Electrocardiographic imaging a valid tool or an inaccurate toy?

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): Learning Health

Background and aim

Electrocardiographic imaging (ECGI) is capable of performing an activation map with a single beat. However, previous studies using the epicardial-only system, have suggested a bad accuracy for the assessment of the epicardial breakthrough. Recent systems using endo-epicardial analysis have shown promising results. The aim of this study was to assess the accuracy and reproducibility of two endo-epicardial ECGI systems using different cardiac sources one based on the extracellular-potential, and the other on the equivalent double layer model, respectively the AMYCARD (EP Solutions SA, Switzerland) and VIVO (Catheter Precision, NJ USA) systems.

Methods

We studied 11 consecutive patients referred for ablation of frequent idiopathic premature ventricular contractions at our center that had an ECGI performed using both systems on the same day. The AMYCARD system uses a dense array of body-surface electrocardiograms with up to 224 leads and VIVO uses just the 12-leads ECG. Both systems use a patient-specific heart torso geometry obtained with a CT-scan or cardiac magnetic resonance. The localisation of the PVCs based on ECGI was done using a segmental model with 22 segments on the left ventricle, to include the classical 17 segment model plus the aortic cusps and the papillary muscles, and 12 segments on the right ventricle including 4 on the right ventricular outflow tract (RVOT): (anterior, lateral, right septum and left septum). A perfect match was defined as a predicted location within the same anatomic segment, whereas a near match as a predicted location within the same segment or a contiguous one.

Results

The median (Q1-Q3) number of leads used for the AMYCARD was 131 (118-144). Seven patients underwent ablation and in 4 ablation is pending. The predicted locations and the ablation site are depicted on the Table. We found a perfect match between both systems in 73% (Figure) and near match in 91% of cases. In patients that underwent ablation the systems localised the site of origin of the PVCs within the same segment or the contiguous segment in all patients with VIVO and in six out of seven with AMYCARD.

Conclusions

ECGI is an accurate diagnostic tool with reproducible results regardless the cardiac source used for analysis.

Assessment of activation duration across the right ventricular outflow tract in patients with premature ventricular contractions using noninvasive electrocardiographic mapping: a validation study

Funding Acknowledgements

Type of funding sources: Private hospital(s). Main funding source(s): Learning Health

Introduction

Previous studies have reported that wavefront propagation speed across the right ventricular outflow tract (RVOT) can distinguish premature ventricular contractions (PVCs) with a RVOT origin from PVCs with a left ventricular outflow tract (LVOT) origin.

Aim

Validate the non-invasive electrocardiographic mapping (ECGI) for assessment of RVOT activation duration (AD) during PVCs and assess its value as a predictor of the origin of the PVCs.

Methods

We studied 18 consecutive patients, 8 males, median age 55 (35-63) years that underwent ablation of frequent (> 10.000 per 24 h) idiopathic PVCs with inferior axis, that had and an ECGI performed before ablation and the RVOT mapped in PVC. The ECGI was performed with the Amycard system, and invasive mapping was performed with the Carto or Ensite system. Isochronal activation maps of the RVOT in PVC were obtained with the activation direction method (ADM) of the ECGI, and with the Carto and Ensite systems. Total RVOT AD was measured as the time interval between the earliest and the latest activated region. Agreement between the two methods was performed using a Bland-Altman plot and linear regression . The cutoff value of AD to predict PVC origin was calculated with ROC curve.

Results

PVCs originated from the RVOT in 11 (61%) patients. The median (Q1-Q3) RVOT AD measured with ECGI was 54 (39-68) ms and with invasive map 57 (36-70) ms. The agreement between both methods was good with an R2 of 0.747, p<0.0001. Figure displays the Bland-Altman plot (panel A), the linear regression plot (panel B). and two examples of the ECGI isochronal map (panel C). The AD was significantly higher in PVCs from the RVOT vs LVOT, both with ECGI and Carto, respectively 62 (58-73) vs 37 (33-40) ms, p<0.0001 and 68 (60-75) vs 34 (30-40) ms, p<0.0001. The cutoff value of 43 ms for AD measured with ECGI, predicted the origin of the PVCs with a sensitivity and specificity of 100%.

Conclusions

We found good agreement between ECGI and Carto. The AD obtained with ECGI was accurate to predict the origin of the PVCs.

Three-dimensional late gadolinium enhancement increases the diagnostic yield of cardiovascular magnetic resonance to detect low voltage in the right ventricular outflow tract

Funding Acknowledgements

Type of funding sources: None.

Background

Cardiac magnetic resonance (CMR) using late gadolinium enhancement (LGE) fails to detect scar tissue in patients with electroanatomical abnormalities and biopsy-proven structural heart disease. It has shown conflicting data regarding existence of structural abnormalities in patients with idiopathic premature ventricular contractions (PVCs) from the right ventricular outflow tract (RVOT). Three- dimensional (3D) LGE enables high-spatial resolution more appropriate to the thin-walled right ventricle than two-dimensional (2D) LGE.

Objective

Our aim was to evaluate if the use of 3D-LGE would improve the performance of CMR to detect low voltage areas in the RVOT of patients with PVCs.

Methods

Since May 2020 we performed 3D-LGE CMR in 11 consecutive patients that underwent ablation of frequent PVCs. A control group of 11 consecutive patients that underwent catheter ablation by the same operator and had a 2D-LGE CMR performed before ablation was also studied. All patients had normal 2D-LGE CMR. A 3D electroanatomical bipolar voltage map of the RVOT was performed in sinus rhythm (0.5 mV-1.5 mV colour display). Areas with electrograms <1.5 mV represented the LVA. The area adjacent to the pulmonary valve usually displays voltage between 0.5 and 1.5 mV and is classified as transitional-voltage zone. Presence of LVAs outside this transitional-voltage zone were estimated.  We compared the accuracy of CMR for detecting LVA in the two groups: 3D LGE and 2D LGE.

Results

The median number of points used for the voltage map was 344 (242-450). 18 patients (82%) displayed LVAs. The site of origin of the PVCs was the RVOT in 17 patients and the left ventricular outflow tract (LVOT) in 5. Comparison between groups is displayed in the table.  2D LGE CMR failed to demonstrate abnormalities of the RVOT in any of the patients that presented with LVAs. 3D CMR showed presence of fibrosis (Figure) in 3 out of 9 patients with LVAs (33%).

Conclusion

CMR using 3-D LGE techniques showed an increased power to diagnose structural abnormalities. This technique may be a better choice in initial stages of RVOT disease. All sampleN = 223D-LGE CMRN = 112D-LGE CMRN = 11p-valueAge in years, median (Q1-Q3)47 (35-68)62 (34-55)42 (34-55)0.243Male gender, n (%)8 (36)3 (27)5 (46)0.330PVCs RVOT/LVOT17/59/28/30.500Nº points in the map, median (Q1-Q3)344 (242-450)350 (259-450)300 (158-345)0.076Low voltage areas, n (%)18 (82)9 (82)9 (82)0.707Abstract Figure.

Assessment of wavefront propagation speed on the right ventricular outflow tract: deceleration zones associated with the presence of low voltage areas

Funding Acknowledgements

Type of funding sources: None.

Background and aims

Activation wavefront is rapid and uniform in normal myocardium. Fibrosis is associated with deceleration zones (DZ) and late activated zones. The presence of low voltage areas (LVAs) in the right ventricular outflow tract (RVOT) of patients with premature ventricular contractions (PVCs) from this origin has been described previously. The aim of this study was to evaluate in sinus rhythm, the RVOT endocardial activation duration (EAD) and the presence of DZs, in patients with PVCs and in controls.

Methods

Consecutive patients with frequent (>10.000/24 h) idiopathic PVCs with inferior axis subjected to ablation that had an activation and voltage map of the RVOT performed in sinus rhythm. A control group of patients without PVCs that underwent ablation of supraventricular arrhythmias was also studied. Patients with structural heart disease, previous ablation or conduction disease were excluded. The RVOT EAD was measured as the time interval between the earliest and the latest activated region. Also evaluated the number of 10 ms isochrones throughout the RVOT and the maximal number of 10 ms isochrones within 1 cm, and a DZ was defined as a zone with > 3 isochrones within 1 cm. Low voltage areas (LVA) were defined as areas with local electrogram amplitude <1.5 mV.

Results

42 patients, 29 in the PVC group and 13 control subjects. The site of origin of the PVCs was the RVOT in 23 patients and the LVOT in 6. The characteristics of the two groups are displayed in the Table. Patients with PVCS had longer RVOT EAD, total number of isochrones and presence of DZ was also significantly higher (See table).  LVAs were more frequent in PVCs from the RVOT than from the LVOT (83% vs 33%, p = 0.033). Patients with LVA had longer EAD 60 (52-67) vs 36 (34-40) ms, p < 0.0001 (Figure A) and more DZ than patients without LVA 95% vs 0%, p < 0.0001 (Figure B and C).

Conclusions

The velocity of the wavefront propagation was slower and DZs were more frequently present in patients with PVCs and were associated with presence of LVAs. All sampleN= 42PVCsN = 29ControlsN = 13p-valueAge in years, median (Q1-Q3)56 (35-65)58 (38-66)53 (28-67)0.648Male gender, n (%)19 (45)14 (48)5 (39)0.401Nº points in the map, median (Q1-Q3)410 (338-589)467 (345-660)345 (333-465)0.056Activation duration in ms, median (Q1-Q3)41.8 (36-61)56 (41-66)39 (35-41)0.001Nº isochrones, median (Q1-Q3)4 (4-6)5 (4-6)4 (4-4)0.037Presence of DZs, n (%)20 (48)20 (69)0 (0)<0.0001Presence of LVAs, n(%)21 (50)21 (72)0 (0)<0.0001Abstract Figure.

The validity of the Patient-Generated Subjective Global Assessment Short-form© in cancer patients undergoing chemotherapy

BACKGROUND & AIMS

The high prevalence of malnourished cancer patients highlights the importance of sensitive and specific tools for nutritional risk and status assessment screening, namely the Patient-Generated Subjective Global Assessment (PG-SGA®). This study aimed to assess whether the short-form version of the PG-SGA® (PG-SGA© SF) would be appropriate to identify the nutritional risk of patients when compared with the final global score of PG-SGA© (long-form version).

METHODS

This transversal and observational study comprised a convenience sample of cancer patients undergoing chemotherapy at the Champalimaud Clinical Centre between December 2016 and February 2018. Clinical data and anthropometric parameters were collected in order to apply PG-SGA® and PG-SGA© SF. The data was statistically analysed through SPSS version 22 (SPSS Inc, Chicago, IL, USA).

RESULTS

In this study 355 patients were enrolled and PG-SGA© SF results showed that 69.3% (n = 246) of the population presented at least one risk factor for malnourishment (Σ (box A) ≥1). Additionally, PG-SGA® revealed that 50% of patients (n = 177) have a risk of developing malnourishment or are already malnourished (B and C classification). The concordance of results showed to be high (coefficient k = 0.62; p < 0.001), meaning that PG-SGA SF© has a good sensibility (95%) and specificity (67%) for the identification of nutritional risk and assessment of nutritional status when compared with the complete version of PG-SGA©.

CONCLUSIONS

According to our results, PG-SGA© SF is a useful and sufficient tool, representing an easier and faster way to identify at-risk or malnourished patients.

Proceedings of the Association for Research in Vision and Ophthalmology and Champalimaud Foundation Ocular Oncogenesis and Oncology Conference

The 2018 Ocular Oncogenesis and Oncology Conference was held through a partnership of the Association for Research in Vision and Ophthalmology (ARVO) and the Champalimaud Foundation. Twenty-one experts from international ocular oncology centers, from the Champalimaud Clinical Centre and the Champalimaud Foundation Cancer Research Program, and from patient advocacy organizations, delivered lectures on subjects that ranged from global ocular oncology, to basic research in mechanisms of ocular malignancy, to clinical research in ocular cancers, and to anticipated future developments in the area. The scientific program of the conference covered a broad range of ocular tumors-including uveal melanoma, retinoblastoma, ocular surface tumors, and adnexal and intraocular lymphomas-and pathogenesis and management were deliberated in the context of the broader systemic cancer discipline. In considering the latest basic and clinical research developments in ocular oncogenesis and oncology, and providing the opportunity for cross-talk between ocular cancer biologists, systemic cancer biologists, ocular oncologists, systemic oncologists, patients, and patient advocates, the forum generated new knowledge and novel insights for the field. This report summarizes the content of the invited talks at the 2018 ARVO-Champalimaud Foundation Ocular Oncogenesis and Oncology Conference.

Differential expression of cell adhesion molecules in the functional compartments of lymph nodes and tonsils

Aims-To analyse the topographical distribution of adhesion molecules involved in lymphocyte recirculation in human lymph nodes and tonsils. The study focused on the expression of LECAM-1 (CD62L), VLA-alpha4 (CD49d), VLA-beta1 (CD29), LFA-1 alphaL (CD11a), LFA-beta2 (CD18), VCAM-1 (CD106), ICAM-1 (CD54), and H-CAM (CD44).Methods-Reactive lymph nodes and palatine tonsils were studied using immunofluorescence methods with fluorescein isothiocyanate (FITC) labelled monoclonal antibodies directed against cell adhesion molecules. To investigate the expression patterns of these molecules in the T and B cell populations, double labelling experiments were performed using Texas Red labelled antibodies against CD2 or CD19, respectively. The images from each fluorochrome were then simultaneously analysed using a laser scanning confocal microscope.Results-LECAM-1, VLA-alpha4 and H-CAM were predominantly expressed by mantle zone B cells, VCAM-1 and ICAM-1 by germinal centre cells, most of which exhibited a reticular staining pattern suggestive of follicular dendritic cells, whereas LFA-1 alphaL and LFA-beta2 were mainly found in extrafollicular and germinal centre T cells. All high endothelial venules expressed VLA-beta1 and ICAM-1, whereas VCAM-1 was present in only a few, with variable intensity.Conclusions-The data show that all of these adhesion molecules are differentially distributed within the distinct functional microenvironments of both organs. The differences observed in the expression patterns among the B and T cells belonging to different compartments probably depend on the momentum of cell traffic, the stage of maturation/activation, as well as on their functional role in the immune response.

[Cost of cancer care in Portugal]

INTRODUCTION

Cancer is the second most important cause of death in Portugal, following cardiovascular diseases (CVD), and shows a constant progressive increase in the proportional share of total deaths. In Portugal, as in most countries, the health care budget is under constant cost-containment pressures. In this context it is necessary to verify if enough resources have been allocated to the disease in terms of health care expenditure. The main objective of this study is to estimate the cost of cancer care in Portugal and to compare it to similar data in Europe and the United States of America (USA), to the cost of CVD. The secondary objective is to evaluate the cost of pharmaceuticals used in the treatment of cancer in Portugal, both in relation to total pharmaceutical expenditure and to other therapeutic areas.

METHODS

Three main sources of information were used: comprehensive literature review, primary and secondary data sources, and a modified Delphi Panel, which was used to fill in gaps in the information derived from the data sources and the literatura review. The burden of cancer was measured through the Disability-adjusted life-year (DALY) and, in order to determine the costs of cancer, detailed information on the costs of medical visits and of inpatient episodes based on Diagnosis Related Groups (DRG), in 2006, was used. To estimate the total cost of cancer, we used a combination of top down (breaking global expenditure data to specific levels) and bottom up methodology (based on the sum of different components).

RESULTS

Based on 2006 data on direct medical care expenditures in Portugal, we found that 565 million euro were spent on cancer in comparison to 1 320 million on CVD representing 3.91% and 9.14% of total cost on health respectively. When we break down total expenditure on drugs by therapeutic area we find that CVD drugs represent about 21.6% of total drug costs in Portugal and cancer drugs represent about 5.6% of the total. Oncology drugs represent 32% of the total expenditure on cancer, while CVD drugs represent 54% of the total expenditure on CVD. In comparison, in terms of BoD in Portugal, 18.6% of DALY's were associated with CVD and 15.3% with cancer.

CONCLUSION

Considering the burden of disease (BoD) of CVD and cancer in Portugal, we can state that the expenditure allocated to cancer is significantly lower than expected. Using the criterion of expenditure according to need, we observed that there is an imbalance of expense/BoD in oncology indicating that cancer seems to be underfunded in Portugal. Even considering that this shouldn't be the only criterion to determine the volume of expense in a certain therapeutic area, the differential observed in this study is sufficiently high to deserve attention from the decision-makers.

[Biosimilars in oncology]

The development of biotechnology drugs represents one of the great advances in medical therapy and it was observed an exponential growth in its use. The resource to these drugs in Oncology and Hematology is no exception and it soon became an essential element of an integrated and directed therapy strategy. The expiry of the first biotechnology drugs patents has opened the door for the development and marketing of biosimilars, which entry in the Portuguese market was recently approved. This article was built on the analysis of the available state-of-the-art information on biotechnology drugs, biosimilars and current legislation and it expresses the opinion of Oncology and Hematology experts about the substituition of biological drugs by biosimilars in clinical practice.

[Use of granulocyte growth factors: recommendations of the Portuguese Society of Hematology]

The administration of cytotoxic chemotherapy may be complicated by the emergence of neutropenia and febrile neutropenia, frequently determining hospital admission and intravenous treatment with broad spectrum antibiotics. Frequently, it is necessary to reduce the dose or to delay the administration of the cytotoxic drugs reducing the relative dose intensity of the chemotherapy regimen. Granulocyte growth factors stimulate the proliferation and differentiation of neutrophils and reduce the number of days of severe neutropenia and febrile neutropenia associated with cytotoxic chemotherapy. They are also indicated for the collection of hematopoietic progenitors for autologous and allogeneic transplantation, as well as in non malignant diseases associated with chronic neutropenia. This article reviews the evidence supporting the use of granulocyte growth factors in Hematology.

Improved reliability of lymphoma diagnostics via PCR-based clonality testing: — Report of the BIOMED-2 Concerted Action BHM4-CT98-3936

The diagnosis of malignant lymphoma is a recognized difficult area in histopathology. Therefore, detection of clonality in a suspected lymphoproliferation is a valuable diagnostic criterion. We have developed primer sets for the detection of rearrangements in the B- and T-cell receptor genes as reliable tools for clonality assessment in lymphoproliferations suspected for lymphoma. In this issue of Leukemia, the participants of the BIOMED-2 Concerted Action CT98-3936 report on the validation of the newly developed clonality assays in various disease entities. Clonality was detected in 99% of all B-cell malignancies and in 94% of all T-cell malignancies, whereas the great majority of reactive lesions showed polyclonality. The combined BIOMED-2 results are summarized in a guideline, which can now be implemented in routine lymphoma diagnostics. The use of this standardized approach in patients with a suspect lymphoproliferation will result in improved diagnosis of malignant lymphoma.

Long-term follow-up of lymphocyte populations and cellular cytokine production in patients with chronic graft-versus-host disease treated with extracorporeal photopheresis

We studied lymphocyte populations and cytokine-expression profiles of ten patients with chronic graft-versus-host disease who at least transiently responded to photoimmunotherapy. The numbers of lymphocytes, monocytes and dendritic cells rose in most cases. Th1 cells always increased during therapy, supporting the hypothesis that a more favorable immune balance contributes to clinical responses.

Design and standardization of PCR primers and protocols for detection of clonal immunoglobulin and T-cell receptor gene recombinations in suspect lymphoproliferations: report of the BIOMED-2 Concerted Action BMH4-CT98-3936

In a European BIOMED-2 collaborative study, multiplex PCR assays have successfully been developed and standardized for the detection of clonally rearranged immunoglobulin (Ig) and T-cell receptor (TCR) genes and the chromosome aberrations t(11;14) and t(14;18). This has resulted in 107 different primers in only 18 multiplex PCR tubes: three VH-JH, two DH-JH, two Ig kappa (IGK), one Ig lambda (IGL), three TCR beta (TCRB), two TCR gamma (TCRG), one TCR delta (TCRD), three BCL1-Ig heavy chain (IGH), and one BCL2-IGH. The PCR products of Ig/TCR genes can be analyzed for clonality assessment by heteroduplex analysis or GeneScanning. The detection rate of clonal rearrangements using the BIOMED-2 primer sets is unprecedentedly high. This is mainly based on the complementarity of the various BIOMED-2 tubes. In particular, combined application of IGH (VH-JH and DH-JH) and IGK tubes can detect virtually all clonal B-cell proliferations, even in B-cell malignancies with high levels of somatic mutations. The contribution of IGL gene rearrangements seems limited. Combined usage of the TCRB and TCRG tubes detects virtually all clonal T-cell populations, whereas the TCRD tube has added value in case of TCRgammadelta(+) T-cell proliferations. The BIOMED-2 multiplex tubes can now be used for diagnostic clonality studies as well as for the identification of PCR targets suitable for the detection of minimal residual disease.

High remission rate in T-cell prolymphocytic leukemia with CAMPATH-1H

T-cell prolymphocytic leukemia (T-PLL) is a chemotherapy-resistant malignancy with a median survival of 7.5 months. Preliminary results indicated a high remission induction rate with the human CD52 antibody, CAMPATH-1H. This study reports results in 39 patients with T-PLL treated with CAMPATH-1H between March 1993 and May 2000. All but 2 patients had received prior therapy with a variety of agents, including 30 with pentostatin; none achieved complete remission (CR). CAMPATH-1H (30 mg) was administered intravenously 3 times weekly until maximal response. The overall response rate was 76% with 60% CR and 16% partial remission (PR). These responses were durable with a median disease-free interval of 7 months (range, 4-45 months). Survival was significantly prolonged in patients achieving CR compared to PR or no response (NR), including one patient who survived 54 months. Nine patients remain alive up to 29 months after completing therapy. Seven patients received high-dose therapy with autologous stem cell support, 3 of whom remain alive in CR 5, 7, and 15 months after autograft. Stem cell harvests in these patients were uncontaminated with T-PLL cells as demonstrated by dual-color flow cytometry and polymerase chain reaction. Four patients had allogeneic stem cell transplants, 3 from siblings and 1 from a matched unrelated donor. Two had nonmyeloablative conditioning. Three are alive in CR up to 24 months after allograft. The conclusion is that CAMPATH-1H is an effective therapy in T-PLL, producing remissions in more than two thirds of patients. The use of stem cell transplantation to consolidate responses merits further study.

BIOMED-I concerted action report: flow cytometric immunophenotyping of precursor B-ALL with standardized triple-stainings. BIOMED-1 Concerted Action Investigation of Minimal Residual Disease in Acute Leukemia: International Standardization and Clinical Evaluation

The flow cytometric detection of minimal residual disease (MRD) in precursor-B-acute lymphoblastic leukemias (precursor-B-ALL) mainly relies on the identification of minor leukemic cell populations that can be discriminated from their normal counterparts on the basis of phenotypic aberrancies observed at diagnosis. This technique is not very complex, but discordancies are frequently observed between laboratories, due to the lack of standardized methodological procedures and technical conditions. To develop standardized flow cytometric techniques for MRD detection, a European BIOMED-1 Concerted Action was initiated with the participation of laboratories from six different countries. The goal of this concerted action was to define aberrant phenotypic profiles in a series of 264 consecutive de novo precursor-B-ALL cases, systematically studied with one to five triple-labelings (TdT/CD10/CD19, CD10/CD20/CD19, CD34/CD38/CD19, CD34/CD22/CD19 and CD19/CD34/CD45) using common flow cytometric protocols in all participating laboratories. The use of four or five triple-stainings allowed the identification of aberrant phenotypes in virtually all cases tested (127 out of 130, 98%). These phenotypic aberrancies could be identified in at least two and often three triple-labelings per case. When the analysis was based on two or three triple-stainings, lower incidences of aberrancies were identified (75% and 81% of cases, respectively) that could be detected in one and sometimes two triple-stainings per case. The most informative triple staining was the TdT/CD10/CD19 combination, which enabled the identification of aberrancies in 78% of cases. The frequencies of phenotypic aberrations detected with the other four triple-stainings were 64% for CD10/CD20/CD19, 56% for CD34/CD38/CD19, 46% for CD34/CD22/CD19, and 22% for CD19/CD34/CD45. In addition, cross-lineage antigen expression was detected in 45% of cases, mainly coexpression of the myeloid antigens CD13 and/or CD33 (40%). Parallel flow cytometric studies in different laboratories finally resulted in highly concordant results (>90%) for all five antibody combinations, indicating the high reproducibility of our approach. In conclusion, the technique presented here with triple-labelings forms an excellent basis for standardized flow cytometric MRD studies in multicenter international treatment protocols for precursor-B-ALL patients.

The PML-RAR alpha transcript in long-term follow-up of acute promyelocytic leukemia patients

BACKGROUND AND OBJECTIVES

Detection of PML-RAR alpha transcripts by RT-PCR is now established as a rapid and sensitive method for diagnosis of acute promyelocytic leukemia (APL). Although the majority of patients in long-term clinical remission are negative by consecutive reverse transcription polymerase chain reaction (RT-PCR) assays, negative tests are still observed in patients who ultimately relapse. Conversion from negative to positive PCR has been observed after consolidation and found to be a much stronger predictor of relapse. This study reports on 47 APL patients to determine the correlation between minimal residual disease (MRD) status and clinical outcome in our cohort of patients.

DESIGN AND METHODS

The presence of PML-RAR alpha t transcripts was investigated in 47 APL patients (37 adults and 10 children) using a semi-nested reverse transcriptase-polymerase chain reaction to evaluate the prognostic value of RT-PCR tests.

RESULTS

All patients achieved complete clinical remission (CCR) following induction treatment with all-trans retinoic acid (ATRA) and chemotherapy (CHT) or ATRA alone. Patients were followed up between 2 and 117.6 months (median: 37 months). Relapses occurred in 11 patients (9 adults and 2 children) between 11.4 and 19 months after diagnosis (median: 15.1 months) while 36 patients (28 adults and 8 children) remained in CCR. Seventy-five percent of patients carried the PML-RAR alpha long isoform (bcr 1/2) which also predominated among the relapsed cases (9 of 11) but did not associate with any adverse outcome (p= 0.37). For the purpose of this analysis, minimal residual disease tests were clustered into four time-intervals: 0-2 months, 3-5 months, 6-9 months and 10-24 months.

INTERPRETATION AND CONCLUSIONS

Children showed persisting disease for longer than adults during the first 2 months of treatment. At 2 months, 10 (50%) of 20 patients who remained in CCR and 4 (80%) of 5 patients who subsequently relapsed were positive. Patients who remained in CCR had repeatedly negative results beyond 5.5 months from diagnosis. A positive MRD test preceded relapse in 3 of 4 tested patients. The ability of a negative test to predict CCR (predictive negative value, PNV) was greater after 6 months (>83%), while the ability of a positive test to predict relapse (predictive positive value, PPV) was most valuable only beyond 10 months (100%). This study (i) highlights the prognostic value of RT-PCR monitoring after treatment of APL patients but only from the end of treatment, (ii) shows an association between conversion to a positive test and relapse and (iii) suggests that PCR assessments should be carried out at 3-month intervals to provide a more accurate prediction of hematologic relapses but only after the end of treatment.

BIOMED-1 concerted action report: flow cytometric characterization of CD7+ cell subsets in normal bone marrow as a basis for the diagnosis and follow-up of T cell acute lymphoblastic leukemia (T-ALL)

The European BIOMED-1 Concerted Action was initiated in 1994 to improve and standardize the flow cytometric detection of minimal residual disease (MRD) in acute leukemia (AL). Three different protocols were defined to identify the normal subsets of B, T and myeloid cells in bone marrow (BM), and were applied to the different types of AL in order to study aberrant immunophenotypes. Using sensitive acquisition methods ('live gate') T cell subsets in normal BM could be identified with five triple-stains: CD7/CD5/CD3, CD7/CD4/CD8, CD7/CD2/CD3, CD7/CD38/CD34 and TdT/CD7/surface or cytoplasmic (cy)CD3 (antibodies conjugated with FITC/PE/PECy5 or PerCP, respectively). The identification of T cell subsets in BM allowed definition of 'empty spaces' (ie areas of flow cytometric plots where normally no cells are found). All studied T-ALL cases (n = 65) were located in 'empty spaces' and could be discriminated from normal T cells. The most informative triple staining was TdT/CD7/cyCD3, which was aberrant in 91% of T-ALL cases. In most cases, two or more aberrant patterns were found. Apparently the immunophenotypes of T-ALL differ significantly from normal BM T cells. This is mostly caused by their thymocytic origin, but also the neoplastic transformation might have affected antigen expression patterns. Application of the five proposed marker combinations in T-ALL contributes to standardized detection of MRD, since cells persistent or reappearing in the 'empty spaces' can be easily identified in follow-up BM samples during and after treatment.

Standardized RT-PCR analysis of fusion gene transcripts from chromosome aberrations in acute leukemia for detection of minimal residual disease. Report of the BIOMED-1 Concerted Action: investigation of minimal residual disease in acute leukemia

Prospective studies on the detection of minimal residual disease (MRD) in acute leukemia patients have shown that large-scale MRD studies are feasible and that clinically relevant MRD-based risk group classification can be achieved and can now be used for designing new treatment protocols. However, multicenter international treatment protocols with MRD-based stratification of treatment need careful standardization and quality control of the MRD techniques. This was the aim of the European BIOMED-1 Concerted Action 'Investigation of minimal residual disease in acute leukemia: international standardization and clinical evaluation' with participants of 14 laboratories in eight European countries (ES, NL, PT, IT, DE, FR, SE and AT). Standardization and quality control was performed for the three main types of MRD techniques, ie flow cytometric immunophenotyping, PCR analysis of antigen receptor genes, and RT-PCR analysis of well-defined chromosomal aberrations. This study focussed on the latter MRD technique. A total of nine well-defined chromosome aberrations with fusion gene transcripts were selected: t(1;19) with E2A-PBX1, t(4;11) with MLL-AF4, t(8;21) with AML1-ETO, t(9;22) with BCR-ABL p190 and BCR-ABL p210, t(12;21) with TEL-AML1, t(15;17) with PML-RARA, inv (16) with CBFB-MYH11, and microdeletion 1p32 with SIL-TAL1. PCR primers were designed according to predefined criteria for single PCR (external primers A <--> B) and nested PCR (internal primers C <--> D) as well as for 'shifted' PCR with a primer upstream (E5' primer) or downstream (E3' primer) of the external A <--> B primers. The 'shifted' E primers were designed for performing an independent PCR together with one of the internal primers for confirmation (or exclusion) of positive results. Various local RT and PCR protocols were compared and subsequently a common protocol was designed, tested and adapted, resulting in a standardized RT-PCR protocol. After initial testing (with adaptations whenever necessary) and approval by two or three laboratories, the primers were tested by all participating laboratories, using 17 cell lines and patient samples as positive controls. This testing included comparison with local protocols and primers as well as sensitivity testing via dilution experiments. The collaborative efforts resulted in standardized primer sets with a minimal target sensitivity of 10-2 for virtually all single PCR analyses, whereas the nested PCR analyses generally reached the minimal target sensitivity of 10-4. The standardized RT-PCR protocol and primer sets can now be used for molecular classification of acute leukemia at diagnosis and for MRD detection during follow-up to evaluate treatment effectiveness.

[The use of peripheral blood progenitor cells as an autologous hematopoietic support in high-dose chemotherapy. I. The rationale and results]

We review the rationale for PBPC transplantation and the results reported in the literature. In order to prolong complete remissions and increase cure rates, high-dose chemotherapy is frequently used in the treatment of selected neoplasias. Hematological toxicity can be overcome by the infusion of autologous hemopoietic progenitors. Recently, peripheral blood is being used as the preferred source for hemopoietic progenitors, since it allows faster hematopoietic recoveries when compared to progenitors harvested from bone marrow. An adequate graft is defined by its content in clonogenic progenitors (mainly CFU-GM) and CD34 positive cells; these two parameters need to be accurately determined by specific laboratory methods. PBPC grafts are harvested using cell separators during leukaphereses; to increase efficiency, hemopoietic progenitors are first mobilized into the circulation with growth factors and or chemotherapy. PBSC transplantation may have procedure-associated toxicity related to the mobilization, harvest or reinfusion of the graft.

[The use of peripheral blood progenitor cells as an autologous hematopoietic support in high-dose chemotherapy. II. The experience of the Hematological Intensive Care Unit of the IPOFG. Franciso Gentil Portuguese Institute of Oncology]

We report the results of PBPC collection by large-volume leukaphereses and the hematologic recovery after high-dose chemotherapy supported by autologous PBPC reinfusion in a series of cancer patients treated at the Hematological Intensive Care Unit (UCHI) (Portuguese Institute of Oncology, Lisbon). Large volume leukaphereses were used to increase the efficacy of the PBPC collection. This modification of the standard apheresis technique allowed the harvesting, in only one session, of enough progenitors to proceed to transplantation in nearly 2/3 of patients and without significant toxicity. From December 1993 until September 1997, 95 autologous PBSC transplants were performed at the UCHI; 45% were performed in solid tumor patients and 55% in patients with hematologic malignancies. Hematologic recovery was similar to that published in the literature and related to the number of CD34+ cells infused. Patients supported with bone marrow in addition to PBPC showed delayed hematopoietic recovery, probably because the bone marrow harvest was only performed when an insufficient number of PBPC had been collected (2 x 10(6) CD34+ cells/Kg). The speed of hematological recovery differed per diagnosis, being higher in multiple myeloma and solid tumor patients and lower in Hodgkin's disease patients.

Flow cytometric analysis of normal B cell differentiation: a frame of reference for the detection of minimal residual disease in precursor-B-ALL

During the last two decades, major progress has been made in the technology of flow cytometry and in the availability of a large series of monoclonal antibodies against surface membrane and intracellular antigens. Flow cytometric immunophenotyping has become a diagnostic tool for the analysis of normal and malignant leukocytes and it has proven to be a reliable approach for the investigation of minimal residual disease (MRD) in leukemia patients during and after treatment. In order to standardize the flow cytometric detection of MRD in acute leukemia, a BIOMED-1 Concerted Action was initiated with the participation of six laboratories in five different European countries. This European co-operative study included the immunophenotypic characterization and enumeration of different precursor and mature B cell subpopulations in normal bone marrow (BM). The phenotypic profiles in normal B cell differentiation may form a frame of reference for the identification of aberrant phenotypes of precursor-B cell acute lymphoblastic leukemias (precursor-B-ALL) and may therefore be helpful in MRD detection. Thirty-eight normal BM samples were analyzed with five different pre-selected monoclonal antibody combinations: CD10/CD20/CD19, CD34/CD38/CD19, CD34/CD22/CD19, CD19/CD34/CD45 and TdT/CD10/CD19. Two CD19- immature subpopulations which coexpressed B cell-associated antigens were identified: CD34+/CD22+/CD19- and TdT+/CD10+/CD19-, which represented 0.11 +/- 0.09% and 0.04 +/- 0.05% of the total BM nucleated cells, respectively. These immunophenotypes may correspond to the earliest stages of B cell differentiation. In addition to these minor subpopulations, three major CD19+ B cell subpopulations were identified, representing three consecutive maturation stages; CD19dim/CD34+/TdT+/CD10bright/CD22dim/CD45dim /CD38bright/CD20- (subpopulation 1), CD19+/CD34-/TdT-/CD10+/CD22dim/CD45+/CD38bright/ CD20dim (subpopulation 2) and CD19+/CD34-/TdT-/CD10-/CD22bright/CD45bright/ CD38dim/CD20bright (subpopulation 3). The relative sizes of subpopulations 1 and 2 were found to be age related: at the age of 15 years, the phenotypic precursor-B cell profile in BM changed from the childhood 'immature' profile (large subpopulations 1 and 2/small subpopulation 3) to the adult 'mature' profile (small subpopulation 1 and 2/large subpopulation 3). When the immunophenotypically defined precursor-B cell subpopulations from normal BM samples are projected in fluorescence dot-plots, templates for the normal B cell differentiation pathways can be defined and so-called 'empty spaces' where no cell populations are located become evident. This allows discrimination between normal and malignant precursor-B cells and can therefore be used for MRD detection.

The nuclear topography of ABL, BCR, PML, and RARalpha genes: evidence for gene proximity in specific phases of the cell cycle and stages of hematopoietic differentiation

The mechanisms whereby chromosomal translocations are consistently associated with specific tumor types are largely unknown. A generally accepted hypothesis is that the physical proximity of the involved chromosomal regions may be one important factor in the genesis of these phenomena. Accordingly, a likely possibility is that such a proximity may occur in a cell-lineage and cell-differentiation stage-specific manner. In this work, we have addressed this issue using as models the ABL and BCR genes of t(9;22) and the PML and RARalpha genes of t(15;17). By using in situ hybridization and confocal microscopy, we have measured the distances between these two pairs of genes in three-dimensionally preserved hematopoietic cells belonging to different cell lineages, at various stages of differentiation, and at various stages of the cell cycle, with the following results. (1) Intergenic distances vary periodically during the cell cycle and a significant association of ABL with BCR and of PML with RARalpha is seen at the transition between S and G2, which persists during G2 and prophase (such a behavior is not observed for distances between ABL or PML and the beta-globin genes, used as a control). (2) The proportion of cells in which PML and RARalpha or ABL and BCR are closely associated is higher in hematopoietic precursors than in B-lymphoid cells (whereas the distances between ABL or PML and the beta-globin genes are not affected by cell type). (3) When intergenic distances in unstimulated bone marrow CD34(+) cells were compared with those in CD34(+) cells treated with interleukin-3 (IL-3), a trend towards a higher proximity of the ABL and BCR genes in the former and of the PML and RARalpha genes in the latter is observed. (4) Analysis of B-lymphoid cells during mitosis shows that intergenic distances at metaphase are strongly influenced by physical constraints imposed by the chromosomal location of the gene, by the size of the respective chromosome, and by the geometry of the metaphase plate. These findings suggest that intrinsic spatial dynamics, established early in hematopoiesis and perpetuated differentially in distinct cell lineages, may facilitate the collision of individual genes and thus reciprocal recombination between them at subsequent stages of hematopoietic differentiation.

Large-volume leukaphereses may be more efficient than standard-volume leukaphereses for collection of peripheral blood progenitor cells

To overcome the need for multiple leukaphereses to collect enough PBPC for autologous transplantation, large-volume leukaphereses (LVL) are used to process multiple blood volumes per session. We compared the efficiency of CD34+ cell collection by LVL (n = 63; median blood volumes processed 11.1) with that of standard-volume leukaphereses (SVL) (n = 38; median blood volumes processed 1.9). To achieve this in patients with different peripheral blood concentrations of CD34+ cells, we analyzed the ratio of CD34+ cells collected per unit of blood volume processed, divided by the number of CD34+ cells in total blood volume at the beginning of apheresis. For LVL, 30% (9%-323%) of circulating CD34+ cells were collected per blood volume compared with 42% (7%-144%) for SVL (p = 0.02). However, in LVL patients, peripheral blood CD34+ cells/L decreased a median of 54% during LVL (similar data for SVL not available). The number of CD34+ cells collected per blood volume processed after 4 and 8 blood volumes and at the end of LVL were 0.32 (0.01-2.05), 0.24 (0.01-1.68), and 0.22 (0.01-2.40) x 10(6) CD34+ cells/kg, respectively (p = 0.0007), despite the 54% decrease in peripheral blood CD34+ cells/L throughout LVL. A median 66% decrease in the platelet count was also observed during LVL. Thus, LVL may be more efficient than SVL for PBPC collection, allowing, in most patients, the collection in one LVL of sufficient PBPC to support autologous transplantation.

HTLV Tax gene expression in patients with lymphoproliferative disorders

AIMS

To study the expression of the human T lymphotropic virus (HTLV) Tax gene in peripheral blood mononuclear cells.

METHODS

Blood was collected from 72 patients with lymphoproliferative disorders. Serum from all patients was assayed for antibodies directed against HTLV-I structural proteins by ELISA and western blotting. RNA was purified from fresh blood cells and amplified by reverse transcription polymerase chain reaction (RT-PCR). After Southern blotting, the PCR products were hybridised with a 32P end-labelled probe specific for the Tax gene.

RESULTS

All samples were seronegative. A specific band for the Tax gene was found in five samples. Each of the patients positive for Tax gene expression had a different type of lymphoproliferative disorder.

CONCLUSIONS

Infection by HTLV-I cannot be assessed solely by immunological assays, particularly when only disrupted virions are used. Sensitive molecular biology assays are essential for detecting viral gene expression in fresh blood cells.

Natural killer cell numbers and activity in mobilized peripheral blood stem cell grafts: conditions for in vitro expansion

Peripheral blood stem cells (PBSC) are increasingly being used as an alternative to autologous bone marrow (BM) for hematologic rescue after high-dose chemoradiotherapy in the treatment of hematologic and nonhematologic malignancies. Mobilization procedures such as chemotherapy and/or hematopoietic growth factor administration are employed to allow for the graft enrichment in hematopoietic stem cells and progenitors and to accelerate trilineage recovery after transplant. The influence of these mobilization procedures on the lymphoid populations in the graft and on immunologic recovery after transplant remains to be determined. We studied six consecutive patients undergoing PBSC high-volume collections after cyclophosphamide (Cyc) and granulocyte colony-stimulating factor (G-CSF) administration and observed that NK cell numbers (phenotypically defined as CD3-CD56+ by flow cytometry) and activity (evaluated by a 51Cr release assay) fully recovered after 4-5 weeks; high numbers of functionally active NK cells (42.1-212.1 x 10(6)/kg b.w.) were present in the grafts, and their percentage and cytotoxic activity rose from the beginning to the end of the harvesting procedure in most cases. CD3-CD56+ and CD34+ cell numbers peaked at the same time point during harvesting, which differed from one patient to another. T (CD3+) cells were always present during harvest, and CD4 and CD8 numbers showed interdonor variability. When we cultured leukapheresed PBSC in the presence of interleukin-2 (IL-2) (10-1000 U/mL) for 6-8 days, we were able to expand the NK population three- to 5.4-fold; 100 U/mL appears to be the best concentration to generate high numbers of cytotoxic NK cells. Pilot studies also suggest that this short exposure to IL-2 does not affect the CD34+ cells. We conclude that PBSC grafts mobilized by combined Cyc and G-CSF and harvested through high-volume leukapheresis contain high numbers of cytotoxic NK cells that can be expanded in vitro by exposure to IL-2. In the setting of PBSC transplant, ex vivo immunomodulation aimed at increasing the NK cell numbers and activity is feasible and may prove to be useful in inducing a graft-vs.-tumor effect, thereby decreasing the relapse rate after transplant.

Splenic lymphoma with villous lymphocytes in two sisters

Splenic lymphoma with villous lymphocytes is a new entity characterised by the presence of atypical lymphocytes in the peripheral blood and bone marrow, and splenic infiltration in the white and red pulp. Cell membrane markers are those of a B mature cell, and no particular chromosomal abnormalities have been associated with this disease. A case of this rare lymphoma occurred in two sisters. Histological examination of splenic tissue was identical in both cases, with the same immunological surface markers, although the clinical and laboratory features were different. Karyotype analysis showed an abnormal pattern in one case; no environmental causative factor could be detected. Familial cases of other lymphoproliferative disorders have been reported, but no consistent common link has been found. It is suggested that further reports of this lymphoma, including cytogenetic and molecular studies, may provide a better understanding of the aetiology.

Configuration of immunoglobulin and T cell receptor beta and gamma genes in acute myeloid leukaemia: pitfalls in the analysis of 40 cases

AIMS

To evaluate the overall incidence of immunoglobulin (Ig) and T cell receptor (TCR) beta and gamma gene rearrangements in a series of 40 cases of acute myeloid leukaemia (AML) and to determine whether structural modifications of these genes could be correlated with the abnormal expression of lymphoid markers in malignant cells.

METHODS

All cases were classified according to the criteria of the FAB group and immunophenotyped with a panel of monoclonal antibodies reactive with myeloid and lymphoid differentiation antigens. DNA analysis was performed by the method of Southern using probes for the Ig JH, TCR-C beta 1, and TCR-J tau 1 regions.

RESULTS

Phenotypic analysis showed that in addition to myeloid markers, 10 cases expressed lymphoid antigens: CD7 in seven (of which three were TdT positive, one CD2 positive, and one CD19 positive) and CD19 in three. Southern blot analysis showed that bands with sizes different from the germ line control were present in the TCR beta genes in 11 cases: in six of 30 with pure myeloid phenotype and in five of 10 of those expressing lymphoid markers. A close observation of the size and patterns of those bands, however, showed that they could be artefactual. Indeed, further analysis showed that they were either due to resistant Eco RI/Hind III sites at the beta locus or to plasmid contamination. Rearranged genes were eventually found in only two of the 40 cases: at the Ig JH region in one of the 30 with pure myeloid phenotype (3.3%) and at the TCR gamma genes in one of 10 with lymphoid markers (10%).

CONCLUSIONS

These observations showed that Ig/TCR gene rearrangements were rare in this AML series (overall incidence of 5%) and that they were not significantly more common in cases with aberrant expression of lymphoid markers. The size and pattern of the potential non-germline bands that can be found in these loci must be carefully evaluated.

Terminal deoxynucleotidyl transferase positive acute myeloid leukaemia: an association with immature myeloblastic leukaemia

The morphology, membrane markers and ultrastructural cytochemistry of 39 cases of acute myeloid leukaemia (AML) with variable proportion (10-99%) of terminal deoxynucleotidyl transferase (TdT) positive blasts was compared with that of 134 cases of TdT negative AML. The incidence of TdT positive AML was 22.5% and this was significantly higher in poorly differentiated myeloblastic (M0 and M1) types (54%) than in all other FAB subtypes (10%; P less than 0.001). Our findings suggest heterogeneity among TdT positive cases. Whilst the majority correspond to genuine TdT positive AML in which evidence for exclusive myeloid nature was demonstrated by phenotypic, cytochemical and ultrastructural markers, a distinct minority (22%) of cases had mixtures of lymphoid and myeloid blasts. A change in phenotype occurred in three out of six cases studied in relapse. There was no difference in the incidence of immunoglobulin (Ig) gene rearrangement between TdT positive (two out of 12) and TdT negative (one out of 11) cases, although published data suggests that Ig gene rearrangement is significantly more common in TdT positive cases. The determination of TdT in AML allows the identification of cases of mixed acute leukaemia which probably represent proliferations of multipotent progenitor cells. The majority of TdT positive cases, nevertheless, correspond to immature types of myeloblastic leukaemia which may constitute a clinically distinct subgroup.

Cytochemical profile of megakaryoblastic leukaemia: a study with cytochemical methods, monoclonal antibodies, and ultrastructural cytochemistry

A cytochemical study using: Sudan black B; alpha-naphthyl acetate (ANAE) staining; estimation of alpha-naphthyl butyrate (ANBE) esterase activity; acid phosphatase activity; and 5' nucleotidase activity was carried out in 15 cases of megakaryoblastic leukaemia. These included cases of M7 acute myeloid leukaemia and blast crises of chronic granulocytic leukaemia. The megakaryoblastic nature of the blasts was first established using two monoclonal antibodies against platelet glycoproteins, and by estimating the platelet/peroxidase reaction at ultrastructural level. Our findings suggest that megakaryoblasts have a typical cytochemical profile comprising positive ANAE staining and acid phosphatase activity with a predominant localisation in the Golgi zone and negative or weak ANBE activity. A similar positive cytochemical pattern was also found in five cases of erythroleukaemia (M6). The specificity of the 5'nucleotidase activity for megakaryoblasts was not confirmed. In most cases of megakaryoblastic leukaemia there was no 5'nucleotidase activity only two cases showed positive reactions--reactions were positive in several cases of myeloblastic and lymphoblastic leukaemia. We suggest that cytochemical methods may be useful in diagnosing M6 and M7 acute leukaemia because less than 40% of leukaemic cells react with specific monoclonal antibodies.

Splenic B cell lymphoma with circulating villous lymphocytes: differential diagnosis of B cell leukaemias with large spleens

The clinical, haematological, morphological and histological features of a series of 22 patients presenting with splenic lymphoma with circulating villous lymphocytes were assessed and compared with those of patients with other forms of chronic B cell leukaemia in an attempt to differentiate this condition from hairy cell leukaemia, prolymphocytic leukaemia, and chronic lymphocytic leukaemia, with which this condition has many features in common. The disease was twice as common in men than in women, with a mean (SD) age at diagnosis of 72 (9) years, and the most consistent presenting feature was massive enlargement of the spleen, which showed white and red pulp disease with a plasmacytic component. Small monoclonal bands were found in 60% of cases.

Immunological reconstitution after bone marrow transplant with Campath-1 treated bone marrow

Immunological reconstitution after allogeneic bone marrow transplant (BMT) was studied in 20 patients who received Campath-1 treated bone marrow. The peripheral blood lymphocyte phenotype was analysed with a panel of monoclonal antibodies at 3, 6 and 12 months. T cell proliferative capacity was evaluated by stimulation with PHA and Con A and in the mixed lymphocyte reaction (MLR). Natural killer (NK) cell activity was analysed against the K562 cell line at specified times after BMT in nine patients. Absolute numbers of T lymphocytes were reduced in all patients at 3 and 6 months. A marked decrease in the number of CD4+ cells persisted beyond 12 months. CD8+ cells regenerated more rapidly and reached normal at 6 months. No correlation was found between changes in lymphocyte subpopulations and the presence of graft-versus-host disease or cytomegalovirus infection. B cells recovered rapidly and maintained normal numbers throughout the study. A moderate increase in HNK1+ (Leu7) cells was observed at 3 and 6 months simultaneously with a low expression of NK15 (Leu11) and OKM1 antigens at 3 and 6 months, suggesting the presence of immature NK cells early after the transplant. A profound decrease of T cell proliferative capacity was observed both after mitogen stimulation and in the mixed lymphocyte reaction. NK cell activity was raised during the first month after transplant in all but one patient but no correlation was found with the presence of GVHD or cell marker analysis.

The effect of 1,25-dihydroxyvitamin D3 on the relationship between growth and differentiation in HL-60 cells

Cells of the human promyelocytic leukaemia line HL-60 may be induced to differentiate along the monocytic lineage by the seco-steroid hormone 1,25-dihydroxyvitamin D3. We used fluorescence-activated cell sorting to show that, in addition to inducing differentiation, the hormone caused HL-60 cells to accumulate in G1/G0 phases of the cell cycle. We also labelled differentiating cells with both a monocyte-specific antibody and a DNA stain simultaneously. Analysis of these cell populations showed that, although cells acquired the differentiated phenotype irrespective of their position in the cell cycle, they eventually became arrested in G1/G0 as a consequence of differentiation. The normal relationship between differentiation and growth which is lost on malignant transformation is therefore restored by treatment of HL-60 cells with 1,25-dihydroxyvitamin D3.

Variant translocation t(8;22) and abnormalities of chromosome 15(q22) and 17(q12-21) in a Burkitt's lymphoma/leukaemia with disseminated intravascular coagulation

Severe disseminated intravascular coagulation was observed in a patient with Burkitt's lymphoma/leukaemia. Immunological studies on leukaemic blasts from relapsed bone marrow revealed a B-cell phenotype (B4+, B1+, HLA-Dr+, J5+) with membrane bound IgM lambda. Cytogenetic investigation revealed a variant Burkitt's translocation t(8;22)(q24;q11) involving the lambda light chain gene region and abnormalities of chromosomes 15 and 17 with breakpoints at q22 and q12 respectively, similar to those observed in the t(15;17) in acute promyelocytic leukaemia. Transmission electron microscopy of the leukaemic blasts showed crystalline cytoplasmic inclusions which may have had a role in precipitating the disseminated intravascular coagulation.

Philadelphia-positive metaphases in the marrow after bone marrow transplantation for chronic granulocytic leukemia

A 28-year-old man with Ph-positive chronic granulocytic leukemia (CGL) was treated by high-dose chemoradiotherapy and transplantation of marrow cells harvested from his HLA-identical brother. One year after bone marrow transplantation (BMT) examination of his marrow showed a minority population of Ph-positive cells; their proportion subsequently fell such that 2 years after transplant analysis of marrow cells showed only cytogenetically normal cells. The patient remains clinically normal with a persisting mild lymphocytosis but without hematological evidence of leukemia. We cannot in this patient distinguish between persisting leukemia that later could no longer be recognized and relapse of leukemia that is now suppressed, perhaps only temporarily. This case emphasizes the need for caution in interpreting chromosomal finding after BMT for CGL.

Correlation between chromosomal abnormalities and blast phenotype in the blast crisis of Ph-positive CGL

We carried out cytogenetic analysis in 23 patients with Ph-positive chronic granulocytic leukemia in blast crisis. In all cases the type of blast cell was characterized by cytochemistry, immunologic markers, and ultrastructural studies. Twelve cases were classified as myeloid transformation, six as lymphoid, two as mixed (lymphoid and myeloid), and two were unclassifiable. Duplication of Ph was the most frequent abnormality in the whole series. Trisomy 8, i(17q) and trisomy 19 were seen only in patients with myeloid blast crisis (53%, 30%, and 23%, respectively). Our findings suggest that the nature of additional chromosome abnormalities arising in blasts with features of myeloid differentiation are different from those in blasts showing lymphoid differentiation.

Monoclonal antibody OKT17 recognizes most cases of T-cell malignancy

Membrane phenotype analysis with monoclonal antibodies (McAb) has demonstrated great heterogeneity within the T-cell malignancies. We describe here the reactivity with an anti-T cell McAb, OKT17, in 80 leukaemia samples. Cells from all types of T-cell leukaemia (48 cases), except from the small group of pre-T-ALL, strongly expressed the antigen identified by OKT17 whereas none of the 32 non-T leukaemias were OKT17 positive. When the reactivity of OKT17 was compared with that of other pan-T markers, OKT17 was positive in a larger number of T-cell leukaemias: 87% of cases compared with 74% with E-rosettes and 73% with the McAb 3A1. In the mature or post-thymic proliferations OKT17 was positive in 96% of cases, compared with 77% with E-rosettes and 61% with 3A1. The latter reagent, on the other hand, was better than OKT17 for detecting leukaemias with a thymic phenotype, 100% and 68% of positive cases respectively. The combined use of OKT17, 3A1 and terminal transferase permits a more precise classification of all the T-cell leukaemias according to the main stages of T-cell differentiation.

Atypical promyelocytic leukemia (M3) with immature primary granules and t(15;17)

An unusual case of acute myeloid leukemia with a standard t(15;17) is described. While light microscopy morphology was suggestive of acute myeloid leukemia M5a and light microscopy cytochemistry showed 80% of blasts to be strongly positive with Sudan Black B--more consistent with a diagnosis of M4--ultrastructural analysis demonstrated that the predominant cells were promyelocytes with immature primary granules hardly visible with the Romanovsky stains by light microscopy. Because typical cytologic and clinical features of M3 or M3 variant were lacking this atypical case would not have been recognized but for the presence of t(15;17) and the demonstration of promyelocytic features by electron microscopy.

Primary plasma cell leukaemia: immunological and ultrastructural studies in 6 cases

The clinical and laboratory studies of 6 patients with primary plasma cell leukaemia are described. The leukaemic cells had a variable morphology, ranging from lymphoplasmacytic and mature plasma cells to poorly differentiated blasts. The neoplastic plasma cells had a characteristic phenotype: they were positive for CyIg and the McAb OKT10 and Ri-3, and did not express the B-cell antigens Ia, B1 and B4. Ultrastructural studies confirmed the plasma cell nature of the leukaemic cells and showed the presence of a meshwork of cytoplasmic fibrils in 50 to 90% of the neoplastic cells from all cases. The distinct ultrastructural and immunological features of PCL described in this study will help the diagnosis and further characterisation of this disease entity.

Characterization of myeloid leukemias with monoclonal antibodies 3C5 and MY9

The expression of two membrane antigens identified by the monoclonal antibodies (McAb) My9 and 3C5 has been investigated in cells from 80 acute leukemias. My9 was positive in the blasts of 33 out of the 38 (87 per cent) cases of acute myeloid leukemia (AML) tested, regardless of FAB subtype, and in 13 of 18 (72 per cent) cases of chronic granulocytic leukemia (CGL) in myeloid blast crisis. The reactivity of 3C5 was confined to myeloblastic (M1) AML, 85 per cent of cases, and to lymphoblastic leukemia (ALL) of B-lineage, 70 per cent of cases, including CGL in lymphoid transformation. My9 was negative in ALL except for an unusual case. The phenotype My9+, 3C5+ was seen exclusively in M1 (69 per cent) and M2 (14 per cent) AML. Ultrastructural analysis with the immunogold method in combination with the myeloperoxidase (MPO) reaction showed that expression of My9 increased in parallel with MPO activity whereas 3C5 was expressed mainly in myeloblasts with little MPO content. We conclude that the use of these two McAb will contribute to the diagnosis and classification of AML and may throw some light to the pathogenesis of biphenotypic acute leukemias, including TdT + AML.