Monitoring of adenoviremia in pediatric patients undergoing hematopoietic stem cell transplantation: Is it alone sufficient to predict adenoviral disease?

BACKGROUND: We aimed to evaluate our pediatric HSCT recipients routinely monitored for adenoviremia and to determine the adequacy of this monitoring in predicting adenoviral disease (AD). METHODS: A retrospective cohort of patients who underwent allogeneic HSCT between January 2021 and August 2022, and routinely monitored for adenoviremia by real-time PCR was included in our survey. Demographic and clinical data of the patients were recorded. Incidence rates, risk factors, and mortality rates related to adenoviremia, and AD were analyzed. RESULTS: Among 104 HSCTs performed in 94 patients adenovirus (AdV) was revealed in 27 (26%) episodes and adenoviremia in 18 (17.3%) HSCT episodes. AD without adenoviremia developed in nine episodes (8.6%). Disseminated disease was significantly more frequently detected in episodes with adenoviremia (p = .008). GVHD was independent risk factor for AdV detection (OR: 8.6, 95% CI: 2.03-33.7, p = .001). Viremia developed within a shorter time interval after HSCT in isolated episodes of adenoviremia compared to those with concomitant AD (p = .006). Initial and peak viral loads were significantly higher in adenoviremia with AD (p < .001). Mortality was higher in the AdV-detected episodes (p < .001) than in the AdV-undetected episodes. AdV-related mortality was found to be 22.2%. Adenoviremia increased the risk of mortality (OR: 1.2, 95% CI: 0.22-1.33, p = .01). CONCLUSIONS: Adenoviremia monitoring is an important process in the detection of AD. Since some patients may develop AD without accompanying by adenoviremia, monitoring for AdV in blood samples should be supported with other monitoring methods in order to evaluate the probable involvement of different organs or systems.

Autologous peripheral blood stem cell mobilization and apheresis in pediatric patients with cancer: A single-center report of 64 procedures.

BACKGROUND: The published experience concerning autologous peripheral blood stem cell collection in children is very limited. METHODS: The data of pediatric patients who underwent autologous stem cell mobilization and apheresis between January 2011 and April 2020 were analyzed retrospectively. RESULTS: We studied retrospectively 64 mobilization and apheresis procedures in 48 pediatric patients (34 males, 14 females), mean age of 7.31 ± 5.38 (range, 1.5-19.7) years, the underlying disease was mostly neuroblastoma (NBL). The body weight of 21 patients (43.75%) was 15 kg or less. The targeted autologous peripheral stem cell apheresis (APSCA) was successfully achieved in 98% of patients. Neuroblastoma patients were younger than the rest of the patients and underwent apheresis after receiving fewer chemotherapy cycles than others and all of them mobilized within the first session successfully. Plerixafor was added to mobilization in nine heavily pretreated patients (18.7%), median two doses (range, 1-4 doses). 11 patients (22.9%) underwent radiotherapy (RT) before mobilization with doses of median 24 Gy (range, 10.8-54.0 Gy). Patients with RT were older at the time of apheresis and had received more chemotherapy courses than patients without RT. As a result, patients with a history of RT had significantly lower peripheral CD34+ cells and CD34+ yields than those without RT. In 17 patients (35.4%), 22 different complications were noted. The most common complications were catheter-related infections (n:10, 20.8%), followed by catheter-related thrombosis in eight patients (16.7%). CONCLUSIONS: Patients who had far less therapy before apheresis were more likely to mobilize successfully. Our study provides a detailed practice approach including complications during APSCA aiming to increase the success rates of apheresis in transplantation centers.

Characteristics and management of hypersensitivity reactions with rabbit anti-thymocyte globulin in pediatric patients.

Background: Anti-thymocyte globulin (ATG) has been successfully used for decades to prevent graft versus host disease before hematopoietic stem cell transplantation (HSCT) as a part of conditioning regimen. However, sometimes hypersensitivity reactions may limit its use. Objective: To evaluate hypersensitivity reactions experienced during rabbit-ATG infusion among children and present successful desensitization protocol. Methods: The medical records of pediatric patients who were given rabbit-ATG treatment at our tertiary center hospital HSCT unit between 2019 and 2022 were reviewed retrospectively. Diagnosis of the patients, age at the time of HSCT, gender, presence of hypersensitivity reaction to rabbit-ATG, and management were evaluated. Characteristics of the reaction and presence of hypersensitivity reaction to other drugs were also noted. If performed, desensitization protocols were evaluated retrospectively. Results: We evaluated 81 patients; 66.6% of them (n = 54) were boys. The mean age of the patients was 8.78 ± 5.48 years. Hypersensitivity to rabbit-ATG was seen in six patients (7.4%). Four of them (4.9%) had anaphylaxis; two (2.4%) had urticaria. Intradermal test performed to every patient before the first dose of ATG infusion was detected a positive result in 1 patient (1.2%) . None of these seven patients had allergic reactions to other drugs before. Successful ATG desensitization was performed in five patients by using a 12-16 step protocol due to patients' reaction severity. Conclusion: This study aimed to evaluate hypersensitivity reactions with rabbit-ATG in children. A successful desensitization protocol with rabbit-ATG is presented. Desensitization must be performed with an experienced team very carefully in the absence of alternative drug.

Role of therapeutic drug monitoring of intravenous Busulfan for prevention of sinusoidal obstructive syndrome in children.

BACKGROUND: Therapeutic drug monitoring (TDM) of intravenous busulfan (Bu) has been recommended for safe engraftment and decreased toxicity in children undergoing hematopoietic stem cell transplantation (HSCT). This study aims to compare HSCT-related outcomes, such as acute or chronic graft-versus-host disease (GvHD), sinusoidal obstructive syndrome (SOS), event-free survival (EFS), and overall survival (OS) in children with and without TDM for busulfan. METHODS: This retrospective study conducted between February 2012 and February 2021 at our Bone Marrow Transplantation Unit included 172 patients (34% girls) with a median age of 4.70 years (IQR 2.41-10.01). Group A consisted of 46 patients whose Bu doses were adjusted according to actual body weight, and group B consisted of 126 patients whose Bu dose adjustments made according to TDM. RESULTS: Totally, 32 patients (19%) developed moderate or severe SOS. The incidence of SOS was significantly higher in the group without TDM (29% vs. 15%, p = .041). A multivariable analysis showed that the presence of acute GvHD and one alkylating drug-containing conditioning regimen compared with two or three were associated with SOS (p = .03 and p = .002, respectively). In patients with TDM, cumulative Bu dose and area under curve also were not associated with SOS. Other HSCT-related outcomes such as acute or chronic GvHD, relapse and graft rejection rates, OS and EFS rates did not differ between the groups. CONCLUSIONS: TDM and making dose adjustments with Bayesian forecasting over four days of Bu therapy optimizes exposure and reduces the risk of SOS in children undergoing HSCT.

Hematopoietic stem cell transplantation activities and HRQOL of refugee or asylum seeker children in Turkey: A multicenter study.

BACKGROUND: Refugee or asylum seekers (RAS) children are at increased risk of physical, developmental, and behavioral health issues. The aim of this study was to evaluate clinical and psychosocial outcomes of hematopoietic stem cell transplantation (HSCT) in RAS children and compare health-related quality of life (HRQOL) to those of Turkish peers. METHODS: This retrospective study included patients who underwent HSCT aged 0-18 years and completed 100-day post-transplant. The PedsQL 4.0 Generic Core Scale was used in children over 5 years old to compare HRQOL. RESULTS: A total of 166 RAS patients (M/F: 106 /60) underwent 174 HSCTs (six patients had two, and one had three HSCT) compared to 66 Turkish patients. The mean age of the patients in the RAS group was 7.8 ± 4.9 years and similar to controls. A total of 124 patients (75%) were from Syria, and 49 (25%) were from other countries in the Middle East and Africa. The cause of migration was war in 121 (74%) RAS patients. Complications of HSCT were no different between the groups. However, the rate of neutropenic sepsis was significantly higher in the RAS group (p = 0.004). The total scores of HRQOL were not different between RAS and controls. In the RAS group, ratings of social functioning were lower in patients with consanguinity or non-malignant disease or who had match-related donors. DISCUSSION: Identifying areas of difficulty in subscales of HRQOL may help physicians to classify patients who need additional supportive care. Regular monitoring and supporting physical needs may result in better functional outcomes after HSCT.

Pneumatosis cystoides intestinalis: A rare complication after hematopoietic stem cell transplantation.

BACKGROUND: Pneumatosis cystoides intestinalis (PCI) is a disorder in which widespread air sacs are present in mucosa, submucosa, subserosa, and intraabdominal area of the intestinal wall. It has a heterogeneous clinical presentation as a rare complication of intestinal graft-versus-host disease (GVHD). Computed tomography is the preferred imaging method for the diagnosis. Since the air sacs could be ruptured spontaneously, the presence of free air in the peritoneal cavity does not confirm intestinal perforation. The conservative treatment approach is sufficient in cases that do not require urgent surgical intervention, such as perforation or obstruction. CASE: Here, we present a 2.5-year-old patient diagnosed with primary hemophagocytic lymphohistiocytosis (pHLH), who underwent allogeneic hematopoietic stem cell transplantation from a matched unrelated donor (MUD) and developed PCI secondary to intestinal GVHD 14th months after HSCT. CONCLUSIONS: Pneumatosis cystoides intestinalis, which is a rare complication, should be kept in mind, especially in patients with intestinal GVHD and receiving intensive immunosuppressive, octreotide, and steroid treatment after HSCT.

Frequency and clinical characteristics of allergic transfusion reactions in children.

Allergic transfusion reactions (ATRs)are a common form of acute transfusion reaction. It was aimed to determine the clinical characteristics and frequency of ATRs in children. This study included children who were transfused with red cell concentrate (RCC), fresh-frozen plasma (FFP), platelet concentrates(PC), apheresis granulocyte, and cryoprecipitate.The patients' sociodemographic characteristics, the blood product that caused the reaction, the type and timing of the reaction, the patient's age at time of reaction and their diagnosis, follow-up period, and clinical data were recorded. A total of 89703 bags of blood products were transfused to 4193 children.Two hundred eleven acute transfusion-related reactions occurred in 157 (3.74%) patients.Of these, 125 reactions (59%) were allergic. ATR occurred in 125 of 89703 infusions (0.14%).The median age of patients was 9.99 years (IQR:4.67-14.38) and ATRs occurred at a median of 30 minutes into the transfusion. Eighteen (18%) of the patients also had a history of drug reaction.When the blood products that caused ATRs were examined, 43(34.5%) occurred with apheresis and single-donor PC, 37(29.6%) with FFP, 32 (25.6%) with RCC, 10(8%) with pooled PC, 2(1.6%) with cryoprecipitate, 1(0.8%) with apheresis granulocyte.Ninety-nine(79%) of the reactions were minor allergic reactions and 26(21%) were anaphylaxis.Compared to minor allergic reactions, the proportion of PCs was statistically higher in anaphylaxis(p=0.02). Patients receiving PC should be monitored more carefully during the first half hour of transfusion. In addition, approximately one-fifth of the patients who developed ATR also had a history of drug reaction. Patients with previous reactions to drugs may be more likely to have ATR.

Therapeutic plasma exchange: A potential management strategy for critically ill MIS-C patients in the pediatric intensive care unit.

This study aimed to evaluate the effectiveness and the role of therapeutic plasma exchange (TPE) in treatment of children with severe MIS-C. In addition, we assessed demographic data, clinical features, laboratory abnormalities, underlying conditions, treatments, and outcomes. Patients with severe MIS-C who were admitted to the pediatric intensive care unit (PICU) between September 01 and October 05, 2020 were included in this observational, descriptive, retrospective study. The data collected included the patients' demographic data, presenting symptoms, clinical features, laboratory parameters, diagnostic investigations, and medications. Of 27 children with MIS-C, 63 % were male. The median age of the patients was nine years. Intravenous immunoglobulin and corticosteroids were used for treatment in 100 % of the patients, anakinra in 51.8 %, vasopressors in 85.1 %, noninvasive mechanical ventilation in 25.9 %, and invasive mechanical ventilation in 18.5 %. Ten of the 27 patients (37 %) underwent TPE. In the patients who underwent TPE, the median PELOD score was 21 (IQR: 11-30.25) before TPE and 10 (IQR: 10-11) after TPE (p < 0.001). Moreover, their median left ventricular ejection fraction (LVEF) was 52 % (IQR: 49.25 %-55 %) before TPE and median LVEF was 66.5 (IQR: 58 %-68.5 %) after TPE (p = 0.012). The median number of TPE sessions was three (IQR: 2-4.75). The mortality rate of the patients with severe MIS-C admitted to the PICU was 7.4 %. We suggest that TPE should be considered as a therapeutic option in children with severe MIS-C. Early initiation of TPE followed by immunomodulatory therapy in critically ill children with MIS-C may help improve clinical and laboratory outcomes.

Renal function and the oxidative status among children with thalassemia major and healthy controls: A cross-sectional study.

BACKGROUND: Renal dysfunction is an underestimated complication of thalassemia major. OBJECTIVES: The aim of this study is to compare the glomerular and tubular functions in children with ß- Thalassemia major (ß- TM) with healthy controls and assess the oxidative stress caused by high ferritin levels. DESIGN AND SETTING: This prospective cross-sectional study was conducted in tertiary care hospital. METHODS: Complete blood count (CBC), calcium (Ca), urea, creatinine (Cr), serum cystatin C before transfusion and urinary calcium (uCa), creatinine (uCr), protein (UPr) levels were analyzed in fresh samples. Beta-2-microglobulin (uß2-MG), N- acetylglucosaminidase (uNAG), retinol binding protein (uRBP), malonedialdehyde (uMDA) secretion and creatinine levels were analyzed. Serum total antioxidant capacity (sTAC) and total oxidant capacity (sTOC) were measured with colorimetric micro-ELISA method. Last four serum ferritin values were recorded and the mean value was used for statistical analyzes. RESULTS: Data from 47 patients and 32 controls were analyzed. The urinary RBP/Cr, Ca/Cr and Protein/Cr, were significantly higher in ß-TM group. A statistically insignificant increase in urinary ß2MG/Cr, uNAG/Cr, MDA/Cr was also found in the TM group. Proteinuria was present in 46 % (n: 22) and hypercalciuria in 34 % (n: 16) of the patients with ß- TM. Serum total antioxidant capacity and total oxidant status (TOS) levels were significantly elevated in the patient group. Serum ferritin was significantly correlated with proteinuria, cystatin C levels, urinary Protein/Cr and uRBP/Cr. CONCLUSION: Asymptomatic renal dysfunction is prevalent in ß- TM patients that necessitate regular screening. Urinary RBP may be useful for early diagnosis.

Two versus three day upfront use of granulocyte-colony stimulating factor in healthy bone marrow donors for pediatric bone marrow transplantation.

In order to decrease donors' exposure to granulocyte-colony stimulating factor (G-CSF), we compared the effect of two versus three days of G-CSF priming on CD34+ yield in bone marrow (BM) harvest. Although the number of BM-CD34+ cells was higher in 3day G-CSF priming, we achieved the same number of CD34+ cells per recipient's weight in 2day G-CSF priming group, too. In addition, the number of total nucleated cells (TNC) harvested from BM were similar with two or three day regimen. But mononuclear cells (MNC) of the BM graft was higher in the 3day G-CSF priming group. Similar to CD34+ cell numbers, BM harvest yielded similar TNC, and MNC numbers per kilogram of the recipient. We also found that, young donors (≤10year) had more peripheral blood MNC, bone marrow MNC and CD34+ cell numbers. Another interesting finding of this study was obtaining adequate number of peripheral blood stem cells for leukapheresis with three day G-CSF administration. Since engrafment times were also similar in two groups, we concluded that 2-days G-CSF priming was resulted in sufficient mobilization of BM stem cells.

The Effect of Granulocyte Colony-Stimulating Factor on Immune-Modulatory Cytokines in the Bone Marrow Microenvironment and Mesenchymal Stem Cells of Healthy Donors.

Granulocyte colony stimulating factor (G-CSF) is sometimes administered to donors before bone marrow (BM) harvest. G-CSF-primed (G-BM) and unprimed BM (U-BM)-derived mesenchymal stem cells (MSC) were obtained from 16 healthy donors and were expanded in vitro. Their proliferative characteristics, morphology, and differentiation capacity were examined. Supernatants of the second passage of MSCs were evaluated for transforming growth factor ß1, hepatocyte growth factor, and prostaglandin E2 (PGE2) levels and compared with controls. The analyses of cytokines in the G-BM- and U-BM-derived MSCs supernatants revealed that PGE2 levels were significantly lower in the G-CSF-primed samples. These cytokines were also measured in BM plasma. The level of hepatocyte growth factor in G-BM plasma was significantly increased. The current study is the first to show the effects of G-CSF on the BM microenvironment of healthy human donors. The preliminary data suggest that G-BM- and U-BM-derived MSCs have similar morphologic/phenotypic properties and differentiation capacity but differ in their secretory capacity. Significant changes in cytokine levels of BM plasma in G-CSF-primed donors were also demonstrated. These findings suggest that BM MSCs and changes in the BM microenvironment may contribute to the effects of G-CSF on inflammation and immunomodulation.

Direct Antiglobulin Test Positivity in Children With Acute Lymphoblastic Leukemia at Diagnosis.

Direct antiglobulin test positivity had been reported in the course of some lymphoproliferative neoplasms. However, there are a few case reports describing direct antiglobulin test (DAT) positivity in children with acute lymphoblastic leukemia (ALL). We herein report 8 patients who had positive DAT among 95 newly diagnosed children with ALL. None of these patients had evidence of hemolysis during the follow-up. An antibody was detected in 2 of 8 patients with positive DAT. These 2 children also had positive indirect antiglobulin test (IAT); an autoantibody that was reactive at 4°C, and an alloantibody (anti E) that was reactive at 37°C was detected. We believe DAT positivity in ALL without significant hemolysis is not a rare disorder, and a need for further prospective studies is apparent.

Bone Marrow Grafts From Pediatric Donors May Contain A Considerable Number of Hematogones.

During CD34 + stem cell count to determine the number of stem cells in the allografts from pediatric donors, we noticed a considerable amount of early hematogones (eHGs) within the stem cell gate in flow cytometry. Since the number of hematogones causes a decrease in the total number of stem cells counted within the graft, we planned a retrospective study to analyze the effect of eHGs on transplant outcomes. We also wanted to show how allografts containing high amounts of early HGs affect transplant outcomes. Quantification of CD34 numbers and the number of eHGs were determined by flow cytometry. Patients were divided into 2 groups according to the number of CD 34+ cells calculated after subtracting the number of hematogones within the allograft. Those who received < 2 × 106/kg CD34+ cells and ≥ 2 × 106/kg were defined as group 1 and 2, respectively. Twenty-six patients and their 26 donors were included in the study. The median age of patients was 6.5 years and 5.4 years in Group 1 and 2, respectively. The median donor age was 9 years in Group 1 and 7 years in Group 2. The ages and genders were similar in the two groups (p > 0.05). The number of nucleated cells given to both groups was not different. The number of early hematogones given to both groups was similar (p = 0.93). The mean times to myeloid and platelet engraftments were also similar in the two groups. In this study, we provided trilineage engraftment to all patients in two groups. We could not find a considerable effect of these eHGs in myeloid and platelet engraftments. However, the number of patients included in our study is low, therefore we suggest a study including a large number of donors in order to confirm our findings.

Different Kinetics and Risk Factors for Isolated Extramedullary Relapse after Allogeneic Hematopoietic Stem Cell Transplantation in Children with Acute Leukemia.

Relapse after allogeneic hematopoietic stem cell transplantation (allo-HSCT) remains the most frequent cause of post-transplantation mortality. Isolated extramedullary (EM) relapse (iEMR) after HSCT is relatively rare and not well characterized, particularly in pediatric patients. We retrospectively analyzed 1527 consecutive pediatric patients with acute leukemia after allo-HSCT to study the incidence, risk factors, and outcome of iEMR compared with systemic relapse. The 5-year cumulative incidence of systemic relapse (either bone marrow [BM] only or BM combined with EMR) was 24.8%, and that of iEMR was 5.5%. The onset of relapse after allo-HSCT was significantly longer in EM sites than in BM sites (7.19 and 5.58 months, respectively; P = .013). Complete response (CR) 2+/active disease at transplantation (hazard ratio [HR], 3.1; P < .001) and prior EM disease (HR, 2.3; P = .007) were independent risk factors for iEMR. Chronic graft-versus-host disease reduced the risk of systemic relapse (HR, 0.5; P = .043) but did not protect against iEMR. The prognosis of patients who developed iEMR remained poor but was slightly better than that of patients who developed systemic relapse (3-year overall survival, 16.5% versus 15.3%; P = .089). Patients experiencing their first systemic relapse continued to have further systemic relapse, but only a minority progressed to iEMR, whereas those experiencing their iEMR at first relapse developed further systemic relapse and iEMR at approximately similar frequencies. A second iEMR was more common after a first iEMR than after a first systemic relapse (58.8% versus 13.0%; P = .001) and was associated with poor outcome. iEMR has a poor prognosis, particularly after a second relapse, and effective strategies are needed to improve outcomes.

Role of a second transplantation for children with acute leukemia following posttransplantation relapse: a study by the Turkish Bone Marrow Transplantation Study Group.

We examined outcomes of 51 pediatric patients with relapsed acute leukemia (AL) who underwent a second allogeneic hematopoietic stem cell transplantation (alloHSCT). After a median follow-up of 941 days (range, 69-2842 days), leukemia-free survival (LFS) and overall survival (OS) at 3 years were 26.6% and 25.6%, respectively. The nonrelapse mortality rate (NMR) and cumulative incidence of relapse (CIR) were 36.4% and 42.4%, respectively. The Cox regression analysis demonstrated that the risk factors at second transplantation for predicting limited LFS were active disease (hazard ratio (HR) = 5.1), reduced intensity conditioning (RIC) (HR = 5.0), matched unrelated donor (MUD) (HR = 3.4) and performance score <80 (HR = 3.2). Pediatric patients with AL who relapsed after their first alloHSCT may survive with a second alloHSCT. Disease status, conditioning intensity, donor type, and performance score at the second transplantation are the relevant risk factors. A score based on these factors may predict the results of the second transplantation.

Hereditary spherocytosis: Retrospective evaluation of 65 children.

Güngör A, Yarali N, Fettah A, Ok-Bozkaya I, Özbek N, Kara A. Hereditary spherocytosis: Retrospective evaluation of 65 children. Turk J Pediatr 2018; 60: 264-269. Hereditary spherocytosis (HS) is a common cause of congenital hemolytic anemia in Caucasians and it could be diagnosed at any age. The aim of this study is to examine the demographic characteristics, clinical features and laboratory findings of children with HS and their complications observed during follow up. Sixty-five patients, with hereditary spherocytosis between January 2008 and September 2013, were enrolled into this retrospective study. The age of patients at the time of diagnosis varied between 15 days and 17 years. The median age of patients at diagnosis was 48 months (IQR 2-78). The female/male ratio was 1.1. Forty-seven patients (72.3%) had a family history of HS. The patients were classified according to laboratory findings: 13 of them (20%) were diagnosed as mild HS, 36 (55.4%) as moderate HS and of 16 (24.6%) as severe HS. During follow-up, nine patients (13.8%) experienced an aplastic crisis. Megaloblastic crisis was not observed in any patient. Twenty patients (30.8%) had cholelithiasis. Splenectomy was performed in 20% of patients and the mean age for splenectomy was 8.3 years. Complications such as sepsis or thrombosis were not detected after splenectomy. Hereditary spherocytosis should be kept in mind in patients with anemia, jaundice and splenomegaly and the family history must be questioned. The most common complication was gallstone; even patients without severe hemolysis should be followed intermittently by abdominal ultrasonography in order to control the development of gallstone.

Relationship Between the Levels of Holotranscobalamin and Vitamin B12 in Children.

The purpose of this study was to evaluate the relationship between the plasma holoTC and serum vitamin B12 in children and to identify a cutoff cobalamin values according to holoTC. One hundred and fifty-five children were enrolled into the study. All children were evaluated for hemoglobin, vitamin B12, folate, ferritin and holoTC levels. Children were grouped as with low vitamin B12 level (≤200 pg/mL, group I) and normal vitamin B12 (>200 pg/mL, group II). Serum vitamin B12, and holoTC levels were performed in each patient in the study. In 101 patients with low vitamin B12 (group I) the mean holoTC was 21.74 ± 1.14 pmol/L. In 54 children with normal vitamin B12 (group II) mean holoTC was 44.0 ± 2.7 pmol/L (p < 0.01). A ROC curve analysis was performed to delineate the optimum cut-off point for vitamin B12 level and it was found to be 165 pg/mL with a sensitivity of 70% and specificity of 74%; the area under curve was 0.783 (p < 0.01). Our study displayed a positive correlation between vitamin B12 and holoTC, and defined an optimum cutoff value for vitamin B12 as 165 pg/mL. Further studies using the markers both MMA, tHcy and holoTC to confirm the findings are needed.

The successful non-invasive management of pulmonary thromboembolism in a child with acute lymphoblastic leukemia.

In childhood, pulmonary thromboembolism (PTE) is an uncommonbut potentially life-threatening disease. The greater numbers of venous thromboembolism (VTE) are complications of underlying risk factors such as malignancies, chemotherapy (L-asparaginase), and central venous catheter. We report a patient with acute lymphoblastic leukemia and PTE, who presented with near-syncope, and was successfully treated with low molecular weight heparin and calcium channel blockers.

Severe Clinical Course in a Patient with Congenital Amegakaryocytic Thrombocytopenia Due to a Missense Mutation of the c-MPL Gene.

Congenital amegakaryocytic thrombocytopenia (CAMT) generally begins at birth with severe thrombocytopenia and progresses to pancytopenia. It is caused by mutations in the thrombopoietin receptor gene, the myeloproliferative leukemia virus oncogene (c-MPL). The association between CAMT and c-MPL mutation type has been reported in the literature. Patients with CAMT have been categorized according to their clinical symptoms caused by different mutations. Missense mutations of c-MPL have been classified as type II and these patients have delayed onset of bone marrow failure compared to type I patients. Here we present a girl with severe clinical course of CAMT II having a missense mutation in exon 4 of the c-MPL gene who was admitted to our hospital with intracranial hemorrhage during the newborn period.