HGG-27. ANTI-CANCER POTENTIAL OF ARGINASE FOR HIGH-GRADE GLIOMA IN VITRO & IN-VIVO

BACKGROUND

High-grade glioma is currently incurable. It was reported that glioma may be auxotrophic to arginine due to the lack of urea cycle genes expressions, suggesting arginase may be a potential agent for high grade glioma. AIM: We investigated the efficacy of pegylated arginase I (pegArg-I) or in combination with other anti-cancer drugs for high-grade glioma in vitro and in vivo.

METHODS

4 high-grade glioma cell lines (U87, U373, U138, D54) were treated with pegArg-I in vitro. The molecular mechanism of pegArg-I-induced cytotoxicity was tested in U87. The ultra-morphological changes of pegArg-I-treated U87 was investigated by both scanning and transmission electron microscopy. Orthotopic glioma xenograft model with luciferase-transfected U87 cell line was tested for anti-cancer efficacy of peg-Arg I in vivo.

RESULTS

We showed that pegArg-I induced significant cell death in all 4 cell lines in vitro. Temozolomide, difluoromethyornithine and chloroquine (CQ) were then tested together with pegArg-I in U87 in vitro. We found that only CQ showed additive effect with pegArg-I against glioma in vitro. Such additive cytotoxic effect may be associated with enhanced autophagy and necrosis as shown in transmission electron microscopy and autophagy markers’ expression by Western blotting. PegArg-I prolonged the survival of glioma mice, suggesting its possible anti-glioma efficacy. However, CQ+pegArg-I didn’t show further significant anti-cancer efficacy in vivo.

CONCLUSION

PegArg-I may be useful in slowing the progression of glioma, but additional drug candidate which works synergistically with pegArg-I remains to be explored.

Inhibitor development after liver transplantation in congenital factor VII deficiency

Congenital factor VII (FVII) deficiency is the commonest type of the rare bleeding disorders. Very few cases of congenital FVII deficiency developed inhibitor and liver transplant is considered as definitive treatment. In the literature, twelve patients with congenital FVII deficiency developed inhibitors. Two had spontaneous resolution of inhibitors and one did not respond to high dose recombinant factor VIIa (rFVIIa) and died. Regarding liver transplant in congenital FVII patients, seven patients underwent liver transplant with good prognosis. We report a 5-year-old girl with confirmed severe congenital FVII deficiency since neonatal period. She suffered from recurrent intracranial bleeding despite rFVIIa replacement. After auxiliary liver transplant at the age of 4, she continued to show persistent deranged clotting profile and was found to have inhibitor towards FVII. Interestingly, she was still responsive to rFVIIa replacement.

Remission With Donor Lymphocyte Infusion in a Child With Marrow Relapse After Haploidentical Stem Cell Transplantation for Relapsed Stage 4 Neuroblastoma

A 7-year-old male with Stage 4 neuroblastoma was treated with chemotherapy and autologous hematopoietic stem cell transplantation (HSCT), resulting in partial response with residual bone and marrow disease. He proceeded to haploidentical-HSCT with his mother as donor and achieved remission. The patient developed marrow relapse 2 years after haploidentical-HSCT with cytopenia and dropping donor chimerism. Donor lymphocyte infusion (DLI) using mother's whole blood was given resulting in clearance of marrow disease, resolution of cytopenia, and full donor chimerism. This is the first report of successful treatment for neuroblastoma relapse after haploidentical-HSCT using DLI alone, supporting the role of adoptive cell therapy post-HSCT in neuroblastoma.

MR quantitative susceptibility imaging for the evaluation of iron loading in the brains of patients with β-thalassemia major

BACKGROUND AND PURPOSE

Patients with β-thalassemia require blood transfusion to prolong their survival, which could cause iron overload in multiple organs, including the heart, liver, and brain. In this study, we aimed to quantify iron loading in the brains of patients with β-thalassemia major through the use of MR quantitative susceptibility imaging.

MATERIALS AND METHODS

Thirty-one patients with thalassemia with a mean (± standard deviation) age of 25.3 (±5.9) years and 33 age-matched healthy volunteers were recruited and underwent MR imaging at 3T. Quantitative susceptibility images were reconstructed from a 3D gradient-echo sequence. Susceptibility values were measured in the caudate nucleus, putamen, globus pallidus, red nucleus, substantia nigra, dentate nucleus, and choroid plexus. General linear model analyses were performed to compare susceptibility values of different ROIs between the patients with thalassemia and healthy volunteers.

RESULTS

Of the 31 patients, 27 (87.1%) had abnormal iron deposition in one of the ROIs examined. Significant positive age effect on susceptibility value was found in the putamen, dentate nucleus, substantia nigra, and red nucleus (P = .002, P = .017, P = .044, and P = .014, respectively) in the control subjects. Compared with healthy control subjects, patients with thalassemia showed significantly lower susceptibility value in the globus pallidus (P < .001) and substantia nigra (P = .003) and significantly higher susceptibility value in the red nucleus (P = .021) and choroid plexus (P < .001).

CONCLUSIONS

A wide range of abnormal susceptibility values, indicating iron overloading or low iron content, was found in patients with thalassemia. MR susceptibility imaging is a sensitive method for quantifying iron concentration in the brain and can be used as a potentially valuable tool for brain iron assessment.

Defective phenotype of mesenchymal stem cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) has been considered as stem cell disorder. The objective of this study was to examine the phenotype, growth and immunomodulatory effect of mesenchymal stem cells (MSCs) from SLE patients compared with those from age- and sex-matched healthy donors. MSCs were expanded from bone marrow aspirate and were examined for morphological appearance, quantified in different passages to determine growth rate and evaluated for ability of adipogenesis and osteogenesis. Telomerase activity was measured by telomerase repeat amplification protocol. The immunomodulatory effect of MSCs was evaluated by mixed lymphocyte reaction. MSCs from SLE patients were found to be bigger and flattened in appearance after passage 3 and demonstrated slower growth rate compared with fibroblast-like MSCs from normal controls. These cells were not able to reach confluence after passage 4. Telomerase activity was upregulated in five SLE patients mostly with active disease compared with two with negative expression with lesser activity. MSCs from SLE patients were, otherwise, comparable to normal controls in terms of their surface marker (CD73, CD90 and CD105) expression and extent of suppression on proliferation of allogeneic T lymphocytes. In conclusion, MSCs from SLE demonstrated early signs of senescence which may be a corollary of active lupus or a contributory factor to disease pathogenesis.

Congenital Rosai-Dorfman disease presenting with anemia, thrombocytopenia, and hepatomegaly

Rosai-Dorfman disease (RDD) is a rare entity of non-Langerhans cell histiocytoses (non-LCH) which usually presents with bilateral painless cervical lymphadenopathy. We describe a neonate with RDD who presented with anemia, thrombocytopenia and hepatomegaly. He recovered spontaneously with conservative management. This represents an atypical presentation of RDD. Conservative management with close monitoring can be adopted for some with systemic involvement.

Quality of life in patients with transfusion-dependent thalassemia after hematopoietic SCT

In this cross-sectional study, we compared the quality of life (QOL) in transfusion-dependent thalassemic patients who survived matched sibling hematopoietic SCT (HSCT, n=24) with patients treated conventionally with transfusion and iron chelation (n=74). WHOQOL-BREF(HK) and PedsQL questionnaires were administered to patients aged >18 years and 5-12 years, respectively. Patients aged 12-18 years received both questionnaires. WHOQOL-BREF(HK) revealed post transplant patients rated overall health better than those treated conventionally (score 3.67 vs 3.06, P=0.01). They are less dependent on medical aids (3.87 vs 2.96, P=0.006), having higher activity level (4.00 vs 3.36, P=0.026) and better personal relationships (4.13 vs 3.69, P=0.014). Physical health domain score was better (75.20 vs 63.94, P=0.007). These differences remained significant after adjustment for comorbidities. PedsQL revealed post transplant patients rated better for running (3.53 vs 2.72, P=0.001) and sports (3.20 vs 2.64, P=0.038), even after adjustment for comorbidities, but were less satisfied for school absence to attend hospital (2.53 vs 3.29, P=0.03). Post transplant patients were significantly more likely to consider marriage (100 vs 75.7%, P=0.033), but not childbearing (66.7 vs 51.4%, P=0.28). In conclusion, transplanted thalassemic patients enjoy better QOL, mainly in physical health, compared with conventionally treated patients. This information is important to patients considering HSCT.

Self-assembled collagen–human mesenchymal stem cell microspheres for regenerative medicine

Mesenchymal stem cells (MSCs)-based therapy is a promising approach in regenerative medicine and tissue engineering. However, the outcomes of existing treatments have not been satisfactory owing to suboptimal localization to implantation site, poor viability, low engraftment efficacy and lack of functional remodeling of the delivered cells. Therefore, adopting an effective cell delivery modality is among the biggest technological challenges for successful clinical applications of MSC-based therapy. We developed a novel microencapsulation technique producing self-assembled collagen-MSC microspheres and demonstrated that these microspheres could serve as excellent cell delivery devices as they were stable, injectable and able to provide a protective, growth- and migration-supporting matrix to MSCs. We also showed that MSCs could preserve their stem cell nature upon microencapsulation and easily be localized with retained viability upon in vivo implantation. These microspheres present novel cell delivery devices with optimal biological and functional profile that may facilitate clinical applications of MSC-based therapy.

Complete recovery from acute encephalopathy of late-onset ornithine transcarbamylase deficiency in a 3-year-old boy

Ornithine transcarbamylase deficiency is the commonest urea cycle disorder which is transmitted in X-linked inheritance. It is mainly characterized in males by acute encephalopathy and hyperammonaemia with fatal outcomes in both classical neonatal and late-onset types. We report a 3-year-old healthy Hong Kong Chinese boy who presented with acute encephalopathy and coma after three days of gastroenteritis. He had no focal neurological deficit and brain CT imaging was normal. His plasma ammonia (54 micromol/L) and glutamine (747 micromol/L) concentrations were normal. The only biochemical abnormalities detected were marked orotic aciduria (700 micromol/mmol creatinine) and elevated urinary uracil. He regained consciousness spontaneously after three days under intensive care with parenteral fluid therapy. He recovered completely without any neurological deficits. Five months after discharge, urinary uracil concentration remained elevated despite normalized orotic acid concentration. Finally, ornithine transcarbamylase deficiency was diagnosed by DNA analysis. A missense mutation of arginine-to-glutamine substitution on amino acid 277 (p.R277Q) was revealed to be a late-onset mutant. Our case strengthens the argument that in any child with coma or acute encephalopathy of undetermined cause, genetic analysis of the OTC gene and the measurement of urinary uracil concentration remain the most reliable indicators of late-onset OTCD during acute and even quiescent phases. Existing neonatal screening programmes for inheritable metabolic disorders fail to detect late-onset variants. Therefore, a high clinical suspicion is a key to correct and timely diagnosis, especially in those patients with atypical presentations.

Risk factors and mortality predictors of hepatic veno-occlusive disease after pediatric hematopoietic stem cell transplantation

A cohort of 138 children with 144 hematopoietic stem cell transplantation (HSCT) performed in 1997-2006 were analyzed to evaluate risk factors and mortality predictors of hepatic veno-occlusive disease (VOD). Nineteen patients (13.2%) developed VOD (nine boys, median age 3.5 years) at 1-21 days after HSCT (median 13 days). Age < or =2 years at transplant (odds ratio (OR)=5.25, P=0.011), BU-CY conditioning (OR=5.16, P=0.001), thalassemia major (OR=3.97, P=0.015), platelet engraftment beyond day +21 (OR=8.67, P=0.025) were univariate risk factors for VOD. The first two remained significant in multivariate regression. Seven patients (36.8%) with VOD died, at a median of 44 days post transplant (range, 30-421 days). The 5-year survival was 62%. All surviving patients had normal liver function on follow-up at 0.5-9 years. Patients with VOD had higher 100-day mortality (16.3 vs 9.6%, P=0.024). Mortality predictors included donors other than autologous or matched sibling (hazard ratio (HR)=23.6, P=0.006), hepatic and cutaneous GVHD (HR=8.15, P=0.038), maximal weight gain >9% (HR=6.81, P=0.023), pleural effusion, intensive care unit admission, peak bilirubin >300 micromol l(-1) (HR=13.6, P=0.016), day +21 bilirubin >200 micromol l(-1) (HR=33.9, P=0.001), and rise of bilirubin >15 micromol l(-1) per day within the first week (HR=19.8, P=0.006). Mortality was substantially higher if >3 predictors were present (HR=33.9, P=0.001). Meticulous monitoring in high-risk patients and early treatment should be considered before VOD progresses beyond salvage.

Improved outcome of acute lymphoblastic leukaemia treated by delayed intensification in Hong Kong children: HKALL97 study

OBJECTIVE

To study the outcome of children with acute lymphoblastic leukaemia who were treated using a protocol including one or two delayed intensifications.

DESIGN

Prospective single-arm multicentre study.

SETTING

Five designated children cancer units of the Hospital Authority of Hong Kong.

PATIENTS

Children aged between 1 and 17.9 years with newly diagnosed acute lymphoblastic leukaemia seen from November 1997 to December 2002.

INTERVENTION

Chemotherapy was modified from a German Berlin-Frankfurt-Muenster 95 (BFM95) protocol that included a delayed intensification similar to the induction phase repeated 5 months after diagnosis. High-risk patients were given double delayed intensification.

MAIN OUTCOME MEASURES

Overall survival and event-free survival of the whole group and the three risk groups (standard-, intermediate-, and high-risk groups), and comparison with historical controls.

RESULTS

A total of 171 patients were recruited with a median age at diagnosis of 5.57 years (range, 1.15-17.85 years). The induction remission rate was 95.3% and non-leukaemia mortality during remission was 2.3%. At 4 years, the relapse rate of this (HKALL97) study was significantly lower than that of the HKALL93 study (15.7 vs 37.3%; P<0.001). The 4-year overall survival of HKALL97 and HKALL93 studies were 86.5% and 81.8%, respectively (P=0.51). The 4-year event-free survival for HKALL97 and HKALL93 studies were 79% and 65%, respectively (P=0.007). Nonetheless the difference of event-free survival was most remarkable in the intermediate-risk group: 75.6% and 53.1% for HKALL97 and HKALL93 studies, respectively (P=0.06).

CONCLUSION

A more intensive delayed consolidation phase improved the outcome for children with acute lymphoblastic leukaemia by reducing relapses at 4 years. The early treatment complications were manageable and non-leukaemia mortality during remission remained low.

Hyperbilirubinemia and cholelithiasis in Chinese patients with hemoglobin H disease

Hemoglobin H disease (HbH) is a hemoglobinopathy peculiar to parts of the world with high incidence alpha-thalassemia mutations. Among 90 HbH cases, 50 cases suffered from clinically significant jaundice (bilirubin >30 mmol/l), including 14 with severe jaundice (bilirubin >60 mmol/l). Cholelithiasis was found in 38 cases. The incidence is roughly eight times higher than that in background control population but 50% lower than that in beta-thalassemia. The risk of gallstones was related to higher bilirubin levels but not alpha-globin genotype, sex, ferritin, and hemoglobin levels. Homozygotes or double heterozygotes for Gilbert alleles (17.2%), but not heterozgyotes (42.2%), were found to have a significantly increased risk of gallstones and jaundice. However, common Chinese Gilbert syndrome alleles do not completely explain the variable risks.

Ventriculo-vascular interactions in patients with beta thalassaemia major

OBJECTIVES

To determine potential interactions between the heart and arterial system in patients with beta thalassaemia major.

DESIGN AND PATIENTS

Vascular compliance, systemic vascular resistance, and left ventricular (LV) contractility was determined in 34 asymptomatic thalassaemia patients at 2-4 hours after blood transfusion and also in 34 age and sex matched controls using a non-invasive device. The results were compared between groups and inter-relationships between LV contractility and indices of vascular load were explored.

SETTING

Tertiary paediatric cardiac centre.

RESULTS

When compared with controls, patients had greater systemic vascular resistance (1633 (259) v 1377 (276) dynes/s/cm5, p < 0.001) and effective arterial elastance (E(a)) (1.86 (0.25) v 1.65 (0.29) mm Hg/ml, p = 0.001), an index of combined pulsatile and static vascular load. On the other hand, their systolic blood pressure (104 (9) v 112 (13) mm Hg, p = 0.006), pulse pressure (45 (9) v 57 (10) mm Hg, p < 0.001), adjusted systemic vascular compliance (1.21 (0.09) v 1.37 (0.14), p < 0.001), adjusted brachial artery distensibility (21 (0.29) v 7.95 (0.29)%/mm Hg, p < 0.001) and LV+dP/dt (1059 (183) v 1239 (237) mm Hg/s, p = 0.001) were significantly lower. Significant determinants of LV contractility, as reflected by LV+dP/dt, were age (standardised beta = -0.24, p = 0.003), body mass index (standardised beta = -0.34, p = 0.004), systolic blood pressure (standardised beta = 0.90, p < 0.001), and effective E(a) (standardised beta = -0.50, p < 0.001) (model R2 = 0.69). No significant correlation existed between serum ferritin concentration and any of the cardiac or vascular indices.

CONCLUSION

An unfavourable ventriculo-vascular interaction, as characterised by impaired cardiac contractility and increased static and pulsatile vascular load, occurs in patients with beta thalassaemia major.

Use of midazolam and ketamine as sedation for children undergoing minor operative procedures

OBJECTIVES

We used intravenous midazolam and ketamine for children undergoing minor operative procedures with satisfactory results. We aimed to further evaluate its efficacy and adverse effects in pediatric ward setting.

METHODS

This was a prospective study of all children undergoing minor operations with sedation in our pediatric general and oncology wards from July 1998 to June 1999. The procedures included lumber puncture+/-intrathecal chemotherapy, bone marrow aspiration+/-trephine biopsy, central venous catheter removal, skin biopsy, or their combination. All sedation procedures were started with midazolam 0.1 mg/kg and ketamine 1 mg/kg; they were increased gradually to 0.4 and 4 mg/kg, respectively, if necessary. Heart rate and SaO2 were continuously monitored.

RESULTS

Altogether, 369 minor operations were performed in 112 patients (male:female=2:1, median age 6 years, range 5 months-17 years). All achieved adequate sedation, with 96% within 30 s and 75% required just the starting dose. Younger children required a higher dosage (p=0.003 for midazolam, p<0.001 for ketamine). The median recovery time was 87 min, with no association with age, sex, or dosage of sedation, but was longer in patients having hallucination (p=0.001). Adverse effects included tachycardia (27.9%), increased secretion (17.6%), agitation (13.6%), nausea and vomiting (9.2%), hallucination (8.7%), desaturation (8.4%), and cataleptic reaction (0.8%). All desaturation episodes were transient and responded to oxygen supplement alone. None developed bronchospasm or convulsion. Some adverse effects were dose-related. Half of the children who received 0.3 mg/kg midazolam developed desaturation.

CONCLUSIONS

Intravenous midazolam-ketamine can provide rapid, effective, and safe sedation for children undergoing minor operations in ward setting. Adverse effects are mild. Midazolam above 0.3 mg/kg should be used with caution.

Chronic benign neutropenia among Chinese children

OBJECTIVE

To delineate the clinical behaviour of chronic benign neutropenia in Chinese children in Hong Kong.

DESIGN

Retrospective study.

SETTING

University teaching hospital, Hong Kong.

PATIENTS

All infants and children with absolute neutrophil count of 1.5 x 10(9) /L or lower for more than 3 months.

MAIN OUTCOME MEASURES

Development of significant infection, and achievement of remission.

RESULTS

Twenty-four children with chronic benign neutropenia were identified between 1992 and 2001. Their median age of diagnosis was 9 months. The mean (standard deviation) initial absolute neutrophil count was 0.28 x 10(9) /L (0.24 x 10(9) /L). Twenty-three patients presented with infection. Of the 19 patients tested, four (21%) were positive for anti-neutrophil antibodies. Bone marrow examination was performed in 17 patients: nine had normal results, but six showed evidence of peripheral consumption, one showed late maturation arrest at band stage, and one showed phagocytosis of myeloid cells by histiocytes. The overall hospitalised infection rate was 51.6 episodes per 1000 patient-months. Ten percent of cases were considered 'significant' infections and required hospital admission with either surgical intervention or intravenous therapy (antibiotics or fluid replacement). In the first year of diagnosis, more than 80% of patients had their lowest absolute neutrophil count (mean, 0.16 x 10(9) /L; standard deviation, 0.11 x 10(9) /L). Granulocyte-colony stimulating factor was used to treat three patients and induced transient elevation of absolute neutrophil count in all three. The projected remission rate was 55.4% at 3 years. Even for those with persistent disease, there was significant recovery in absolute neutrophil count to a mean of 0.5 x 10(9) /L (P<0.01).

CONCLUSIONS

Patients with chronic benign neutropenia experienced a relatively benign clinical course regardless of their remission status. Only a small proportion of patients developed significant infections. A multi-centre prospective study may help identify predictive factors of remission.

Comparison of subcutaneous infusion needles for transfusion-dependent thalassemia patients by the intrapersonal cross-over assessment model

Needle-induced trauma is one of the major contributing factors for poor compliance in patients with thalassaemia major on iron chelation therapy. A new generation of needles is currently available on the market, but their theoretical advantages have not been tested clinically. We performed a study to compare the pros and cons of the representative prototypes from each of the new (Thalaset needle) and old (butterfly scalp vein needle) generations of needles. Patients with thalassemia major who had been receiving subcutaneous iron chelation therapy for at least 2 years were recruited. Patients using butterfly needles were instructed to switch to the newer form of needle (Thalaset) for 2.5 months and then to change back to butterfly needles for another 2.5 months. Comparison was done by the intrapersonal cross-over model using three identical sets of questionnaires collected at the beginning of the study and after the use of Thalaset and butterfly needles, respectively. Fifty-four (22 females; 32 males) patients were included in the statistical analysis. The median age was 24.1 years (range = 7.6-47.2 years). Local reactions such as pain, itchiness, tenderness, and swelling were significantly different among the three evaluation periods and were all in favor of the Thalaset needle (all with P < 0.001), even after adjusting for the intention-to-treat calculation. The Thalaset needle is significantly better than the butterfly needle in reducing needle-related trauma. It induced fewer local skin reactions such as pain, itchiness, tenderness, and swelling. However, recommendations for its routine clinical use require further cost-effectiveness analysis.

Bone marrow transplantation for therapy-related acute myeloid leukemia in congenital retinoblastoma associated with 13q deletion syndrome

Children with constitutional deletion of the long arm of chromosome 13 are at risk for retinoblastoma (RB) due to loss of the RB tumor suppressor gene. The prognosis is poor since the tumors are often bilateral, aggressive, and recurrent and the patients often harbor other congenital abnormalities. One further complication is that of therapy-related malignancies later in life. We report a case of allogeneic stem cell transplantation for therapy-related acute myeloid leukemia in an 8-year-old girl after multimodality treatment for refractory bilateral relapsing RB, with excellent outcome in both the ophthalmic and marrow disease.

Magnetic resonance screening of iron status in transfusion-dependent β-thalassaemia patients

The clinical utility of dual sequence (T1- and T2-weighted) magnetic resonance (MR) imaging in estimating liver iron concentration (LIC) in 32 transfusion-dependent beta-thalassaemia major (24 females; age 18.5+/-5.9 years) patients on desferrioxamine was evaluated. Signal intensity ratios (SIR) between liver, spleen and pancreas to psoas muscle were determined on both sequences. Relationships between clinical and MR parameters, and accuracy of SIR thresholds in determining adequacy of chelation from LIC were analysed. Liver T1- and T2-SIR were related to LIC (P < 0.001). T1-SIR < 0.60 predicted severe iron overload (LIC > 15 mg/g) with sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of 100%, 87%, 33% and 100% respectively. T2-SIR < 0.1 yielded 100% sensitivity, 93% specificity, 50% PPV and 100% NPV. T1-SIR > or = 1.1 predicted LIC < 7 mg/g with 69% sensitivity, 88% specificity, 85% PPV and 74% NPV. T2-SIR > or = 0.20 yielded 56.5% sensitivity, 94% specificity, 90% PPV and 71% NPV. LIC correlated with liver T1-SIR, liver T2-SIR and serum ferritin (r = -0.76, -0.65, 0.47, respectively; P < 0.01). Serum ferritin was inversely related to liver T1-SIR, liver T2-SIR and spleen T2-SIR (r = -0.35, -0.43, -0.40, respectively; P < 0.05). Mean total transfusion burden was not related to any MR parameter. Although neither MR sequence was a highly accurate predictor of LIC, SIR thresholds are useful to determine presence of iron overload and adequacy of chelation treatment.

Treatment of acute lymphoblastic leukemia in Hong Kong children: HKALL 93 study

A population-based multicentre study for childhood acute lymphoblastic leukemia (ALL) was conducted in Hong Kong from 1993 to 1997. One hundred and forty-five newly diagnosed ALL patients were treated by the HKALL 93 protocol. Patients were stratified into three risk groups according to age, presenting white cell count, immunophenotyping and cytogenetic study. The patients received the same induction and early and late intensification at week 5 and week 20. Fifty-eight standard risk (SR) patients received regular intrathecal methotrexate as CNS preventive therapy, while 49 intermediate risk (IR) patients received high dose intravenous methotrexate and regular intrathecal methotrexate. Thirty-eight high risk (HR) patients were treated with prophylactic cranial irradiation and an additional intensification block at week 35. The induction remission rate was 97.2% with 2% induction death. Two patients died during first complete remission. Relapse occurred in 20.7, 42.9 and 42.1% of SR, IR and HR patients respectively. By multivariate logistic regression, age> or =10 years and white cell count> or =100 x 10(9)/l were the two significant variables accounting for mortality. The 5-year overall and event-free survival of the whole group was 81.3 and 62.6% respectively. According to risk groups, the event-free survival was 79, 49 and 61% for SR, IR and HR patients respectively, while the overall survival was 96, 73 and 68% for SR, IR and HR patients respectively. In conclusion, the treatment protocol had low treatment-related mortality but was associated with a rather high relapse rate, especially in IR patients. Salvage therapy achieved sustained second remission in some patients. More intensive treatment especially a late intensification is required to improve the outcome.

Klebsiella infection in patients with thalassemia

Klebsiella infection has previously been reported in a few patients with transfusion-dependent thalassemia. The incidence and clinical spectrum of this infection in our cohort of patients were reviewed retrospectively. Among 160 patients observed for 12 years, there were 15 episodes of Klebsiella infection that occurred in 12 patients (7.5%), resulting in an incidence of 0.78 infections per 100 patient-years. The clinical spectrum included sinusitis (4 cases), intracranial infection (5 cases), septicemia (4 cases), and abscesses of the liver, lung, kidney, and parotid gland (1 case each). Three patients had recurrent infections involving different sites, 2 (16%) died of fulminant septicemia, and 3 (25%) had significant permanent neurological deficits. The antibiotic susceptibility pattern for the isolates was similar to the pattern for isolates recovered in the community. With regard to predisposing factors, iron overload and liver function derangement were found to be significant on univariate analysis (P=.046 and P=.049, respectively) but insignificant on multivariate analysis. Klebsiella infection was a serious and frequently encountered complication in our patients with transfusion-dependent thalassemia, resulting in high mortality and morbidity rates.

Post-transplantation lymphoproliferative disease in Chinese: the Queen Mary Hospital experience in Hong Kong

Post-transplantation lymphoproliferative disease (PTLD) is an unique iatrogenic complication after bone marrow transplantation (BMT) and solid organ transplantation (SOTx). The pattern of EBV related lymphoma in Chinese is different from Caucasians. We surveyed the incidence, clinical and pathological spectrum of PTLD among 541 cases of allogeneic BMT, 145 cases of renal transplant, 35 cases of heart/lung transplantation and 146 cases of orthotopic liver transplantation (OLT). From 1994 to 2001, 13 consecutive cases of PTLD were diagnosed, ranging from disseminated NK cell lymphoma to localized plasmacytoma. Both donor and recipient derived PTLD was documented. Disease was often heralded by cytomegaloviral disease and antithymocyte globulin (ATG) usage. Two cases were diagnosed post-mortem, and six patients died of PTLD at a median of 3 months. Complete and partial remission was only achieved in 3 and 2 cases, respectively, despite a range of treatment (reduced immunosuppression, explantation, radiotherapy, combination chemotherapy, donor lymphocytes, autologous marrow infusion and rituximab). Most responding patients died subsequently of rejection, infection and graft versus host disease (GVHD). The incidence of PTLD is not increased in Chinese patients. However, some patients may be at increased risk, especially mismatched allogeneic BMT, parental OLT (especially involving young infants) and heavy ATG exposure.

Imaging of peripheral PNET: common and uncommon locations

AIM

We present the imaging features of peripheral primitive neuroectodermal tumour (PNET) in eight children, highlighting the unusual locations of this tumour in three children.

MATERIALS AND METHODS

At presentation, the tumours were studied with magnetic resonance imaging (MRI; n = 6), computed tomography (CT; n = 7) and ultrasound (US; n = 1). The diagnoses were confirmed histologically (n = 8), immunohistochemically (n = 8), by cytogenetics (n = 3) and electron microscopy (n = 1). Correlation with gross pathology, histology, treatment and outcome were obtained.

RESULTS

The tumours were located in the chest wall (n = 2), shoulder, pelvis, small bowel mesentery, adrenal gland, dura mater and skin and subcutaneous tissue of the abdominal wall (n = 1 each). Peripheral PNET arising from the small bowel mesentery, adrenal gland and dura mater have not been previously reported in the English literature. The tumours were mainly large (mean size: 10.6 cm) and infiltrative. All tumours were heterogeneously hyperintense on T2-weighted MRI, heterogeneously iso/hypodense on CT and had variable contrast enhancement. Most tumours were heterogeneously hypointense to muscle on T1-weighted MRI. US showed a hypoechoic mass with a cystic component.

CONCLUSION

Peripheral PNET can occur in unusual locations. The clinical and imaging features of peripheral PNET are non-specific, making tissue diagnosis essential. PNET should be included in the differential diagnosis of aggressive soft tissue tumours in children.

Paediatric hepatoblastoma and hepatocellular carcinoma: retrospective study

OBJECTIVES

To compare and contrast clinical characteristics and outcomes of hepatoblastoma or hepatocellular carcinoma in paediatric patients.

DESIGN

Retrospective study.

SETTING

University teaching hospital, Hong Kong.

PATIENTS AND METHODS

Medical records of 22 paediatric patients with hepatoblastoma (n=11) or hepatocellular carcinoma (n=11) admitted to Queen Mary Hospital between 1989 and 2000 were reviewed. Data gathered included demographic data, results of liver function tests, hepatitis A, B, and C titres, and alpha-foetoprotein levels, and imaging studies including chest X-ray, ultrasound study, computed tomography scan, and magnetic resonance imaging/hepatic angiogram for tumour staging and resectability.

RESULTS

The mean age of patients with hepatoblastoma was 18 months (range, 5 months to 3 years), while that of patients with hepatocellular carcinoma was 10.2 years (range, 2 to 16 years). Females predominated in the hepatoblastoma group (female:male, 8:3) and males in the hepatocellular carcinoma group (male:female, 10:1). None of the patients with hepatoblastoma were hepatitis B surface antigen positive, in contrast to 64% of the hepatocellular carcinoma group. Only 45% of the hepatocellular carcinomas were resectable at presentation and this figure remained unchanged following chemotherapy. A total of 91% of hepatoblastomas were resectable, four at presentation, and a further six after chemotherapy. Tumour rupture was more common in patients with hepatoblastoma than in those with hepatocellular carcinoma (36% versus 9% of cases, respectively). Mortality rates were considerably higher among the hepatocellular carcinoma group than the hepatoblastoma group in this series.

CONCLUSION

Childhood hepatoblastoma and hepatocellular carcinoma differ with respect to age and tumour stage at presentation, hepatatis B surface antigen status, tendency to rupture, chemosensitivity, and prognosis.