The Frequency of Glycophosphatidyl Inositol-Anchored Protein-Negative Paroxysmal Nocturnal Hemoglobinuria Cells in Pediatric Aplastic Anemia Analyzed by Flow Cytometry / 대한소아혈액종양학회지

PURPOSE: Paroxysmal nocturnal hemoglobinuria (PNH) has been known to be a late clonal complication of aplastic anemia (AA). Flow cytometric analysis using CD55 and CD59 antibodies became the gold standard of diagnosing PNH, replacing a traditional, less sensitive Ham's test, as the pathophysiologic mechanism was identified as the deficiency of glycophosphatidyl-inositol anchored protein. Although the incidence of AA seems to be higher in Korea than that of other Western countries, the study of PNH in Korean pediatric AA has never been accomplished. We studied the frequency of PNH in AA, and tried to compare the characteristics of them with those from other countries. METHODS: Twenty-two pediatric AA patients were enrolled for the study. As a control, 5 patients with inherited bone marrow failure syndromes (Fanconi anemia, 1; Diamond-Blackfan anemia, 3; dyskeratosis congenita, 1) and 11 normal children were pooled. For the flow cytometry, 10muL each of CD55-PE and CD59-FITC was mixed with 50muL of whole blood and incubated for 15 min. Red cells were lysed with Q-prep apparatus (Coulter, Fullerton, USA). Beckman Coulter XL flow cytometer was used for the analyses. RESULTS: The median age for the patients was 14 years (range, 2~21). CD55- and CD59-negative cells from controls were 0.13+/-0.18%. Cut-off value for the diagnosis for PNH was designated as > 0.49%, which was mean +2 S.D. of controls. All the patients showed CD55- and CD59-negative PNH cell proportions within the normal ranges, except for a 19-year-old boy who was still cyclosporine-dependent after initial response to immunosuppressive therapy 4 years before. He had 4.79% of CD55- and CD59-negative PNH population. CONCLUSION: The frequency of PNH clones in Korean children with AA was low (1/22=4.5%). This might reflect the relatively low association of PNH in childhood AA, the limitation caused by small numbers of the study population, or true ethnic differences. A further study incorporating more patients seems to be warranted.

MYH9-related Disorder in a Family: Autosomal Dominant Epstein Giant Platelet Syndrome / 대한소아혈액종양학회지

The term MYH9-related disorders indicates a group of autosomal dominant illnesses, formerly known as May-Hegglin anomaly, Sebastian syndrome, Fechtner syndrome and Epstein syndrome, caused by mutations of MYH9, the gene encoding for the heavy chain of non-muscle myosin IIA (NMMHC-IIA). We experienced a family with macrothrombocytopenia without leukocyte inclusion. A 5-year-old girl was found to have macrothrombocytopenia incidentally. Her father also had macrothromtocytopenia, but had been suffering from hearing loss and chronic renal failure. Meticulous search by light and electron microscopy failed to detect leukocyte inclusions. To our knowledge, these cases seem to be the first description of autosomal dominant Epstein giant platelet syndrome in Korea.

Invasive Aspergillosis in Immunocompromised Children / 대한소아혈액종양학회지

PURPOSE: An increasing number of immunocompromised patients are contracting opportunistic infections caused by Aspergillus, resulting in a significant morbidity and mortality. We reviewed the clinical presentation, radiologic characteristics, histopathologic findings, treatment strategies, and outcome of invasive aspergillosis (IA) in immunocompromised children. METHODS: Thirteen children having IA were retrospectively analyzed. RESULTS: Acute myelogenous leukemia (n=9, 69.2%) was the most common underlying disease, followed by acute lymphocytic leukemia (n=2), Fanconi anemia (n=1), and chronic granulomatous disease (CGD, n=1). Pulmonary involvement was present in 12 patients (92.3%). The sinuses or nose were involved in 4 (30.8%). The patient with CGD had lung, soft tissue, and bone involvement. Central nervous system, gastrointestinal, heart involvement were not documented. Histology or culture proven IA were found in 6 patients (46.2%). In pulmonary IA, typical findings of thoracic computed tomography, such as halo sign or air-crescent sign, was observed in 6 patients. Amphotericin B was given to all patients along with itraconazole (69.2%), G- or GM-CSF (84.6%). AmBisome was subsequently substituted for Amphotericin in 4. One patient with pulmonary mycetoma underwent lobectomy. Seven patients (53.8%) were improved by antifungal measures, but no patients achieved a long term survival. IA was implicated as a cause of death in 7 (4 with massive pulmonary hemorrhage). Most of the rest succumbed to the relapse of underlying leukemia. CONCLUSION: IA remains a formidable infection in immunocompromised children despite current treatment. Lung was the most common site of infection and massive pulmonary hemorrhage might ensue. Early diagnosis and development of effective measures, including surgery, are warranted.