Recent progress of national banking project on homozygous HLA-typed induced pluripotent stem cells in South Korea.

Induced pluripotent stem cells (iPSCs) can be generated by introducing several factors into mature somatic cells. Banking of iPSCs can lead to wider application for treatment and research. In an economical view, it is important to store cells that can cover a high percentage of the population. Therefore, the use of homozygous human leukocyte antigen-iPSCs (HLA-iPSCs) is thought as a potential candidate for effective iPSC banking system for further clinical use. We screened the database stored in the Catholic Hematopoietic Stem Cell Bank of Korea and sorted the most frequent homozygous HLA types of the South Korean population. Blood cells with the selected homozygous HLA types were obtained and transferred to the GMP facility in the Catholic Institute of Cell Therapy. Cells were reprogrammed to iPSCs inside the facility and went through several quality controls. As a result, a total of 13 homozygous GMP-grade iPSC lines were obtained in the facility. The generated iPSCs showed high pluripotency and normal karyotype after reprogramming. Five HLA-homozygous iPSCs had the type that was included in the top five most frequent HLA types. Homozygous HLA-iPSCs can open a new opportunity for further application of iPSCs in clinical research and therapy.

Extramedullary Relapse of Acute Myeloid and Lymphoid Leukemia in Children: A Retrospective Analysis.

BACKGROUND: Extramedullary relapse (EMR) is a recurrence of leukemia in sites other than the bone marrow, and it exhibits a relatively rare presentation of relapse of acute leukemia. However, EMR is an important cause of treatment failure among patients with acute leukemia. Therefore, early detection of these relapses may improve the prognosis. OBJECTIVES: To describe the disease-related demographic and clinical features and radiologic findings for children diagnosed with EMR in acute leukemia. PATIENTS AND METHODS: The study was based on 22 children (M: F = 14: 8; mean age 7.30 (2.1 - 15.7) years) with 8 acute myeloid leukemia (AML) and 14 acute lymphoid leukemia (ALL) who had experienced an EMR. Age, gender, clinical symptoms, initial extramedullary disease (EMD), French-American-British (FAB) morphology, cytogenetics, time to and site of EMR, concurrent bone marrow relapse (BMR), radiologic findings, and outcomes were evaluated. RESULTS: No definite relationship was found between initial EMD and EMR. A predilection for AML to relapse in the central nervous system (CNS), except for the CSF and bone, and for ALL to relapse in the CSF and kidney seemed to occur. Patients with EMR had a significantly higher incidence of t(8: 21) cytogenetics and FAB M2 and L1 morphologies. EMR accompanied with concurrent BMR occurred in 31.8% of the patients, who exhibited a relatively grave clinical course. Radiologic findings were nonspecific and had a great variety of structure involved, including bulging enhancing mass in the CT scan, hypoechoic mass in the US, and enhanced mass-like lesion in the MRI. CONCLUSIONS: Knowledge of the potential sites of EMR, their risk factors, and their clinical and radiologic features may be helpful in the early diagnosis of relapse and planning for therapy.

Improved Outcome of a Reduced Toxicity-Fludarabine, Cyclophosphamide, plus Antithymocyte Globulin Conditioning Regimen for Unrelated Donor Transplantation in Severe Aplastic Anemia: Comparison of 2 Multicenter Prospective Studies.

Hematopoietic stem cell transplantation (HSCT) is a curative therapy for severe aplastic anemia (SAA); however, the optimal conditioning regimen for HSCT with an unrelated donor has not yet been defined. A previous study using a fludarabine (FLU), cyclophosphamide (Cy), and antithymocyte globulin (ATG) conditioning regimen (study A: 50 mg/kg Cy once daily i.v. on days -9, -8, -7, and -6; 30 mg/m(2) FLU once daily i.v. on days -5, -4, -3, and -2; and 2.5 mg/kg of ATG once daily i.v. on days -3, -2, and -1) demonstrated successful engraftment (100%) but had a high treatment-related mortality rate (32.1%). Therefore, given that Cy is more toxic than FLU, we performed a new phase II prospective study with a reduced-toxicity regimen (study B: 60 mg/kg Cy once daily i.v. on days -8 and -7; 40 mg/m(2) FLU once daily i.v. on days -6, -5, -4, -3, and -2; and 2.5 mg/kg ATG once daily i.v. on 3 days). Fifty-seven patients were enrolled in studies A (n = 28) and B (n = 29), and donor type hematologic recovery was achieved in all patients in both studies. The overall survival (OS) and event-free survival (EFS) rates of patients in study B was markedly improved compared with those in study A (OS: 96.7% versus 67.9%, respectively, P = .004; EFS: 93.3% versus 64.3%, respectively, P = .008). These data show that a reduced-toxicity conditioning regimen with FLU, Cy, and ATG may be an optimal regimen for SAA patients receiving unrelated donor HSCT.

Correlation of the clinical parameters with sonographic findings of hemorrhagic cystitis in pediatric hematooncology patients.

To find a relationship between clinical and sonographic appearance of hemorrhagic cystitis (HC) in pediatric hematooncology patients. Clinical and sonographic findings of 31 children (M:F = 18:13; mean age, 12.7 years) with HC in pediatric hematooncology patients were reviewed. For each patient, the onset of HC after transplantation, use of bladder-toxic agent, presence of BK viruria, and duration of disease were reviewed. Sonographic findings including bladder wall thickness (BWT), the type of bladder wall thickening (nodular vs. diffuse), occurrence of hydronephrosis or pyelonephritis were reviewed. We analyzed sonographic appearance and clinical manifestations of HC. HC occurred within 4 months after HSCT/BMT. 27 patients (87.0 %) were positive for BK viruria and 24 patients (77.4 %) took bladder-toxic agents. On sonography, nodular type bladder wall thickening was more frequent (54.8 %), and BWT was thicker in this group (p = 0.003). There was a positive correlation between the BWT on initial sonography and duration of cystitis (r (2) = 0.340). Hydronephrosis developed in 25.8 % of patients with HC, and as HC persisted longer, hydronephrosis occurred more (p = 0.004). In patients with HC after HSCT/BMT, the BWT on initial sonography correlates well with the duration of cystitis. And, longer time of HC develops the risk of hydronephrosis.

Long-term Outcome of Extranodal NK/T Cell Lymphoma Patients Treated With Postremission Therapy Using EBV LMP1 and LMP2a-specific CTLs.

Extranodal NK/T-cell lymphoma (ENKTCL) is associated with latent Epstein-Barr virus (EBV) infection and frequent relapse even after complete response (CR) to intensive chemotherapy and radiotherapy. The expression of EBV proteins in the tumor provides targets for adoptive immunotherapy with antigen-specific cytotoxic T cells (CTL). To evaluate the efficacy and safety of EBV latent membrane protein (LMP)-1 and LMP-2a-specific CTLs (LMP1/2a CTLs) stimulated with LMP1/2a RNA-transferred dendritic cells, we treated 10 ENKTCL patients who showed complete response to induction therapy. Patients who completed and responded to chemotherapy, radiotherapy, and/or high-dose therapy followed by stem cell transplantation (HDT/SCT) were eligible to receive eight doses of 2 × 10(7) LMP1/2a CTLs/m(2). Following infusion, there were no immediate or delayed toxicities. The 4-year overall survival (OS) and progression-free survival (PFS) were 100%, and 90% (95% CI: 71.4 to 100%) respectively with a median follow-up of 55·5 months. Circulating IFN-γ secreting LMP1 and LMP2a-specific T cells within the peripheral blood corresponded with decline in plasma EBV DNA levels in patients. Adoptive transfer of LMP1/2a CTLs in ENKTCL patients is a safe and effective postremission therapeutic approach. Further randomized studies will be needed to define the role of EBV-CTLs in preventing relapse of ENKTCL.

Neurocognitive outcome in survivors of childhood acute lymphoblastic leukemia: experience at a tertiary care hospital in Korea.

This study was conducted to investigate long-term neurocognitive outcomes and to determine associated risk factors in a cohort of Korean survivors of childhood acute lymphoblastic leukemia (ALL). Forty-two survivors of ALL were compared with 42 healthy controls on measures of a neurocognitive test battery. We analysed potential risk factors (cranial irradiation, sex, age at diagnosis, elapsed time from diagnosis, and ALL risk group) on neurocognitive outcomes. ALL patients had lower, but non-significant full-scale intelligence quotient (FSIQ, 107.2±12.2 vs. 111.7±10.2), verbal intelligence quotient (VIQ, 107.7±13.6 vs. 112.2±11.4), and performance intelligence quotient (PIQ, 106.3±14.2 vs. 110.1±10.7) scores than healthy controls. However, patients treated with cranial irradiation performed significantly lower on FSIQ (102.2±8.1), VIQ (103.3±11.7), and PIQ (101.4±13.2) compared to non-irradiated patients and healthy controls. ALL patients also had poor attention, concentration, and executive functions. Among ALL survivors, cranial irradiation was a risk factor for poor FSIQ, being male was a risk factor for poor PIQ, and younger age was a risk factor for poor attention. Therefore, the delayed cognitive effects of ALL treatment and its impact on quality of life require continuing monitoring and management.

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

BACKGROUND: 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. METHODS: The Korea Histiocytosis Working Party retrospectively analyzed data on 251 pediatric patients diagnosed with HLH between 1996 and 2011. RESULTS: In the study cohort, 25 cases were categorized with familial HLH, 64 with presumed secondary HLH, and 162 with unspecified HLH. Of 217 evaluable patients, 91 (42%) had concomitant Epstein-Barr virus infection. Of 238 evaluable patients, central nervous system (CNS) involvement, which was more frequent in the familial group, was evident in 81 cases (34%). Genetic tests revealed a predominant UNC13D mutation with a high incidence of two recurrent splicing mutations (c.118-308C>T and c.754-1G>C). The 5-yr overall survival rate was 68% (38% in the familial group and 81% in the presumed secondary group). The 5-yr overall survival rate among 32 patients who underwent allogeneic hematopoietic stem cell transplantation was 64%. In multivariate analysis, a younger age at diagnosis, severe transaminasemia, and a coagulation abnormality were independent prognostic factors for survival. Responses during initial treatments were also significant indicators of outcome. CONCLUSION: Our study showed the unique predominance of a UNC13D mutation and vulnerability to Epstein-Barr virus infection in Korean children with HLH and emphasizes the prognostic significance of age, liver dysfunction, and treatment responses in this disease. A multicenter prospective trial that builds on the present results is warranted to identify subgroups of patients with a poor prognosis and identify optimal treatments.

Cushing syndrome secondary to CRH-producing Wilms tumor in a 6 year old.

Abstract Cushing syndrome is caused by prolonged exposure to elevated serum cortisol. It is uncommon in children, and etiology includes pituitary adenoma, adrenal tumor, and exogenous glucocorticoid administration. Rarely, it is paraneoplastic in origin. We present a case of paraneoplastic Cushing syndrome due to Wilms tumor that secreted corticotropin-releasing hormone (CRH). A 6-year-old male presented with polyphagia and weight gain. He showed Cushingoid appearance, hypertension, and palpable left flank mass. Serum cortisol and adrenocorticotropic hormone (ACTH) levels were elevated. Computed tomography showed a neoplasm originating from the left kidney. Pathologic diagnosis of Wilms tumor was made upon nephroureterectomy. Immunohistochemical staining was positive for CRH and negative for ACTH. All features of Cushing syndrome disappeared after surgery. This represents a rare case of Cushing syndrome secondary to Wilms tumor in which CRH production has been demonstrated.

Relationship between modified CT severity index and clinical features of L-asparaginase-associated pancreatitis in pediatric acute lymphoblastic leukemia.

PURPOSE: To describe clinical and CT features of L-asparaginase-associated pancreatitis (L-AP) and to correlate CT grades with clinical parameters. METHODS: A total of 16 children (M:F = 9:7; mean age, 8.1 years) who developed L-AP after L-asparaginase (L-asp) treatment and underwent abdominal CT scan were included. We retrospectively reviewed clinical data (age, sex, signs, and symptoms related to pancreatic toxicity and its complications, the number of L-asp doses receiving before L-AP); laboratory test results (serum amylase, lipase, C-reactive protein (CRP), calcium, blood urea nitrogen (BUN), lactate dehydrogenase (LDH), aspartate aminotransferase (AST), glucose, and serum albumin); and clinical course (the number of days of hospitalization, number of NPO days, use of nasogastric tube, intravenous (IV) narcotics, total parenteral nutrition (TPN) or any surgical intervention). We also reviewed CT images and modified CT severity index (MCSI) for grading the severity of AP and classified to three groups (mild, moderate, and severe) or two groups (low and high score) according to MCSI. RESULTS: L-AP typically occurred early in the course of therapy. Use of IV narcotics (P = .014) and peak amylase (P = .009) showed a significant difference between mild and severe L-AP groups according to MCSI. Between the low and high score groups, Use of IV narcotics (P = .046), BUN (P = .039), and peak amylase level (P = .013) was significantly different. However, the L-asp dose, hospital day, and other clinical date associated with prognosis did not show any significant difference. CONCLUSION: In L-AP with pediatric ALL patients, MCSI may correlate with usage of IV narcotics, BUN, and peak amylase levels.

Alveolar soft part sarcoma arising from the kidney: imaging and clinical features.

Alveolar soft part sarcoma (ASPS) is an extremely rare malignant soft tissue sarcoma primarily affecting young patients. It usually occurs in the lower extremities, although it can occur in soft tissue anywhere in the body. However, to our knowledge, there has been no case of primary ASPS originating from the kidney in the literature. We herein present the imaging and clinical features of an ASPS which occurred in a 16-year-old male presented as a palpable mass in the left side of the abdomen.

Fluctuations in pathogenic CD4+ T-cell subsets in a murine sclerodermatous model of chronic graft-versus-host disease.

To determine the roles of CD4+ T-cell (Th) subsets, including Th17 cells, in the development of chronic graft-versus-host disease (cGVHD), we used a Th-dependent cGVHD model comprising B10.D2 donor and BALB/c recipient mice. The clinical GVHD score increased beginning at day +14, peaked at day +42, and remained elevated until day +70. In the skin, increased dermal thickness was apparent at day +14, and maintained with few changes until day +70. In contrast, the liver had peak pathologic scores at day +28, and the tissue damage began to improve at day +56. To determine possible associations between improvement of liver pathology and changes in Th subsets, we analyzed Th subsets using flow cytometry. Th1 frequencies in the livers were greater than other Th subsets throughout the disease course, but the frequencies decreased over time. Notably, Th17 cells were rarely detected during earlier periods, but emerged at day +56, which correlated with the improved hepatic inflammation. In contrast, other Th subsets (Th2 and regulatory T cells) did not change significantly during the disease course. These results indicate the association of attenuation on cGVHD with a later emergence of Th17 cells and concomitant decrease of Th1 cells.

Clinical features and treatment outcomes of Langerhans cell histiocytosis: a nationwide survey from Korea histiocytosis working party.

A nationwide survey was conducted to clarify the clinical features and outcomes of Korean children with Langerhans cell histiocytosis (LCH). Korea Histiocytosis Working Party analyzed the data of 603 patients who were diagnosed with LCH between 1986 and 2010 from 28 institutions in Korea. Median age at diagnosis was 65 months (range, 0 to 276 mo). Bone was the most frequently affected organ (79.6%) followed by skin (19.2%). Initially, 419 patients (69.5%) had single-system involvement (SS), 85 (14.1%) with multisystem (MS) disease without risk organ involvement (MS-RO), and 99 (16.4%) multisystem disease with risk organ involvement (MS-RO). The 5-year overall survival (OS) rates in the SS, MS-RO, and MS-RO groups were 99.8%, 98.4%, and 77.0%, respectively (P<0.001), and the 5-year reactivation rates were 17.9%, 33.5%, and 34.3%, respectively (P<0.001). The OS rate was lower in patients with RO involvement (P=0.025) and lack of response to initial treatment (P=0.001). MS involvement (P=0.036) was an independent risk factor for reactivation. Permanent consequences were documented in 99 patients (16.4%). Reactivation of disease, MS involvement, and age at diagnosis ≤ 2 years were associated with higher incidence of permanent consequences. This study emphasized that further efforts are required to improve survival of MS-RO patients and reduce reactivation in younger patients with MS involvement.

Langerhans cell sarcoma in two young children: imaging findings on initial presentation and recurrence.

Langerhans cell sarcoma (LCS) is a neoplastic proliferation of Langerhans cells with malignant cytological features and multi-organ involvement that typically has a poor prognosis. We experienced 2 cases of LCS in children less than 2 years of age and report them based primarily on CT and MR findings. Both children had findings of hepatosplenomegaly with low-attenuation nodular lesions, had multiple lymphadenopathy, and had shown recurrent lesions invading the skull during follow-up after chemotherapy.

Pre-engraftment syndrome after unrelated cord blood transplantation: a predictor of engraftment and acute graft-versus-host disease.

Pre-engraftment syndrome (PES) is poorly characterized, and its clinical significance and the prognostic impact after unrelated cord blood transplantation (CBT) are unclear. To address these issues, we retrospectively analyzed the incidence, risk factors, and clinical outcomes of PES in unrelated CBT recipients. Data of 381 patients who received unrelated CBT from 18 medical centers in Korea were reviewed. PES was defined as unexplained fever >38.3°C not associated with infection, and/or unexplained skin rash with or without evidence of fluid retention before neutrophil recovery. PES developed in 102 patients (26.8%) at a median of 7 days after CBT. Of these patients, 74 patients (72.5%) received intravenous corticosteroid at a median dose of 1 mg/kg/day, and of these, 95% showed clinical improvement. Risk factors for developing PES included low risk disease, myeloablative conditioning, graft-versus-host disease (GVHD) prophylaxis without methotrexate or corticosteroid, and >5.43 x 10(7)/kg infused nucleated cells. Absence of PES was one of the risk factors for graft failure in multivariate analysis. The cumulative incidence of grade II to grade IV acute GVHD by 100 days after CBT was higher in patients with PES than in those without PES (56.0% versus 34.4%, P < .01). PES was not associated with chronic GVHD, treatment-related mortality, relapse, or overall survival. PES seems to be common after CBT and may be associated with enhanced engraftment without significant morbidity.

Life-threatening scrub typhus with hemophagocytosis and acute respiratory distress syndrome in an infant.

Scrub typhus is a rickettsial disease, caused by Orientia tsutsugamushi, which is transmitted via the bite of a chigger. This disease is one of the most important infectious diseases in the Asia-Pacific area; however, a severe infant case has not yet been reported. Here, we present the case of an 8-month-old boy with scrub typhus accompanied by hemophagocytic lymphohistiocytosis (HLH). His rapid course was complicated by acute respiratory distress syndrome (ARDS), status epilepticus and disseminated intravascular coagulation (DIC). He recovered after clarithromycin therapy and intensive supportive care. Although being extremely rare, scrub typhus can be life-threatening in an infant; therefore, physicians in endemic countries should be aware of the necessity for early recognition and prompt treatment of suspected cases.

Somatic mutation of IL7R exon 6 in acute leukemias and solid cancers.

Inframe insertion and deletion/insertion (delins) mutations of the IL7R gene in exon 6 have recently been reported in childhood T-cell acute lymphoblastic leukemia (T-ALL). The recurrent nature of the IL7R mutations in the same region strongly suggests that the IL7R mutations may play an important role in the pathogenesis of childhood T-ALL. The aim of this study was to address whether IL7R exon 6 mutation occurs in other human tumors besides childhood T-ALL. For this, we analyzed 1792 tumor tissues from various origins, including 432 hematologic and 1360 nonhematopoietic tumors by single-strand conformation polymorphism analysis to detect the exon 6 mutations. Overall, we found 10 IL7R exon 6 mutations in seven hematologic malignancies (three childhood T-ALL [12%], one adult T-ALL [7%], two childhood precursor B-cell acute lymphoblastic leukemia (B-ALL) [2%] and one adult acute myelogenous leukemia (AML) [1%]) and three nonhematopoietic malignancies (one lung cancer [0.6%] and two colorectal cancer [0.5%]), but none in other tumors. IL7R mutations detected in hematologic tumors were exclusively inframe insertion and delins mutations, whereas those detected in non-hematologic tumors were missense and frameshift mutations. Our data indicate that IL7R exon 6 inframe mutations occur not only in childhood T-ALL but also other acute leukemias at slightly lower frequencies. Our data suggest that the IL7R mutations may contribute to the development of diverse types of acute leukemias, and that possible therapies targeting the IL7R exon 6 mutation should include not only childhood T-ALL but also T-ALL, childhood precursor B-ALL, and adult AML.

Predisposing factors of posterior reversible encephalopathy syndrome in acute childhood leukemia.

A retrospective chart review was performed on 19 patients aged <18 years who developed posterior reversible encephalopathy syndrome as a complication during treatment of acute childhood leukemia. Posterior reversible encephalopathy syndrome was most often observed during acute lymphoblastic leukemia induction chemotherapy (n = 9, 47.4%) and after hematopoietic stem cell transplantation (n = 8, 42.1%). Among eight patients with the complication of posterior reversible encephalopathy syndrome after hematopoietic stem cell transplantation, five (62.5%) had a history of hypertension. In contrast, among 11 patients with the complication of posterior reversible encephalopathy syndrome without hematopoietic stem cell transplantation, only one (9.1%) had a history of hypertension. Moreover, unlike other leukemia induction chemotherapy, posterior reversible encephalopathy syndrome developed only in patients who received acute lymphoblastic leukemia induction chemotherapy. Posterior reversible encephalopathy syndrome patients required long-term anticonvulsant therapy (n = 9, 50.0%) and manifested intractable seizures (n = 3, 16.7%). Sequelae were evident in long-term follow-up magnetic resonance images (n = 5, 26.3%). Acute lymphoblastic leukemia chemotherapy regimens apparently comprised the main predisposing factors for posterior reversible encephalopathy syndrome complicated during induction chemotherapy, compared with hypertension and immunosuppressive agents after hematopoietic stem cell transplantation.

Clinical and hematologic manifestations in patients with Diamond Blackfan anemia in Korea.

BACKGROUND: Diamond Blackfan anemia (DBA), characterized by impaired red cell production, is a rare condition that is usually symptomatic in early infancy. The purpose of this study was to assess nationwide experiences of DBA encountered over a period of 20 years. METHODS: The medical records of 56 patients diagnosed with DBA were retrospectively reviewed from November 1984 to July 2010. Fifteen institutions, including 13 university hospitals, participated in this study. RESULTS: The male-to-female ratio of patients with DBA was 1.67:1. The median age of diagnosis was 4 months, and 74.1% were diagnosed before 1 year of age. From 2000 to 2009, annual incidence was 6.6 cases per million. Excluding growth retardation, 38.2% showed congenital defects: thumb deformities, ptosis, coarctation of aorta, ventricular septal defect, strabismus, etc. The mean hemoglobin concentration was 5.1±1.9 g/dL, mean corpuscular volume was 93.4±11.6 fL, and mean number of reticulocytes was 19,700/mm(3). The mean cellularity of bone marrow was 75%, with myeloid:erythroid ratio of 20.4:1. After remission, 48.9% of patients did not need further steroids. Five patients with DBA who received hematopoietic transplantation have survived. Cancer developed in 2 cases (3.6%). CONCLUSION: The incidence of DBA is similar to data already published, but our study had a male predilection. Although all patients responded to initial treatment with steroids, about half needed further steroids after remission. It is necessary to collect further data, including information regarding management pathways, from nationwide DBA registries, along with data on molecular analyses.

Acute appendicitis in children with acute leukemia: experiences of a single institution in Korea.

PURPOSE: Acute appendicitis has been reported to be relatively rare in pediatric leukemia patients but there is no official data for this in Korea. And there is no consensus for its treatment in this population. MATERIALS AND METHODS: We conducted a retrospective study of 7 patients diagnosed with appendicitis among 1209 pediatric patients who were diagnosed with leukemia from 1996 to 2008 at a single institution in Korea. RESULTS: The median age at the time of the diagnosis of appendicitis was 12 years (range: 3-15 years), and 3 of the patients were male. The median absolute neutrophil count (ANC) at the time of diagnosis was 0.99×109/L (range: 0-3×109/L). The mean time from the onset of symptoms to the diagnosis was 4 days. All 7 leukemia patients with appendicitis underwent surgery and they demonstrated a survival of 100% without significant complications. CONCLUSION: The incidence of appendicitis in pediatric leukemia patients was 0.57% in our study. Early diagnosis with abdominal ultrasound or computed tomography and early surgical resection in leukemic patient with acute appendicitis may be a safer and more effective treatment option. Even when perforation has already occurred and when the patient has an ANC of 0×109/L, surgical treatment may improve overall survival without incurring significant complications.

Assessment of serologic immunity to diphtheria-tetanus-pertussis after treatment of Korean pediatric hematology and oncology patients.

The aim of this study was to investigate the diphtheria-tetanus-pertussis antibody titers after antineoplastic treatment and to suggest an appropriate vaccination approach for pediatric hemato-oncologic patients. A total of 146 children with either malignancy in remission after cessation of therapy or bone marrow failure were recruited. All children had received routine immunization including diphtheria-tetanus-acellular pertussis vaccination before diagnosis of cancer. The serologic immunity to diphtheria, tetanus and pertussis was classified as: completely protective, partially protective, or non-protective. Non-protective serum antibody titer for diphtheria, tetanus and pertussis was detected in 6.2%, 11.6%, and 62.3% of patients, respectively, and partial protective serum antibody titer for diphtheria, tetanus and pertussis was seen in 37%, 28.1%, and 8.9% of patients. There was no significant correlation between the severity of immune defect and age, gender or underlying disease. Revaccination after antineoplastic therapy showed significantly higher levels of antibody for each vaccine antigen. Our data indicates that a large proportion of children lacked protective serum concentrations of antibodies against diphtheria, tetanus, and pertussis. This suggests that reimmunization of these patients is necessary after completion of antineoplastic treatment. Also, prospective studies should be undertaken with the aim of devising a common strategy of revaccination.