Ettore Mariano Schiavone

All-Trans Retinoic Acid (ATRA) and the Regulation of Adhesion Molecules in Acute Myeloid Leukemia

A review of recent information on the expression and the ATRA-driven modulation of cell surface adhesion molecules of acute myelogenous leukemia blast cells is presented. Cytofluorometric studies on fresh blast cells have demonstrated that CD11a, CD11b CD11c, CD15, CD45RO and CD54 expression is significantly lower in acute promyelocytic leukemia (APL) than is acute myeloid leukemia of other subtypes (AML). In vitro treatment with ATRA dramatically modifies the adhesion phenotype of APL blast cells, promoting a consistently striking up-regulation of CD11b, CD11c, CD15, CD65, CD54, and CD38. Which is in general, poorly demonstrable in AML. The behaviour of CD15s is variable and fully independent from CD15 and CD65 in induction experiments, suggesting a differential enzyme regulation within the selectin ligand system. ATRA is capable, in both APL and AML, of producing a switch from the high- (RA) to the low- (RO) molecular weight isoform of CD54, Moreover, treatment with this retinoid exerts a negative regulation of the membrane expression of CD49e, CD58 and CD11a in APL as well as in AML. Of particular interest is the fact that the negative effect on CD1 1a expression generates an asynchronous phenotype in APL (CD11a-, CD11b+, CD15+), undetectable on normal maturing myeloid cells. In the last part of this review the possible implications of adhesion molecule modulation in the pathogenesis of ATRA syndrome are discussed.

ALL-TRANS RETINOIC ACID PROMOTES A DIFFERENTIAL REGULATION OF ADHESION MOLECULES ON ACUTE MYELOID LEUKAEMIA BLAST CELLS

Summary. In the present study we investigated the membrance expression of selectin ligands (CD15/Lex, CDw65/VIM2, CD15s/sLex), β2 integrins (CD11a/LFA‐1, CD11b/Mac‐1) and CD45 phosphatase isoforms (CD45RA, CD45RO on leukaemic cells from 28 patients with acute myeloid malignancies cultured with and without all‐trans retinioc acid (ATRA). Within each adhesion system, ATRA was bale to differentially regulate distinct molecules. Furthermore, it was able to exert effects specific for acute promyelocytic leukaemia (APL) blast cells, as well as to induce a series of non‐cytotype‐restricted phenotypic changes. An impressive feature of ATRA induction was a simultaneous increase in the expression of CD15, CDw65 and CD11b on leukaemic promyelocytes. The sialylated antigen CD15s, however, Showed results independent from the other two carbohydrates (CD15 and CDw65), suggesting a differential enzymatic regulation within the selectin ligands system.

De novo acute myeloid leukemia with multilineage dysplasia: treatment results and prognostic evaluation from a series of 44 patients treated with fludarabine, cytarabine and G-CSF (FLAG)

Abstract: Objectives : To evaluate therapeutic results and prognostic factors from a series of 44 patients affected by de novo acute myeloid leukemia with multilineage dysplasia (MD‐AML), treated with the combination of fludarabine, cytarabine and G‐CSF (FLAG). Methods : Forty‐four patients with de novo MD‐AML were treated with the FLAG regimen. The median age was 61 yr (range 31–75 yr). Induction therapy consisted of the FLAG regimen; consolidation included idarubicin plus cytarabine. Patients with a compatible donor and aged less than 55 yr were programmed to receive allogeneic bone marrow transplantation (BMT), while in those without a donor and aged less than 65 yr autologous transplantation with peripheral blood stem cells mobilized by a consolidation regimen plus G‐CSF was planned. Bone marrow harvest was performed in poor mobilizers. Results : Complete remission (CR) was achieved in 28 out of 44 patients (64%). Death in induction occurred in four patients (9%), while 12 patients (27%) were resistant to FLAG. Toxicity of consolidation was negligible. Most patients aged less than 60 yr and achieving CR were eligible for transplantation procedures, the main reason of exclusion being early relapse. Median overall survival and disease free survival were 16 and 22 months, respectively. Unfavorable cytogenetics was the only parameter significantly related to inferior clinical outcome following multivariate analysis. Conclusion : Multilineage dysplasia per se is not an adverse prognostic factor in AML patients treated with the FLAG regimen. Favorable results are obtained in patients with intermediate karyotype, while in those with adverse cytogenetics new approaches are clearly needed. The toxicity of the regimen is also acceptable in the elderly, and following induction/consolidation, most patients may be submitted to transplantation procedures.

Stem cell factor receptor (c‐kit, CD117) is expressed on blast cells from most immature types of acute myeloid malignancies but is also a characteristic of a subset of acute promyelocytic leukaemia

Investigating 208 patients with acute haematological malignancies, we found that stem cell factor receptor (SCFR) was expressed on high numbers of blast cells from the vast majority of patients (93%) with refractory anaemia with excess of blasts in transformation. SCFR was also detected in 62% of AMLs, in which it was directly associated to the expression of CD7, interleukin 6 receptor and CD34, and inversely to that of CD11b and CD14. SCFR‐positive cases were preferentially represented in AML‐M1 (70%) and in AML‐M2 (83%) subsets, whereas only 45% of the remaining samples (M3–M4–M5) exhibited SCFR positivity. Interestingly, 50% of cases with acute promyelocytic leukaemia expressed SCFR and this molecule was heterogenously regulated by in vitro treatment with all‐trans retinoic acid.

Fludarabine plus cyclophosphamide for the treatment of advanced chronic lymphocytic leukemia

Abstract: Objectives: Therapeutic results in advanced chronic lymphocytic leukemia (CLL) are still unsatisfactory in terms of complete remission achievement and duration, in spite of the extensive use of purine analogs. The objective of this study was to describe the clinical characteristics and treatment results from a series of 32 patients managed with a therapeutic program based on the combination of fludarabine and cyclophosphamide (CTX).

Ifosfamide, Epirubicin and Etoposide (IEV) Regimen as Salvage and Mobilization Therapy for Refractory or Early Relapsing Patients with Aggressive Non-Hodgkin's Lymphoma

The prognosis of early relapsing or refractory aggressive non-Hodgkins lymphoma (NHL) is still poor. Effective salvage therapy should be able to induce high response rate as well as to mobilize hematopoietic precursors. A combination of ifosfamide, epirubicin and etoposide (IEV) was given to 28 patients with refractory or relapsing high grade NHL (4 lymphoblastic lymphoma and 24 large cell lymphoma). All patients were evaluated for response. After 2 courses of IEV, the overall and complete response rate were 64% and 39%, respectively. All patients were controlled for mobilization of peripheral blood stem cells, which was successful in 26 out of 28 (93%). Overall, 25 out of 26 patients proceeded to autologous stem cell transplantation (ASCT). Toxicity was mild, with no occurrence of severe persisting extra-hematologic side-effects. Following the entire therapeutic program, including IEV and ASCT, median progression free survival has not yet been reached and 21 patients are alive (18 in continuous complete remission) after a median follow-up of 18 months. Our results demonstrate that treatment with IEV regimen is effective in refractory or relapsing aggressive NHL, resulting in a high percentage of successful stem cell mobilization and feasibility of ASCT.

High-dose cytarabine as consolidation treatment for patients with acute myeloid leukemia with t(8;21).

Seventeen patients affected by acute myeloid leukemia (AML) with t(8;21) were prospectively programmed to receive three courses of high-dose cytarabine (HDARA-C) as post-remission therapy. The median age was 39 years and in all cases t(8;21) was the only karyotypic abnormality. Complete remission (CR) was achieved in 14 out of 17 cases (82%) and, after first consolidation with NOVIA regimen (intermediate dose ARA-C plus mitoxantrone), all patients received the three planned courses of HDARA-C (3g/m(2) q12h on days 1, 3, 5). There were two documented infections, while all patients experienced fever of unknown origin (FUO). Nonhematological toxicity was mild. Thirteen out of 14 patients are in continuous CR after a median follow-up of 44 months. One patient relapsed at 16 months and, following CR2 achievement, underwent allogeneic transplantation; he died 3 months later while in CR from acute graft versus host disease (GVHD). Survival at 5 years is projected at 79%. Our data confirm the efficacy of repeated courses of HDARAC for patients with t(8;21) AML.

Expression of the leucocyte common antigen (LCA, CD45) isoforms RA and RO in acute haematological malignancies: possible relevance in the definition of new overlap points between normal and leukaemic haemopoiesis

Summary. The membrane expression of CD45RA and CD45RO on fresh leukaemic cells taken from 529 cases of acute haemopoietic malignancies, including 117 B‐origin acute lymphoblastic leukaemia (B‐origin ALL), 3 7 T‐origin acute lymphoblastic leukaemia (T‐origin ALL), 297 de novo acute myeloid leukaemia (AML), 42 refractory anaemia with excess of blasts in transformation (RAEB‐T) and 36 myeloid blastic phase of chronic myelogenous leukaemia (CML‐BP‐my), was analysed. B‐origin ALLs were characterized by the lack of the RO isoform along with the consistent presence of RA. Conversely, a differential expression of the two isoforms was detected in different subsets of T‐origin ALL, in that T‐stem cell leukaemias (T‐SCL: CD7+, CD4−, CD8−, CD1−) preferentially expressed CD45RA whereas conventional T‐acute lymphoblastic leukaemias (T‐ALL: CD7+, CD4+ and/or CD8+ and/or CD1+) were consistently marked by CD45RO. Within myeloid malignancies, most of AMLs displayed CD45RA, while a substantial group of CML‐BP‐my preferentially exhibited CD45RO. As a general rule, a reciprocal exclusion of the two isoforms was observed in AML as well as in ALL. Nevertheless, a frequent coexpression of CD45RA and CD45RO was observed in CD14+ AML.

Differential regulation of GPI‐linked molecules on leukaemic promyelocytes treated in vitro with all‐trans retinoic acid

It has been demonstrated that certain cell‐surface proteins are anchored to the cell membrane by a unique structure known as the glycosylphosphatidylinositol (GPI) anchor whose absence has been reported on blood cells from patients with paroxysmal nocturnal haemoglobinuria. We have investigated the expression of CD16/FcτR‐III and CD66b GPI‐linked molecules at the surface of blast cells from five acute promyelocytic leukaemia (APL) patients before and after in vitro stimulation with all‐trans retinoic acid (ATRA). We observed that whereas CD66b antigen exhibited a strong ATRA‐driven up‐regulation in all cases studied, CD16 expression was unaffected by the treatment with the drug.

B-cell acute lymphoblastic leukaemia (B-ALL) heterogeneity.

A paper published by Michiels et a1 (1988) and subsequent letters from Reid (1988) and Shende et a1 (1988) drew our attention to three cases of TdT positive B cell acute lymphoblasticleukaemia (ALL) without L3 morphology. SmIgpositive ALL is an intriguing field of haematophathology, in that this rare disorder, previously considered as a quite homogeneous subset of B-lineage ALL, displays some heterogeneity of morphological findings and immunological markers expression. So, along with classical TdT -, Burkitt like, SmIg + cases, several examples of different phenotypic patterns have been reported. In 1985 we described a TdT+, SmIg + acute leukaemia with L3 morphology, showing an exceptional surface membrane pattern. characterized by surface p chain expression in absence of light chains. This case resembled a new ‘early-B’ phenotype, intermediate, for its immunological features, between pre-B and B-ALL. At the time of our report this case represented an unique example of ‘p chain only’ acute leukaemia. The patient, a 5-year-old child, received 2 years of treatment and remains alive and off therapy till now. ALSO in the case reported by Reid, uncombined p chains were expressed at the cell surface as an apparently stable mem-