Catharina Dhooge

Haematopoietic stem cell transplantation for sickle cell anaemia: the first 50 patients transplanted in Belgium

Fifty patients affected by sickle cell anaemia underwent transplantation of HLA-identical haematopoietic stem cells (bone marrow, 48; cord blood, 2). Two groups of patients were considered for transplantation. Group 1 included 36 permanent residents of a European country who, retrospectively, met the inclusion criteria accepted at a consensus conference held in Seattle in 1990, wherein children were selected because they already had evidence of a morbid course. Group 2 included 14 patients who were transplanted earlier, had not received more than three blood transfusions and were transplanted because they had decided to return to their country of origin. Kaplan–Meier estimates of overall survival, event-free survival and disease-free survival at 11 years of the whole grafted population are 93, 82 and 85%, respectively. In group 1, overall survival, EFS and DFS were 88, 76 and 80% and in group 2, 100, 93 and 93%, respectively. Clinical manifestations of the disease, as well as disease associated haemolytic anaemia, disappeared in all successfully treated patients. Recovery of spleen function was present in seven out of 10 evaluated patients. Adverse events (death, absence of engraftment, mixed chimerism and relapse) occurred more frequently in group 1 than in group 2 (25% vs 7%, P < 0.001). acute graft-versus-host disease (gvhd) was present in 20 patients (grade i or ii, 19; grade iii, 1), chronic gvhd in 10 (limited, 7; extensive, 3). one patient developed an acute myeloid leukaemia. gonadal dysfunction was present in all patients (six boys and eight girls) transplanted close to or after puberty, although transient in one adolescent girl.

Endoscopic treatment of suprasellar arachnoid cysts

SummaryFour cases of large suprasellar arachnoid cysts in children are described. The authors propose a large fenestration into the lateral ventricles and into the basal cisterns as the treatment of choice. A specific multipurpose cerebral endoscope has been designed by the first author. The endoscopic technique with different instruments and with the use of a laser is illustrated. Results and complications are discussed.

EURAMOS-1, an international randomised study for osteosarcoma: results from pre-randomisation treatment.

This manuscript describes the experience from registration until randomisation for a cohort of 2260 patients with osteosarcoma who joined the EURAMOS-1 trial. This includes pre-operative chemotherapy and surgery. It sets out the practical issues in collaboration and in achieving randomisation.

P-glycoprotein is an independent prognostic factor predicting relapse in childhood acute lymphoblastic leukaemia : results of a 6-year prospective study

P‐glycoprotein (P‐gp), a cellular drug‐efflux pump, is thought to be one of the major causes of multidrug resistance (MDR) in malignancies. Since therapeutic strategies are being developed to circumvent drug resistance by inhibiting P‐gp function, large prospective studies evaluating the clinical relevance of P‐gp in childhood acute lymphoblastic leukaemia (ALL) are warranted. P‐gp expression was evaluated over a period of 6 years in 102 consecutive patients with de novo childhood ALL and in 35 children with relapse of ALL. Bone marrow and blood smears were studied immunocytochemically with two monoclonal antibodies at initial diagnosis and at relapse. P‐gp expression was found in 14 (14%) patients at initial diagnosis. After induction treatment, complete remission was achieved in 100/102 patients (98%), of whom 19 relapsed. Cumulative event‐free survival was significantly higher in the P‐gp‐negative group compared with the P‐gp‐positive population (Logrank P = 0.02). Multivariate analysis showed the results to be independent of age, WBC count and karyotype, and concomitantly underlined the importance of MDR1 phenotype detection in childhood ALL. P‐gp expression was more frequently found at relapse (34%) than at primary diagnosis (P = 0.01). In the relapsed patient group, P‐gp‐positive patients had a 2‐fold greater risk for adverse clinical outcome than the P‐gp‐negative relapsed patients. P‐gp expression was not induced by exposure to previous chemotherapy since the majority of P‐gp‐negative patients remained negative at relapse. P‐glycoprotein expression in newly diagnosed childhood ALL is an independent adverse prognostic parameter with a predictive value for relapse.

Diagnosis, Management and Surgical Treatment of Non-Tuberculous Mycobacterial Head and Neck Infection in Children

The aim of this study was to present our experience with the clinical characteristics of non-tuberculous mycobacterial (NTM) head and neck lymph node infections, the use of modern diagnostic tools and the appropriate therapeutic measures. We have reviewed the cases of 14 Caucasian children with NTM head and neck lymphadenitis who were treated in our clinic in the last 5 years. Three of the patients were male and 11 were female. Their age ranged from 15 to 98 months (mean age 45.7 ± 21.76 months). Cervical lymph nodes were involved in all of our cases, while the submandibular region was found to be the area mostly affected. Overlying skin was involved in 7 cases. Diagnosis was based on intradermal skin testing with specific antigens for atypical mycobacteria, histological examination and specimen culture. Skin tests were positive for NTM in all of the patients with a predilection for Mycobacteriumavium complex. The diagnosis was confirmed by histological examination in 13 cases. Specimen culture was positive in 9 cases, most of them growing M. avium-intracellulare complex. Treatment included complete surgical excision of the affected lymph nodes and the overlying skin, as well as functional neck dissection when required. A second procedure was performed in 2 patients. Successful evaluation of NTM infections of the head and neck lymph nodes should include a detailed history, thorough physical examination and specific laboratory investigations. The treatment of choice is complete surgical excision of all affected tissue.

Distortion product otoacoustic emissions: An objective technique for the screening of hearing loss in children treated with platin derivatives

In order to develop a sensitive audiometric protocol for identifying ototoxicity in children, a retrospective study of 16 children treated with cisplatin and/or carboplatin was performed. Audiometric testing was done by means of pure-tone threshold audiometry (PTA), high-frequency audiometry (HFA), and distortion product otoacoustic emissions (DPOAEs). Cisplatin caused a sensorineural high-frequency hearing loss in the study group compared to the controls (p < 0.01). Sixty-six percent of the cisplatin patients had a grade 2 or 3 ototoxicity. However, ototoxicity was not found in the patients treated with carboplatin. An excellent correlation was found between DPOAE levels and results obtained by audiometry (r = 0.82). Patients exposed to cisplatin are at significant risk for the development of drug-induced sensorineural hearing loss. Because of the several advantages of DPOAEs (noninvasive, objective, rapid, easy to use, sensitive) this method should be added in the audiological follow-up in infants and toddlers.

Surveillance of cytomegalovirus (CMV) DNAemia in pediatric allogeneic stem cell transplantation: incidence and outcome of CMV infection and disease

Abstract: Cytomegalovirus (CMV) remains a serious problem after hematopoietic stem cell transplantation (HSCT). To investigate the incidence of CMV infection and outcome we retrospectively analyzed 70 consecutive pediatric allogeneic HSCTs monitored by CMV polymerase chain reaction (PCR), with at least 1‐year follow‐up or until death. All patients at risk for CMV infection (CMV‐seropositive patients and CMV‐seronegative recipients transplanted from CMV‐seropositive donors) received hyperimmune anti‐CMV globulins whereas in the group of HSCT patients with both donor and recipient CMV negativity, polyvalent immunoglobulins were given, both at a dose of 400 mg/kg. All patients received acyclovir at prophylactic doses for at least 6 months. Patients were monitored twice a week by CMV PCR. Patients with 2 positive results for CMV DNAemia received ganciclovir for 14 days and continued until 2 consecutive negative results were obtained. The incidence of CMV DNAemia was 12.8% (9/70) in the whole group, with significant higher risk for patients with CMV‐seropositive recipient status, 8 out of 22 (36%), vs. patients with seronegative status, 1 out of 48 (2%) (P=0.0002). Three out of 9 patients with DNAemia developed CMV disease despite adequate preemptive treatment. The transplant‐related mortality was higher in the CMV‐seropositive recipient group (P=0.05). Age, use of hyperimmune anti‐CMV globulins at a high dose, and the low incidence of graft‐versus‐host disease might be contributing factors to this low incidence.

Expression of the MDR1 gene product P‐glycoprotein in childhood neuroblastoma

In cancer treated with chemotherapy, multidrug resistance is characterized by increased genetic expression of P‐glycoprotein (P‐gp), which acts as an ATP‐dependent drug‐efflux pump. However, the clinical significance of the expression of the multidrug resistance gene (MDR1) product P‐gp in neuroblastoma (NB) is still a matter of debate. In this study, the role of the expression of P‐gp in NB was evaluated.

Prevalence of c-KIT Mutations in Gonadoblastoma and Dysgerminomas of Patients with Disorders of Sex Development (DSD) and Ovarian Dysgerminomas

Activating c-KIT mutations (exons 11 and 17) are found in 10–40% of testicular seminomas, the majority being missense point mutations (codon 816). Malignant ovarian dysgerminomas represent ∼3% of all ovarian cancers in Western countries, resembling testicular seminomas, regarding chromosomal aberrations and c-KIT mutations. DSD patients with specific Y-sequences have an increased risk for Type II Germ Cell Tumor/Cancer, with gonadoblastoma as precursor progressing to dysgerminoma. Here we present analysis of c-KIT exon 8, 9, 11, 13 and 17, and PDGFRA exon 12, 14 and 18 by conventional sequencing together with mutational analysis of c-KIT codon 816 by a sensitive and specific LightCycler melting curve analysis, confirmed by sequencing. The results are combined with data on TSPY and OCT3/4 expression in a series of 16 DSD patients presenting with gonadoblastoma and dysgerminoma and 15 patients presenting pure ovarian dysgerminomas without DSD. c-KIT codon 816 mutations were detected in five out of the total of 31 cases (all found in pure ovarian dysgerminomas). A synonymous SNP (rs 5578615) was detected in two patients, one DSD patient (with bilateral disease) and one patient with dysgerminoma. Next to these, three codon N822K mutations were detected in the group of 15 pure ovarian dysgerminomas. In total activating c-KIT mutations were found in 53% of ovarian dysgerminomas without DSD. In the group of 16 DSD cases a N505I and D820E mutation was found in a single tumor of a patient with gonadoblastoma and dysgerminoma. No PDGFRA mutations were found. Positive OCT3/4 staining was present in all gonadoblastomas and dysgerminomas investigated, TSPY expression was only seen in the gonadoblastoma/dysgerminoma lesions of the 16 DSD patients. This data supports the existence of two distinct but parallel pathways in the development of dysgerminoma, in which mutational status of c-KIT might parallel the presence of TSPY.

Detection of residual neuroblastoma cells in bone marrow: comparison of flow cytometry with immunocytochemistry.

Because the cytomorphologic examination of bone marrow (BM) aspirates appears not sensitive enough to detect residual neuroblastoma cells, two four‐color flow cytometric assays using different combinations of CD9, CD81, CD56, CD45, and anti‐GD2 were evaluated.