Emel Özyürek

Virus-associated immune thrombocytopenic purpura in childhood.

Idiopathic thrombocytopenic purpura (ITP) in children is usually a self-limiting disorder. It may follow a viral infection or immunization and is caused by an inappropriate response of the immune system. Many viruses, such as human immuno deficiency virus, cytomegalovirus (CMV), Epstein-Barr virus (EBV), varicella, rubeola, mumps, and parvovirus, have been implicated in childhood ITP. This study is a retrospective chart review of pediatric patients diagnosed with virus-associated ITP at the Hacettepe University, G hsan Do < ramaci Childrens Hospital from 1997 to end of 2000. In viral serological studies, the EBV, CMV, and rubella antibodies were investigated for all patients at diagnosis (ELISA). The proportion of children whose ITP was associated with documented acute viral infection was 13.3% in this group. In the present study, clinical manifestations and laboratory data of virus-associated or not associated groups are similar except age. Median age of the virus-associated group is younger than that of the other, but it is not statistically significant.

Primary hemophagocytic lymphohistiocytosis in Turkish children

Nineteen children with hemophagocytic lymphohistiocytosis (HLH) were studied in the Department of Pediatric Hematology, Hacettepe University. Patients were divided into two groups. Group 1 : Thirteen patients were classified as having a genetic etiology (7 familial, 6 presumed familial) on the basis of an affected sibling and consanguinity. There was a history of consanguineous marriage in 13 of the families. Seven of them had a history of a sibling with HLH. Group 2 : Six patients were diagnosed with sporadic HLH. The age at presentation for familial patients was 0.7-84 months (mean 21.9 - 24.9 months), and for sporadic cases it was 2.5-48 months (mean 22.7 - 19.8 months). The clinical and laboratory data of these two groups were similar at diagnosis. Thirteen cases were diagnosed premortem by bone marrow aspiration. Splenic biopsy was performed in 2 patients. Four patients were diagnosed by postmortem examination. Elevated LDH levels were found in all patients tested. No significant differences for clinical and laboratory data were found between the two groups.

Benefit of high-dose methylprednisolone in comparison with conventional-dose prednisolone during remission induction therapy in childhood acute lymphoblastic leukemia for long-term follow-up.

Eight-year event-free survival (EFS) was evaluated in 205 patients with acute lymphoblastic leukemia (ALL), to consider the efficacy of high-dose methylprednisolone (HDMP) given during remission induction chemotherapy between 1 and 29 days. The St Jude Total XI Study protocol was used after some minor modifications in this trial. Patients were randomized into two groups. Group A (n = 108) received conventional dose (60 mg/m2/day orally) prednisolone and group B (n = 97) received HDMP (Prednol-L, 900–600 mg/m2 orally) during remission induction chemotherapy. Complete remission was obtained in 95% of the 205 patients who were followed-up for 11 years; median follow-up was 72 months (range 60–129) and 8-year EFS rate was 60% overall (53% in group A, 66% in group B). The EFS rate of group B was significantly higher than of group A (P = 0.05). The 8-year EFS rate of groups A and B in the high-risk groups was 39% vs 63% (P = 0.002). When we compared 8-year EFS rate in groups A and B in the high-risk subgroup for both ages together ⩽2 or ⩾10 years, it was 44% vs 74%, respectively. Among patients in the high-risk subgroup with a WBC count ⩾50 × 109/l, the 8-year EFS was 38% in group A vs58% in group B. During the 11-year follow-up period, a total of 64 relapses occurred in 205 patients. In group A relapses were higher (39%) than in group B (23%) (P = 0.05). These results suggest that HDMP during remission-induction chemotherapy improves the EFS rate significantly for high-risk patients in terms of the chances of cure.

Children with acute myeloblastic leukemia presenting with extramedullary infiltration: the effects of high-dose steroid treatment

To evaluate whether children with acute myeloblastic leukemia (AML) presenting with extramedullary infiltration (EMI) have different clinical, morphologic features and prognosis from children without EMI, a 127 consecutive previously untreated children with AML were entered in this study. Fifty-one children (40%) had EMI at diagnosis and 27% of these showed multiple site involvement. Twenty-seven of 127 children (21%) presented myeloid tumors. No age related differences in the incidence of EMI was noted. However, analysis of clinical and biological features at diagnosis showed that WBC count > or =50 x 10(9) l(-1), hepatosplenomegaly >5 cm, FAB AML-M4 and AML-M5 subtypes and CD13, CD14 expression of bone marrow (BM) leukemic cells (>20%) were more frequent in children with EMI. Two consecutive treatment protocols were used. In both protocols remission was achieved with combined high-dose methylprednisolone (HDMP) as a differentiating and apoptosis inducing agent with mild cytotoxic chemotherapy (low-dose cytosine arabinoside (LD Ara-C), weekly mitoxantrone and Ara-C or 6-thioguanine). Administration of short-course (4-7 days) HDMP (20-30 mg/kg per day) alone resulted in a remarkable decrease in peripheral blood, BM blasts and in the size of EMI in responding patients. In both protocols, remission rate in patients with EMI was 71 and 80%, which was lower than that of the patients without EMI (87 and 89%). This may be attributed to the higher frequency of unfavorable features in children with EMI. However, in patients who presented with myeloblastoma and treated with a more intensive post-remission therapy (AML-94), the 4-year disease-free survival (DFS) and event-free survival (EFS) rates were not found to be significantly different from children who had no EMI (P>0.05). Whereas, the outcome of children who presented with gingival infiltration did not improve. In further studies, the prognostic significance of different localisation of EMI and the effect of addition of HDMP to cytotoxic chemotherapy should be explored in larger series.

Parvovirus B19 infection associated with severe aplastic anemia in an immunocompetent patient.

Human parvovirus B19 (PVB19) infection may cause mild pancytopenia characterized by transient and spontaneous recovery in healthy subjects. Severe aplastic anemia associated with PVB19 infection in patients without an underlying disease has been described in a number of reports. Here, a previous healthy, 10-year-old girl with severe aplastic anemia associated with PVB19 infection is described. The patient underwent bone marrow transplantation from her HLA-identical sibling resulting in complete recovery. PVB19 infection should be considered as one of the causes of aplastic anemia in patients without an underlying disease.

Significance of factor V, prothrombin, MTHFR, and PAI-1 genotypes in childhood cerebral thrombosis.

The aim of this study was to evaluate the significance of factor V (FV) G1691A, prothrombin G20210A, methylenetetrahydrofolate reductase (MTHFR) C677T, and plasminogen activator inhibitor-1 (PAI-1) 4G/5G genotypes in development of childhood cerebral thrombosis (CT). A total of 113 Turkish children with CT were studied and compared with the control group. The carrier frequency of the factor V G1691A mutation was found to be significantly higher in the patient group (17.7%) than controls (7.4%). The presence of this genotype was associated with a 2.7-fold increased risk of developing CT (95% confidence interval [CI], 1.0—7.0). The prevalence of prothrombin G20210A mutation in 110 patients (4.5%) was insignificantly higher than controls (2.3%) (odds ratio, 2.0; 95% CI, 0.4—10.7). A statistically significant increase in the frequency of homozygous MTHFR C677T genotype was observed in 62 patients (11.3%) compared to controls (4.3%), and this genotype was associated with 2.8-fold increased CT risk (95% CI, 1.0—8.0). The incidence of PAI-1 4G/4G genotype in 65 patients (21.5%) was slightly lower than that of controls (26.0%), but the differences did not reach statistical significance (odds ratio, 0.8; 95% CI, 0.4—1.5). The results of this study suggested that factor V G1691A and MTHFR C677T genotypes may be associated with an increased risk of developing CT in Turkish children.

Invasive fungal infections in children with hematologic and malignant diseases.

Background: To evaluate the clinical feature and outcome of invasive fungal infections (IFI) in children with hematologic and malign diseases. Patients and Methods: The medical records of children with hematologic and malignant diseases, who were hospitalized at our hospital between January 2010 and December 2011, were reviewed. Proven, probable, and possible IFIs were diagnosed according to the revised definitions of the European Organization for Research and Treatment of Cancer/Mycosis Study Group. The demographic, clinical, and laboratory characteristics of the patients who met the study criteria were evaluated. Results: IFI was diagnosed in 67 (7.2%) febrile episodes of 56 patients, of which 10 (1.2%) were proven, 20 (2%) probable, and 37 (4%) possible IFI. Blood culture of 10 cases with proven IFI yielded yeast and the most common isolated agent was Candida parapsilosis. Seventy percent of cases with fungemia had central venous catheter (CVC). Twenty cases with probable IFI had invasive mold infection. The cases with mold infection had higher median C-reactive protein values, lower neutrophil counts, and longer duration of neutropenia compared with the cases with yeast infection. A total of 14 patients (20.9%) died. Presence of CVC, bone marrow transplantation, total parenteral nutrition, prolonged fever, and proven/probable IFI were detected more often in patients who died, compared with patients who survived. Conclusions: IFIs are important causes of death in children with hematologic and malignant diseases. Mold infections are seen more frequently in cases with prolonged and profound neutropenia, and invasive yeast infections, especially with non-albicans Candida species, in cases with CVC. Early and effective treatment considering these findings will help to decrease the mortality.

Antiphospholipid antibodies in Turkish children with thrombosis.

Antiphospholipid syndrome is a systemic disorder characterized by arterial and/or venous thrombosis, thrombocytopenia, recurrent fetal loss, and presence of antiphospholipid antibodies (APA). The importance of APA in Turkish children with thrombosis is unknown. This study aimed to evaluate the frequency of APA positivity, associated risk factors other than APA, and outcome in children with APA and thrombosis. The presence of APA was investigated in 138 children presenting for evaluation of thrombosis; other prothrombotic risk factors were also studied. The frequency of APA positivity among 138 children was 11.6% (16/138). The mean age of these 16 children (10 female, 62.5%) was 9.57 ± 4.59 years (range, 2.5–18.0 years). The mean follow-up period was 31.7 ± 21.7 months (range, 5–60 months). Recurrence was observed during follow-up in two patients (12.5%). Ten patients (62.5%) had arterial thrombosis, five patients (31.3%) venous thrombosis, and one patient (6.3%) purpura fulminans. Among the thrombotic children with APA, 11 (68.8%) had more than one prothrombotic risk factor other than circulating APA [five patients (31.3%) had two risk factors, two patients (12.5%) had three, and four patients (25.0%) had four]. Five patients (31.3%) had no additional risk factors. APA should be tested in all children with thrombosis, especially those with arterial thrombosis.

Haematological findings in children with inborn errors of metabolism

SummaryEarly detection and therapy of haematological abnormalities and/or diseases may improve the prognosis of metabolic disorders. Accordingly, we aimed to evaluate the frequency and types of haematological abnormalities in children[-31pc] with various inherited metabolic disorders. The study group comprised 46 children with metabolic disorders who were followed at the Pediatric Metabolism Unit and were referred to the Pediatric Hematology Unit for evaluation of anaemia between June 2000 and 2005. The mean age of the children was 55.2 ± 64.8 months at haematological evaluation (range 1 month–18 years, median 22.0 months); 16 were female and 30 were male. Of these 46 patients with anaemia, 25 of (54.3%) had anaemia of chronic disease (ACD), 9 (19.6%) had iron-deficiency anaemia (IDA), 7 (15.2%) had megaloblastic anaemia due to vitamin B12 deficiency, 3 (6.5%) had chronic haemolytic anaemia, 2 (4.3%) had autoimmune haemolytic anaemia, 1 had β-thalassaemia major, and 1 had hereditary spherocytosis. In addition to the anaemia, bicytopenia or pancytopenia was found in 8 of 46 children (17.4%). The study indicated that in organic acidaemias including methylmalonic acidaemia, propionic acidaemia, isovaleric acidaemia, and argininosuccinic acidaemia, the majority of patients had ACD (75%), which was followed by vitamin B12 deficiency anaemia and IDA (p < 0.001). In PKU, both nutritional anaemias and ACD were present at about same frequency: 46.7% and 40%, respectively (p > 0.05). This study suggested that congenital anaemias such as hereditary spherocytosis or thalassaemias should be kept in mind as a coexisting haematological diseases in young patients with inborn errors of metabolism. In conclusion, ACD and nutritional anaemias are the most prevalent anaemias seen in patients with inborn errors of metabolism. Early detection of the disease, early administration of specific diet, and close monitoring of the patients are very important factors to prevent the development of haematological diseases in patients with inborn errors of metabolism.

VACCINATION-ASSOCIATED IMMUNE THROMBOCYTOPENIC PURPURA IN FIVE CHILDREN

In the literature, patients developing thrombocytopenic purpura following rubella, measles, cytomegalovirus (CMV), or Epstein-Barr virus (EBV) infections or rubella, measles, or mumps vaccinations have been reported [1 ± 4]. We summarize clinical features and follow-up of our patients with thrombocytopenia after vaccination in this letter. Fifty-three cases with immune thrombocytopenic purpura (ITP) followed between 1996 and 2000 in Hacettepe University, Ç Ihsan DoÆ gramacõ Children’s Hospital were included in this study. The following criteria were used for the diagnosis of ITP: acute isolated thrombocytopenia, thrombocyte count lower than 10 £ 109/L, increase in megakaryocyte number, no malignant and/or depot cells, as well as normal elements of other series in the bone marrow aspiration materials. A detailed history of medication use, infection, and immunization were obtained from the patients and their families. Coombs test, pharyngeal culture, viral serology for CMV, rubella, EBV by employing ELISA, immunoglobulin level, ANA, and anti-DNA were performed routinely in all patients. Fifty-three patients were diagnosed as ITP according to above criteria between 1996 and 2000. There was history of routine childhood immunizations in 5 patients (3 girls, 2 boys) shortly before the onset of thrombocytopenia. All of the patients were under 2 years old, 3 being less than 1 year of age. The median time interval between the immunization procedure and the onset of thrombocytopenia was 18 days (range 14± 23) and platelet counts ranged between 4 £ 109/L and 41 £ 109/L (median 23 £ 109/L). Physical examination was unremarkable in all patients except for minor