing of FHL2-4, targeted tests for c.118-308C>T and large intronic rearrangement mutations of UNC13D were performed. Haplotype analysis was performed for founder effects using polymorphic markers in the FHL3 locus. FHL mutations were detected in 20 patients (28xa0%). Seventeen patients had UNC13D mutations (FHL3, 85xa0%) and three had PRF1 mutations (FHL2, 15xa0%). UNC13D:c.118-308C>T was detected in ten patients, accounting for 38xa0% of all mutant alleles of UNC13D, followed by c.754-1G>C (26xa0%). Haplotype analyses revealed significantly shared haplotypes in both c.118-308C>T and c.754-1G>C, indicating the presence of founder effects. The deep intronic mutation UNC13D:c.118-308C>T accounts for the majority of previously missing mutations and is the most frequent mutation in FHL3 in Korea. Founder effects of two recurrent intronic mutations of UNC13D explain the unusual predominance of FHL3 in Korea.

Haploidentical haematopoietic stem cell transplantation using CD3 or CD3/CD19 depletion and conditioning with fludarabine, cyclophosphamide and antithymocyte globulin for acquired severe aplastic anaemia

Fitzgibbon, J., Iqbal, S., Davies, A., O’Shea, D.,Carlotti, E., Chaplin, T., Matthews, J., Raghavan,M., Norton, A., Lister, T.A. & Young, B.D.(2007) Genome-wide detection of recurring sitesof uniparental disomy in follicular and trans-formed follicular lymphoma. Leukemia, 21,1514–1520.Mao, Z., Quintanilla-Martinez, L., Raffeld, M.,Richter, M., Krugmann, J., Burek, C., Hartmann,E., Rudiger, T., Jaffe, E.S., Muller-Hermelink,H.K., Ott, G., Fend, F. & Rosenwald, A. (2007)IgVH mutational status and clonality analysis ofRichter’s transformation: diffuse large B-celllymphoma and Hodgkin lymphoma in associa-tion with B-cell chronic lymphocytic leukemia(B-CLL) represent 2 different pathways of diseaseevolution. American Journal of Surgical Pathology,31, 1605–1614.Rossi, D. & Gaidano, G. (2009) Richter syndrome:molecular insights and clinical perspectives.Hematologcal Oncology ,27, 1–10.Scandurra, M., Rossi, D., Deambrogi, C., Rancoita,P.M., Chigrinova, E., Mian, M., Cerri, M., Rasi,S., Sozzi, E., Forconi, F., Ponzoni, M., Moreno,S.M., Piris, M.A., Inghirami, G., Zucca, E., Gattei,V., Rinaldi, A., Kwee, I., Gaidano, G. & Bertoni,F. (2010) Genomic profiling of Richter’ssyndrome: recurrent lesions and differences withde novo diffuse large B-cell lymphomas. Hema-tologcal Oncology, 28, 62–67.Smit, L.A., van Maldegem, F., Langerak, A.W., vander Schoot, C.E., de Wit, M.J., Bea, S., Campo,E., Bende, R.J. & van Noesel, C.J. (2006) Anti-gen receptors and somatic hypermutation inB-cell chronic lymphocytic leukemia with Rich-ter’s transformation. Haematologica 91, 903–911.Timar, B., Fulop, Z., Csernus, B., Angster, C., Bog-nar, A., Szepesi, A., Kopper, L. & Matolcsy, A.(2004) Relationship between the mutational sta-tus of VH genes and pathogenesis of diffuse largeB-cell lymphoma in Richter’s syndrome. Leuke-mia, 18, 326–330.

Haploidentical hematopoietic stem cell transplantation in children and adolescents with acquired severe aplastic anemia

Severe aplastic anemia (SAA) is a life-threatening disorder for which allogeneic hematopoietic stem cell transplantation (HSCT) is the current available curative treatment. HSCT from matched sibling donors (MSDs) is the preferred therapy for children with acquired SAA. For patients who lack MSDs, immunosuppressive therapy (IST) is widely accepted as a first-line treatment before considering HCT from an unrelated donor (URD). Given the recent progress in HSCT using URDs for childhood SAA, well-matched URDs became a realistic alternative for pediatric patients who have no suitable related donors and who are refractory to IST. However, it is quite challenging to treat patients with refractory SAA who lack suitable related or URDs. Even though haploidentical HSCT from genetically mismatched family members seemed to be an attractive procedure with the amazing benefit of readily available donors for most patients, early attempts were disappointing because of refractory graft-versus-host disease (GVHD) and excessively high transplant-related mortality. Recent advances with effective ex vivo depletion of T cells or unmanipulated in vivo regulation of T cells, better supportive care, and optimal conditioning regimens have significantly improved the outcome of haploidentical transplant. Besides considerable progress in the treatment of malignant diseases, recent emerging evidences for haploidentical HSCT in SAA has provided additional therapeutic options for patients with refractory diseases. Further improvements to decrease the rates of graft failure, GVHD, and infectious complications will facilitate the emergence of haploidentical HSCT as a front-line therapy for treating acquired SAA in children and adolescents who have no suitably matched donors.

Comparison Study of the Eosin-5′-Maleimide Binding Test, Flow Cytometric Osmotic Fragility Test, and Cryohemolysis Test in the Diagnosis of Hereditary Spherocytosis

OBJECTIVESnCurrent guidelines recommend the eosin-5-maleimide (EMA) binding test and cryohemolysis test for screening for hereditary spherocytosis (HS), and the flow cytometric osmotic fragility (FC OF) test was recently developed to replace the classic OF test. We evaluatedthe performance of the EMA binding test, FC OF test, cryohemolysis test, and the hemoglobin (Hb)/mean corpuscular hemoglobin concentration (MCHC) ratio in the diagnosis of HS and assessed whether these tests reflect the clinical severity of HS.nnnMETHODSnA total of 153 patients with anemia (33 with HS, 40 with autoimmune hemolytic anemia, 40 with anemia of chronic disease, and 40 with iron deficiency anemia [IDA]) and 140 healthy controls were enrolled, and the performance of the three tests was evaluated.nnnRESULTSnBoth the EMA binding test (area under the curve [AUC], 0.996) and the FC OF test (AUC, 0.992) performed satisfactorily, but the cryohemolysis test (AUC, 0.723) performed significantly worse because of false positivity in patients with IDA. The Hb/MCHC ratio (P < .001) was able to reflect the clinical severity of HS.nnnCONCLUSIONSnOur results demonstrate that both the EMA binding and FC OF tests are useful as screening tests for the diagnosis of HS, but the cryohemolysis test has limited use due to its false positivity in IDA, with the Hb/MCHC ratio the most useful parameter for assessing the clinical severity of HS.

Successful rescue of early graft failure in pediatric patients using T-cell-depleted haploidentical hematopoietic SCT

Graft failure (GF) is a significant complication after allogeneic hematopoietic stem cell transplantation (HCT) and is associated with a high mortality rate. We performed re-transplantation using haploidentical-related donors to rescue children with early GF. Between 2008 and 2013, 10 patients received re-transplantation from haploidentical family donors. The median age at HCT was 13.5 years and the median time between transplantations was 52.5 days. Conditioning regimen with fludarabine and CY was used in seven patients, and TBI was added in three patients. All 10 patients received T-cell-depleted grafts using CD3 or CD3/CD19 MoAb. The median numbers of CD34+ and CD3+ cells were 5.52 × 106/kg and 1.08 × 106/kg, respectively. For GVHD prophylaxis, mycophenolate mofetil (MMF) and tacrolimus or MMF and CYA were used. All 10 patients achieved a sustained neutrophil engraftment and maintained a complete donor chimerism at the time of analysis (median 23 months, range 6–62 months). Nine of 10 patients were alive, and one patient with moyamoya disease with AML died of encephalopathy 7 months post transplant. This study suggests that fludarabine- and CY-based conditioning with T-cell-depleted haploidentical HCT is a feasible option to rescue pediatric patients with primary GF.

Preferential occurrence of spliceosome mutations in acute myeloid leukemia with preceding myelodysplastic syndrome and/or myelodysplasia morphology

Spliceosome mutations are associated with myelodysplasia. Here, we aimed to evaluate the frequency and clinical associations of these mutations in 204 patients with acute myeloid leukemia with myelodysplasia-related changes (AML with MRC) and 37 with therapy-related AML (t-AML). The frequency of mutation-positive patients was 17.0%, including U2AF1 (8.3%), SRSF2 (5.8%) and SF3B1 (2.9%). Mutations were detected almost exclusively in patients with AML with MRC, especially in cases with a preceding myelodysplastic syndrome (MDS) history or myelodysplastic morphology. By contrast, mutations were rare in patients with only MDS-related cytogenetics or t-AML. The presence of a mutation had no impact on survival. In a paired analysis, 16.7% of mutation-negative patients in the MDS phase acquired mutations during leukemogenesis. Our observations highlight the preponderance of spliceosome mutations within a specific AML subgroup with myelodysplasia, and suggest that these mutations might contribute pathologically to leukemogenesis in such patients.

Recent advances in haploidentical hematopoietic stem cell transplantation using ex vivo T cell-depleted graft in children and adolescents

Allogeneic hematopoietic stem cell transplantation (HSCT) is a curative treatment for children and adolescents with various malignant and non-malignant diseases. While human leukocyte antigen (HLA)-identical sibling donor is the preferred choice, matched unrelated volunteer donor is another realistic option for successful HSCT. Unfortunately, it is not always possible to find a HLA-matched donor for patients requiring HSCT, leading to a considerable number of deaths of patients without undergoing transplantation. Alternatively, allogeneic HSCT from haploidentical family members could provide donors for virtually all patients who need HSCT. Although the early attempts at allogeneic HSCT from haploidentical family donor (HFD) were disappointing, recent advances in the effective ex vivo depletion of T cells or unmanipulated in vivo regulation of T cells, better supportive care, and optimal conditioning regimens have significantly improved the outcomes of haploidentical HSCT. The ex vivo techniques used to remove T cells have evolved from the selection of CD34+ hematopoietic stem cell progenitors to the depletion of CD3+ cells, and more recently to the depletion of αβ+ T cells. The recent emerging evidence for ex vivo T cell-depleted haploidentical HSCT has provided additional therapeutic options for pediatric patients with diseases curable by HSCT but has not found a suitable related or unrelated donor. This review discusses recent advances in haploidentical HSCT, focusing on transplant using ex vivo T cell-depleted grafts. In addition, our experiences with this novel approach for the treatment of pediatric patients with malignant and non-malignant diseases are described.

Role of p16 in the pathogenesis of Langerhans cell histiocytosis.

Background It has been hypothesized that genetic alteration at the cellular level may have a significant effect on cellular mechanisms controlling the proliferation and apoptosis of Langerhans cells (LCs). Methods We examined whether p16 protein expression can be used to predict the outcome of Langerhans cell histiocytosis (LCH). Archival paraffin blocks from children diagnosed with LCH and followed at the Asan Medical Center and Chungnam National University Hospital between March 1998 and February 2008 were studied. Results Slides were stained with p16 antibody and evaluated semi-quantitatively using the following scale: negative, no staining; ±, weakly positive; 1+, staining similar to lymphocytes surrounding the LCs; 2+, stronger staining than lymphocytes; 3+, much stronger staining than lymphocytes. Negative and ± groups were assigned to a lower expression group (LEG) and the 1+, 2+, and 3+ groups were assigned to a higher expression group (HEG). The median age of the 51 patients (24 girls, 27 boys) was 49 (range, 0.6-178) months, and LCH was diagnosed based on CD1a positivity. p16 protein was expressed to varying degrees in all but one specimen. There was a greater tendency toward multisystem disease, risk organ involvement, and relapse in the HEG than in the LEG. Conclusion The p16 protein may have a significant effect on cellular mechanisms controlling the proliferation and apoptosis of LCs, and thus may influence the clinical outcome and prognosis of LCH.