Targeting HDAC2-Mediated Immune Regulation to Overcome Therapeutic Resistance in Mutant Colorectal Cancer

A large body of clinical and experimental evidence indicates that colorectal cancer is one of the most common multifactorial diseases. Although some useful prognostic biomarkers for clinical therapy have already been identified, it is still difficult to characterize a therapeutic signature that is able to define the most appropriate treatment. Gene expression levels of the epigenetic regulator histone deacetylase 2 (HDAC2) are deregulated in colorectal cancer, and this deregulation is tightly associated with immune dysfunction. By interrogating bioinformatic databases, we identified patients who presented simultaneous alterations in HDAC2, class II major histocompatibility complex transactivator (CIITA), and beta-2 microglobulin (B2M) genes based on mutation levels, structural variants, and RNA expression levels. We found that B2M plays an important role in these alterations and that mutations in this gene are potentially oncogenic. The dysregulated mRNA expression levels of HDAC2 were reported in about 5% of the profiled patients, while other specific alterations were described for CIITA. By analyzing immune infiltrates, we then identified correlations among these three genes in colorectal cancer patients and differential infiltration levels of genetic variants, suggesting that HDAC2 may have an indirect immune-related role in specific subgroups of immune infiltrates. Using this approach to carry out extensive immunological signature studies could provide further clinical information that is relevant to more resistant forms of colorectal cancer.

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-Hodgkin's 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.

Feasibility of autologous peripheral blood stem cell transplantation in elderly patients with acute myeloid leukemia

Most studies showing that autologous stem cell transplantation (ASCT) is feasible in older patients with acute myeloid leukemia (AML) referred to highly selected patients considered as eligible after complete remission (CR) achievement and bone marrow or peripheral blood stem cell (PBSC) collection. This study evaluated the feasibility of ASCT from 155 consecutive AML patients aged over 60 years (median age 72 years, range 61 - 94) programmed to receive ASCT by using PBSCs after CR achievement. Overall, 90 out of 155 patients (58%) were judged as eligible for aggressive chemotherapy and 45 (50%) achieved CR. Among these, 36 (80%) received consolidation and 32 (89% of consolidated) were monitored for PBSC mobilization. A successful collection was registered in 25/32 patients (78% of monitored). Finally, 20 patients received ASCT. Reasons for not autografting five mobilizing patients included relapse pre-ASCT, toxicity, and refusal. Median survival was 4 months for the whole patient population and 19 months for patients actually autografted. Overall, 20 out of 90 patients accrued into intensive chemotherapy (22%) and 20 out of the entire patient population (13%) underwent ASCT. It is concluded that APBSCT can result in an improvement of therapeutic results in AML of the elderly, but it is feasible in a minority of selected patients.

Feijoa sellowiana derived natural Flavone exerts anti-cancer action displaying HDAC inhibitory activities

Curative properties of some medicinal plants such as the Feijoa sellowiana Bert. (Myrtaceae), have been often claimed, although the corresponding molecular mechanism(s) remain elusive. We report here that the Feijoa acetonic extract exerts anti-cancer activities on solid and hematological cancer cells. Feijoa extract did not show toxic effects on normal myeloid progenitors thus displaying a tumor-selective activity. In the Feijoa acetonic extract, fractionation and subsequent purification and analyses identified Flavone as the active component. Flavone induces apoptosis which is accompanied by caspase activation and p16, p21 and TRAIL over-expression in human myeloid leukemia cells. Use of ex vivo myeloid leukemia patients blasts confirms that both the full acetonic Feijoa extract and its derived Flavone are able to induce apoptosis. In both cell lines and myeloid leukemia patients blasts the apoptotic activity of Feijoa extract and Flavone is accompanied by increase of histone and non-histone acetylation levels and by HDAC inhibition. Our findings show for the first time that the Feijoa apoptotic active principle is the Flavone and that this activity correlates with the induction of HDAC inhibition, supporting the hypothesis of its epigenetic pro-apoptotic regulation in cancer systems.

Rexinoid-triggered differentiation and tumor-selective apoptosis of acute myeloid leukemia by protein kinase A-mediated desubordination of retinoid X receptor

Apart from PML-retinoic acid receptor-alpha (RARalpha) acute promyelocytic leukemia all other acute myeloid leukemias (AML) are unresponsive to retinoid differentiation therapy. However, elevating the levels of cyclic AMP (cAMP) confers onto retinoid X receptor (RXR)-selective agonists ("rexinoids") the ability to induce terminal granulocyte differentiation and apoptosis of all-trans retinoic acid-resistant and insensitive AML cells and patients' blasts. Protein kinase A activation leads to corepressor release from the RAR subunit of the RAR-RXR heterodimer, resulting in "desubordination" of otherwise silent RXR, which acquires transcriptional competence in response to cognate ligands. Rexinoid-cAMP induction of endogenous RARbeta is blunted in mouse embryo fibroblasts lacking RARs, but reintroduction of exogenous RARalpha reestablishes responsiveness, thus confirming that the RARalpha-RXR heterodimer is the rexinoid mediator. The apoptogenic effect of this treatment involves enhanced expression of the death receptor DR5 and its cognate ligand, tumor necrosis factor-related apoptosis inducing ligand, both of which are known to induce apoptosis in a tumor cell-selective manner and lead to the activation of initiator caspases. Immunohistochemistry confirmed induction of tumor necrosis factor-related apoptosis inducing ligand and DR5 in AML patient blasts cultured ex vivo. AML patients' blasts responded to rexinoid-cAMP combination treatment with induction of maturation and apoptosis, independent of karyotype, immunophenotype, and French-American-British classification status. Clonogenic assays revealed complete inhibition of blast clonogenicity in four out of five tested samples. Our results suggest that despite the genetic, morphologic, and clinical variability of this disease, the combination of rexinoids and cAMP-elevating drugs, such as phosphodiesterase inhibitors, might lead to a novel therapeutic option for AML patients by inducing a tumor-selective death pathway.

Fludarabine and cytarabine as continuous sequential infusion for elderly patients with acute myeloid leukemia

BACKGROUND AND OBJECTIVES

A phase II study was conducted to investigate the effects of a therapeutic program based on the combination of fludarabine and cytarabine (ARA-C) administered as a sequential continuous infusion in untreated elderly patients with acute myeloid leukemia (AML).

DESIGN AND METHODS

Sixty-three patients with non-M3 AML, median age 69 years (range 61-81), were accrued. Twenty-four patients (38%) had AML secondary to myelodysplastic syndrome. Fludarabine and ARA-C were administered as a continuous sequential infusion for 72 and 96 hours, respectively, after a loading dose. Patients achieving complete remission (CR) were intended to receive an additional course, followed by autologous stem cell transplantation (ASCT).

RESULTS

Overall, 42 patients (67%) achieved CR. There were 10 induction deaths (16%), while 11 patients were refractory (17%). Among those achieving a remission, 35 patients (83%) received the planned consolidation course and 29 underwent mobilization of CD34+ cells into the peripheral blood for collection, which was successful in 23 (79%). Overall, 17 patients (27% of the whole population) received ASCT. The median overall and disease-free survival were both 10 months.

INTERPRETATION AND CONCLUSIONS

Patients with an intermediate karyotype and those receiving ASCT had a significantly better clinical outcome. Results in terms of CR achievement, CD34+ cell collection and ASCT feasibility. A longer follow up is needed in order to evaluate the actual benefit on long-term survival.

High-dose idarubicin and busulphan as conditioning to autologous stem cell transplantation in adult patients with acute myeloid leukaemia

Between 30 and 50% of patients with acute myeloid leukaemia (AML) relapse after autologous stem cell transplantation (ASCT). One possibility of reducing the relapse rate could be the adoption of conditioning regimens specifically designed for AML. We report treatment results achieved with a new conditioning for ASCT, based on high-dose idarubicin (IDA) plus oral busulphan. Patients (n = 40) were conditioned with a regimen consisting of 3 d continuous intravenous infusion IDA at 20 mg/m2, followed by 4 d conventional dose oral busulphan. Unpurged peripheral blood stem cells were used in all cases. All patients had non-M3-AML and were in first complete remission (CR). The median number of CD34+ cells infused was 6.9 x 10(6)/l (2.6-24). No case of transplant-related mortality occurred. In all cases, left ventricular ejection fraction remained unmodified after ASCT. Thirty-three of 40 patients (82%) had grade 3-4 mucositis requiring total parenteral nutrition in all cases. After a median follow up for surviving patients of 32 months from ASCT, 30 patients (75%) are alive and 26 (65%) are in continuous CR. Our data show that a conditioning regimen based on high-dose IDA plus busulphan results in an encouraging reduction of the relapse rate after ASCT in AML.

Outpatient-based peripheral blood stem cell transplantation for patients with multiple myeloma

INTRODUCTION

There is a growing demand for autologous stem cell transplantation (ASCT) in newly diagnosed patients with multiple myeloma (MM), resulting in an increasing pressure on available hospital beds. In addition, more rational utilization of health resources should induce physicians to attempt therapeutic strategies aiming at reduction of costs. The aim of this study was to explore the feasibility and safety of performing ASCT on an outpatient basis, according to an early discharge method.

MATERIALS AND METHODS

A total of 28 patients affected by MM and in complete or partial remission were selected to receive ASCT on an outpatient basis. In particular, after conditioning with high-dose melphalan and stem cell infusion, patients were programmed to go home and to be rehospitalized in the case of febrile neutropenia or other severe toxicities.

RESULTS

All patients accepted the outpatient-based procedure. Out of 28 patients. 18 (64%) did spend the aplastic phase entirely at home following high-dose chemotherapy and stem cell infusion. A second hospital admission was required in 10 patients (36%). Febrile neutropenia and severe mucositis needing total parenteral nutrition were the most frequent causes of hospitalization. However, there were no documented infections and either fever or mucositis was easily resolved at the time of hematopoietic recovery in all patients.

CONCLUSION

ASCT on an outpatient basis is feasible and safe in patients with MM. More than 60% of patients are manageable at home, provided that a caregiver is available.

Fludarabine plus cyclophosphamide for the treatment of advanced chronic lymphocytic leukemia

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).

METHODS

Thirty-two patients (median age 63 yr, range 42-75 yr) with newly diagnosed (47%) or refractory-relapsed (53%) CLL were programmed to receive six courses of a 3-d combination of fludarabine at 30 mg/m2/d plus CTX at 300 mg/m2/d. Refractory-relapsed patients had previously received different chemotherapy lines from 1 to 5.

RESULTS

Fourteen of 32 (44%) patients achieved a complete remission, 16 (50%) obtained partial remission and two (6%) failed to respond. The CR rate was higher in untreated patients; in particular, CR was achieved in nine of 15 (60%) newly diagnosed cases as opposed to five of 17 (29%) among pretreated patients. Toxicity was caused by myelosuppression and/or infections in most cases. After a median follow-up of 24 months (range 8-48 months), 20 of 32 patients (62%) are alive, and 14 of 32 (44%) are free from progression. Median overall survival and median time to progression were 35 and 25 months, respectively.

CONCLUSION

The combination of fludarabine with CTX is effective in advanced CLL with acceptable toxicity, either as first-line therapy or in refractory-relapsed patients. In particular, a considerable rate of complete remission can be achieved in untreated patients. Myelosuppression represents the major side-effect.

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.

Patients treated with antitumor drugs displaying neurological deficits are characterized by a low circulating level of nerve growth factor

The aim of our study was to explore whether nerve growth factor (NGF) plays any role in the development of peripheral neuropathy induced by anticancer treatment. We measured the circulating NGF levels in 23 cancer patients before and after chemotherapy. We evaluated whether the development of peripheral neurotoxicity was associated with changes in basal NGF concentrations in patients studied with a comprehensive neurological and neurophysiological examination. The results of these studies showed that the circulating levels of NGF, which are about 20 pg/ml in plasma of controls, decrease during chemotherapy and in some cases completely disappeared after prolonged treatment with antitumor agents. The decrease in NGF levels seems to be correlated with the severity of neurotoxicity. These results clearly suggest that NGF might become a useful agent to prevent neuropathies induced by antineoplastic drugs and restore peripheral nerve dysfunction induced by these pharmacological compounds.

Nerve growth factor: a neurotrophin with activity on cells of the immune system

Numerous studies published in the last two decades provide evidence that nerve growth factor (NGF), a polypeptide originally discovered because of its neurotrophic activity, acts on a variety of cells of the immune system, including mast cells, eosinophils, and B and T lymphocytes. NGF has been shown to increase during inflammatory responses, autoimmune disorders, parasitic infections, and allergic diseases. Moreover, stress, which is characterized also by activation of a variety of immune cells, causes a significant increase in basal plasma NGF levels. Recently published studies reveal that hematopoietic progenitor cells seem to be able to produce and/or respond to NGF. We report these data and discuss the hypothesis of the possible implication of NGF on the functional activities of immune cells.

Nerve growth factor: a survey of activity on immune and hematopoietic cells

Nerve growth factor (NGF) is a well characterized molecule required for the survival and differentiation of a variety of cell types both in the peripheral and central nervous system. Numerous studies published in recent years have demonstrated that NGF affects different functional activities of mature immune and hematopoietic cells. Other studies have revealed that hematopoietic progenitor cells from bone marrow, umbilical cord blood and peripheral blood are receptive to the action of NGF and that bone marrow stromal cells produce/respond to NGF during different steps of normal hematopoiesis. Elevated levels of NGF have been found in a number of inflammatory diseases, including those of autoimmune nature and in myeloproliferative pathologies. This review presents these data and discusses the hypothesis of a possible functional role of NGF in immune and hematopoietic disorders.

P-glycoprotein expression in de novo acute myeloid leukemia

Detection of the multidrug resistance P-glycoprotein (PGP) phenotype was performed at the time of diagnosis in 223 patients with acute myeloid leukemia (AML) by flow cytometry using C219 Monoclonal Antibody (MoAb). On the other hand, JSB1 MoAb was tested in 173 of these samples. At onset, PGP was detected in 57.4% of cases with C219 and 75.9% of cases with JSB1. There was no correlation between PGP expression and sex, age, marrow blast percentage or extramedullary disease. On the contrary, strict correlations were noted either between C219 negativity and FAB M3 subtype or between C219 positivity and FAB M5 group (P = 0.003). Significant correlation was found between PGP phenotype and CD7, as 143 of 223 samples had similar patterns of staining with C219 (P < 0.0001). Finally, there was a close relationship between C219 and JSB1 positivity: all the C219+ cases were positive for JSB1 (P < 0.0001). Concerning the karyotype, most patients with monosomy or del (7) were MDR positive; on the other hand, most patients with t(8;21) or t(15;17) were MDR negative. Rh123 accumulation studies showed a significant decrease of mean fluorescence intensities both in C219 and in JSB1 positive cases in comparison with PGP negative ones (P < 0.001). A significant decrease of remission induction rates (CR) was highlighted both between C219+ and C219- and between JSB1+ and JSB1- cases (32.1% v 62.1% and 32.6% v 73.8%, respectively, with P < 0.0001). The overall survival and the remission duration (CCR) were significantly shorter both in C219+ and in JSB1+ patients with no relationship to age. Furthermore, a higher rate of early relapses was noted among MDR+ when compared with MDR- patients both for C219+ and JSB1+ cases. The combination (C219- JSB1+) identified a subset of patients with an intermediate prognosis. On multivariate analysis, C219 and JSB1 were confirmed to be independent prognostic factors for achievement of CR, overall survival and CCR. In conclusion, the assessment of MDR phenotype by flow cytometry is a crucial prognostic factor of treatment outcome in AML.

Minimally differentiated acute myeloid leukemia (AML-M0): comparison of 25 cases with other French-American-British subtypes

We compared the immunophenotypic and karyotypic features of 25 cases of minimally differentiated acute myeloid leukemia (AML-M0) with those of 247 cases comprising all AML French-American-British (FAB) classification. Myeloperoxidase (MPO) was detectable with a specific monoclonal antibody in all cases of AML-M0, whereas CD13 and CD33 were both negative in 4 of the 25 cases. Thus, anti-MPO reliably detects minimal myeloid differentiation in AML-M0. CD34 and terminal deoxynucleotidyl transferase (TdT) were more frequently expressed in AML-M0 (96% and 68% of the cases, respectively) than in the other FAB subsets (P < .001 for both). By contrast, GP-170 and CD7 were less frequently expressed in AML-M0 than in FAB classes such as M1, M4, and M5 (P = .02 and .003, respectively). A total of 80% of AML-M0 cases carried lymphoid markers (including TdT), and 48% showed a coordinate positivity for two or more of them. CD2, CD5, CD10, and CD19 were expressed in a similar fashion among the different FAB groups, whereas CD4 expression was significantly more frequent in AML-M0, AML-M4, and AML-M5 (P = .014). AML-M0 was characterized by a more frequent occurrence of complex karyotypes. In addition, approximately 20% of cases had TdT positivity, complex karyotypes, and anomalies of chromosome 5 and/or 7, a pattern not observed in the other FAB subsets. Finally, 80% of anomalies of chromosome 5 and/or 7 in AML-M0 were comprised within complex karyotypes, whereas only 13% of the remaining FAB cases carried this feature. In summary, AML-M0 frequently expresses immunophenotypic and karyotypic aspects that are likely to identify a "stem cell" pattern.

Minimally differentiated acute myeloid leukemia (AML-M0): a distinct clinico-biologic entity with poor prognosis

FAB proposals for the diagnosis of AML-M0 represent the formal recognition of a distinct entity which has been described over the past few years by several authors and called minimally differentiated acute myeloid leukemia. By definition, AML-M0 includes acute leukemias which do not fit morphological and cytochemical criteria for the diagnosis of AML, and for which myeloid lineage assignment can be made by immunological assay showing positivity for MPO, CD13, and CD33 and negativity for lymphoid markers. Involvement of an early myeloid progenitor in the leukemic process is a possible theory hypothesized to explain the existence of such a form. Validity of this assumption has been based on the observation that AML-M0 frequently bears "stem cell" markers such as CD34, HLA-DR, Tdt, CD7, and promiscuous IgH/TCR gene rearrangements, which are thought to occur in uncommitted cells. Finally, AML-M0 very frequently carries cytogenetic abnormalities common to MDS or secondary AML, such as -5/5q- or -7/7q- deletions and or complex karyotype. In our experience, AML-M0 is also very often associated with the MDR phenotype, which in turn has been found strictly linked to "stem cell" features, especially in MDS. These biological aspects, altogether, translate into a very unfavorable prognosis, confirming even from a clinical point of view that AML-M0 is a distinct entity. In conclusion, "stem cell" markers, MDR phenotype, complex chromosome lesions, frequent occurrence in elderly patients, and intrinsic chemoresistance characterize AML-M0 and indicate the need for tailored treatments, possibly involving the use of MDR modulators and/or differentiating agents.

Contribution of immunophenotypic and genotypic analyses to the diagnosis of acute leukemia

Diagnostic accuracy in acute leukemia (AL) can be improved if traditional morphology and cytochemistry are supplemented with immunophenotypic and genotypic analyses. This multiparameter approach is of crucial importance for the management of patients, as it enables the identification of leukemic syndromes with distinct biological features and response to treatment. Immunophenotyping using monoclonal antibodies has been universally accepted as a useful adjunct to morphological criteria. This technique is particularly valuable in diagnosing and subclassifying acute lymphoblastic leukemia and is also essential in certain types of acute myeloid leukemia (AML), such as AML with minimal differentiation or acute megakaryoblastic leukemia. Cytogenetic findings can be quite helpful in establishing the correct diagnosis and can add information of prognostic significance. A number of specific chromosomal abnormalities have been recognized that are very closely, and sometimes uniquely, associated with morphologically and clinically distinct subsets of leukemia. An even more basic understanding of normal and malignant hematopoietic cells has begun to evolve as molecular biology begins to unravel gene misprogramming by Southern and Northern blot analysis, the polymerase chain reaction, and fluorescence in situ hybridization. With the extensive use of these techniques it has become apparent that a proportion of leukemias exhibit the biologically relevant molecular defect in the absence of a karyotypic equivalent. On the other hand, apparently uniform chromosomal abnormalities such as the t(1;19) (q23;p13), t(9;22) (q33;q11), t(8;14) (q24;q32), or t(15;17) (q21;q21) may differ at the molecular level. Data collected from these modern technologies have introduced a greater complexity, which needs to be taken into consideration to improve both the diagnostic precision and the reproducibility of current classifications.

CD7 expression in acute myeloid leukemia

The clinical significance of the expression of CD7 antigen on the blasts of 207 consecutive patients with de novo acute myeloid leukemia (AML) was evaluated. For this purpose, fifty-three CD7+ patients (23 females and 30 males; mean age 52 years) were analyzed and classified into the following subtypes according to French-American-British (FAB) classification: 7 M0, 13 M1, 9 M2, 1 M3, 9 M4, 14 M5. Immunophenotypic studies were carried out by flow cytometry and blast cells were selected on the basis of forward light scatter gating and pan-myeloid marker, either CD13 or CD33. All the CD7+ patients were negative for surface CD3 and T-cell-receptor (TCR) molecules. We found no correlation between CD7 expression and sex, age, hepatosplenomegaly and/or central nervous system involvement. The immaturity of CD7+ leukemic cells was supported by the high expression of CD34 (P = 0.001). CD7 positivity was significantly associated with a white blood cell count (WBC) greater than 100 x 10(9)/L (P = 0.003). P-Glycoprotein (P-170) expression was also evaluated in 135 patients by a flow-cytometric assay: there was a close relationship between CD7 and P-170 positivity (P < 0.001). For remission induction, all patients received therapeutic regimens routinely used for AML. The complete remission (CR) rate was significantly lower in CD7+ cases (32% vs 74%, P = 0.001). The overall survival and disease free survival rate of CD7+ AML was lower than those of CD7- patients (P < 0.001 and = 0.002, respectively). CD7+ AML with coexpression of CD14 had a particularly unfavourable response and prognosis in comparison with CD7+ patients without CD14.(ABSTRACT TRUNCATED AT 250 WORDS)

Minimally differentiated acute myeloid leukaemia (AML-M0): cytochemical, immunophenotypic and cytogenetic analysis of 19 cases

We describe our experience in the identification of 19 cases of AML-M0 categorized among 200 consecutive AML cases. Leukaemic cells from our cases were morphologically marked by agranular basophilic cytoplasm, finely dispersed chromatin and prominent nucleoli. In two cases heavily vacuolated and monocytoid-shaped blasts were also observed. Cytochemistry (MPO, SBB, alpha ANAE, alpha NBE, NASDCAE, AP, PAS) was negative in 14 cases, five cases expressing a very faint cytoplasmic positivity for alpha NBE (not exceeding 30% of the blasts) and alpha ANAE (not exceeding 41%) which was sodium fluoride resistant. In these five cases other monocytic markers (e.g. CD14) were not in favour of myelomonocytic differentiation. All the cases were anti-MPO positive at frequency > 10%. Phenotypic analysis also revealed myeloid features with all the patients having at least one myeloid antigen (CD13, CD33, CD15), Tdt was expressed in nine cases and CD7 in six cases. All cases but one were positive for CD34. Cytogenetic analysis, performed in 16 cases, showed no adequate growth in two cases and no consistent abnormality in four; among the remaining 10 cases no consistent abnormality was observed, the most common finding was trisomy 8 (two cases) and 4 (two cases) and aberrations of chromosomes 2, 3, 5, 7, 9, 12 and 21. No cases of (t9;22), Ph chromosome were observed. Interestingly three out of five patients with faint alpha NBE/alpha ANAE positivity relapsed as typical M4 (one case) or M5a (two cases).

Triple immunofluorescence evaluation of CD15, CD34 and class II expression by flow cytometry in normal and leukemic bone marrows

BACKGROUND

The CD15/CD34 phenotype has been reported as aberrant and exploited for monitoring minimal residual disease in acute myeloid leukemia (AML) patients. Moreover, CD15/CD34 has been described as a rare phenotype in normal bone marrow (NBM) (< 0.10%). We used a triple immunofluorescence assay to investigate the expression of CD15, CD34 and class II antigens in normal (NMB) and leukemic (LBM) bone marrows.

METHODS

A FACScan for quantitative fluorescence and the PAINT-A-GATE program for multiparametric analysis were utilized. Fifteen normal bone marrow and fifteen leukemic bone marrow samples were studied with a triple immunofluorescence assay. A FACSorter was used for sorting.

RESULTS

Eleven out of 15 normal marrows contained less than 0.67% (range 0.01-0.66) cells which coexpressed CD15, CD34 and class II antigens. Three normal marrows contained more than 0.67% but less than 1.84% (range 1.05-1.83) triple stained cells. The entire group of leukemic marrows coexpressed triple stained cells with a frequency higher than 1% (range 1.1-48.6); furthermore, 10 samples contained the same population at frequencies higher than 10%. The difference between normal and leukemic marrows was statistically significant (p = < 0.001). Triple positive cells (TPc) from NBM were sorted for morphology, which proved to be consistent with myeloid progenitor features (early myeloblasts). This confirms that CD15+ CD34+ Class II+ precursors are commonly expressed in NMB, although at low frequency. Interestingly, 12 (80%) AMLs out of 15 were diagnosed as M1 (5) or M2 (7), while the remaining were M4 (2) and M5a (1). Additionally, all M2 cases were positive at percentages higher than 10%. Apparently CD15, CD34, class II expression correlates mainly with granulocyte differentiation. Two complete remission (CR) LBM, positive at onset for the triple combination, were regularly monitored. In one case the TPc percentage always remained near the normal values found in NBM (0.72%), and this patient is still in CR. In the other, overt relapse was preceded by a progressive increase in the TPc percentage.

CONCLUSIONS

Although the presence in NBM of CD15+ CD34+ and class II+ precursors hinders minimal residual disease detection, we conclude that this unusual combination may distinguish a leukemic population and may allow monitoring of "early relapse".

Soluble factors levels in the initial staging of high-grade non-Hodgkin's lymphomas

Plasma levels of several soluble factors were assayed in 31 untreated patients with high-grade non-Hodgkin's lymphomas (NHL). The results showed statistically significant higher average levels of interleukin-2 (IL-2), interleukin-6 (IL-6), interleukin-8 (IL-8), interleukin-2 receptor (IL-2r) and transferrin receptor (TF-r) in NHL patients compared to controls (p = 0.045, p = 0.047, p = 0.020, p = 0.026 and p = 0.033 respectively). IL-2, IL-2r and TF-r levels were found more elevated in Stages III/IV than in Stages I/II (p = 0.031, p = 0.016 and p = 0.048 respectively), whereas IL-6 concentrations were higher in patients presenting B symptoms (p = 0.011). Significant correlations were found between the erythrocyte sedimentation rate (ESR) and IL-6 (r = 0.681), and between beta 2 microglobulin (B2-m) and IL-2r (r = 0.622).