Risk Factor Analysis for Secondary Malignancy in Dexrazoxane-Treated Pediatric Cancer Patients / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: Dexrazoxane has been used as an effective cardioprotector against anthracycline cardiotoxicity. This study intended to analyze cardioprotective efficacy and secondary malignancy development, and elucidate risk factors for secondary malignancies in dexrazoxane-treated pediatric patients. MATERIALS AND METHODS: Data was collected from 15 hospitals in Korea. Patients who received any anthracyclines, and completed treatment without stem cell transplantation were included. For efficacy evaluation, the incidence of cardiac events and cardiac event-free survival rates were compared. Data about risk factors of secondary malignancies were collected. RESULTS: Data of total 1,453 cases were analyzed; dexrazoxane with every anthracyclines group (D group, 1,035 patients) and no dexrazoxane group (non-D group, 418 patients). Incidence of the reported cardiac events was not statistically different between two groups; however, the cardiac event-free survival rate of patients with more than 400 mg/m2 of anthracyclines was significantly higher in D group (91.2% vs. 80.1%, p=0.04). The 6-year cumulative incidence of secondary malignancy was not different between both groups after considering follow-up duration difference (non-D, 0.52%±0.37%; D, 0.60%±0.28%; p=0.55). The most influential risk factor for secondary malignancy was the duration of anthracycline administration according to multivariate analysis. CONCLUSION: Dexrazoxane had an efficacy in lowering cardiac event-free survival rates in patients with higher cumulative anthracyclines. As a result of multivariate analysis for assessing risk factors of secondary malignancy, the occurrence of secondary malignancy was not related to dexrazoxane administration.

Outcome and Prognostic Factors for ETV6/RUNX1 Positive Pediatric Acute Lymphoblastic Leukemia Treated at a Single Institution in Korea / Journal of the Korean Cancer Association, 대한암학회지

PURPOSE: ETV6/RUNX1 (+) acute lymphoblastic leukemia (ALL), which is the most common genetic subtype of pediatric ALL, has a favorable prognosis. In this study, we analyzed the outcome of ETV6/RUNX1 (+) ALL patients treated at our institution with the aim of identifying significant prognostic variables. MATERIALS AND METHODS: Sixty-three patients were diagnosed with ETV6/RUNX1 (+) ALL from 2005 to 2011. Prognostic variables studied included minimal residual disease (MRD) as detected by ETV6/RUNX1 (+) fusion, and the presence of additional cytogenetic abnormalities. RESULTS: The 5-year event-free survival was 84.1±4.6%, with 10 patients relapsing at a median of 28.3 months from diagnosis for a 5-year cumulative incidence of relapse of 15.9±4.6%. Multivariate analysis revealed that the presence MRD, as detected by real-time quantitative-polymerase chain reaction or fluorescence in situ hybridization for ETV6/RUNX1 fusion at end of remission induction, and the presence of additional structural abnormalities of 12p (translocations or inversions) negatively affected outcome. Despite treatment such as allogeneic hematopoietic cell transplantation, eight of the 10 relapsed patients died from disease progression for overall survival of 82.5±6.9%. CONCLUSION: ETV6/RUNX1 (+) ALL may be heterogeneous in terms of prognosis, and variables such as MRD at end ofremission induction or additional structural abnormalities of 12p could define a subset of patients who are likely to have poor outcome.

Treatment and response of autoimmune cytopenia occurring after allogeneic hematopoietic cell transplantation in children

BACKGROUND: Autoimmune cytopenia (AIC) is a rare complication of allogeneic hematopoietic cell transplantation (HCT). In this study, we reviewed the diagnosis, treatment and response to therapy for pediatric patients with post-HCT AIC at our institution. METHODS: Of the 292 allogeneic HCTs performed from January, 2011 to December, 2015 at the Department of Pediatrics, The Catholic University of Korea, seven were complicated by post-HCT AIC, resulting in an incidence of 2.4%. RESULTS: All seven patients with post-HCT AIC had received unrelated donor transplant. Six of seven patients had a major donor-recipient blood type mismatch. The subtypes of AIC were as follows: immune thrombocytopenia (ITP) 2, autoimmune hemolytic anemia (AIHA) 2, Evans syndrome 3. Median time from HCT to AIC diagnosis was 3.6 months. All but one patient responded to first line therapy of steroid±intravenous immunoglobulin (IVIG), but none achieved complete response (CR) with this treatment. After a median duration of treatment of 15.3 months, two patients with ITP achieved CR and five had partial response (PR) of AIC. Five patients were treated with rituximab, resulting in the following response: 2 CR, 2 PR, 1 no response (NR). Median time to response to rituximab was 26 days from first infusion. All patients are alive without event. CONCLUSION: Post-HCT AIC is a rare complication that may not resolve despite prolonged therapy. Rapid initiation of second line agents including but not limited to B cell depleting treatment should be considered for those that fail to achieve CR with first line therapy.

Clinical characteristics and outcomes of varicella zoster virus infection in children with hematologic malignancies in the acyclovir era

BACKGROUND: Although intravenous acyclovir therapy is recommended for varicella zoster virus (VZV) infection in immunocompromised children, the clinical characteristics and outcomes of VZV infection in the acyclovir era have rarely been reported. METHODS: The medical records of children diagnosed with varicella or herpes zoster virus, who had underlying hematologic malignancies, were retrospectively reviewed, and the clinical characteristics and outcomes of VZV infection were evaluated. RESULTS: Seventy-six episodes of VZV infection (herpes zoster in 57 and varicella in 19) were identified in 73 children. The median age of children with VZV infection was 11 years (range, 1-17), and 35 (46.1%) episodes occurred in boys. Acute lymphoblastic leukemia was the most common underlying malignancy (57.9%), and 90.8% of the episodes occurred during complete remission of the underlying malignancy. Acyclovir was administered for a median of 10 days (range, 4-97). Severe VZV infection occurred in 16 (21.1%) episodes. Although the finding was not statistically significant, a previous history of hematopoietic cell transplantation (HCT) appeared to be associated with the development of more severe episodes of herpes zoster (P=0.075). CONCLUSION: Clinical characteristics of VZV infection in immunocompromised children were not significantly different from those without it, and clinical outcomes improved after the introduction of acyclovir therapy. However, risk factors for severe VZV infection require further investigation in a larger population and a prospective setting.

Subclinical left ventricular dysfunction in children after hematopoietic stem cell transplantation for severe aplastic anemia: a case control study using speckle tracking echocardiography / 소아과

PURPOSE: Severe aplastic anemia (SAA), a fatal disease, requires multiple transfusion, immunosuppressive therapy, and finally, hematopoietic stem cell transplantation (HSCT) as the definitive treatment. We hypothesized that iron overloading associated with multiple transfusions and HSCTrelated complications may adversely affect cardiac function. Left ventricular (LV) function was assessed in children after HSCT for SAA. METHODS: Forty-six consecutive patients with a median age of 9.8 years (range, 1.5-18 years), who received HSCT for SAA and who underwent comprehensive echocardiography before and after HSCT, were included in this study. The data of LV functional parameters obtained using conventional echocardiography, tissue Doppler imaging (TDI), and speckle-tracking echocardiography (STE) were collected from pre- and post-HSCT echocardiography. These data were compared to those of 40 age-matched normal controls. RESULTS: In patients, the LV ejection fraction, shortening fraction, end-diastolic dimension, mitral early diastolic E velocity, TDI mitral septal E' velocity, and STE LV longitudinal systolic strain rate (SSR) decreased significantly after HSCT. Compared to normal controls, patients had significantly lower post-HSCT early diastolic E velocity and E/A ratio. On STE, patients had significantly decreased LV deformational parameters including LV longitudinal systolic strain (SS), SSR, and diastolic SR (DSR), and circumferential SS and DSR. Serum ferritin levels showed weak but significant correlations (P<0.05) with LV longitudinal SS and SSR and circumferential SS and DSR. CONCLUSION: Subclinical LV dysfunction is evident in patients after HSCT for SAA, and was associated with increased iron load. Serial monitoring of cardiac function is mandatory in this population.

Increase in Antibiotic-Resistant Gram-Negative Bacterial Infections in Febrile Neutropenic Children / 감염과화학요법

BACKGROUND: The incidence of bacteremia caused by Gram-negative bacteria has increased recently in febrile neutropenic patients with the increase of antibiotic-resistant Gram-negative bacterial infections. This study aimed to identify the distribution of causative bacteria and the proportion of antibiotic-resistant bacteria in bacteremia diagnosed in febrile neutropenic children. MATERIALS AND METHODS: The medical records of febrile neutropenic children diagnosed with bacteremia between 2010 and 2014 were retrospectively reviewed. The causative bacteria and proportion of antibiotic-resistant bacteria were investigated and compared yearly during the study period. The clinical impact of antibiotic-resistant bacterial infections was also determined. RESULTS: A total of 336 bacteremia episodes were identified. During the entire study period, 181 (53.9%) and 155 (46.1%) episodes were caused by Gram-negative and Gram-positive bacteria, respectively. Viridans streptococci (25.9%), Klebsiella spp. (16.7%), and Escherichia coli (16.4%) were the most frequent causative bacteria. The overall distribution of causative bacteria was not significantly different annually. Antibiotic-resistant bacteria were identified in 85 (25.3%) episodes, and the proportion of antibiotic-resistant bacteria was not significantly different annually. Extended-spectrum β-lactamase-producing E. coli and Klebsiella spp. were most common among antibiotic-resistant Gram-negative bacteria, and they accounted for 30.6% (n = 34) of the identified E. coli and K. pneumoniae. Methicillin-resistant coagulase-negative staphylococci were most common among antibiotic-resistant Gram-positive bacteria, and it accounted for 88.5% (n = 23) of the identified coagulase-negative staphylococci. Antibiotic-resistant bacterial infections, especially antibiotic-resistant Gram-negative bacterial infections, caused significantly higher mortality due to bacteremia compared with non-antibiotic-resistant bacterial infections (P <0.001). CONCLUSION: Recently, Gram-negative bacteria caused more bacteremia cases than Gram-positive bacteria in febrile neutropenic children, and antibiotic-resistant Gram-negative bacterial infections increased. Antibiotic-resistant bacterial infections caused poorer prognosis compared with non-antibiotic-resistant bacterial infections, and therefore, continuous surveillance for changing epidemiology of antibiotic-resistant bacterial infections and their clinical impact is necessary.

Early Left Ventricular Dysfunction in Children after Hematopoietic Stem Cell Transplantation for Acute Leukemia: A Case Control Study Using Speckle Tracking Echocardiography

BACKGROUND AND OBJECTIVES: Cardiovascular complications are the leading cause of morbidity and mortality in childhood cancer survivors. Hematopoietic stem cell transplantation (HSCT) is a curable therapy for pediatric cancer. However, changes in cardiac function in children after HSCT are not well known. We assessed left ventricular (LV) function in children after HSCT using speckle tracking echocardiography (STE). SUBJECTS AND METHODS: Forty consecutive patients with median age of 11.9 years (range, 1.5-16 years) who received HSCT for acute leukemia and had comprehensive echocardiography before and after (median 9.2 month) HSCT were included in this study. The LV function parameters including conventional tissue Doppler imaging (TDI) and STE data were collected from pre- and post-HSCT echocardiography. These data were compared to those of 39 age-matched normal controls. RESULTS: Compared to normal controls, post HSCT patients had similar (p=0.06) LV ejection fraction. However, the following three LV function parameters were significantly decreased in post HSCT patients: rate-corrected velocity of circumferential fiber shortening (p=0.04), mitral inflow E velocity (p400 mg/m2 showed significantly (p<0.05) lower circumferential systolic strain and circumferential diastolic SR. CONCLUSION: Subclinical cardiac dysfunction is evident in children after HSCT. It might be associated with pre-HSCT anthracycline exposure with little effect of conditioning regimens. Serial monitoring of cardiac function is mandatory for all children following HSCT.

Invasive Pulmonary Aspergillosis after Recent Influenza in a Child with Acute Myeloid Leukemia / 임상소아혈액종양

Respiratory viral infection has been reported as a risk factor for invasive pulmonary aspergillosis (IPA) in hematopoietic cell transplantation (HCT) recipients, and IPA following influenza has been reported. We report a 13-year-old boy diagnosed with IPA following influenza. He received allogeneic HCT and then received glucocorticoids for chronic graft-versus-host disease. On admission, he complained of non-neutropenic fever and dyspnea. He was diagnosed with influenza A via a polymerase chain reaction (PCR) test from nasopharyngeal swab, and oseltamivir was administered. Fever re-emerged nine days later and repeat PCR was positive for influenza A. His fever did not resolve despite triple antiviral and empirical antibiotic therapy. On hospital day 22, IPA was diagnosed based on chest computed tomography and positive serum galactomannan results, and his symptoms improved with voriconazole therapy. However, he died of uncontrolled bronchiolitis obliterans on hospital day 128. IPA should be considered a complication of influenza in immunocompromised children.

Invasive Pulmonary Aspergillosis after Recent Influenza in a Child with Acute Myeloid Leukemia / 임상소아혈액종양

Respiratory viral infection has been reported as a risk factor for invasive pulmonary aspergillosis (IPA) in hematopoietic cell transplantation (HCT) recipients, and IPA following influenza has been reported. We report a 13-year-old boy diagnosed with IPA following influenza. He received allogeneic HCT and then received glucocorticoids for chronic graft-versus-host disease. On admission, he complained of non-neutropenic fever and dyspnea. He was diagnosed with influenza A via a polymerase chain reaction (PCR) test from nasopharyngeal swab, and oseltamivir was administered. Fever re-emerged nine days later and repeat PCR was positive for influenza A. His fever did not resolve despite triple antiviral and empirical antibiotic therapy. On hospital day 22, IPA was diagnosed based on chest computed tomography and positive serum galactomannan results, and his symptoms improved with voriconazole therapy. However, he died of uncontrolled bronchiolitis obliterans on hospital day 128. IPA should be considered a complication of influenza in immunocompromised children.

Clinical Features and Prognosis of Invasive Pulmonary Aspergillosis in Korean Children with Hematologic/Oncologic Diseases

Invasive pulmonary aspergillosis (IPA) is the most frequent form of invasive fungal diseases in immunocompromised patients. However, there are only a few studies on IPA in immunocompromised children in Korea. This study was designed to characterize IPA in Korean children with hematologic/oncologic diseases. Medical records of children with hematologic/oncologic diseases receiving antifungal therapy were reviewed. The enrolled children were divided into the IPA group (proven and probable IPA) and non-IPA group, and the clinical characteristics and prognosis were compared between the two groups. During the study period, 265 courses of antifungal therapy were administered to 166 children. Among them, two (0.8%) episodes of proven IPA, 35 (13.2%) of probable IPA, and 52 (19.6%) of possible IPA were diagnosed. More children in the IPA group suffered from neutropenia lasting for more than two weeks (51.4% vs. 21.9%, P<0.001) and showed halo signs on the chest computed tomography (78.4% vs. 40.7%, P<0.001) than in the non-IPA group. No other clinical factors showed significant differences between the two groups. Amphotericin B deoxycholate was administered as a first line antifungal agent in 33 (89.2%) IPA group episodes, and eventually voriconazole was administered in 27 (73.0%) episodes. Ten (27.0%) children in the IPA group died within 12 weeks of antifungal therapy. In conclusion, early use of chest computed tomography to identify halo signs in immunocompromised children who are expected to have prolonged neutropenia can be helpful for early diagnosis of IPA and improving prognosis of children with IPA.

Clinical and Laboratory Features of Severe Neutropenia Developed in Childhood / 임상소아혈액종양

BACKGROUND: Neutropenia is not uncommon in children. We performed this study to investigate the etiology, clinical course and laboratory characteristics for prediction of recovery in children with severe neutropenia. METHODS: In this study, we studied the clinical course and hematological features of 107 patients with severe neutropenia who were diagnosed and treated at the Department of Pediatrics, The Catholic University of Korea from April 2009 to July 2014. Patients with hematologic disorders and malignant disease were excluded. Chronic severe neutropenia (CSN) was defined as an absolute neutrophil count of 0.5x109/L or less for at least 3 months. Acute severe neutropenia (ASN) were defined who recovered within 3 months from diagnosis. RESULTS: Among 107 patients, 72 patients showed ASN and 35 patients were CSN. Median age of ASN (15.2 months) was higher than that of CSN (10.7 months). The median duration of recovery from neutropenia was 7 days (range: 2-35) in ASN. ASN was commonly related to infectious diseases and 24 cases (33.3%) had documented etiologic agents. Median duration of recovery from neutropenia was 18 months in CSN. Three of 35 patients in CSN had ELANE gene mutation. The number of white blood cells, platelets, monocytes, and eosinophils were significantly higher in group of CSN compared with ASN (P<0.05). CONCLUSION: We confirmed the great etiological heterogeneity of severe neutropenia in this study. The kinetics of recovery from neutropenia was different between the ASN and CSN group and the complete blood counts may be useful indices for discriminating ASN from CSN.

Clinical and Laboratory Features of Severe Neutropenia Developed in Childhood / 임상소아혈액종양

BACKGROUND: Neutropenia is not uncommon in children. We performed this study to investigate the etiology, clinical course and laboratory characteristics for prediction of recovery in children with severe neutropenia.METHODS: In this study, we studied the clinical course and hematological features of 107 patients with severe neutropenia who were diagnosed and treated at the Department of Pediatrics, The Catholic University of Korea from April 2009 to July 2014. Patients with hematologic disorders and malignant disease were excluded. Chronic severe neutropenia (CSN) was defined as an absolute neutrophil count of 0.5x109/L or less for at least 3 months. Acute severe neutropenia (ASN) were defined who recovered within 3 months from diagnosis.RESULTS: Among 107 patients, 72 patients showed ASN and 35 patients were CSN. Median age of ASN (15.2 months) was higher than that of CSN (10.7 months). The median duration of recovery from neutropenia was 7 days (range: 2-35) in ASN. ASN was commonly related to infectious diseases and 24 cases (33.3%) had documented etiologic agents. Median duration of recovery from neutropenia was 18 months in CSN. Three of 35 patients in CSN had ELANE gene mutation. The number of white blood cells, platelets, monocytes, and eosinophils were significantly higher in group of CSN compared with ASN (P<0.05).CONCLUSION: We confirmed the great etiological heterogeneity of severe neutropenia in this study. The kinetics of recovery from neutropenia was different between the ASN and CSN group and the complete blood counts may be useful indices for discriminating ASN from CSN.

Use of intravenous immunoglobulin in a disseminated varicella infection in an immunocompromised child / 소아과

Varicella-zoster virus infection can lead to severe illness in immunocompromised patients. Further the mortality rate of disseminated varicella infection is extremely high particularly in immunocompromised children. We report a case of disseminated varicella infection in a child with acute lymphoblastic leukemia who was receiving chemotherapy, but was initially admitted with only for acute abdominal pain. The patient rapidly developed severe complications, including acute respiratory distress syndrome, acute hepatitis, disseminated intravascular coagulation, and encephalopathy. Acyclovir is a highly potent inhibitor of varicella-zoster virus infection. However, owing to rapid disease progression, it might not be sufficient to control a disseminated varicella infection, especially in immunocompromised patients. Immunoglobulin neutralize virus invasion and suppress viremia, acting synergistically with acyclovir. In this case, early administration of acyclovir and a high-dose of immunoglobulin, combined with mechanical respiratory support, proved adequate for treatment of this severe illness.

Efficacy of imatinib mesylate-based front-line therapy in pediatric chronic myelogenous leukemia / 소아과

PURPOSE: Despite the established role of imatinib (IM) in chronic myelogenous leukemia (CML) in adults, there are few reports on its efficacy in children. In this study, we compared the outcomes of children with CML before and after the advent of IM-based treatment. METHODS: The study cohort consisted of 52 patients treated for CML at the Department of Pediatrics, The Catholic University of Korea from January 1995 to October 2010. Patients were divided and analyzed according to the preImatinib group (pre-IMG) and imatinib group (IMG). RESULTS: Median age at diagnosis for the overall cohort (pre-IMG, n=27; IMG, n=25) was 9 years, with a median follow-up duration of survivors of 84 months. Except for 5 patients in the IMG, all were diagnosed in chronic phase (CP). The overall survival (OS) of patients diagnosed in CP was 45.7% and 89.7% for pre-IMG and IMG, respectively (P=0.025). The OS of hematopoietic stem cell transplantation (HSCT) recipients in the 2 groups was similar, but the OS of patients diagnosed in CP who did not receive HSCT was superior in IMG (91.7% vs. 16.7%, P=0.014). Of the 12 patients in IMG who remained on IM without HSCT, 2 showed disease progression, compared to 11 of 12 in pre-IMG. No difference was observed in the progression free survival (PFS) of matched donor HSCT recipients and IM-based treatment recipients. CONCLUSION: Similar PFS of patients treated with IM and those who received matched donor HSCT underscore the potential of IM as effective first-line treatment in childhood CML.

Gastric Burkitt Lymphoma in a Six Year-old Boy Presenting with Upper Gastrointestinal Bleeding / 임상소아혈액종양

Childhood Burkitt lymphoma is most often diagnosed in the abdomen, with the majority of intra-abdominal cases arising from the small or large intestines. Involvement of the gastric mucosa is rare. Here, we present a six-year-old boy who was found to have gastric Burkitt lymphoma through biopsy obtained by esophagogastroduodenoscopy. The child was treated with six cycles of chemotherapy without surgery, and he remains free of disease fourteen months since initial diagnosis. Early definitive diagnosis through endoscopic biopsy and appropriate treatment are necessary for rare instances where children present with upper gastrointestinal tract tumors.

Gastric Burkitt Lymphoma in a Six Year-old Boy Presenting with Upper Gastrointestinal Bleeding / 임상소아혈액종양

Childhood Burkitt lymphoma is most often diagnosed in the abdomen, with the majority of intra-abdominal cases arising from the small or large intestines. Involvement of the gastric mucosa is rare. Here, we present a six-year-old boy who was found to have gastric Burkitt lymphoma through biopsy obtained by esophagogastroduodenoscopy. The child was treated with six cycles of chemotherapy without surgery, and he remains free of disease fourteen months since initial diagnosis. Early definitive diagnosis through endoscopic biopsy and appropriate treatment are necessary for rare instances where children present with upper gastrointestinal tract tumors.

Evaluation of risk for graft-versus-host disease in children who receive less than the full doses of mini-dose methotrexate for graft-versus-host disease prophylaxis in allogeneic hematopoietic stem cell transplantation / 소아과

PURPOSE: The use of cyclosporine and mini-dose methotrexate (MTX) is a common strategy for graft-versus-host disease (GVHD) prophylaxis in allogeneic transplants. We investigated whether patients who receive fewer than the planned MTX doses are at increased risk for GVHD. METHODS: The study cohort included 103 patients who received allogeneic transplants at the Department of Pediatrics of The Catholic University of Korea College of Medicine, from January 2010 to December 2011. MTX was administered on days 1, 3, 6, and 11 after transplant at a dose of 5 mg/m2 each. Within the cohort, 76 patients (74%) received all 4 doses of MTX [MTX(4) group], while 27 patients (26%) received 0-3 doses [MTX(0-3) group]. RESULTS: Although there was no difference in neutrophil engraftment between the 2 groups, platelet engraftment was significantly faster in the MTX(4) group (median, 15 days), compared to the MTX(0-3) group (median, 25 days; P=0.034). The incidence of grades II-IV acute GVHD was not different between the MTX(4) and MTX(0-3) groups (P=0.417). In the multivariate study, human leukocyte antigen mismatch was the most significant factor causing grades II-IV acute GVHD (P=0.002), followed by female donor to male recipient transplant (P=0.034). No difference was found between the MTX(4) and MTX (0-3) groups regarding grades III-IV acute GVHD, chronic GVHD, and disease-free survival. CONCLUSION: Our results indicate that deviations from the full dose schedule of MTX for GVHD prophylaxis do not lead to increased incidence of either acute or chronic GVHD.

Gastric Burkitt Lymphoma in a Six Year-old Boy Presenting with Upper Gastrointestinal Bleeding / 임상소아혈액종양

Childhood Burkitt lymphoma is most often diagnosed in the abdomen, with the majority of intra-abdominal cases arising from the small or large intestines. Involvement of the gastric mucosa is rare. Here, we present a six-year-old boy who was found to have gastric Burkitt lymphoma through biopsy obtained by esophagogastroduodenoscopy. The child was treated with six cycles of chemotherapy without surgery, and he remains free of disease fourteen months since initial diagnosis. Early definitive diagnosis through endoscopic biopsy and appropriate treatment are necessary for rare instances where children present with upper gastrointestinal tract tumors.

Immune reconstitution after allogeneic hematopoietic stem cell transplantation in children: a single institution study of 59 patients / 소아과

PURPOSE: Lymphocyte subset recovery is an important factor that determines the success of hematopoietic stem cell transplantation (HSCT). Temporal differences in the recovery of lymphocyte subsets and the factors influencing this recovery are important variables that affect a patient's post-transplant immune reconstitution, and therefore require investigation. METHODS: The time taken to achieve lymphocyte subset recovery and the factors influencing this recovery were investigated in 59 children who had undergone HSCT at the Department of Pediatrics, The Catholic University of Korea Seoul St. Mary's Hospital, and who had an uneventful follow-up period of at least 1 year. Analyses were carried out at 3 and 12 months post-transplant. An additional study was performed 1 month post-transplant to evaluate natural killer (NK) cell recovery. The impact of pre- and post-transplant variables, including diagnosis of Epstein-Barr virus (EBV) DNAemia posttransplant, on lymphocyte recovery was evaluated. RESULTS: The lymphocyte subsets recovered in the following order: NK cells, cytotoxic T cells, B cells, and helper T cells. At 1 month post-transplant, acute graft-versus-host disease was found to contribute significantly to the delay of CD16+/56+ cell recovery. Younger patients showed delayed recovery of both CD3+/CD8+ and CD19+ cells. EBV DNAemia had a deleterious impact on the recovery of both CD3+ and CD3+/CD4+ lymphocytes at 1 year post-transplant. CONCLUSION: In our pediatric allogeneic HSCT cohort, helper T cells were the last subset to recover. Younger age and EBV DNAemia had a negative impact on the post-transplant recovery of T cells and B cells.

Papillary Thyroid Cancer in a Child with Very Severe Aplastic Anemia / 임상소아혈액종양

The concurrent occurrence of both aplastic anemia and thyroid cancer in a child is a very rare event. Although cancer may occur in patients with aplastic anemia who previously received immunosuppressive therapy or hematopoietic stem cell transplantation (HSCT), cancer in patients who are naive to such therapies is rare. We report a 12-year-old patient with idiopathic very severe aplastic anemia who was subsequently diagnosed with papillary thyroid cancer. This patient had a unique clinical presentation in that thyroid cancer was diagnosed prior to hematopoietic stem cell transplantation given to treat very severe aplastic anemia.