Application of flow cytometry in pediatric hematology-oncology

Applications of flow cytometry in pediatric cancers have expanded substantially in recent years. In acute leukemias, the commonest childhood cancer, flow cytometry can now define complex antigenic profiles that are associated with specific cytogenetic/molecular defects and can also directly identify BCR-ABL fusion protein. Flow cytometry based scoring system has been described for diagnosis of myelodysplastic syndromes. In solid tumors, flow cytometry was previously used mainly to determine DNA content for prognosis; however, recent studies in children with neuroblastoma and Ewing sarcoma have identified its diagnostic utility. In this review, we will discuss the current and future applications of flow cytometry in pediatric hematology-oncology.     

流式细胞仪测定血液病骨髓细胞DNA的临床意义

目的 探讨小儿常见血液病骨髓细胞的异倍体,细胞周期分布及其临床意义。方法 应用流式细胞仪测定４５例血液病患儿骨髓单个核细胞的ＤＮＡ的含量,计算细胞周期各时相比例。结果 白血病组异倍体检出率明显高于非白血病组的异倍体检出率。１２例非白血病中４例为异倍体,其中２例癌变。白血病组骨髓细胞Ｓ％明显低于对照组。３例接受治疗的急性淋巴细胞性白血病。患儿达到完全缓解后,其Ｓ％明显高于治疗前,非白血病组的骨髓细胞     

Analysis of basophil activation by flow cytometry in pediatric house dust mite allergy

Detection of allergen‐induced basophil activation by flow cytometry has been shown to be a useful tool for allergy diagnosis. The aim of this study was to assess the potential of this technique for the diagnosis of pediatric house dust mite allergy. Quantification of total and specific IgE and basophil activation test were performed to evaluate mite allergic (n = 24), atopic (n = 23), and non‐allergic children (n = 9). Allergen‐induced basophil activation was detected as a CD63‐upregulation. Receiver operating characteristics (ROC) curve analysis was performed to calculate the optimal cut‐off value of activated basophils discriminating mite allergic and non‐allergic children. ROC curve analysis yielded a threshold value of 18% activated basophils when mite‐sensitized and atopic children were studied [area under the curve (AUC) = 0.99, 95% confidence interval (CI) = 0.97–1.01, p < 0.001] with a sensitivity and specificity of 96% for 16 μg/ml mite extract. Analysis of the data obtained with 1.6 μg/ml mite extract defined a cut‐off value of 8% activated basophils (AUC = 0.96, 95% CI = 0.91–1.01; p < 0.001) with a sensitivity of 82% and specificity of 100%. Comparison between mite allergic and non‐allergic children produced a cut‐off of 8% activated basophils (AUC = 1.0) with 16 μg/ml allergen extract and a sensitivity and specificity of 100%. The same threshold and specificity values were obtained with 1.6 μg/ml extract (AUC = 97%, 95% CI = 0.92–1.02; p < 0.001) but sensitivity decreased to 83%. Two atopic children showed negative skin prick and basophil activation tests and high specific IgE (>43 kU/l) values for Dermatophagoides pteronyssinus allergen. They also showed positive prick (wheal diameter >1.0 cm) and basophil activation (>87%) tests and high specific IgE (>100 kU/l) with shrimp allergen. Shrimp sensitization was demonstrated by high levels of Pen a 1‐specific IgE (>100 kU/l). Cross‐reactivity between mite and shrimp was confirmed by fluorescence enzyme immunoassay (FEIA‐CAP) inhibition study in these two cases. This study demonstrated that the analysis of allergen‐induced CD63 upregulation by flow cytometry is a reliable tool for diagnosis of mite allergy in pediatric patients, with sensitivity similar to routine diagnostic tests and a higher specificity. Furthermore, this method can provide additional information in case of disagreement between in vivo and in vitro test results.     

Comparison of multidimensional flow cytometry with standard morphology for evaluation of early marrow response in pediatric acute lymphoblastic leukemia

PURPOSE: We compared multidimensional flow cytometry (MDF) with morphology in evaluating early marrow response to induction chemotherapy in pediatric ALL. METHODS: Chemotherapy response was determined by standard morphology or by MDF assessed by residual leukemic cell percentage remaining in the marrow on days 7, 14, and 28 of induction. Bone marrow response was classified as M3 (>25% leukemic blasts) or M1/M2 (< or = 25% leukemic blasts). Multidimensional flow cytometry evaluation was compared with that of standard morphology. Available day-7 and day-14 marrow slides were also reevaluated by a single pathologist without patients' clinical information. RESULTS: Of 46 day-7 specimens, eight (17%) had discordant MDF and morphologic results (P < 0.001), including six classified as M3 by morphology but were M1/M2 by MDF, and two were classified as M3 by MDF but were M1/M2 by morphology. Of 24 day-14 bone marrow specimens, five (20.5%) were discordant (P < 0.001), including two classified as M3 by morphology but were M1/M2 by MDF, and three were classified as M3 by MDF but were M1/M2 by morphology. Reevaluation of the blinded day-7 and day-14 marrow slides yielded discordance between repeated pathology readings of 11% (P < 0.001) and 6% (P = 0.04), respectively. CONCLUSION: Our data show significant discordance between the morphologic and MDF evaluation of early marrow response. Early response to therapy is a significant prognostic indicator in pediatric acute lymphoblastic leukemia and is used to alter subsequent treatment; thus, precise assessment of response is important. A larger comparison of MDF with morphology for the evaluation of early response, including correlation with clinical outcome, is warranted.     

六色流式细胞术用于儿童急性B系淋巴细胞白血病相关免疫表型的检测

目的比较六色流式细胞术与三色流式细胞术在急性B系淋巴细胞白血病(B-ALL)中检测出白血病相关免疫表型(LAIP)的差异。方法利用两组六色抗体组合CD20/CD34/CD10/CD22/CD45/CD19、CD7/CD5/CD13/CD33/CD45/CD19对25例三色流式免疫分型诊断为B-ALL的初诊患儿骨髓标本进行检测,通过FSC/SSC、CD45/SSC、CD19/SSC设门,在多个双参数二维点图上对幼稚细胞群、CD19+细胞群进行分析。结果三色流式免疫分型使用23种抗体共检测出CD19strong、CD10strong、CD34strong、CD22strong、CD19+/CD45-/dim+、CD19+/CD34+/CD38-、CD19+/CD13+、CD19+/CD15+、CD19+/CD33+9种LAIP。25例患儿中23例检测出LAIP,其中1个LAIP 4例,2个LAIP 8例,3个LAIP 5例,4个LAIP 3例,5个LAIP 3例。六色流式细胞术使用10种抗体共检测出CD10strong、CD34strong、CD22strong、CD45-/dim+、CD19+/CD13+、CD19+/CD33+、CD19+/CD34+/CD20+、CD19+/CD34+/CD22++、19+/CD34+/CD10dim+、19+/CD45-/dim+/CD34-/dim+、19+/CD10-/CD20-/CD34-11种LAIP。25例中23例检测出LAIP,其中1个LAIP 4例,2个LAIP 5例,3个LAIP 3例,4个LAIP 6例,5个LAIP 5例。结论儿童B-ALL患者具有LAIP者比例较高,适用于运用流式细胞术对B-ALL患儿进行化疗骨髓缓解(CR)后微小残留病(MRD)检测。六色流式细胞术使用的抗体总数较少,但通过FSC/SSC、SSC/CD45、SSC/CD19设门,对幼稚细胞群、CD19+细胞群在多个双参数点图上进行分析,能发现比三色流式细胞术更多的LAIP,并且六色流式细胞术可在同一试管中同时检测6种抗原,能根据患儿初诊时免疫分型结果进行灵活调整,更有利于进行CR后MRD的检测。     

DNA content and proliferative activity in pediatric genitourinary rhabdomyosarcoma

Most of the studies have reported that cases of pediatric rhabdomyosarcoma (RMS) with hyperdiploid DNA and low cellular proliferative activity have better outcomes. The aim of our study was to evaluate the possible clinical relevance of DNA ploidy and proliferative activity in childhood genitourinary RMS. Twelve childhood genitourinary RMS cases were reexamined histologically and correlated with clinical features and patient survival. DNA analysis was performed on cytospin single-cell preparations obtained from the paraffin-embedded tissue blocks. MIB-1 was the proliferative marker used on paraffin sections. All patients were male with a mean age at diagnosis of 65 months. There were 5 tumors on the bladder, 5 on the pàratesticular region, and 2 on the prostate. All cases were treated with multimodality therapy using the protocols proposed by the International Society of Pediatric Oncology. The following subtypes of RMS were recognized: embryonal (n=6), spindle cell (n=4), and botryoid (n=2). DNA hyperdiploid was detected in 11 tumors (92%) and high MIB-1 index (>19%) in 4 cases (33%). Now, 10 patients are alive without evidence of disease and 2 patients are alive with evidence of disease. Our data suggested that childhood RMS of the genitourinary tract are preponderantly DNA hyperdiploid and have low cellular proliferative activity. It is also interesting that 83% of our genitourinary pediatric RMS patients are alive. As consequence of this study, we propose that DNA content and proliferative activity is a useful method to supplement findings in children with RMS.     

儿童肾上腺肿瘤104例临床分析

目的分析儿童肾上腺肿瘤的临床特征,提高对儿童肾上腺肿瘤诊断和处理的认识。方法回顾分析1991—2002年12年间中山大学附属第一医院收治的104例儿童肾上腺肿瘤的临床特点、诊断和病理的关系。结果发病年龄0～14岁,男63例,女41例。神经母细胞瘤75例;肾上腺皮质肿瘤22例,其中癌及腺瘤各11例;嗜铬细胞瘤2例;其他5例。神经母细胞瘤患儿以发热、腹痛、腹部包块为主要表现,尿香草杏仁酸(VMA)可不升高;肾上腺皮质肿瘤患儿中外周性性早熟的临床及内分泌激素改变多于库欣综合征表现。血乳酸脱氢酶(LDH)水平对鉴别良/恶性肿瘤有提示意义。结论儿童肾上腺肿瘤以神经母细胞瘤及肾上腺皮质肿瘤最为常见,临床表现异于成人,应结合临床及影像学特征综合诊断。     

Endosurgical procedures for pediatric solid tumors

The aim of this study was to evaluate the advantages and complications of endosurgical procedures for benign and malignant pediatric solid tumors. Endosurgical techniques of biopsy and excision were used for diagnosis and treatment of solid tumors, respectively. Since July 1997, a total of 24 biopsies and 24 excisions have been performed laparoscopically for neuroblastoma (n=24), ovarian solid tumors (n=10) and other tumors. Seventeen biopsies and six excisions were performed for abdominal neuroblastoma, while ten excisions were performed for ovarian tumor. In these patients, the length of the operation, blood loss, time to start postoperative feeding, time to start postoperative chemotherapy and length of hospital stay were evaluated and compared to the those of the open surgery group. Furthermore, intra- and postoperative complications were analyzed in all patients of both groups. The length of the hospital stay and time to start postoperative feeding were significantly shorter in the group of patients who underwent endosurgical procedures for either abdominal neuroblastoma or ovarian tumor when compared to the open procedure group. The time to start postoperative chemotherapy was shorter only in the abdominal neuroblastoma group. The procedure for two patients undergoing endosurgical tumor excision had to be converted to open surgery due to large tumor size. Two weeks after thoracoscopic excision of a dumb bell-type neurofibroma, one patient underwent open repair of the dura mater because of leakage of cerebrospinal fluid. There were no port-site recurrences in any tumor types. Endosurgical procedures for solid tumors are effective and minimally invasive. However, better indicators are needed for their implementation in order to prevent complications and subsequent conversions to open procedures.     

Pulmonary metastasectomy for pediatric solid tumors

Most pediatric thoracic malignancy is pulmonary disease secondary to solid tumors of childhood. The management of isolated pulmonary metastases in adulthood is well documented. Little has been published to document the long-term outcome of pulmonary metastasectomy in childhood. A retrospective study was undertaken to assess the results of surgery for isolated pulmonary metastases. Twenty children underwent surgery over 12 years (mean follow-up 8 years). Five had Wilms tumor (mean age 51 months), eight had osteogenic sarcoma (mean age 141 months), three had rhabdomyosarcoma (mean age 92 months), two had hepatoblastoma (mean age 30 months) and two had teratoma (mean age 72 months). Four had bilateral synchronous metastases and thoracotomies, and one had bilateral metachronous metastases and thoracotomies. Nineteen children were discharged well within 10 days of surgery. There was one early complication: a death due to pneumonia. Four children subsequently died postoperatively with cranial metastases (mean 29 months postoperatively). The remaining 16 children remain alive and well. As part of the combined therapy, these results would support an aggressive surgical approach to this disease. Preoperative assessment should include contrast enhanced computed tomogram of the head and chest as well as chest X-ray taken immediately preoperatively to exclude metastases. Bilateral synchronous and metachronous thoracotomy is well tolerated in childhood.     

Innovative therapies for pediatric brain tumors

Success in the treatment of pediatric brain tumors has lagged behind that of other pediatric cancers. This paper highlights many of the advances that have taken place over the past few years in the surgical, radiotherapeutic, and chemotherapeutic approaches to central nervous system lesions that we hope will lead to a dramatic improvement in outcome. Innovations in neurosurgical and radiotherapeutic techniques have resulted in decreasing toxicity although substantial improvement in cure rates has not been observed. Many new techniques such as gene therapy, angiogenesis inhibitors, immunotherapy, and others that have not been part of the classic approach to these lesions are now in clinical trials in the hope that they will impact on the survival of these patients. The scientific basis for these new treatment modalities and preliminary clinical results are discussed.     

In vitro determination of the apoptotic effect of heparin on lymphoblasts using DNA analysis and measurements of Fas and Bcl-2 proteins by flow cytometry

Heparin has an apoptotic effect beside its anticoagulant, anti-inflammatory, antihypertensive, and antiproliferative effects. In this study, the authors detected the percentages of apoptotic lymphoblasts and the expressions of apoptotic Fas protein and antiapoptotic Bcl-2 protein with flow cytometry in vitro after the incubation of lymphoblasts with heparin. Eleven newly diagnosed acute lymphoblastic leukemia (ALL) children were included in the study. Lymphoblasts were incubated in all different levels of heparin concentrations (0, 10, and 20 U/mL) and the percentages of apoptotic lymphoblasts and the percentages of Fas protein and Bcl-2 proteins were simultaneously measured by flow cytometry at 0, 1, and 2 h. At 0, 1, and 2 h, apoptosis was determined when heparin was added in 10- and 20-U/mL concentrations (p <.05). The apoptotic effect of heparin on lymphoblasts was higher at the first hour than at 0 and 2 h in 10- and 20-U/mL heparin concentrations (p <.01). The highest apoptosis was detected in the 20-U/mL heparin concentration at the first hour. The expression levels of Fas protein on lymphoblasts were higher at the first hour than at 0 and 2 h in 10- and 20-U/mL heparin concentrations (p <.001). The highest expression of Fas protein was observed in the 20-U/mL heparin concentration at the first hour. The expression levels of Bcl-2 protein on lymphoblasts were lower at the first hour than at 0 and 2 h in 10- and 20-U/mL heparin concentrations (p <.001). The lowest expression of Bcl-2 protein was detected in the 20-U/mL heparin concentration at the first hour. Increased concentrations of heparin had an increasing effect on the percentages of apoptotic lymphoblasts. The expression percentages of Fas protein on lymphoblasts also increased, whereas the expression percentages of Bcl-2 protein on lymphoblasts decreased (p <.05). These results suggest that low-dose heparin may cause significant apoptosis of lymphoblasts in newly diagnosed ALL patients.     

Comparison of methods for teaching developmental milestones to pediatric residents

Background  

Interactive media are effective tools in teaching and allow for self-directed study, which develops skills for life-long learning among health professionals. With this type of study, the learner can review material at his/her own pace and target areas that require emphasis. Pediatric residents require an accurate understanding of developmental milestones in children of various ages and their normal variations. The best representation of developmental milestones requires video recordings of children demonstrating appropriate skills. However, such recordings are not always available, so printed materials are most often used. In this realm, a computer-based interactive learning tool using animated cartoons gives flexibility for presentation using drawings. We compared pediatric residents’ knowledge of developmental milestones in neonates to 5-year-olds before and after study with either an interactive DVD or paper-based materials.     

Limb sparing surgery for pediatric musculoskeletal tumors

There has been an unprecedented improvement in the survival outcome of children with extremity sarcoma as well as a corresponding increase in percentage of limb-sparing surgeries being performed over the past many decades. This has been, in part, due to the improved imaging modalities, newer surgical techniques, and advences in neoadjuvant chemotherapy. Limb-sparing surgery for primary bone and soft-tissue malignancies in children is becoming an acceptable option of surgical treatment in most cases today. This article outlines the demographics, classification, clinical presentation, imaging, and molecular genetics of pediatric mosculoskeletal tumors and discusses the current treatment principles with emphasis on the state-of-the-art surgical management and limb-sparing techniques for children with extremity sarcoma.     

多色流式细胞术在222例儿童急性白血病免疫分型中的应用

目的　探讨多色流式细胞术在儿童急性白血病 (AL)免疫分型中的应用价值 ,了解儿童AL抗原表达规律和免疫亚型的分布情况。方法　采用CD45/侧散射 (SSC)双参数散点图设门方法进行三色或四色流式细胞术细胞表面及浆内分化抗原的分析。结果　 2 2 2例儿童白血病免疫分型可分为 4类 :未分化型占 0 9% ,急性髓细胞性白血病 (AML)占 35 1% ,急性淋巴细胞白血病 (ALL)占5 5 9% ,混合型急性白血病占 8 1%。 12 4例儿童ALL中 ,B淋巴细胞白血病 (B ALL)占 75 8% ,T淋巴细胞白血病 (T ALL)占 2 4 2 %。AML伴淋巴系抗原表达为 2 4 4 % ,主要表达CD7(12 8% ) ,其次为CD19(6 4 % )和CD2 (5 1% )。B ALL及T ALL伴髓系抗原表达分别为 36 2 %及 30 0 % ,主要表达CD13(18 5 % ) ,其次为CD15(11 3% )、CD11b(6 5 % )和CD3 3 (4 3% )。CD117和CD56主要在AML中表达 ,分别为 73 3%和 38 6 % ,而在ALL中表达率极低 ,仅为 2 0 % (P <0 0 1)。胞浆内抗原CD2 2 、CD3 及髓过氧化物酶 (MPO)分别特异地表达在B ALL、T ALL及AML ,并比胞膜抗原检测更为敏感。结论　应用多色流式细胞术几乎能对所有儿童急性白血病进行准确分型 ,对儿童白血病患者的治疗方案选择及预后判断等均有重要价值。