Pulmonary complications after bone marrow transplantation in children: twenty-four years of experience in a single pediatric center.

In children, pulmonary sequelae contribute to early and late morbidity after bone marrow transplantation (BMT). Between 1975-1999, we performed 152 BMTs in 138 pediatric patients with malignant and nonmalignant diseases. Allogenic bone marrow was used from 99 HLA identical siblings and from 23 other related or unrelated donors. Autologous marrow was used in 30 transplantations. Median age was 8. 6 years (range, 1.1-22.4) at time of BMT. The median survival was 42%, the survival time was 6.5 years (range, 0.8-23.1), and the median follow-up time was 6.8 years (range, 0.8-23.2). Seventeen patients had severe respiratory complications. Early severe respiratory complications leading to death within the first 4 months after BMT were due to pulmonary edema (n = 1), or fungal (n = 3), bacterial (n = 1), or viral (n = 2) pneumonia. Late severe respiratory sequelae were defined as persistent respiratory symptoms for more than 4 months despite treatment, and these occurred in 10 patients, of whom 5 died. Underlying diagnoses covered a wide spectrum, including bronchiolitis obliterans (n = 3), severe restrictive lung disease (n = 2), idiopathic pneumonia syndrome (n = 3), chronic bronchitis (n = 1), and hepatopulmonary syndrome (n = 1). The overall probability for death was 0.58, and for death from severe respiratory complications, 0.16. With improved HLA matching, fewer BMTs after relapsed or primary progressive disease, and improved supportive care, including the usage of CMV negative blood products, after 1990 the probability of death from severe respiratory complications was only 0.04, whereas before 1990 it was 0.23 (P = 0.029; in each time period, n = 69). The disease spectrum has changed from initially more infectious complications to bronchiolitis obliterans and idiopathic pneumonia syndrome. Lung function measurements performed in 85 of 138 patients usually showed a mild restrictive pattern. To identify those children as early as possible who are at risk for severe respiratory complications, a close longitudinal follow-up after BMT by pediatric pulmonologists is necessary.

Toxicity and effectiveness of high-dose idarubicin during AML induction therapy: results of a pilot study in children.

BACKGROUND: Idarubicin (IDR) is one of the most effective, but also toxic drugs in the treatment of AML. The standard dose used in children and adults is 8-12 mg/m2 during induction. PATIENTS AND METHODS: To improve outcome, we increased the IDR dose from 12 mg/m2 (standard dose in study AML-BFM 93), applied over three days during induction therapy (AIE = Ara-C, Idarubicin, Etoposide) to 14 mg/m2 in a pilot study including 17 patients (16 with de novo AML, one with secondary AML). Outcome and toxicities were compared with the other patients of study AML-BFM 93, treated with 3 x 12 mg/m2 IDR or 6 x 30 mg/m2 daunorubicin (DNR). RESULTS: Patients of the pilot study achieved a good blast cell reduction in the bone marrow on day 15, a high CR rate of 94% and a low relapse rate (3/17 pts.), however, not significantly different to the IDR (12 mg/m2) group. Hematological toxicity was high, median duration until neutrophil recovery > 500/microliter was 25.0 (12-66) days, and similar to the IDR (12 mg/m2) and DNR groups. Duration of thrombocytopenia (time to > 20,000/microliter) was 21 (10-66) days in the pilot study compared to 19 (7-26) days in DNR patients (p = 0.08). Four of 17 pilot patients presented with severe WHO grades 3/4 of mucositis during induction. One patient died in long-lasting aplasia after the 3rd treatment block. CONCLUSION: Results of this pilot study show that the IDR 14 mg/m2 regimen was effective but also toxic. According to our results which, however, are based on small patient numbers, an improved outcome compared to the IDR 12 mg/m2 regimen seems to be unlikely, therefore the possibly increased toxicity might not be acceptable.

Hepatopulmonary syndrome after allogeneic bone marrow transplantation.

A 10-year-old girl with aplastic anemia received an allogeneic bone marrow transplantation (BMT). Three years after an uneventful course apart from chronic graft-versus-host disease (GVHD) she presented with chronic hypoxemia, reduced diffusion capacity of the lungs, normal spirometric lung function and increased bilirubin and liver enzymes. Intrapulmonary vascular dilatations were demonstrated. Pulmonary complications after BMT may include a hepatopulmonary syndrome (liver disease, hypoxemia, intrapulmonary vascular dilatations).

Duration of first remission predicts remission rates and long-term survival in children with relapsed acute myelogenous leukemia.

Although treatment of childhood acute myelogenous leukemia (AML) has substantially improved in the last 15 years, in nearly half of the patients disease recurs. The aim of this study was to establish the prognosis of relapsed childhood AML and to identify prognostic factors for achievement of second remission and survival. From February 1988 to July 1996, 134 children with first relapse of AML were reported to the study center of the AML-BFM group. 102 patients treated intensively to induce second remission were prospectively followed. With various regimens, complete remission was achieved in 52 of 102 patients (51%), 27 children were alive in median 2.5 years (range, 0.4-7 years) after relapse. Disease-free survival was observed in seven of 16 patients transplanted from a matched sibling donor, one of four after matched unrelated bone marrow transplantation, 10 of 22 after autologous transplantation and five of nine patients after chemotherapy alone (two patients were lost to follow-up). Time until relapse reflecting the duration of first remission is the only variable correlating CR and survival rates. Defining early relapse as less than 1.5 years from diagnosis to relapse resulted in a 5-year survival of 10%, s.e. 5% for early relapses and 40%, s.e. 10% for late relapses (P-logrank test, 0.0001). Duration of first remission is a strong predictor for achievement of second CR and survival. It should be considered in reporting results of experimental therapies.

Relapse and clonal disease in children with aplastic anemia (AA) after immunosuppressive therapy (IST): the SAA 94 experience. German/Austrian Pediatric Aplastic Anemia Working Group.

Since the introduction of combined immunosuppressive therapy (IST) into management of aplastic anemia (AA) in childhood response and probability of survival improved. In contrast to bone marrow transplantation (BMT), however, patients after IST are not considered cured as high rates of relapse and development of clonal disease demonstrate. From 11/93 to 9/97 114 children (65 m, 49 f; median age 9.5 y.) from 37 centers in Germany and Austria were registered in the SAA 94 study. 86 patients lacking a matched sibling donor received IST. Most of the patients suffered from very severe (VSAA: PMN < 200/microliter) or severe AA (SAA: PMN < 500/microliter). All patients were treated with combined IST consisting of ALG and Cyclosporin A (CSA). VSAA and SAA patients were additionally treated with G-CSF. Therapy response was evaluated at day 112, after 6, 12 and 18 months. 8/86 patients died, the probability of survival being 87% after 4 years. At d 112 61% of evaluable patients became independent of transfusions (IST response: CR + PR), 13% with normal blood counts (CR). After 6 months 33% showed CR. At 12 and 18 months response improved to 74% resp. 80%, 39% resp. 55% CR. The best response was achieved in the subgroup of VSAA with 90% (PR + CR) and 65% CR after 18 months. 4 patients developed AML 3-19 months after the beginning of IST. In 2/4 pts. an aberrant clone (-7; 5q-) could be detected retrospectively in BM at diagnosis of AA. 3 nonresponders developed chromosomal aberrations (+19; -7, +12; +8) after 4, 12 and 16 months without morphological signs of AML or MDS. Overall 11 relapses occurred at a median time of 12 months (range 5-27 months) after the beginning of IST. 2 of them relapsed under CSA therapy, 2 under tapering of CSA and 7 after cessation of CSA. 7 patients responded again to CSA monotherapy. Overall response rate is 77% with a probability of event free survival (EFS) of 54% after 4 years regarding all complications mentioned as events.

[Prognosis of children with acute myelocytic leukemia after first relapse]. / Prognose von Kindern mit AML nach dem ersten Rezidiv.

UNLABELLED: Nearly 40% of children treated within the AML BFM studies experience recurrence of their disease after having achieved remission. In our retrospective analysis we tried to estimate prognosis after relapse in children treated with intensive relapse regimens and studied the impact of prognostic factors for second remission and survival. PATIENTS: 102 patients suffering from first relapse were treated intensively according to the relapse protocols BFM REZ91 and REZ93 or intensive salvage therapy consisting of double induction with high dose Ara-C, mitoxantrone and VP-16. Once in CR, patients continued to receive a 6-week consolidation and either allogeneic or autologous bone marrow transplantation (BMT). RESULTS: Time to relapse was in median 1.1 years, range 0-8 years. Fifty-two of 102 pts. (51%) achieved 2nd remission (CR), 10 (10%) partial remission, 37 (36%) were nonresponders, and 3(3%) died early during salvage therapy. Twenty-seven were still in CR, median 2.5 years, range 0.4-7.0 years, with an overall survival of 21%, SE 5% after 5 years. The response and survival rate was similar in all treatment groups. Fifty patients were transplanted, 43 being in 2nd CR, and 7 with residual blasts. Twenty-seven patients received an allograft: Twenty-one from a matched sibling (MSD), 1 from a haploid and 5 from a matched unrelated donor (MUD); 23 received an autograft. None of the patients transplanted in partial remission survived. Whereas 7 of 16 patients were alive after MSD in 2nd CR, 1 after haploid BMT. Four of 5 patients died after MUD BMT. Multivariate risk factor analysis revealed duration until relapse to be the most important factor for survival after relapse. The maximum risk-ratio was obtained at a threshold value of 1.5 years after diagnosis resulting in a 5-year survival of 10%, SE 5% for early relapse, and 40%, SE 10% for late relapse, p logrank 0.0001. CONCLUSION: Intensive relapse regimens can induce a 2nd CR in half of the patients. Children with late relapse (> 1.5 years after diagnosis) have a realistic chance for longtime survival.

The role of intensive AML-specific therapy in treatment of children with RAEB and RAEB-t.

To determine the role of intensive chemotherapy and allogeneic bone marrow transplantation (BMT) in treatment of refractory anemia with excess of blasts (RAEB) or RAEB-t (in transformation), the outcome of 37 consecutive children, 12 with RAEB and 25 with RAEB-t, diagnosed between 1985 and 1995 was analyzed. Fourteen patients received intensive chemotherapy according to the AML-BFM protocols 83, 87, or 93 (group 1). Seven patients were treated less intensively with the 6-week consolidation phase as induction (group 2). Allogeneic BMT was performed in 10 children of group 1 and 2 after, and in eight (group 3) without prior chemotherapy. Eight children received minimal or no chemotherapy (group 4). Of 21 children (groups 1 and 2) 17 (81%) achieved complete or partial remission after chemotherapy, 12 of them (10 of group 1) remained in remission, eight after BMT. Five-year survival in 29 children treated intensively (groups 1-3) was 46%, SE 12%. Two of the other eight children (group 4) remained alive, one after spontaneous remission. Outcome after BMT was related to the blast count in the bone marrow prior to BMT. None of 10 children (including two with minimal or no chemotherapy) with < or = 12% blasts before BMT relapsed, in contrast to five of eight patients with a higher blast count (P log rank 0.02). We conclude that a substantial number of children with RAEB or RAEB-t can achieve remission with intensive AML-specific chemotherapy. In patients responding to intensive chemotherapy an increase in long-term survival after allogeneic BMT can be expected.

Use of intravenous immune globulin in addition to antiviral therapy in the treatment of CMV gastrointestinal disease in allogeneic bone marrow transplant patients: a report from the European Group for Blood and Marrow Transplantation (EBMT). Infectious Diseases Working Party of the EBMT.

The best treatment of CMV gastrointestinal disease has been controversial, with some centers adding intravenous (i.v.) Ig to antiviral chemotherapy. The aim of this retrospective survey was to compare the outcome of antiviral chemotherapy with or without i.v. Ig. A questionnaire was sent to centers belonging to the EBMT. Thirty-three patients with CMV gastrointestinal disease were reported, 22 patients were given antiviral chemotherapy alone and 11 patients a combination of antiviral chemotherapy and i.v. Ig. Eighteen of 33 (55%) patients responded to therapy, 13 of those treated with antiviral chemotherapy alone and five (45%) of those treated with the combination (P = NS). Patients with acute GVHD of grades II-IV had significantly worse outcomes than patients with acute GVHD grades 0-I. In a Cox proportional hazards model corrected for acute GVHD there was no difference in outcome of CMV gastrointestinal disease with or without addition of Ig. Survival at 100 days after diagnosis of CMV gastrointestinal disease was 64%. There was no difference in survival in patients treated with or without i.v. Ig. The results of this retrospective survey indicate that addition of i.v. Ig to antiviral chemotherapy might not improve outcome in patients with biopsy-proven CMV gastrointestinal disease.

Persistence of neurological damage induced by dietary vitamin B-12 deficiency in infancy.

A case is reported of a 14 month old boy with severe dietary vitamin B-12 deficiency caused by his mother's vegan diet. Clinical, electroencephalography (EEG), and haematological findings are described. Cranial magnetic resonance imaging (MRI) showed severe frontal and frontoparietal cranial atrophy. Vitamin B-12 supplements led to a rapid improvement of haematological and neurological symptoms. Serum vitamin B-12 and urinary methylmalonate excretion were normal 10 days after treatment began. After six weeks, EEG was normal and cranial MRI after 10 weeks showed complete disappearance of all structural abnormalities. Cognitive and language development, however, remained seriously retarded at the age of 2 years. It is concluded that infantile vitamin B-12 deficiency induced by maternal vegan diets may cause lasting neurodisability even though vitamin B-12 supplementation leads to rapid resolution of cerebral atrophy and electroencephalographic abnormality.

Does megatherapy contribute to survival in metastatic neuroblastoma? A retrospective analysis. German Cooperative Neuroblastoma Study Group.

To evaluate the impact of megatherapy on the outcome of high risk neuroblastoma, 39 patients with stage IV neuroblastoma, who underwent megatherapy, were analyzed retrospectively and compared to 49 patients, who continued chemotherapy according to the German cooperative trial NB85. The groups were comparable concerning age, primary localisation, pattern of metastases, clinical risk groups and response to induction therapy. Overall survival of the megatherapy group was 0.23 +/- 0.07 compared to 0.14 +/- 0.05 of the chemotherapy group (p = 0.0149). In particular patients with partial response to induction chemotherapy appeared to gain from megatherapy, while patients in complete remission did not benefit. Subset analysis confirmed the superiority of megatherapy in patients with bone marrow infiltration at diagnosis, in patients with or without bone metastases at diagnosis and in patients older than 2 years. On the background of the poor prognosis of stage 4 neuroblastoma and lack of other effective treatment modalities these data support the utilization of megatherapy in treatment strategies for stage IV neuroblastoma.

Do patients with metastatic and recurrent rhabdomyosarcoma benefit from high-dose therapy with hematopoietic rescue? Report of the German/Austrian Pediatric Bone Marrow Transplantation Group.

Patients with primary metastatic or recurrent rhabdomyosarcoma (RMS) have a very poor prognosis. Since high-dose chemotherapy (HDC) +/- TBI was thought to improve survival, many centers performed this therapy using different types of hematopoietic rescue (auto BM or PBSC, allo BM). This is a retrospective, multi-center analysis of the results of treatment in 36 patients with primary metastatic or relapsed RMS who were given HDC +/- TBI and hematopoietic rescue between 1986 and 1994. The median age was 6 years (< 1-22 years). Primary therapy was given according to either one of the Cooperative German Soft Tissue Sarcoma Studies CWS-81, -86, -91 or the European Study for Stage IV Malignant Mesenchymal Tumors in Childhood. There were 22 alveolar RMS, 13 embryonal RMS and one undifferentiated sarcoma. The indication for HDC was primary metastatic disease (27 patients) or a relapse of a primary localized tumor (nine patients). Thirty-two patients were in 1st or 2nd CR when given HDC and four in VGPR. The median time from last event to HDC was 44 weeks (21-110). HDC consisted of fractionated melphalan ((4 x 30-45 mg/m2), VP16 40-60 mg/kg, carboplatin 3 x 400-500 mg/m2) in 26 patients, 10 of whom received additional FTBI. Seven patients were treated with melphalan alone or in combination with carboplatin. Two patients received cyclophosphamide/busulphan with TLI (total lymphoid irradiation) and one cyclophosphamide with FTBI. Thirty-one patients were given autologous BM or PBSC as hematopoietic rescue and five allogeneic bone marrow from HLA-identical siblings. Fourteen patients received GM-CSF or G-CSF after hematopoietic stem cell transfusion (HSCT). Ten patients received adjuvant IL-2. There was one toxic HDC-related death. Nine patients are alive and free of disease with a median observation time of 57 months (32-108). The median time from HDC to relapse was 4 months (1-17). The tumor recurred in the majority of patients at previously known sites; in three cases new metastatic sites were observed. Patients with primary localized tumors who had been treated with HDC because of relapse did slightly better (four of nine alive with NED) than patients with primary metastatic disease (five of 27 alive with NED). HDC is still of uncertain value in the therapy of poor-risk rhabdomyosarcoma and should be performed only as part of controlled clinical trials.

Allogeneic bone marrow transplantation for chronic myelomonocytic leukemia in childhood: a report from the European Working Group on Myelodysplastic Syndrome in Childhood.

PURPOSE: To evaluate the role of allogeneic bone marrow transplantation (BMT) in children with chronic myelomonocytic leukemia (CMML). PATIENTS AND METHODS: Forty-three children with CMML given BMT and reported to the European Working Group on Myelodysplastic Syndrome in Childhood (EWOG-MDS) data base were evaluated. In 25 cases, the donor was a human leukocyte antigen (HLA)-identical or a one-antigen-disparate relative, in four cases a mismatched family donor, and in 14 a matched unrelated donor (MUD). Conditioning regimens consisted of total-body irradiation (TBI) and chemotherapy in 22 patients, whereas busulfan (Bu) with other cytotoxic drugs was used in the remaining patients. RESULTS: Six of 43 patients (14%), five of whom received transplants from alternative donors, failed to engraft. There was a significant difference in the incidences of chronic graft-versus-host disease (GVHD) between children transplanted from compatible/one-antigen-mismatched relatives and from alternative donors (23% and 87%, respectively; P < .005). Probabilities of transplant-related mortality for children given BMT from HLA-identical/one-antigen-disparate relatives or from MUD/ mismatched relatives were 9% and 46%, respectively. The probability of relapse for the entire group was 58%, whereas the 5-year event-free survival (EFS) rate was 31%. The EFS rate for children given BMT from an HLA-identical sibling or one-antigen-disparate relative was 38%. In this latter group, patients who received Bu had a better EFS compared with those given TBI (62% v 11%, P < .01). CONCLUSION: Children with CMML and an HLA-compatible relative should be transplanted as early as possible. Improvement of donor selection, GVHD prophylaxis, and supportive care are needed to ameliorate results of BMT from alternative donors.

[Concept and interim result of the ALL-BFM 90 therapy study in treatment of acute lymphoblastic leukemia in children and adolescents: the significance of initial therapy response in blood and bone marrow]. / Konzeption und Zwischenergebnis der Therapiestudie ALL-BFM 90 zur Behandlung der akuten lymphoblastischen Leukämie bei Kindern und Jugendlichen: Die Bedeutung des initialen Therapieansprechens in Blut und Knochenmark.

In the ongoing trial ALL-BFM 90 for the treatment of childhood non-B cell acute lymphoblastic leukemia (ALL) 1468 unselected patients (pts) were enrolled from 84 centers in Germany and Switzerland from 4/90 to 12/93. Based on the results of the previous trial ALL/NHL-BFM 86 this treatment program focused especially on therapy modifications for average (MRG) and high risk (HRG) pts, on the evaluation of therapy response for prognosis, and on the identification of high risk pts by molecular genetics. For average risk pts consolidation therapy was intensified by the addition of L-asparaginase (L-ASP) on a randomized basis. In HRG induction and consolidation therapy was modified by introduction of early intensification elements that had proved to be effective in relapsed pts. This patient group was randomized for the evaluation of the effects of G-CSF administered in the intervals between the intensification elements. Distribution of the 1376 eligible pts into the three treatment arms SRG (standard risk), MRG, and HRG was as expected (17 pts not yet assigned): 385 pts (28.0%), 834 pts (60.6%), and 140 pts (10.2%), respectively. Treatment consisted of the 8-drug induction (Protocol I), consolidation (Protocol M), reinduction (Protocol II), and maintenance therapy (total therapy duration 24 months). The drug doses and combinations were only slightly modified compared to the previous study ALL-BFM 86 with the exception of the randomized L-ASP containing arm MRG-2 (Protocol M-A) and group HRG. Preventive cranial irradiation was reduced to 12 Gy and applied to MRG and HRG pts only. As in study ALL-BFM 86, the initial response to a 7-day exposure to prednisone and to the first intrathecal injection of MTX at diagnosis was evaluated at day 8 of treatment with regard to blast count in peripheral blood (PB). In addition, pts were now investigated for the presence of blasts in the bone marrow (BM) at day 15 of treatment to compare the prognostic power of both response parameters. Identification of translocation t(9; 22) and/or BCR-ABL rearrangement characterized a small subgroup of pts that were not detected by poor initial therapy response. These pts were enrolled in HRG for more intensive treatment including allogeneic bone marrow transplantation (BMT). After a median observation time of 22 months, the overall probability for event-free survival (p-EFS) is 82 +/- 2%. 11 pts (0.8%) died before complete remission (CR) was achieved, 15 pts (1.1%) died while in CR for reasons other than relapse.(ABSTRACT TRUNCATED AT 400 WORDS)

[Treatment of aplastic anemia--aims and development of the SAA 94 pilot protocol]. / Die Behandlung der Aplastischen Anämie--Zielsetzung und Aufbau des Pilotprotokolls SAA 94.

Aplastic anemia (AA) is a rare, life threatening disease. Allogeneic bone marrow transplantation (BMT) offers the only possibility of cure, i. e. life-long remission. The probability of survival after BMT from an HLA-identical sibling has clearly improved over the last years and at present is about 80% in patients < 16 years. Transplantation from alternative donors, however, faces unsolved immunological problems. For demographic reasons most patients lack a matched sibling donor. For these patients immunosuppressive therapy (IST) is the only alternative therapeutic approach. However this treatment has frequently resulted in clonal, i. e. potentially malignant disease. Overall probability of survival here is only 50%, in severely granulocytopenic patients (< 0.2 G/l) even lower. These individuals represent an important subgroup in pediatric AA. Some patients show only partial reconstitution of their hematopoiesis but satisfactory quality of life. Based on the results of prospective studies a protocol for IST in AA using anti-lymphocyte globulin (ALG), cyclosporin A (CSA) and G-CSF is presented. For BMT-patients likewise a protocol for conditioning (ALG, cyclophosphamide) and GvHD-prophylaxis is suggested. Standardisation and improvement of supportive therapy is the third important objective of this pilot protocol.

[Imaging methods in diagnosis of cerebrovascular complications with L-asparaginase therapy]. / Bildgebende Verfahren in der Diagnostik zerebrovaskulärer Komplikationen unter L-Asparaginase-Therapie.

During or immediately following L-asparaginase (L-asp) therapy especially intracranial thromboembolic or hemorrhagic complications due to hemostatic imbalance have been observed. We report about 6 children who had intracranial thrombosis or hemorrhage after 3 to 8 doses of L-asp. Initial symptoms of the cerebral events were similar--seizure, coma, hemiparesis and disorientation. All patients were examined by cerebral computerized tomography (CT) or/and magnetic resonance imaging (MRI). Three patients had a dural sinus thrombosis, one had an intracranial hemorrhage and two a hemorrhagic infarction with typical findings in the cerebral CT or MRI. Two other patients were interpreted as having peripheral thrombosis. They showed nontypical hypodense cortical and subcortical areas without any contrast medium enhancement in CT and hyperintense areas in T2-weighted MRI scan. All patients recovered from neurological symptoms, and showed obvious regression of CT and MRI findings which correlate with the good prognosis of these complications. Both CT and MRI are useful in diagnosis and follow-up of cerebrovascular complications of L-asp therapy. The CT and MRI findings of the reported cases seem to reflect different appearances of the same entity, i.e. thrombosis of venous vessels of different size with or without congestive edema and hemorrhagic complication.

High-dose consolidation with local radiation and bone marrow rescue in patients with advanced neuroblastoma.

Twenty-six children with advanced neuroblastoma were consolidated with cisplatin, BCNU, etoposide, melphalan, 21 Gy of local radiotherapy, and bone marrow rescue in a multicenter study. All patients were over 1 year of age at diagnosis. Twenty-two patients were treated in first complete or partial remission and four in second complete or partial remission. Hematologic rescue was autologous (n = 23), allogeneic (n = 2), or syngeneic (n = 1). Extrahematological toxicity involved primarily the gastrointestinal mucosa. Among five fatal toxicities, three included intestinal hemorrhage. Fourteen patients relapsed after BMT, four of them at the primary site. Seven children survive progression-free after 16-56 months. These results are essentially not different from a single-center study with the same protocol or from other published studies. The value of megatherapy for patients with advanced neuroblastoma or for a subgroup of them can only be established on a larger number of patients than most national trials accrue.

Detection of neuron-specific gamma-enolase messenger ribonucleic acid in normal human leukocytes by polymerase chain reaction amplification with nested primers.

BACKGROUND: NNE (non-neuronal alpha-enolase) is a glycolytic enzyme detected in most tissues. NSE (neuron-specific gamma-enolase) is detected in normal neurons and tumors such as neuroblastoma. Staining with antibodies against NSE is therefore used to detect neuroblastoma cells invading bone marrow. Since staining of normal leukocytes has been reported we asked whether bona fide NSE is in fact expressed in normal blood and marrow. EXPERIMENTAL DESIGN: We designed nested coding region specific primers for NSE and NNE and, after reverse transcription of mRNA, we amplified the coding region between these primers in a semi-nested polymerase chain reaction. In order to distinguish both iso-mRNAs from each other, we amplified a long (1,047 bp) template in a first round of 30 cycles with primers specific for NNE or NSE. One percent of this product was used in a second round of 30 cycles in which both sense primers and two nested anti-sense primers of alternate specificities yielding shorter products of discernible sizes (768 bp or 619 bp) were added together in the same reaction tube. With this combination of four primers, only that shorter product was amplified to visibility, the specificity of which was homologous to the template produced in the first 30 cycles. Restriction enzyme digestion of the amplified products was used to verify this polymerase chain reaction-based approach for the distinction of isoforms of RNA. RESULTS: This semi-nested polymerase chain reaction clearly allows for the distinction of mRNA for NNE or NSE and shows the presence of transcripts for NSE in normal human leukocytes from blood and bone marrow. CONCLUSIONS: This method exploiting short stretches of nucleotide differences in the coding regions for priming can more generally be applied to the distinction of all isoforms of RNA where nested specific primers can be designed. However, the presence of NSE specific transcripts in normal human leukocytes invalidates the use of this highly sensitive method as a disease marker in neuroblastoma.