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Leukemia cutis in congenital leukemia. Analysis and review of the world literature with report of an additional case.

BACKGROUND: Congenital leukemia cutis is rarely reported in the dermatology literature despite various authors citing 50% of infants with congenital leukemia have skin involvement. These seemingly disparate facts prompted a review of the world literature that was performed by searching the MEDLINE database from 1966 up to and through December 1992, reviewing Index Medicus for the years prior to computerized MEDLINE search, and reviewing appropriate case report references. OBSERVATIONS: A 2-month premature male infant was born with 182 x 10(9)/L circulating monoblasts, prominent hepatosplenomegaly, and multiple firm blue and red cutaneous nodules. CONCLUSION: Approximately 175 cases of congenital leukemia have been reported with at least 41 and possibly 56 cases identified with leukemia cutis. Specific cutaneous leukemic infiltrates occur in 25% to 30% of infants with congenital leukemia and usually appear as firm blue, red, or purple nodules in a generalized distribution. In contrast to the 50% incidence of gingival and oral infiltrates reported in adult monocytic leukemia, only 1% of congenital leukemia patients have oral involvement. Congenital leukemia cutis may precede other manifestations of leukemia by as much as 4 months. Whereas leukemia cutis is associated with a poor prognosis in adult leukemics, the natural history of congenital leukemia is not altered by leukemia cutis.

Humans↗

Suppression of murine leukemias by L-asparaginase. Incidence of sensitivity among leukemias of various types: comparative inhibitory activities of guinea pig serum L-asparaginase and Escherichia coli L-asparaginase.

A survey of 109 recently derived leukemias of the mouse revealed that sensitivity to suppression by guinea pig serum is a common property of transplanted leukemias of certain classes. The sensitive leukemias included five that arose spontaneously in mice of strains with a low incidence of leukemia and 21 that were induced by X-radiation. Two GPS-sensitive leukemias were not more sensitive than a GPS-resistant leukemia to a range of standard chemotherapeutic agents. The effectiveness of L-asparaginase EC-2 from Escherichia coli in suppression of the GPS-sensitive leukemia EARAD1 depends upon the conditions of assay. Whereas it is not inhibitory when administered as a single dose at the time of inoculation of the leukemia it is considerably more effective than GPS when used in the treatment of established leukemia. Permanent cures of 7-day generalized transplants of EARAD1 can be effected by the administration of 2000 or more units of EC-2. Immunological factors apparently do not contribute to cure as treated survivors are fully susceptible to rechallenge with minimal numbers of cells from the same leukemia. Reinoculated survivors with progressively growing transplants have been successfully retreated with EC-2. The blood clearance of EC-2 L-asparaginase injected into mice is much more rapid than that of GPS L-asparaginase. After intraperitoneal inoculation of the EC-1 L-asparaginase, which does not have leukemia-inhibitory activity, only very low levels of enzyme activity could be detected in the serum. The effectiveness of EC-2 from E. coli and its availability from a virtually limitless source will make it possible to extend the study of inhibition of leukemias and other tumors by L-asparaginase to species other than small rodents.

Amidohydrolases↗

Expression of L-myc and N-myc proto-oncogenes in human leukemias and leukemia cell lines.

The myc proto-oncogenes encode nuclear phosphoproteins, which are believed to participate in the control of cell proliferation and differentiation. Deregulated expression of c-myc has been implicated in several human hematopoietic malignancies. We have studied the expression and mRNA processing of human L-myc, N-myc, and c-myc genes in a panel of human leukemias, leukemia cell lines, and normal hematopoietic cells. L-myc mRNA was expressed in three acute myeloid leukemias (AML) studied and in several myeloid leukemia cell lines. Only low expression levels were observed in adult bone marrow and in fetal spleen and thymus. The K562 and Dami leukemia cell lines showed a unique pattern of L-myc mRNA processing, with approximately 40% of L-myc mRNA lacking exon III and intron I. N-myc was expressed in five of six AML cases studied, in one of nine acute lymphocytic leukemia (ALL) cases, and in several leukemia cell lines, while c-myc mRNA was detected in all leukemias and leukemia cell lines studied. Coexpression of all three myc genes was observed in Dami and MOLT-4 cell lines and in two AMLs, and either L-myc or N-myc was coexpressed with c-myc in several other cases. These results show that in addition to c-myc, the L-myc and N-myc genes are expressed in some human leukemias and leukemia cell lines, and suggest a lack of mutually exclusive cross-regulation of the myc genes in human leukemia cells.

Blotting, Northern↗

Features and outcome of neonatal leukemia in Japan: experience of the Japan infant leukemia study group.

BACKGROUND: Neonatal leukemia characterized by early stem cell origin and extramedullary infiltration in the first 4 weeks of life is rare. We analyzed the features and outcome of neonatal leukemia in Japan to establish an appropriate treatment strategy for this rare disorder. PROCEDURE: Patients with infant leukemia registered and treated in the Japan Infant Leukemia Study between 1996 and 2001 were analyzed. RESULTS: Among 162 infant leukemia patients, 11 exhibited neonatal leukemia; frequencies for all infant leukemias were 6.9% (8/116) for acute lymphoblastic leukemia (ALL) and 7.3% (3/41) for acute myeloid leukemia (AML). Positive MLL gene rearrangement was observed in all eight patients with ALL; a single patient with AML displayed germline configuration. Acute monoblastic leukemia was apparent in all three patients with AML (M5a in the FAB classification). Most of the patients demonstrated hepatoplenomegaly and hyperleukocytosis at diagnosis. Cutaneous and central nervous system involvement were detected in half of the patients. Four patients (one with AML, and three with ALL) have survived following stem cell transplantation (SCT); however, growth impairment related to SCT was observed in these patients. CONCLUSIONS: These results suggest an improvement attributable to treatment of neonatal leukemia. International-based collaborative studies are necessary to investigate the biology of this condition and to establish appropriate therapeutic strategies.

Acute Disease↗

Leukemia induction by a new strain of Friend mink cell focus-inducing virus: synergistic effect of Friend ecotropic murine leukemia virus.

A new strain of Friend recombinant mink cell focus-inducing retrovirus, FMCF -1-E, was found to induce leukemias in NFS and IRW mice. Although the isolate was obtained from a stock of FMCF -1 ( Troxler et al., J. Exp. Med. 148:639-653, 1978), FMCF -1-E was distinguishable from FMCF -1 by oligonucleotide fingerprinting and antigenic analysis, using monoclonal antibodies. These analyses suggested that FMCF -1-E is a distinct FMCF isolate rather than a simple variant of FMCF -1. After neonatal inoculation, the latency for leukemia induction was 3 to 8 months. A similar long latency was also seen when Friend murine leukemia virus 57 was inoculated into adult (6-week-old) IRW mice. However, sequential inoculation of FMCF -1-E at birth followed by Friend murine leukemia 57 at 6 weeks of age led to a shortened latency period (2.5 to 4 months). Only neonatal inoculation of Friend murine leukemia virus 57 was able to induce a more rapid appearance of leukemia. The leukemia cell type in the majority of cases, regardless of virus inoculation protocol, was erythroid, but occasional myeloid, lymphoid, and mixed leukemias were also observed. In contrast to NFS and IRW mice, BALB/c mice were resistant to leukemia induction by FMCF -1-E and also showed some transient resistance to leukemia induction by Friend murine leukemia virus 57.

Animals↗

Phenotyping of Evi1, Evi11/Cb2, and Evi12 transformed leukemias isolated from a novel panel of cas-Br-M murine leukemia virus-infected mice.

Cas-Br-M murine leukemia virus (MuLV) is a slow-transforming retrovirus that potently induces leukemias in mice and therefore is well suited for retroviral insertional mutagenesis. We used Cas-Br-M MuLV in NIH/Swiss mice to establish a new panel of mainly myeloid leukemias. All tumors found in leukemic animals were classified by gross pathology, morphology, and immunophenotype, as well as the incidence of known common virus integration sites (VISs) in MuLV-induced myeloid malignancies (i.e., Evi1, Evi11/Cb2, Evi12, Fli1, and c-Myb). Interestingly, male mice were more susceptible than females to the induction of leukemia by Cas-Br-M MuLV. Seventy-four of the Cas-Br-M MuLV-inoculated mice developed a severe splenomegaly, sometimes in association with a thymoma. Although most of the immunophenotyped Cas-Br-M MuLV tumors were of myeloid origin (58%), numerous T-cell leukemias (21%) and mixed myeloid/T-cell leukemias (21%) were found. The myeloid leukemias and myeloid compartment of the mixed leukemias were further characterized by immunophenotyping with stem cell-, myeloid-, and erythroid-specific antibodies. The known Cas-Br-M MuLV common VISs (Evi1, Evi11/Cb2, and Evi12) were demonstrated in 19%, 12%, and 20% of the cases, respectively, whereas no Fli1 and c-Myb rearrangements were found. Integrations into Evi1 were restricted to myeloid leukemias, whereas those in Evi11/Cb2 and Evi12 were identified in myeloid as well as T-lymphoid leukemias. This panel of well characterized Cas-Br-M MuLV-induced hematopoietic tumors may be useful for the isolation and characterization of new proto-oncogenes involved in myeloid or T-cell leukemias.

3T3 Cells↗

The role of B7 costimulation by murine acute myeloid leukemia in the generation and function of a CD8+ T-cell line with potent in vivo graft-versus-leukemia properties.

Relapse is more frequent after autologous than allogeneic bone marrow transplantation (BMT), due in part to lack of T-lymphocyte mediated allogeneic graft-versus-leukemia (GVL) effects. Infusions of leukemia-reactive T cells to patients after autologous BMT may be a means for providing a GVL effect. Costimulation of T cells by binding of the CD28 receptor on T cells with B7-counter receptors on antigen presenting cells amplifies antigen-specific T-cell responses. To enhance generation of leukemia reactive cytotoxic T lymphocytes (CTL), the murine B7-1- and B7-2-costimulatory molecule cDNAs were introduced into the MHC class I+, class II-, murine meyloid leukemia cell line C1498. B7-1 expression greatly enhanced the ability of the leukemia cells to generate and expand leukemia reactive CTL in vitro. A highly cytolytic and C1498 specific CD8+ CTL line was generated by B7-1 costimulation. This CTL line proliferated autonomously and produced interleukin-2 when provided B7-1 or B7-2 costimulation by C1498 leukemia cells. To test the in vivo antileukemia properties of this CTL line, irradiated syngeneic BMT recipients were given graded doses of leukemia cells on day 0, followed by CTL infusions beginning on day 1 post-BMT. Recipients of 10(7) CTL had a 3 log reduction in leukemia burden such that 100% of mice were protected from a supralethal leukemic cell dose. Sustained immune responses were detectable up to 3 months postinfusion of the CTL line. B7-1 or B7-2 costimulation in vivo did not augment antileukemia effects of infused CTL post BMT. These results suggest that B7 costimulation of leukemia reactive CTL may be important for their ex vivo generation and expansion for use in human adoptive immunotherapy of leukemia.

Acute Disease↗

Clinical relevance of circulating immune complexes in human leukemia. Association in acute leukemia of the presence of immune complexes with unfavorable prognosis.

The occurrence of circulating immune complexes was investigated in 467 serum samples from 230 leukemia patients using the [(125)I]Clq-binding test. There was an increased serum [(125)I]Clq-binding activity in 40% of patients with acute myeloid leukemia, 23% with acute lymphatic leukemia, 46% in blastic crisis of chronic myeloid leukemia, 12% with chronic lymphatic leukemia, and 13% with chronic myeloid leukemia. In 48 patients, serum was also tested for soluble immune complexes by the Raji cell radioassay; the correlation between results of the two tests was significant. The Clq-binding material had properties identical with those of immune complexes. It sedimented as 14-28s material on sucrose density gradient. It contained IgG which could be dissociated at acid pH. Its Clq-binding properties could be removed after passage through anti-IgG immuno-absorbant or after a mild reduction-alkylation treatment, but were not sensitive to deoxyribonuclease treatment. Circulating immune complexes were found most commonly during the blastic stage of leukemia.Remission took place in 75.4% of patients with no detectable circulating immune complexes at the onset of acute leukemia, but in only 32.7% of those with detected complexes during this period. Median survival times of the former group of patients were more than 18 mo in acute myeloid leukemia and acute lymphatic leukemia and more than 8(1/2) mo in blastic crisis of chronic myeloid leukemia. The corresponding median survival times in the latter patient group were 64, 135, and 90 days. These findings were unrelated to prognostic features already known.

Adolescent↗

The expression pattern of erythrocyte/megakaryocyte-related transcription factors GATA-1 and the stem cell leukemia gene correlates with hematopoietic differentiation and is associated with outcome of acute myeloid leukemia.

To understand the clinical implications of transcription factors and their biologic roles during cellular differentiation in the hematopoietic system, we examined the expression of GATA-1, GATA-2, and stem cell leukemia (SCL) gene in human leukemia cell lines and various leukemia patients using the reverse transcriptase-polymerase chain reaction. Cell lines exhibiting megakaryocytic or erythrocytic phenotypes had GATA-1, GATA-2, and SCL gene transcripts, while monocytic cell lines had no detectable GATA-1, GATA-2, or SCL gene mRNA. In some myeloid cell lines, GATA-1 expression, but not SCL gene expression, was detected; GATA-1 expression in HL-60 cells was downregulated during the process of monocytic differentiation. We next examined GATA-1, GATA-2, and SCL gene expression in 110 leukemia samples obtained from 76 patients with acute myeloid leukemia (AML), 19 with acute lymphoblastic leukemia (ALL), and 15 with chronic myeloid leukemia in blast crisis (CML-BC). SCL gene expression was usually accompanied by GATA-1 expression and was preferentially detected in patients with leukemia exhibiting megakaryocytic or erythrocytic phenotypes, while patients with monocytic leukemia were clustered in the group with no detectable GATA-1 expression. None of the patients with ALL or CML-lymphoid-BC expressed SCL. De novo AML patients with SCL gene expression had a lower complete remission (CR) rate and had a significantly poorer prognosis. Among the patients with AML not expressing SCL, a high percentage of patients with CD7+ AML and CD19+ AML had detectable GATA-1, while patients with GATA-1-negative AML had the best CR rate (87.5%). Our results suggest that the expression pattern of transcription factors reflects the lineage potential of leukemia cells, and GATA-1 and SCL gene expression may have prognostic value for the outcome of patients with AML.

Acute Disease↗

Enzymatic differences between chronic lymphocytic leukemia and prolymphocytic leukemia.

Chronic lymphocytic leukemia and prolymphocytic leukemia of the B-cell immunophenotype are closely related disorders, but differ in their cytomorphologic and clinical features. In an attempt to differentiate further between these two forms of leukemia, we measured adenosine deaminase and purine nucleoside phosphorylase activities by using a linked-enzyme spectrophotometric assay on peripheral-blood leukemic cells from seven patients with chronic lymphocytic leukemia, three patients with prolymphocytic leukemia, and one patient with prolymphocytoid transformation of chronic lymphocytic leukemia. By using discriminant analysis, we were able to distinguish the two groups only on the basis of purine nucleoside phosphorylase activity (F1,9; p less than 0.001). The purine nucleoside phosphorylase activity in leukemic cells with prolymphocytic cytomorphology was significantly elevated (mean = 58.6 nM/min/mg protein) compared to the activity in leukemic cells with lymphocytic cytomorphology (mean = 25.6 nM/min/mg protein). There was only one patient with chronic lymphocytic leukemia who was assigned to the prolymphocytic leukemia group on the basis of her purine nucleoside phosphorylase activity. Our study suggests that purine nucleoside phosphorylase activity in leukemic cells may be useful in the distinction of prolymphocytic leukemia from chronic lymphocytic leukemia, and that it may be an enzymatic marker for the early detection of prolymphocytoid transformation of chronic lymphocytic leukemia.

Adenosine Deaminase↗

Cancer and leukemia group B leukemia correlative science committee: major accomplishments and future directions.

The Cancer and Leukemia Group B (CALGB) Leukemia Correlative Science Committee (LCSC) has a remarkable history of outstanding productivity and has been at the cutting edge of correlative science for adult leukemia for almost 25 years. Its work, initially focused on the use of immunophenotyping for diagnosis and prognosis of acute lymphoblastic leukemia and acute myeloid leukemia, has, for the last 15 years, focused on the clinical use of cytogenetic and molecular genetic markers in acute myeloid leukemia and acute lymphoblastic leukemia as well as in chronic lymphocytic leukemia. Numerous CALGB LCSC studies have had a major effect on the way we currently diagnose, predict outcome, select appropriate treatment, document complete remission, and monitor residual disease in adults with acute leukemia. In part as a result of the work of the CALGB LCSC, we are increasingly moving toward molecularly targeted therapy in acute and chronic leukemias. In this report, we briefly review those contributions from the CALGB LCSC that have had, or are likely to have in the future, a major effect on how we currently manage leukemia and outline directions of ongoing and future research conducted by the CALGB LCSC.

Adult↗

Specific killing of human T-leukemia cells by immunotoxins prepared with ricin A chain and monoclonal anti-human T-cell leukemia antibodies.

In this study, immunotoxins containing monoclonal anti-human T-cell leukemia antibodies are shown to be capable of specific killing of human T-leukemia cells in vitro. These immunotoxins were prepared by conjugating ricin A chain (RIA) with our recently generated murine monoclonal antibodies, SN1 and SN2, the latter of which was obtained from a hybridoma clone N6/D11 described previously by Negoro and Seon (Cancer Res., 42: 4259-4262, 1982), directed to two unique human T-cell leukemia antigens. We have shown previously that these monoclonal antibodies do not react with non-T-leukemia cells nor with various normal cells including normal T-cells, thymocytes, and bone marrow cells (Proc. Natl. Acad. Sci. U. S. A., 80: 845, 1983; Cancer Res., 42: 4259, 1982). Control conjugate was also prepared by conjugating RIA with a murine monoclonal immunoglobulin G (IgG), the isotype of which is the same as that of SN1 and SN2, i.e., IgG1-kappa. In initial experiments, the cytotoxic activity of an SN1 IgG:RIA conjugate preparation and the control IgG conjugate preparation against leukemic T-cell lines and normal B-cell lines was tested by two different test procedures, i.e., by measuring direct killing of the cells and by measuring inhibitory activity against protein synthesis in the cells. In each test, the SN1 conjugate showed specific cytotoxic activity against T-leukemia cells, whereas the control conjugate was not cytotoxic against either T-leukemia cells or normal B-cells. Nearly complete killing of T-leukemia cells and inhibition of protein synthesis in T-leukemia cells were observed at the concentrations of 10(-8) to 10(-7) M of the SN1 IgG:RIA conjugate. In subsequent experiments, another preparation of SN1 IgG:RIA conjugate and an SN2 IgG:RIA conjugate preparation were tested individually and together for their inhibitory activity against protein synthesis in T-leukemia cells and control cells. With T-leukemia cells, specific inhibition was observed for both SN1 IgG:RIA and SN2 IgG:RIA. The combined use of these conjugates did not display a synergistic effect. Nevertheless, the combined use of different immunotoxins directed to different antigen molecules will be important in clinical use, since uncultured tumor cells derived freshly from patients, in general, display heterogeneity with respect to the expression of tumor-associated antigens. These immunotoxins may be useful for the in vitro eradication of tumor cells in the bone marrow taken from patients with T-cell leukemia.(ABSTRACT TRUNCATED AT 400 WORDS)

Antibodies, Monoclonal↗

Clinical aspects of infant leukemia--experiences of a single institution of Japan: high level of serum immunoglobulin M in infant leukemia.

The prognosis and clinical and biological characteristics of infant leukemia differ from those of leukemia in children 1 year or older. We reviewed the charts of patients younger than 1 year in whom leukemia was diagnosed from January 1981 through December 2003 at our institution. Fourteen infants had leukemia, 6 had acute lymphoblastic leukemia (ALL), and 8 had acute myeloid leukemia (AML). The age of patients at diagnosis ranged from 2 to 11 months. Five of 8 AML patients presented with cutaneous manifestations, such as erythema and nodules, at diagnosis. Central nervous system (CNS) involvement was seen in 1 AML patient at diagnosis. Hyperleukocytosis of more than 50 x 10(9)/L was seen in 4 of 6 ALL patients and in 4 of 8 AML patients at diagnosis. All ALL patients showed a morphological diagnosis of L1 using the French-America-British classification system. For patients with AML, the morphological diagnoses were M0 for 1 patient, M2 for 1 patient, M4 for 2 patients (1 with eosinophilia), M5b for 2 patients, and M7 for 2 patients. One patient showing M7 morphology had Down syndrome. Surface markers were examined in 5 of 6 ALL patients and all AML patients. Five ALL patients showed a B-cell precursor immunophenotype. Two of 5 patients with ALL had CD10-positive leukemic cells and 3 of 5 patients with ALL had CD10-negative leukemic cells. All AML patients were positive for CD13 or CD33 or both. Three of 5 patients with ALL showed abnormal chromosomes related to 11q. Six of 7 patients with AML showed abnormal karyotypes. MLL gene rearrangements were seen in 3 (2 ALL, 1 AML) of 5 (2 ALL, 3 AML) patients. Serum immunoglobulin M levels were increased in 9 of 14 patients. Complete remission (CR) was achieved in all infants with ALL. Three patients relapsed and then died of the original disease. One of these 3 patients died after cord blood transplantation. Three ALL patients are alive without leukemia. CR was achieved in 6 of 8 AML patients. Four of 6 patients are alive without leukemia. Infant leukemia patients in our institution had some special features. CNS involvement at diagnosis was seen in only 1 patient and serum IgM levels were higher than those in children whose leukemia was diagnosed at 1 to 10 years of age.

Chromosome Aberrations↗

Terminal deoxynucleotidyl transferase (TdT)-positive cells in cerebrospinal fluid and development of overt CNS leukemia: a 5-year follow-up study in 113 children with a TdT-positive leukemia or non-Hodgkin's lymphoma.

We investigated whether an indirect nuclear terminal deoxynucleotidyl transferase (TdT) immunofluorescence (IF) assay on single cells present in the cerebrospinal fluid (CSF) is more effective than conventional cytomorphology for early detection or exclusion of (minimal) meningeal leukemic infiltration in patients with a TdT+ malignancy. During a 5-year follow-up study, 1,661 consecutive CSF samples from 113 children with a TdT+ acute lymphoblastic leukemia (ALL) (n = 100), a TdT+ acute nonlymphoblastic leukemia (ANLL) (n = 8), or a TdT+ non-Hodgkin's lymphoma (NHL) (n = 5) were analyzed. In 1,511 (91.9%) of 1,643 evaluable CSF samples, the positive and negative findings of both cytomorphology and the TdT-IF assay were concordant. In 47 (2.9%) samples from 28 patients, the cytomorphology was suspect while the TdT-IF assay was negative; follow-up as long as 58 months revealed no CNS leukemia in any patient. In 85 (5.2%) samples, cytomorphology was negative (n = 70) or suspect (n = 15) but TdT+ cells were detected. RBC contamination seriously hampered evaluation in 31 of these 85 samples. From the remaining 54 TdT+ samples from 29 patients, 40 samples preceded overt CNS leukemia in 20 patients. Two consecutive findings of TdT+ cells in the CSF were always followed by overt CNS leukemia. At initial diagnosis, 11 children had TdT+ cells in their RBC-free CSF. In one of these children, morphology was suspect; a repeated lumbar puncture was positive on both assays. Thus, initial CNS leukemia was diagnosed. In the other ten children, morphology was negative. In six of them, CNS leukemia was diagnosed 2 to 20 months later. In 32 other children examined at initial diagnosis, neither TdT+ cells nor blasts were observed in the CSF. In none of these patients was a CNS leukemia diagnosed after a follow-up of 2.5 to 57 months (median 24 months). In 207 control CSF samples from 58 children with TdT- oncologic, hematologic, or infectious diseases, no TdT+ cells could be detected. The TdT-IF assay is easy to perform and is a more reliable diagnostic tool for detection of CNS leukemia at an early stage than is cytomorphology. At initial diagnosis, the finding of Tdt+ cells in a RBC-free CSF sample with a negative cytomorphology is highly predictive for development of overt CNS leukemia.

Brain Neoplasms↗

Leukemia-associated phenotypes: their characteristics and incidence in acute leukemia.

Leukemia-associated phenotypes have been suggested to be a valuable tool for the detection of minimal residual disease in acute leukemia patients, as they allow to distinguish leukemic blasts from normal hematopoietic progenitor cells. The aim of the present study was to analyze the proportion of acute leukemia patients (both with lymphoid and myeloid leukemias) in which the immunological detection of leukemia-associated phenotypes was convenient for the distinction of leukemic and normal cells. For this purpose we have studied the blast cells from 186 acute leukemia patients at diagnosis with a large panel of monoclonal antibodies by flow cytometry using double staining combinations. From aberrant phenotypes on blast cells we followed lineage infidelity (coexpression of myeloid markers in lymphoid leukemia cells and vice versa, as well as the simultaneous expression of both, T and B cell markers in one lymphoid blast cell) and asynchronous marker expression (simultaneous expression of early and late markers in one cell). One hundred and five of the 186 acute leukemia cases analyzed (56%) showed the presence of leukemia-associated phenotypes. In 41 of the 90 ALL cases followed (46%) and in 40 of the 96 AML cases studied (42%) lineage infidelity was observed. Asynchronous antigen expression was detected in 24 followed cases (13%). Evaluation of the cell marker density by means of calibration microbeads demonstrated abnormal mean channel immunofluorescence and molecules of equivalent soluble fluorescein for CD8 in two patients with T cell malignancies at diagnosis. Abnormal CD8 density might thus represent a characteristic feature of malignant CD8-positive T cell clone. Quantitative marker evaluation therefore seems to be another important mean for the detection of aberrant phenotypes on leukemia cells suitable for the detection of minimal residual disease.

Acute Disease↗