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H Löffler

Publications and source records attributed to H Löffler.

At least 109 records · Page 6Linked to original sources
PubMed1995

Clinical, morphologic, cytogenetic and prognostic implications of CD34 expression in childhood and adult de novo AML.

Expression of CD34 by leukemic blasts was analyzed in 230 pediatric and 251 adult patients with de novo AML enrolled in two large multicenter trials (AML-BFM-87 and AMLCG respectively). The association between CD34 positivity and morphological classification according to FAB criteria, cytogenetic aberrations, immunophenotypic features and clinical characteristics was investigated. CD34 was expressed (> or = 20%) by leukemic cells from 45% of childhood and 43% of adult AML patients. CD34+ AML was often associated with M1/M2 morphology as well as the coexpression of CD7 and TdT. Translocation t(8;21), inv(16) and chromosome 5 and 7 aberrations were more frequently observed in CD34+ AML. There was a low frequency of CD34 expression in infant AML but no age dependency was evident in adult patients. CD34 expression exerted no influence on the rate of complete remissions (CR) after intensive multidrug induction therapy. In adults, 56% of the CD34-positive and 64% of CD34-negative cases achieved CR (P = 0.29), and the childhood trial even revealed a slight advantage for CD34+ AML with a CR rate of 80% vs. 71% for CD34-negative cases (P = 0.068). Long-term follow-up disclosed no significant differences in remission duration or event-free survival between the CD34-positive and CD34-negative groups. In conclusion, CD34+ AML patients comprise a heterogeneous group with good as well as poor risk factors. Though characterized by some distinct features, CD34 lacks prognostic significance in de novo AML patients submitted to intensive polychemotherapy.

Adolescent↗
PubMed1995

AML M1 and M2 with eosinophilia and AML M4Eo: diagnostic and clinical aspects.

AML with eosinophilia belongs to the morphologic cytogenetic entity M1/M2 t(8;21) with the involvement of the genes AML1/ETO. These eosinophils differ only slightly from normal eosinophils with one rare exception i.e. Auer rods in eosinophils which has only been found on peroxidase staining: This subtype belongs to the good prognosis group of AML. AML with inv(16) (mostly M4Eo) per se is a morphologic-cytogenetic entity with inv(16),--rarely t(16;16), and the genes MYL 11/CBF beta involved. The eosinophils show special abnormalities. AML with inv(16) also belongs to the good prognosis group of AML.

Bone Marrow↗
PubMed1995

Acute megakaryoblastic leukemia.

In 1985 acute megakaryoblastic leukemia was included in the FAB classification system of hematological neoplasias with the designation of AML M7. It occurs in all age groups with two peaks in distribution. The one is in adults and the other in children 1 to 3 years of age especially in those with Down's syndrome. The diagnosis of AML M7 requires more than 30% of the nucleated bone marrow cells being megakaryoblasts. The more common types of AML MO-M6 have to be excluded by morphological and cytochemical analysis whereas immunology is needed to exclude ALL. The megakaryocytic nature of the leukemia has to be proven by ultrastructural demonstration of platelet peroxidase or by immunological demonstration of CD61, CD42, CD41 on the surface of the leukemic blasts. Megakaryocytic/megakaryoblastic leukemias show a wide morphologic spectrum. In some instance small cells dominate, clearly showing megakaryocytic differentiation with scant amounts of cytoplasm and with nuclei showing dense chromatin. On the other hand, there are cases with larger cells resembling ALL-L2 blasts with moderate amounts of rather basophilic cytoplasm which in some instances contain azurophilic granules. Cytoplasmic blebs and protrusions are the most prominent feature of many cases. The nuclei of these cells are round with more finely reticulated chromatin and with prominent nucleoli. The megakaryoblastic nature of these cells can be suggested by morphology. However, according to our experience there are cases of c-ALL with the very same morphologic picture. Consequently, immunologic phenotyping of these cases is necessary in any instance. Cytochemistry is of limited diagnostic value in megakaryoblastic leukemias. Usually it is used to exclude the more common types of leukemia.

Adult↗
PubMed1995

G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: comparison of T cell depletion strategies using different CD34+ selection systems or CAMPATH-1.

Allogeneic transplantation of granulocyte colony-stimulating factor (G-CSF)-mobilized peripheral blood progenitor cells (PBPC) appears to be an attractive alternative to allogeneic bone marrow transplantation (BMT). However, because vast amounts of potentially graft-vs.-host-reactive T cells are transfused with PBPC grafts, the use of PBPC in the allogeneic setting may be associated with an increased incidence or severity of graft-vs.-host disease (GVHD). To evaluate strategies for prevention of GVHD after PBPC allografting, we have studied T cell depletion (TCD) of G-CSF-mobilized PBPC samples harvested from six healthy donors and from five patients scheduled for autologous PBPC transplantation. Three approaches (CAMPATH-1 plus autologous complement [C], immunomagnetic CD34+ cell selection, and biotin-avidin-mediated CD34+ cell selection) were compared. TCD of PBPC samples with the monoclonal antibody (MAb) CAMPATH-1 plus autologous C resulted in a median elimination of 2.16 log CD3+ T cells, whereas 39% of CD56+ natural killer (NK) cells and 56% of CD34+ progenitor cells were recovered. TCD by CD34+ cell selection with the Isolex (Baxter, Munich, Germany) or Ceprate (CellPro, Bothell, WA) devices achieved median depletions (Isolex vs. Ceprate) of 4.04 vs. 3.12 log T cells and > 5 vs. 3.27 log NK cells while allowing the recovery of 36 vs. 27% CD34+ cells. The median purity of CD34+ cells in the final product was 1.7 (CAMPATH-1), 94 (Isolex), and 65% (Ceprate). We conclude that all methods tested effectively deplete T cells from PBPC preparations harvested from healthy donors. Whereas immunomagnetic CD34+ selection is most effective in terms of elimination of T cells, the less intensive T and NK cell depletions achieved with CAMPATH-1 might be advantageous with regard to retaining engraftment potential and graft-vs.-leukemia (GVL) activity of PBPC allografts.

Adolescent↗
PubMed1995

Radiation-induced alterations of the proliferation dynamics of human skin fibroblasts after repeated irradiation in the subtherapeutic dose range.

PURPOSE: The aim of this study was to determine the effect of single and multiple irradiations on the differentiation and proliferation pattern of the stem cell system of human fibroblasts. METHODS: The pattern of differentiation of fibroblast cultures was analyzed by morphological criteria using colony forming assays. Proliferation rates were assessed by cell counting and measuring the incorporation of BrdU. RESULTS: Ionizing radiation both in low and high dose ranges exerts differential effects on the cellular processes of differentiation and proliferation in human fibroblasts. Single irradiations of fibroblasts in the dose range of 1 to 8 Gy induced terminal differentiation into postmitotic fibrocytes at high percentage level. Irradiation of long-term cultures of fibroblasts with repeated doses of 0.2, 0.6 and 1.0 Gy revealed that only in cultures, which were irradiated repeatedly (x 10) with 0.6 and 1.0 Gy a marked reduction of the proliferation capacity was apparent. Inhibition of proliferation by repeated irradiations with cumulative doses up to 10 Gy was not more pronounced as compared to single irradiations. CONCLUSION: 1. These results of radiation-induced changes in the proliferation and differentiation pattern of cells may be a basis for the understanding of the cellular processes leading to radiation-induced fibrosis and tissue aging. 2. Multiple irradiations with single doses up to 1 Gy and cumulative doses up to 10 Gy did not change the radiosensitivity of fibroblast cultures regarding effects on cell proliferation.

Cell Differentiation↗
PubMed1995

Rapid engraftment of peripheral blood progenitor cell grafts purged with B cell-specific monoclonal antibodies and immunomagnetic beads.

PBPC harvesting was performed in two patients with advanced-stage low-grade non-Hodgkin's lymphoma after mobilization with dexa-BEAM chemotherapy plus G-CSF. The collected grafts were subjected to immunomagnetic purging using B cell-specific moAbs and paramagnetic beads. Immunophenotypic and/or molecular analysis of the resulting products (PCR amplification of t(14;18) or CDR-III rearrangements) demonstrated successful depletion of lymphoma cells. Rapid and durable hematopoietic recovery occurred after reinfusion of the purged grafts following myeloablative radiochemotherapy (9-10 days to neutrophils > 0.5 x 10(9)/l; 9-11 days to platelets > 20 x 10(9)/l). We conclude that effective immunomagnetic purging of PBPC grafts is feasible without affecting engraftment.

Antibodies, Monoclonal↗
PubMed1994

Randomized comparison of interferon-alpha with busulfan and hydroxyurea in chronic myelogenous leukemia. The German CML Study Group.

As curative bone marrow transplantation is available only to a minority of patients with chronic myelogenous leukemia (CML), drug therapy remains of central interest. Several nonrandomized studies have suggested that interferon-alpha (IFN) may prolong survival in CML. In a randomized multicenter study the influence of IFN versus busulfan or hydroxyurea (HU) on survival of Philadelphia-positive (Ph+) CML was examined. A total of 513 Ph+ patients were randomized for treatment as follows: 133 for IFN, 186 for busulfan, and 194 for HU. IFN-treated CML patients have a significant survival advantage over busulfan-treated (P = .008), but not over HU-treated patients (P = .44). The longer survival is due to slower progression to blast crisis. Median survival of IFN-treated patients is 5.5 years [5-year survival, 59%; 95% confidence interval (CI), 48%-70%], of busulfan-treated patients, 3.8 years (5-year survival, 32%; CI, 24%-40%), and of HU-treated patients, 4.7 years (5-year survival, 44%; CI, 36%-53%). Patients who continue on IFN survive longer than those in whom IFN is discontinued before blast crisis (P = .007). Complete hematologic IFN-responders have a survival advantage over partial responders or nonresponders (P = .02). Cytogenetic IFN-responders have no significant survival advantage over nonresponders (P = .2). Patients who attain white blood cell (WBC) counts of 10 x 10(9)/L or less have a survival advantage in the IFN (P = .007) and HU (P = .05) groups. Whereas toxicity in the IFN group was considerably higher than in the busulfan or HU groups, long-lasting cytopenias necessitating discontinuation of therapy as observed with busulfan have not been seen with IFN or HU. The problems of conventional prognostic scores (Sokal's score, Score 1) that we observed in IFN-treated patients support the idea that IFN changes the natural course of CML. We conclude that, with regard to survival of CML in the chronic phase, IFN is superior to busulfan and as effective as HU. Whether and to what extent IFN is superior to HU appears to depend, at least in part, on the degree of WBC suppression by HU-therapy and on the risk profile of the patients.

Adolescent↗
PubMed1994

Disseminated histoplasmosis in a non-immunocompromised host.

Histoplasma infections in Europe are rare, and acute disseminated histoplasmosis has only been observed in immunocompromised persons. We describe a case of acute disseminated histoplasmosis in a young, nonimmunocompromised European woman. The probable source of infection was Sri Lanka or the Maldives. At presentation she was severely ill with fever, lymphadenopathy, anemia, thrombocytopenia, hepatosplenomegaly, and polyserositis. Histologically, myelofibrosis and osteosclerosis were observed with extramedullary hematopoiesis. Histoplasma capsulatum yeasts were detected in bone marrow trephine biopsy by methenamine silver staining. Treatment with conventional and liposomal amphotericin B and subsequent itraconazole led to rapid and complete recovery.

Acute Disease↗
PubMed1994

Morphology and cytochemistry of acute lymphoblastic leukaemia.

ALL is characterized by small to medium sized leukaemic blasts with a rather low grade of cell-to-cell variability. The nucleocytoplasmic ratio is high with just a small cytoplasmic rim in many cases. The cytoplasm tends to be moderately basophilic. Usually, though not in each instance, it is agranular and free of vacuoles. The chromatin is more condensed than in AML and the nucleoli tend to be indistinct. The FAB classification of haematological malignancies separates ALL into three categories: ALL L1, L2, and L3. However, just the identification of the L3 variant is of major importance. The L3 cells are medium sized to large and are characterized by intensely basophilic and moderately abundant cytoplasm with prominent cytoplasmic vacuolation in the bone marrow but not necessarily in the peripheral blood. According to our experience there is a high but not universal correlation of the L3 phenotype as defined by morphology with the immunologically defined B-ALL with surface expression of immunoglobulins. Until recently, acute leukaemias proving negative for all cytochemical tests especially for the PAS reaction and for the focal type of acid phosphatase, were termed 'acute undifferentiated leukaemia' (AUL). However, this morphological/cytochemical diagnosis may be confused with the immunological diagnosis of unclassifiable leukaemia. Since almost any of these cases can be recognized as ALL or AML by immunology, the term AUL should be reserved for cases which can be classified neither by morphology/cytochemistry nor by immunology. The morphological and cytochemical distinction of ALL from poorly differentiated AML remains a problem, especially if the FAB criteria for distinguishing ALL from AML by cytochemistry (3% of the blasts positive for peroxidase) are applied rigidly. A small but significant percentage of poorly differentiated leukaemias have less than 3% of the blasts positive for peroxidase and the myeloid nature of the leukaemia can be identified by cytochemistry. The absence of blasts being positive for peroxidase is no reliable indicator for the lymphatic nature of a leukaemia, even if the PAS reaction is typical for ALL. The morphological diagnosis of ALL needs confirmation by immunology in each instance.

Adult↗
PubMed1994

G-CSF-mobilized peripheral blood progenitor cells for allogeneic transplantation: safety, kinetics of mobilization, and composition of the graft.

Allogeneic transplantation of peripheral blood progenitor cells (PBPC) makes the general anaesthesia of the donor unnecessary and may result in more rapid engraftment and faster recovery of the immune system. We have studied G-CSF-mediated PBPC mobilization in healthy donors and analysed the cellular composition of the resulting PBPC grafts. PBPC grafts were obtained from nine healthy donors (18-67 years old) for allogeneic or syngeneic transplantation. Six donors received 10 micrograms/kg G-CSF per day, the others 5-6 micrograms/kg. Mobilization and harvesting were well tolerated except for moderate bone pain which occurred in all donors primed with 10 micrograms/kg. With 10 micrograms/kg, a 31-fold (9-62) enrichment of circulating CD34+ cells was observed with peak values constantly occurring on day 5 after the start of G-CSF administration. Starting harvest on day 5, one to three collections on consecutive days yielded 5.5 x 10(6)/kg (0.9-10.7) CD34+ cells, 219 x 10(6)/kg (106-314) T cells, and 34 x 10(6)/kg (23-67) NK cells per 10 litres leukapheresis volume. Altogether, PBPC grafts contained 3 times more CD34+ cells, 7 times more T cells, and 20 times more NK cells than five allogeneic marrow grafts that were analysed for comparison. The yield of CD34+ cells per 10 litres apheresis volume as well as the height of the CD34+ peak in peripheral blood were inversely correlated to the age of the donor. In the donors primed with 5-6 micrograms/kg G-CSF the increase of circulating CD34+ cells (4-7-fold enrichment) and the CD34+ cell yield per 10 litres leukapheresis volume (1 x 10(6)/kg [0.8-2.2]) was much smaller compared with the 10 micrograms/kg group. In conclusion, sufficient amounts of PBPC capable of restoring haemopoiesis in allogeneic recipients can be mobilized safely by administration of G-CSF (10 micrograms/kg s.c. for 5 d) in healthy donors, and harvested with one or two leukapheresis procedures. Whether the large numbers of T-cells and NK cells that are contained in the collection products may influence graft-versus-host and graft-versus-leukaemia reactivities of PBPC grafts remains to be determined.

Adolescent↗
PubMed1994

Immunophenotypic features of childhood and adult acute lymphoblastic leukemia (ALL): experience of the German Multicentre Trials ALL-BFM and GMALL.

Immunophenotyping prospectively performed in about 2800 children and adults within the framework of the German multicentre ALL trials revealed marked differences in frequency distribution of immunologic subgroups with a higher incidence of immature B-cell precursor and pre-T/T phenotypic features in adults. Detailed immunophenotypic characterization by applying monoclonal antibodies to lymphoid- and myeloid-associated antigens as well as non-lineage-restricted molecules underlined the diagnostic value of pan-B and pan-T antigens that were expressed in virtually all cases of B-cell precursor (CD19, CD24) or T-cell ALL (cytoplasmic CD3, CD7) for lineage affiliation of leukemic blasts. About 10% of children and 20% of adults disclosed simultaneous expression of lymphoid markers and at least one myeloid-lineage-associated antigen. Our data confirm that immunophenotyping in ALL provides a solid basis for a biologically oriented and reliable classification of this heterogeneous disease.

Adult↗
PubMed1994

Solitary fibromastocytic tumor arising in an inguinal lymph node: the first description of a unique spindle cell tumor simulating mastocytosis.

A 77-yr-old man presented with a right inguinal mass. At herniotomy, an enlarged inguinal lymph node was also removed. Gross examination revealed a firm gray tumorous nodule measuring 3 cm in maximum diameter. On histological examination, the lymphatic tissue was found to have been almost completely replaced by spindle-shaped tumor cells arranged in whorls and bundles. In Giemsa-stained sections, about one-third of the tumor cells were seen to be strongly metachromatic tissue mast cells. The other tumor cells reacted only with a monoclonal antibody against vimentin out of a broad panel of antibodies directed against various antigens expressed by leukocytes, mesenchymal cells, and epithelial cells. A small fraction of the nonmetachromatic tumor cells reacted with the proliferation-associated antibody MIB1. Immunostaining with an antibody against p53 tumor-suppressor gene products was negative. Electron-microscopic examination revealed mast cells containing abundant granules, which were intermingled with fibroblasts that had bizarre, elongated nuclei. No myofibroblasts, desmosomes, or basement membrane material were detected. Clinical examination revealed no abnormalities, and blood and bone marrow findings were completely normal. A diagnosis of solitary (apparently benign) fibromastocytic tumor was established on the basis of the relative tumor cell numbers, the cytological features, and the clinical data. To the authors' knowledge, this is the first description of a solitary spindle cell tumor arising in a lymph node and simulating mastocytosis.

Aged↗
PubMed1993

Randomized comparison of busulfan and hydroxyurea in chronic myelogenous leukemia: prolongation of survival by hydroxyurea. The German CML Study Group.

In a randomized multicenter study the influence of hydroxyurea versus busulfan on the duration of the chronic phase and on survival of chronic myelogenous leukemia (CML) was determined. In addition cross resistance and adverse reactions of the drugs were analyzed. From July 1983 to January 1991, 441 CML patients were randomized to receive hydroxyurea or busulfan. Of these, 90.7% were Philadelphia positive; 25.7% were low, 38.2% intermediate, and 36.2% high risk patients according to Sokal's score. The median survival of the busulfan treated Philadelphia-positive patients is 45.4 months and of the hydroxyurea group 58.2 months (P = .008). The survival advantage for the hydroxyurea treated patients is recognized in all risk groups. Sixty four patients reached therapy resistance before blast crisis and were crossed over to the alternative drug. The 23 patients with primary hydroxyurea had a median survival of 5.6 years, the 41 patients with primary busulfan therapy a median survival of 2.7 years (P = .02). Adverse reactions were less frequent with hydroxyurea with no severe adverse effects (lung fibrosis, long lasting bone marrow aplasia). The analysis of white blood cell counts in the course of treatment showed lower counts in the hydroxyurea patients. We conclude that hydroxyurea is superior to busulfan in therapy of CML in chronic phase and should be used as first line therapy. Busulfan may have a role as secondary therapy after hydroxyurea resistance or intolerance.

Blast Crisis↗
PubMed1993

Amplification of a Y-chromosomal DNA sequence by the polymerase chain reaction for documentation of residual recipient cells in small samples from bone marrow, peripheral blood and cerebrospinal fluid after bone marrow transplantation.

The long arm of the human Y-chromosome contains about 800 to 5000 copies of the tandemly repeated DNA sequence DYZ1. A major part of the repeating unit (pHY10) has been cloned and sequenced. Primers were designed to match a part of this repeat sequence for the amplification of a 154 bp fragment spanning the EcoRI restriction site of the unit. Typical dilution experiments showed that this polymerase chain reaction (PCR) method allows the detection of 5 to 10 male cells among 100,000 female cells, or in 500 microL of cerebrospinal fluid containing only one cell per microL. In addition, the quality of the DNA used for the amplification reaction is less critical, thus allowing analysis of long-term stored samples such as bone marrow smears or dried blood stains spotted onto filter paper, which might contain partially degraded DNA. We applied this technique to detect residual host cells in the clinical setting of human sex-mismatched bone marrow transplantation (BMT). Fourteen patients, receiving transplantations because of leukemias could be supervised so far. Throughout the whole period of monitoring (days +14 until +911 post BMT; median: 160 days), residual host cells were detected in all but three patients. Persistence of host cells in the early phase post-BMT was mostly transient and probably due to long-term surviving host T-lymphocytes. Reappearance of host cells several months after BMT is highly suspicious of relapse from the underlying malignancy. Due to its high sensitivity, PCR is a valuable tool in monitoring the switch from recipient to donor cell population.(ABSTRACT TRUNCATED AT 250 WORDS)

Base Sequence↗