Ulker Kocak

Invasive fungal infections in pediatric leukemia patients receiving fluconazole prophylaxis.

Children with acute leukemia have increased risk for invasive fungal infections (IFI) but the role of long term antifungal prophylaxis (AFP) in morbidity and mortality of IFI is not well‐known.

The effect of steroid and intravenous immunoglobulin on thrombopoietin levels in pediatric patients with immune thrombocytopenic purpura

Thrombopoietin (TPO), which is the main regulator of megakaryo/thrombopoiesis, has been recently cloned and purified, and shown to be useful in discriminating thrombocytopenia due to decreased production or increased platelet destruction. However, there are no detailed investigations about the drug effects on TPO levels during childhood. This study was conducted to measure the TPO levels of children with immune thrombocytopenic purpura (ITP) during steroid and immunoglobulin treatment. Twelve patients with acute ITP were treated with high-dose methyl prednisolone and five patients were treated with intravenous immunoglobulin. Neither steroids nor immunoglobulin were found to have any effect on TPO levels.

A novel single point mutation of the LYST gene in two siblings with different phenotypic features of Chediak Higashi syndrome.

Chediak Higashi syndrome (CHS) is an autosomal‐recessive disorder characterized by oculocutaneous albinism, recurrent infections and a progressive primary neurological disease. Here, we describe two siblings with CHS due to a novel homozygous R1836X mutation in the LYST gene associated with loss of NK cell degranulation and cytotoxicity. While one sibling was born with fair skin and hair and died of hemophagocytic lymphohistiocytosis (HLH) at 5 months of age, the other sibling had dark black hair and skin and developed HLH at the age of 4 years. Pediatr Blood Cancer 2011;56:1136–1139.

Functional and clinical impact of novel TMPRSS6 variants in iron-refractory iron-deficiency anemia patients and genotype-phenotype studies.

Iron‐refractory iron‐deficiency anemia (IRIDA) is a rare autosomal‐recessive disorder characterized by hypochromic microcytic anemia, low transferrin saturation, and inappropriate high levels of the iron hormone hepcidin. The disease is caused by variants in the transmembrane protease serine 6 (TMPRSS6) gene that encodes the type II serine protease matriptase‐2, a negative regulator of hepcidin transcription. Sequencing analysis of the TMPRSS6 gene in 21 new IRIDA patients from 16 families with different ethnic origin reveal 17 novel mutations, including the most frequent mutation in Southern Italy (p.W590R). Eight missense mutations were analyzed in vitro. All but the p.T287N variant impair matriptase‐2 autoproteotylic activation, decrease the ability to cleave membrane HJV and inhibit the HJV‐dependent hepcidin activation. Genotype–phenotype studies in IRIDA patients have been so far limited due to the relatively low number of described patients. Our genotype–phenotype correlation analysis demonstrates that patients carrying two nonsense mutations present a more severe anemia and microcytosis and higher hepcidin levels than the other patients. We confirm that TMPRSS6 mutations are spread along the gene and that mechanistically they fully or partially abrogate hepcidin inhibition. Genotyping IRIDA patients help in predicting IRIDA severity and may be useful for predicting response to iron treatment.

EVALUATION OF RENAL FUNCTION IN TURKISH CHILDREN RECEIVING BFM-95 THERAPY FOR ACUTE LYMPHOBLASTIC LEUKEMIA

This study examined renal function in 42 children with acute lymphoblastic leukemia (ALL) treated according to BFM-95 protocol. Fifteen (group 1) were investigated longitudinally at 3 time points: before (T1), 4 weeks after (T2), and 2–6 months after (T3) consolidation therapy with high-dose methotrexate (HDMTX). The frequency of abnormalities in glomerular and tubular tests were nil at T1 and ranged from 13 to 40% at T2 and 7 to 33% at T3 in group 1. Twenty percent of the patients (n = 10) in group 2, who were examined at a single time point 7–36 months after consolidation, had glomerular and tubular abnormalities. There was only mild tubular abnormality in 5.8% of patients (n = 17) in group 3, who were examined at a single time point a mean of 56.1 ± 12.5 months after completion chemotherapy. These data show that consolidation therapy with HDMTX is frequently associated with acute renal toxicity in children with ALL but does not leave clinically significant late sequelae.

Candida vertebra osteomyelitis in a girl with factor X deficiency

Summary.  Candidal vertebra osteomyelitis is a rare condition which occurs primarily in immunocompromised patients. We report a 14‐year‐old girl with factor X deficiency who developed candida vertebra osteomyelitis during home therapy. The microorganism was probably from a contaminated peripheral cannula used for infusion of factor concentrate. This is the first such case in bleeding disorders to our knowledge.

A Novel Mutation in the SLC19A2 Gene in a Turkish Female with Thiamine-responsive Megaloblastic Anemia Syndrome

Reported here is a 2-year-old girl who was diagnosed to have thiamine-responsive megaloblastic anemia during evaluations for her bilateral neurosensorial deafness. Besides reporting a new mutation on the gene SLC19A2 for the first time in the literature, we highlight the recognition of this syndrome--when megaloblastic anemia and diabetes mellitus coexists--and the role of thiamine replacement for the treatment of both disorders.

Serum fibronectin in neonatal sepsis: Is it valuable in early diagnosis and outcome prediction?

The value of the serum fibronectin level in early diagnosis of neonatal sepsis and as a prognostic indicator was investigated. The serum fibronectin levels and Töllners sepsis scores of 45 neonates who were hospitalized for the suspicion of infection and of 20 healthy neonates as controls were evaluated. Depending on the findings it was concluded that serum fibronectin level varies according to the gestational age, and that the serum fibronectin level is a useful acute phase reactant in the early diagnosis of neonatal sepsis. It can also be used as a prognostic indicator in neonatal sepsis.

Thyroid Abnormalities in Survivors of Childhood Cancer

Objective: To investigate the late side effects of childhood cancer therapy on the thyroid gland and to determine the risk factors for development of thyroid disorder among childhood cancer survivors. Methods: One hundred and twenty relapse-free survivors of childhood cancer (aged 6-30 years) were included in this study. The diagnoses of patients were lymphoma, leukemia, brain tumor, rhabdomyosarcoma and nasopharyngeal carcinoma (NPC). The patients were divided into two groups depending on the treatment: group 1-chemotherapy (ChT) only (n=52) and group 2-combination therapy of ChT + radiotherapy (RT) (head/neck/thorax) (n=68). Thyroid function tests, urinary iodine levels, and thyroid gland ultrasound examinations were evaluated in both groups. Results: Incidence of thyroid disease was 66% (n=79) in the survivors. The thyroid abnormalities were: hypothyroidism (HT) (n=32, 27%), thyroid nodules (n=27, 22%), thyroid parenchymal heterogeneity (n=40, 33%), autoimmune thyroiditis (n=36, 30%), and thyroid malignancy (n=3, 2%). While the incidence of HT and thyroid nodules in group 2 was significantly higher than in group 1, the incidence of thyroid parenchymal heterogeneity and autoimmune thyroiditis was similar in the two patient groups. HT and thyroid malignancy were seen only in group 2. In multivariate logistic regression analysis, a history of Hodgkin lymphoma (HL), brain tumor and NPC, as well as cervical irradiation and 5000-5999 cGy doses of radiation were found to constitute risk factors for HT. History of HL and 4000-5999 cGy doses of radiation were risk factors for thyroid nodules. Head/neck irradiation and treatment with platinum derivatives were risk factors for autoimmune thyroiditis. In univariate analysis, a history of NPC, cervical + nasopharyngeal irradiation, and treatment with platinum derivatives were risk factors for thyroid parenchymal heterogeneity. Conclusion: Our results indicate that there is especially an increased risk of HT and thyroid nodules in patients treated with combination therapy of ChT with head/neck/thorax RT. Although chemotherapeutic agents per se do not seem to cause HT, longer follow-up is needed to assess whether or not there is an increased risk for autoimmune thyroiditis and thyroid parenchymal heterogeneity after antineoplastic therapy.

Prognostic Factors and Long-Term Outcome in 52 Turkish Children With Hemophagocytic Lymphohistiocytosis.

Objectives: Hemophagocytic lymphohistiocytosis is a syndrome of pathologic immune activation that shares similar clinical and laboratory phenotypes with severe sepsis. Recent studies led to better recognition of hemophagocytic lymphohistiocytosis by clinicians, but no consensus exists on the criteria for high-risk patients. Design: We retrospectively reviewed the medical records of patients diagnosed with hemophagocytic lymphohistiocytosis to analyze the risk factors associated with poor outcome. Setting: Pediatric intensive care and hematology units of three tertiary hospitals in Turkey. Participants: Fifty-two children with hemophagocytic lymphohistiocytosis. Interventions: None. Measurement and Main Results: There were a total of 52 children meeting the diagnostic criteria of Histiocytic Society. Of them, 28 (54%) had a primary hemophagocytic lymphohistiocytosis. Mutation studies were performed in 18 of 28 patients (65%). Fourteen of them had PRF1, STX11, STXBP2, and UNC13D mutations, and four had Rab27a and LYST mutations. The remaining 24 patients (46%) were defined as having secondary hemophagocytic lymphohistiocytosis. Twenty-one of them had infection-associated hemophagocytic lymphohistiocytosis, and three had lysinuric protein intolerance. The mortality rate was significantly higher in primary hemophagocytic lymphohistiocytosis (64%) than in secondary hemophagocytic lymphohistiocytosis (16%) (p < 0.05). There were no significant differences for survival rate between hemophagocytic lymphohistiocytosis 94 (44%) and hemophagocytic lymphohistiocytosis 2004 (64%) protocols (p > 0.05). Age below 2 years, hyperferritinemia, thrombocytopenia, high disseminated intravascular coagulation score at diagnosis, and no clinical response at 2 weeks of treatment were independent prognostic factors for poor prognosis. Conclusions: Our data suggest that disseminated intravascular coagulation score greater than or equal to 5 can be used in the definition of high-risk patients. Early recognition of poor risk factors has important prognostic and therapeutic implications.