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Biomedical subjects

I Schwarzinger

Publications and source records attributed to I Schwarzinger.

At least 37 records · Page 2Linked to original sources
PubMed2000

Low curative potential of bone marrow transplantation for highly aggressive acute myelogenous leukemia with inversioin inv (3)(q21q26) or homologous translocation t(3;3) (q21;q26).

Structural rearrangements of the long arm of chromosome 3 involving bands 3q21 and 3q26 and leading either to a paracentric inversion inv (3)(q21q26) or a translocation between both homologous chromosomes--t(3;3)(q21q26)-- have been reported in patients with acute myelogenous leukemia (AML), myelodysplastic syndromes, myeloproliferative disorders, and chronic myelogenous leukemia in blast crisis. We describe three patients with de novo AML with these structural abnormalities who received multiple courses of conventional chemotherapy followed by unrelated donor (n=2) and autologous (n = 1) bone marrow transplantation (BMT). All three patients had early relapse: patients 1 and 2 had relapse 69 days and 306 days after BMT, respectively, and patient 3 immediately after autologous BMT. Despite further chemotherapy, they died without achieving another remission. These findings, together with other recorded similar cases, show that AML with structural abnormalities of the long arm of chromosome 3 as described has an extremely poor prognosis even with the most potent anti-leukemic treatment modalities.

Adult↗
PubMed2000

Fludarabine therapy in Waldenström's macroglobulinemia.

Seven patients with macroglobulinemia (six previously untreated, one with minimal pretreatment) were treated with fludarabine (25 mg/m2/day for 5 days, repeated every 4 weeks). The median age was 58 years. The time from diagnosis to treatment with fludarabine was 4.5 months to 175 months (median 32.6 months). The patients received six (n =5), five (n =1), and three (n = 1) courses of fludarabine. One patient showed only a slight decrease of immunoglobulin (Ig) M (from 5,750 mg/dl to 4,700 mg/dl) and no improvement of anemia. Therefore, treatment was stopped after three cycles. In the other six patients, a marked reduction of IgM levels (from 6,140 mg/dl to 1,220 mg/dl median), a normalization of hemoglobin (from 10.8 g/dl to 12.3 g/dl median), a reduction of lymphocyte count (from 1992/>microl to 652/microl median), and a reduction of beta2 microglobulin (from 2.3mg/l to 1.8 mg/l median) were achieved. A 50% IgM reduction was achieved 5.4 months (median) after the beginning of therapy, and the maximum response was observed 17.3 months (median) after the end of treatment. The responses were sustained without further therapy in six patients for 20.8-55.2 months. In one patient, disease progression was observed 12.5 months after the end of therapy. Fludarabine therapy was well tolerated with few side effects. In three patients, febrile episodes occurred. No opportunistic infections were recorded. We conclude that fludarabine is an effective treatment in previously untreated or in minimally pretreated patients with Waldenström's macroglobulinemia.

Adult↗
PubMed2000

Excellent disease eradication by myeloablative therapy and stem-cell transplantation in patients with acute myelogenous leukemia.

Between February 1982 and 1999, 118 consecutive patients (65 male, 53 female) with acute myelogenous leukemia (AML), with a median age of 35 years (range 17-56 years), received stem-cell grafts from a human leukocyte antigen-identical sibling (n = 71), one-antigen-mismatched family member (n=2), matched unrelated donor (n=15), one-antigen-mismatched unrelated donor (n = 4) or an autologous (n = 26) graft. At the time of transplant, 56 patients were in the first complete remission (CR), 27 in the second CR, 6 in untreated relapse, 17 in primary refractory, and 12 in refractory relapse. The French-American-British classification (FAB) subtypes were as follows: M1 (n=25), M2 (n=28), M3 (n=11), M4 (n =32), M5 (n=16), M6 (n = 6). For conditioning, most patients underwent total body irradiation-containing regimens. As of 28 February, 1999, probability of leukemia-free survival (LFS) is 58% for patients after related and 45% after unrelated stem-cell transplantation (SCT). The probability of LFS is 70% for patients given allogeneic transplants in the first CR compared with 33% for those beyond the first CR at SCT. In autologous stem-cell graft recipients, the probability of LFS is 37%. Transplant-related mortality was 28% after related, 20% after unrelated, and 4% after autologous SCT. Probability of relapse for patients given related-donor stem-cell grafts in the first CR and beyond the first CR is 30% and 67%, 55% after unrelated and 63% after autologous stem-cell grafting. Thus, myeloablative therapy followed by allogeneic stem-cell infusion has a high curative potential for patients with AML in remission and offers substantial benefits to patients in advanced disease.

Adolescent↗
PubMed2000

Monitoring of minimal residual disease in patients with MLL-AF6-positive acute myeloid leukaemia by reverse transcriptase polymerase chain reaction.

We studied 210 unselected patients with acute myeloid leukaemia (AML) for MLL abnormalities. Twenty-seven patients (13%) with rearranged MLL genes were identified by means of Southern blot analysis. An MLL-AF6 fusion transcript was detected in six patients by a reverse transcriptase polymerase chain reaction (RT-PCR) for the MLL-AF6 translocation. Sequence analysis showed fusion of MLL exon 7 as well as exon 6 (two patients) or MLL exon 6 as well as exon 5 (four patients) to AF6 exon 2. In only three patients could the t(6;11) also be identified by cytogenetic and/or fluorescence in situ hybridization (FISH) analysis. The MLL-AF6-positive patients were monitored by RT-PCR for a period of 6-33 months. Complete haematological remission (CR) was achieved in all six cases, but was short in 5/6 patients (range 2.6-8.3 months). In these five patients, the MLL-AF6 transcripts were detected in every sample tested after induction and consolidation chemotherapy. One patient received autologous bone marrow transplantation (BMT) which also did not lead to PCR negativity. Intensive salvage therapy was unable to induce a second remission in the relapsed patients. One of the six MLL-AF6-positive patients achieved a molecular CR. He is still in CR at 33 months after diagnosis. Survival analysis indicates a poor prognosis in MLL-AF6-positive patients. The median event-free survival was 6.8 months, the median overall survival 15 months. Persistent PCR positivity was consistently associated with relapse. Thus, RT-PCR provides a valuable and sensitive tool for the identification of t(6;11)-positive AML and the monitoring of response to treatment in these patients. The results of RT-PCR may be useful to evaluate therapeutic procedures and to make treatment decisions, which will enable molecular remissions to be achieved and improve the clinical outcome in this group of patients.

Acute Disease↗
PubMed2000

High concordance of karyotype analysis and RT-PCR for CBF beta/MYH11 in unselected patients with acute myeloid leukemia. A single center study.

Identification of the inversion 16 in patients with acute myeloid leukemia (AML) is of great practical value since these patients have a relatively favorable prognosis, especially when treated with high-dose cytarabine. We compared the results of cytogenetic analysis and reverse transcriptase-polymerase chain reaction (RT-PCR) for core binding factor (CBF) beta/myosin heavy chain (MYH11) in 241 unselected cases of AML. In contrast with other studies, we found a high concordance between these 2 methods. Eighteen of 241 patients showed a cytogenetic anomaly of the chromosome 16. We detected the fusion transcript by RT-PCR in all 18 cases and in 2 additional patients with AML without any cytogenetic anomaly of chromosome 16. One patient had a normal diploid karyotype, and the second patient showed a trisomy 22 in karyotype analysis, which often is associated with inv(16). Only 8 of 20 CBF beta/MYH11-positive patients had M4Eo morphologic features. The much higher discrepancy between cytogenetic analysis and RT-PCR in other studies, especially in AMLs other than M4Eo, possibly indicates the necessity for PCR screening regardless of the French-American-British classification.

Acute Disease↗
PubMed1999

Hyperfibrinolysis in a case of myelodysplastic syndrome with leukemic spread of mast cells.

Mast cells (MC) are multipotent hemopoietic effector cells producing diverse mediators like histamine, heparin, or tissue type plasminogen activator. We report a 75-year-old male patient with myelodysplastic syndrome (MDS) of recent onset (3 months' history) associated with a massive leukemic spread of immature tryptase+ MC (tentative term: myelomastocytic leukemia). The patient presented with pancytopenia, bleeding, hypofibrinogenemia, and an increased cellular tryptase level. Moreover, an excessive elevation of plasmin-antiplasmin complexes (9,200 ng/ml; normal range: 10-150), an elevated D-dimer, and an increase in thrombin-antithrombin III complexes were found. The identity of the circulating MC was confirmed by immunophenotyping (CD117/c-kit+, CD123/IL-3R alpha-, CD11b/C3biR-), biochemical analysis (cellular ratio [ng:ng] of tryptase to histamine >1), and electron microscopy. Bone marrow (bm) examination showed trilineage dysplasia (17% blasts), 30% diffusely scattered MC, and a complex karyotype. No dense, compact MC infiltrates (mastocytosis) were detectable in bm sections. Despite hyperfibrinolysis and mediator syndrome (flushing, headache), the patient received remission induction polychemotherapy (DAV) followed by two cycles of consolidation with intermediate dose ARA-C (2 x 1 g/m2/day on days 1, 3, and 5). He entered complete remission after the first chemotherapy cycle without evidence of recurring MDS. Moreover, in response to chemotherapy, the hyperfibrinolysis and mediator syndrome resolved, and the circulating c-kit+ MC disappeared. We suggest consideration of polychemotherapy as a therapeutic option in patients with high-risk MDS of recent onset, even in the case of MC lineage involvement.

Aged↗
PubMed1999

Long-term follow-up of patients after related- and unrelated-donor bone marrow transplantation for chronic myelogenous leukemia.

Between January 1983 and December 1997, 88 patients (36 female, 52 male, median age 37 years, range 19-57) with chronic myelogenous leukemia (CML) underwent allogeneic bone marrow transplantation (BMT) at the University Hospital of Vienna. Sixty patients were in chronic phase, 18 in accelerated phase, and ten in blast crisis. Marrow donors were HLA-identical siblings for 64 patients (BM 58, PBSC 6), 2-antigen-mismatched related donors (RD) for two, HLA-identical unrelated donors (URD) for 17, and 1-antigen-mismatched URD for five. The median time from diagnosis to BMT was 22 months (range 2-91), and 63 patients had received prior interferon (IFN)-alpha therapy, 46 (73%) for more than 6 months. Conditioning therapy consisted of cyclophosphamide (CY) and total body irradiation (TBI) in 71 patients and CY and busulfan (BU) in 16. One patient received etoposide and TBI. For graft-versus-host disease (GVHD) prophylaxis methotrexate (MTX) was given to 12 patients, MTX and cyclosporin A (CSA) to 67, CSA alone to four, and CSA and methylprednisolone to five. Durable engraftment was documented in 80 of 82 patients (98%). As of December 31, 1997, 52 patients (59%) were alive, 38 (58%) after sibling transplantation with a median observation time of 73 months and 14 (64%) after URD transplantation with a median observation time of 12 months. Probability of overall survival is 59%, for patients undergoing transplantation in chronic phase and 44% for patients undergoing transplantation in advanced stage CML. Probability of disease-free survival (DFS) after sibling and URD BMT is 55% and 59%, respectively. Ten patients (12%) experienced relapse of CML. Transplant-related mortality was 32% both after RD and after URD transplantation. Acute GVHD occurred in 53 of 80 evaluable patients (66%), consisting of grade III or IV in 14 patients (18%). Chronic GVHD developed in 40 of 63 eligible patients (63%), including extensive disease in 26 patients (41%). Thus, sibling and URD BMT offer high cure rates with acceptable toxicity to patients with CML.

Acute Disease↗
PubMed1999

Low transplant-related mortality in patients receiving unrelated donor marrow grafts for leukemia.

Transplantation with unrelated donor (UD) marrow has been shown to potentially cure patients with leukemia. Between January 1991 and April 1998, 54 patients with leukemia have received an UD BMT at our institution. Five patients received their UD BMT as a second transplant after a preceding autologous or syngeneic BMT and were excluded from further analysis. Forty-nine patients with leukemia (acute leukemia n = 26; CML n = 23) and a median age of 36 years (range 19-51) were analyzed. For conditioning, all patients received a combination of fractionated TBI and CY. GVHD prophylaxis consisted of MTX and CsA in all patients. As of 30 April 1998, 27 of 49 (55%) patients survive after a median observation time of 18 months. The probability of overall survival for standard risk and high risk patients is 54% and 31% (P = 0.05). Probability of transplant-related mortality (TRM) is 27%, 24% in standard risk and 31% in high risk patients (P = 0.44). Patients younger than 40 years (n = 33) had a similar TRM as patients 40 years and older (n = 16). The probability of relapse is 41% for the whole group, 29% for standard risk and 55% for high risk pts (P<0.05). Our data confirm that UD BMT is an effective treatment for patients with leukemia. TRM is almost similar to related sibling BMT, most probably due to improvements in HLA typing technology, conditioning regimen and supportive patient care.

Adult↗
PubMed1999

Post-transplant acute myeloid leukemia (PT-AML).

Acute myeloid leukemia following organ transplantation (PT-AML) is a rare event with only a few published cases in the literature. We present three patients who developed AML (FAB M1, M5, M4) after renal, double lung or liver transplantation. Molecular analysis detected a t(9;11) in one patient and documented the recipient origin of AML in a second patient. All patients were treated with chemotherapy. Immunosuppression was reduced to cyclosporin A (CsA) and prednisone in two patients and to prednisone alone in one patient. Two patients achieved a complete remission (CR), with a remission duration of 4.6 months in one patient, the other patient died from septicemia after 15.2 months in CR. One patient was refractory to chemotherapy and died from septicemia. This report together with the documented cases in the literature suggests that PT-AML (1) develops after a median interval of 5 years after transplantation with variable latency (range, <1-17 years); (2) is heterogeneous with respect to FAB classification; (3) shows chromosomal and molecular changes typical of therapy-related AML (t-AML: -7, +8, 11q23, inv16, t(15;17)); (4) standard chemotherapy is feasible after reduction of immunosuppression and produces a CR rate of 56% with a median remission duration of 4.6 months and an overall survival of 2.6 months; (5) the major complications are early death (25%), gram-negative septicemia, progressive disease or relapse. This review provides diagnostic and therapeutic experiences and guidelines for the management of this increasing group of post-transplant patients.

Acute Disease↗
PubMed1999

Monitoring of minimal residual leukemia in patients with MLL-AF9 positive acute myeloid leukemia by RT-PCR.

Twenty-seven patients with AML and MLL gene rearrangement were analyzed by a reverse transcriptase polymerase chain reaction (RT-PCR) for the MLL-AF9 translocation. The MLL-AF9 fusion transcript was detected in six patients. In five patients, the breakpoint of the AF9 gene was located within the recently described site A; in one patient, a novel breakpoint (AF9 site D) mapped to a position 377 bp 3' of site A. Five patients could be serially monitored for a period of 4-23 months. Two patients became two-step PCR negative in bone marrow and peripheral blood. Molecular remission was achieved rapidly after one cycle of induction chemotherapy. Both patients are in continuous complete remission (CR) at 22 and 15 months, respectively. Two patients who had achieved hematological CR did not become PCR negative and MLL-AF9 fusion transcripts were detectable in all samples after induction and consolidation chemotherapy. One patient relapsed 5 months after achieving CR. The other patient received allogeneic bone marrow transplantation from an HLA-identical sibling 2 months after achieving hematological CR and became PCR negative 4 weeks after transplantation. In the fifth patient, hematological CR could not be achieved with two cycles of intensive induction chemotherapy, and MLL-AF9 transcripts were present in all samples tested. Our data indicate that MLL-AF9 RT-PCR is specific for the t(9;11) translocation. PCR negativity can be achieved in responding patients already 1 month after induction chemotherapy. The fast reduction of MLL-AF9 positive blast cells below the detection limit of RT-PCR seems to be a prerequisite for long-term CR. The results of RT-PCR may be useful for treatment decisions (eg BMT).

Acute Disease↗
PubMed1999

Quantification of minimal residual disease in patients with BCR-ABL-positive acute lymphoblastic leukaemia using quantitative competitive polymerase chain reaction.

We analysed 20 patients with BCR-ABL-positive acute lymphoblastic leukaemia (ALL) by quantitative competitive polymerase chain reaction (QC-PCR) to study the kinetics of the leukaemic clone. Consecutive samples of 16 patients (minor-bcr, n = 10; major-bcr, n = 6) were analysed after conventional chemotherapy and/or bone marrow transplantation (BMT). DNA competitor templates co-amplifying with either p210 or p190 BCR-ABL cDNA were used for quantification of leukaemia-specific BCR-ABL mRNA. In all samples, total ABL transcripts were measured as internal control, and the percentage of BCR-ABL/ABL molecules was calculated. Following induction chemotherapy the number of BCR-ABL transcripts was reduced by a maximum of 2-3 logs. In most patients, additional chemotherapy did not lead to further reduction of BCR-ABL mRNA. In two patients, conventional chemotherapy plus autologous BMT in complete haematological remission resulted in a total reduction of the transcript level of more than 3 logs. In two other patients, allogeneic BMT caused a transient reduction of the BCR-ABL transcripts below the detection level of our method (<1 blast cell in 105 normal cells) for a period of 7 and 11 months, respectively. The achievement of PCR negativity did not guarantee sustained remission. Both patients relapsed and BCR-ABL transcript levels rose by more than 1 log prior to frank relapse. Our data demonstrate that quantification of BCR-ABL mRNA allows the evaluation of the dynamics of the leukaemic clone and thus is valuable for the evaluation of minimal residual leukaemia following various therapies and the early detection of increasing BCR-ABL transcripts prior to relapse.

Adult↗
PubMed1999

The proportion of reticulated platelets is higher in bone marrow than in peripheral blood in haematological patients.

Since the detection that platelets originate from megakaryocytes (MK), the site of megakaryocyte fragmentation has been disputed. Some authors have even postulated that platelets are solely produced in the lungs. Thus, we have directly measured platelet generation in the bone marrow (BM) by comparing the relative number of young RNA-containing, so-called reticulated platelets (%RP) in the BM and in the peripheral blood (PB). Two separate prospective, cross sectional trials have been conducted in patients routinely undergoing BM biopsies for diagnostic purposes. In the first part of the study 30 patients with stem cell or bone marrow transplantation were examined. The second part of the study was performed in 62 haematological patients visiting the outpatient's clinic. Median %RP were higher in BM than in PB (p <0.001). In the second part of the study the difference averaged 133% (interquartile range: 30-383%). There was a moderate correlation between %RP in BM and in PB (r = 0.67; p <0.001). The absolute number of RP in PB correlated weakly with the number of megakaryocytes (0.42; p = 0.001), which was due to a correlation between the platelet counts and the megakaryocyte counts (r = 0.55; p <0.001 in biopsies). Two patients with autoimmune antibodies against GPIIb/IIIa exhibited 10% and 16% RP in PB, and had 29% and 59% RP in BM, respectively. It is concluded that the relative number of RP is significantly higher in BM than in blood. This supports the notion that platelets are at least in part released from MK in the bone marrow, particularly in patients suffering from immune thrombocytopenia.

Antigens, Surface↗
PubMed1998

Detection of mi transcription factor (MITF) mRNA in a case of myelodysplastic syndrome and bone marrow mastocytosis.

Myelodysplastic syndromes (MDS) may be accompanied by systemic mastocytosis. The mechanisms which play a role in the evolution of mastocytosis, however, are not well understood. We report on a case of refractory and anemia with ringed sideroblasts (RARS), and co-existing bone marrow mastocytosis. Compact mast cell (MC) infiltrates were detected in bone marrow sections by immunohistochemistry using an antibody to tryptase. In addition, the MC were found to express c-kit, the tyrosine kinase receptor for MGF (mast cell growth factor = stem cell factor, SCF). Activating point mutations in the kinase domain of c-kit (often found in mastocytosis) were not detectable. However, the mononuclear cells (MNC) of the bone marrow expressed mRNA specific for MITF, a transcription factor that regulates expression of c-kit and differentiation of MC. Surprisingly, the c-kit ligand SCF was found to augment expression of MITF mRNA in bone marrow MNC. Whether this augmentation represents a general response (preventing loss of growth factor receptor expression during cell maturation) common to all types of hemopoietic progenitors, or is confined to (some forms of) mastocytosis, remains unknown.

Aged↗
PubMed1998

Graft-versus-host disease following second syngeneic stem cell transplantation for relapsed chronic myeloid leukemia.

Allogeneic bone marrow transplantation is the only curative treatment for patients with Philadelphia chromosome-positive chronic myeloid leukemia (CML); however, recurrence of disease remains a major cause of treatment failure. A 26-year-old man with chronic myeloid leukemia who had a cytogenetic relapse 49 months after his first syngeneic bone marrow transplant (BMT) and hematologic relapse 23 months thereafter progressed to blast crisis despite treatment with IFN-alpha for 15 months. He underwent a second transplantation in early second blast crisis, 92 months after the first BMT with PBPC from his previous donor. Successful hematological reconstitution occurred. On day 50 after the second transplantation the patient developed a generalized rash, hepatomegaly, and cholestatic signs. Skin and liver biopsy revealed changes compatible with acute graft-versus-host disease (GVHD). Treatment with cyclosporin A (CSA) and prednisone was started, and the GVHD resolved. Fifteen months after PBPC transplantation he had a molecular relapse. Despite discontinuation of CSA, the patient progressed into blast crisis 7 months later. The occurrence of GVHD and disappearance of the BCR-ABL-positive clone suggest that a graft-versus-leukemia (GVL) effect may have been operative for 15 months in a patient given a second syngeneic BMT in blast crisis.

Adult↗
PubMed1998

Hypofibrinogenemia in non-M3 acute myeloid leukemia. Incidence, clinical and laboratory characteristics and prognosis.

Among 379 patients with AML with FAB type M1, 2 and M4-7 diagnosed between 1978 and 1997 in our institution, 19 (5%) had hypofibrinogenemia (HF), ie a fibrinogen level <180 mg/dl. Compared to patients with normal fibrinogen (n = 360) patients with HF had significantly elevated markers of activation of coagulation (TAT, F1.2, FPA) and fibrinolysis (D-dimer, FDP) indicating that disseminated intravascular coagulation/hyperfibrinolysis was the cause of hypofibrinogenemia. Patients with HF had significantly longer prothrombin times, thrombin clotting and reptilase times. Factor X and VIII were significantly lower than in patients without HF. With the exception of M7, HF occurred in all FAB subtypes, but was most common in M5 (12.1%). Patients with HF did not differ from those with normal fibrinogen with regard to age, sex, leukocyte count and other hematological parameters. During induction chemotherapy fibrinogen normalized rapidly (median 5 days) and there was no increased incidence of early hemorrhagic death. The overall and disease-free survival was similar to that of patients without HF.

Adult↗
PubMed1998

Recombinant human megakaryocyte growth and development factor increases levels of circulating haemopoietic progenitor cells post chemotherapy in patients with acute myeloid leukaemia.

By participating in a randomized safety and efficacy study of pegylated-recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) post induction and consolidation chemotherapy for de novo acute myeloid leukaemia, serial determinations of circulating haemopoietic progenitor cells were performed during 18 chemotherapy courses in eight patients (three receiving placebo; one, 2.5; and four, 5.0 microg/kg/d MGDF, respectively). Whereas failure to achieve complete remission (CR) was generally associated with poor progenitor cell increments following chemotherapy, substantial progenitor cell mobilization consistently occurred during haemopoietic recovery in patients entering, or in CR, with significantly higher peak values in patients receiving 5 microg/kg/d of MGDF as compared to controls. The median increases of progenitor cell numbers by chemotherapy alone and chemotherapy plus 5.0 microg/kg/d MGDF over that in normal individuals with steady-state haemopoiesis were 10- and 45-fold for CFU-GM, 3- and 17-fold for BFU-E, and 2- and 18-fold for CFU-mix. CFU-Mk levels were not increased above normal by chemotherapy alone but were 15-fold enhanced by chemotherapy plus MGDF. Recruitment of CD34+ cells post chemotherapy was also potentiated by MGDF. Our results suggest MGDF as a potent agent to augment progenitor cell mobilization after successful induction or consolidation chemotherapy in patients with AML.

Acute Disease↗
PubMed1998

Systemic mastocytosis associated with acute myeloid leukaemia: report of two cases and detection of the c-kit mutation Asp-816 to Val.

A subset of patients with systemic mastocytosis (SM) develop acute myeloid leukaemia (AML). However, little is known about the biology of such leukaemias and their relationship to the mast cell (MC) lineage. We report on two female patients who suffered from SM and AML. According to FAB criteria, the leukaemias were classified as AML-M4 (patient 1) and AML-MO (patient 2). The coexistence of the two distinct neoplasms (AML and SM) was demonstrable by immunostaining of serial bone marrow (BM) sections with monoclonal antibodies (mAb). In particular, the MC infiltrates were found to react with mAb against MC-tryptase and MC growth factor receptor c-kit (CD117), but not with mAb to CD15 or CD34. In contrast, the AML blasts were immunoreactive for CD15 (patient 1) or CD34 (patient 2), but did not express tryptase. The c-kit point mutation Asp-->Val at codon 816, considered to play a role in the transformation of MC progenitors, was detected in patient 1 in a BM cell fraction containing 4% MC. However, no c-kit mutation was found in pure AML blasts (<1% MC). These findings argue against an evolution of the AML clone from neoplastic MC or MC-committed progenitors.

Acute Disease↗