Interleukin-11 (IL-11) acts as a synergistic factor for the proliferation of human myeloid leukaemic cells

Interleukin-11 is a stromal cells derived cytokine which stimulates the proliferation of primitive haemopoietic progenitor cells. For this paper we have studied the constitutive expression of IL-11 mRNA in a panel of wellknown leukaemic cell lines and samples from AML patients at diagnosis. Moreover, the same cellular populations were evaluated for their proliferative response to recombinant-human-(r-hu). IL-11 alone and combined with r-hu-IL-3, granulocyte-macrophage colony stimulating factor (GM-CSF) and stem cell factor (SCF, c-kit ligand). The colony-forming ability of HL60, K562, KG1 cells and eight fresh AML cell populations was assessed by a clonogenic assay in methylcellulose. In eight additional AML cases the number of S-phase leukaemic cells induced by IL-11 was determined by the bromodeoxyuridine (BRDU) incorporation assay after 3d of liquid culture. IL-11, as single cytokine, did not stimulate the colony formation of the three myeloid cell lines under serum-containing and serum-free conditions. In contrast, the proliferation of the leukaemic cells in response to IL-3, GM-CSF and SCF was enhanced by co-incubation with IL-11, and this effect was reversed in blocking experiments by the anti-IL-11 Moab. When tested on primary AML samples, IL-11 alone showed little, if any, proliferative activity. However, it increased the IL-3-dependent blast colony formation in eight out of eight cases and GM-CSF in seven cases. IL-11 also augmented synergistically the number of CFU-L stimulated by SCF in seven cases. A combination of three factors (IL-11, SCF and IL-3) yielded optimal colony formation. The BRDU studies showed the significant increase of AML cells in S-phase when IL-11 was combined with SCF, whereas the two CSF had no activity on their own. Positive interaction was also observed when IL-11 was added to IL-3 supplemented cultures in five out of eight cases tested. Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) demonstrated the constitutive expression of IL-11 mRNA in all the cell lines and 11/12 AML samples studied at diagnosis. These results indicate that IL-11 is expressed in leukaemic myeloid cells and that their proliferation is regulated by the cytokine which acts as a synergistic factor.

Solitary plasmacytoma of bone and extramedullary plasmacytoma: two different entities?

BACKGROUND

The objective of this study was to evaluate the similarities between solitary plasmacytoma of bone (SPB) and extramedullary plasmacytoma (EP).

PATIENTS AND METHODS

The clinical features, treatment and survival of 54 patients with localized plasmacytoma (LP) 1990 were carefully reviewed. Follow-up was expected to continue until June 1993.

RESULTS

Thirty-two patients were classified as having SPB and 22 EP. Most of the patients were males. particularly those in the SPB group. Their median age at diagnosis was 54 years and no significant difference between the two groups was observed. SPB occurred most frequently in the vertebral column (42%) and EP in the upper respiratory tract (73%). Fifteen patients with SPB and 2 with EP had paraproteinemia at diagnosis, multiple myeloma (MM) became evident in 75% of the patients with persistent paraprotein after therapy, and in only 22% of those in whom it disappeared. Four patients in the SPB group had immunoparesis, and 3 developed MM. Disease progression toward MM was significantly different (p=0.003) in the two groups, while overall survival differences were not significant (p=0.07) unless unrelated causes were excluded (p=0.02). Adjuvant chemotherapy did not seem to limit diffusion of the disease.

CONCLUSIONS

Although EP and SPB are both localized forms of plasma cell dyscrasias, SPB seems to have a greater tendency to progression MM. It appears, however, that the apparent stronger propensity of SPB to progress is actually due to the great number of cases that at diagnosis conceal an occult MM.

Molecular analysis of HLA genes for the selection of unrelated bone marrow donor

The selection of fully matched unrelated volunteer donors (UVD) in BMT requires a molecular characterization of MHC polymorphism, since most phenotypically HLA-identical donors can be non-identical when analyzed at a genomic level. The present report describes a molecular typing protocol for HLA genes developed for the selection of UVD, and its application to some donor-recipient pairs. The protocol involves three successive steps. Firstly, PCR with sequence-specific primers for HLA-DRB1 and -DQB1 genes is performed to identify the major alleles of the recipient. PCR-fingerprint matching is then introduced for HLA-A, B, C and DRB, DQB and DPB genes to screen prospective donors. Those showing matched fingerprinting patterns are finally submitted to direct sequencing of the DRB1 gene. DPB compatibility is assessed by oligotyping when there are several potential class I and DRB matched donors. This strategy was applied retrospectively to three BMT recipients and their previously selected donors. Three other patients and their 12 prospective donors were submitted to our protocol before BMT. Clinical evaluation of transplant outcomes indicates the primary importance of complete DRB and class I matching, while DQB and DPB compatibility seems to be less critical.

Allogeneic bone marrow transplantation for the treatment of multiple myeloma. An overview of published reports

Allogeneic bone marrow transplantation (BMT) was first explored for the treatment of multiple myeloma (MM) in the mid 1980s. Since then, there has been a rapidly growing clinical demand for the use of this modality of treatment, so that the number of patients receiving worldwide transplants from HLA-identical siblings is actually estimated to be at least several hundreds. Although it is difficult to compare results between different centers because of differences in patient characteristics, selection criteria for transplantation and conditioning regimens, a certain number of conclusions have emerged from these experiences. There is evidence that allogeneic BMT performed in different phases of MM and with different conditioning regimens yields a high frequency of complete remissions (CR), in the range of 50% to 60%, and long-term survival and remission rates, both averaging approximately 20%. Although a toxic-related mortality rate of 40% has been consistently reported for many years, the outcome of patients in whom BMT was performed as consolidation of remission has recently improved. Prior responsiveness to conventional chemotherapy, also the presence of low tumor cell mass (both at diagnosis and before transplant) predicts for increased CR rate (up to 70% or more), as well as long-term survival and remission rates (both averaging approximately 50%). The continued relapse-free survival, up to and beyond ten years, reported for some of these patients provides strong evidence that allogeneic BMT has the potential ability to cure MM, probably as the result of an immunologic effect of the infused donor's marrow T lymphocytes against residual myeloma cells (graft-versus-myeloma).(ABSTRACT TRUNCATED AT 250 WORDS)

Cytofluorimetric and functional analysis of c-kit receptor in acute leukemia

The SR-1 monoclonal antibody (MoAb) recognizes an epitope of the c-kit receptor (KR), present on normal hemopoietic CD34+ stem cells as well as on blasts from patients with acute leukemia. Cytometric analysis by indirect immunofluorescence with the SR-1 MoAb was performed in 98 patients with acute myeloblastic leukemia (AML) and in 37 patients with acute lymphoblastic leukemia (ALL) in order to detect the presence of the KR and to examine its prognostic significance. Sixty-nine of 98 (70%) AML patients were SR-1 positive independently of the FAB subtype, although a higher incidence of SR-1 positive cases was observed in M4 and M5 AML and in those cases that also coexpressed lymphoid antigens. Fourteen AML samples were studied by Northern blot analysis and the KR mRNA was detected in the majority of SR-1 positive cases and also in 2 of 3 SR-1 negative samples. Furthermore, "in vitro" cultures from 15 cases showed that recombinant human Stem cell factor (rhSCF) induced an increased proliferative activity in most tested cases (11/15); this was further enhanced when rhSCF was combined with rhIL-3 + rhGM-CSF (p = 0.007) and with the GM-CSF/IL-3 fusion protein PIXY321 (p = 0.003). Thirty-seven ALL cases were also studied and all but one were SR-1 negative. Interestingly, the only SR-1 positive case also coexpressed myeloid antigens and showed an "in vitro" response when stimulated with rhSCF. Finally, the complete remission (CR) rate, survival and event-free survival were evaluated in 75 AML patients who received standard and identical chemotherapy; unlike previous studies which utilized a different anti-KR MoAb (YB5.B8) and which showed a poor prognosis for KR positive patients, we were unable to document any significant difference in CR rate, survival and event-free survival.

An update of prognostic factors for allogeneic bone marrow transplantation in multiple myeloma using matched sibling donors. European Group for Blood and Marrow Transplantation

Analysis of prognostic factors has been made in 369 allogeneic transplants for multiple myeloma reported to the registry of the European Group for Blood and Bone Marrow Transplantation (EBMT). Favorable prognostic factors for obtaining a complete remission (CR) were stage I at diagnosis (CR 77%), one line of treatment before conditioning (CR 52%), CR before conditioning (CR 60%), and Ig A or light chain myeloma (CR 43% and 42%). Factors that predicted significantly for favorable survival in a univariate analysis included having received only one line of treatment, female sex, stage I at diagnosis, stage I at conditioning and a beta 2-Microglobulin less than 4 mg/l. Favorable post-BMT factors consisted of obtaining a CR following BMT and not being in graft-versus-host disease stage III or IV. A multivariate analysis of pre-BMT factors showed that the sex of the patient and the number of lines of treatment pretransplant were independent prognostic factors. Allogeneic BMT is a promising treatment method for patients who have received only one line of treatment, particularly if they are of the female sex. BMT late in the course of the disease is usually unsuccessful.

The presence of lymphoid-associated antigens in adult acute myeloid leukemia is devoid of prognostic relevance

The immunophenotype of 110 adult patients with diagnosis of acute myeloblastic leukemia (AML) was analyzed using a wide panel of monoclonal antibodies (mAbs). Leukemic blasts were tested by applying direct immunofluorescence analysis and dual-fluorescence staining, and two groups of patients were identified: 56/110 (51%) expressing only myeloid antigens (My/AML) and 54/110 (49%) expressing both myeloid and lymphoid antigens (Ly/AML). CD13 and CD33 were expressed in almost all FAB subtypes, whereas CD14, frequently expressed in M4 and M5 subtypes (70%), was rarely expressed in M0 + M1 cases (9%). On the contrary, CD34, expressed in 77% of M0 + M1 cases, was practically absent in M3 and M5 subtypes (6% and 7%, respectively). CD2 and CD7 antigens were found in 34% and 42% of patients respectively, whereas B cell-associated antigens, such as CD10 and CD19, were found in 31% and 18% of patients. Cytogenetic abnormalities characteristically present in AML patients were also analyzed and, except for t(8;21) which was found in both groups of patients, the other abnormalities were frequently found in cases coexpressing lymphoid-associated antigens. Finally, the complete remission (CR) rate, survival and event-free survival were analyzed according to the presence of lymphoid markers and also of some specific antigens such as CD7 and CD34. The only prognostic difference was represented by CD34+ patients who showed a reduction in the CR rate compared with CD34- patients (65% versus 82%) (p = 0.05) which became more evident when the mean intensity of fluorescence was considered.(ABSTRACT TRUNCATED AT 250 WORDS)

Prognostic factors in allogeneic bone marrow transplantation for multiple myeloma

PURPOSE

To analyze prognostic factors for allogeneic bone marrow transplantation (BMT) in multiple myeloma.

PATIENTS AND METHODS

One hundred sixty-two reports of allogeneic matched sibling-donor transplants in multiple myeloma received by the European Group for Blood and Marrow Transplantation (EBMT) registry between 1983 and early 1993 were analyzed for prognostic factors. End points were complete remission, survival, and duration of complete remission.

RESULTS

Following BMT, 44% of all patients and 60% of assessable patients entered complete remission. The overall actuarial survival rate was 32% at 4 years and 28% at 7 years. The overall relapse-free survival rate of 72 patients who were in complete remission after BMT was 34% at 6 years. Favorable pretransplant prognostic factors for survival were female sex (41% at 4 years), stage I disease at diagnosis (52% at 4 years), one line of previous treatment (42% at 4 years), and being in complete remission before conditioning (64% at 3 years). The subtype immunoglobulin A (IgA) myeloma and a low beta 2-microglobulin level (< 4 g/L) also tended to have a favorable prognostic impact. The most important post-transplant prognostic factor was to enter a complete remission. Grade III to IV graft-versus-host disease (GVHD) was associated with poor survival.

CONCLUSION

Patients with a low tumor burden who respond to treatment before BMT and are transplanted after first-line therapy have the best prognosis following BMT.

Fludarabine treatment in resistant Waldenstrom's macroglobulinemia

Fludarabine (FLU) is a fluorinated purine analogue with a promising antineoplastic activity in lymphoproliferative disorders. In this study, we evaluated the efficacy of FLU in 12 previously treated (primary refractory and refractory relapse) patients with Waldenstrom's macroglobulinemia. All patients were treated at a dosage of 25 mg/m2 per day for 5 consecutive days for a total of six courses. Of the 12 patients, 5 (41%) achieved partial response (PR), and the remaining 7 showed no benefit from the treatment. An increased response rate was obtained in the 4 primary refractory patients in which 2 PR were documented. Treatment was well-tolerated and there were no Fludarabine-related fatalities. With a mean follow-up of 10 months, only 1 PR patient has relapsed. Fludarabine is an interesting new salvage agent effective against recurrent/resistant Waldenstrom's macroglobulinemia and should be evaluated in further studies in untreated patients with Fludarabine in monochemotherapy or in combination with other active modalities.

Factor VIII inhibitor prior to and during secondary acute nonlymphocytic leukemia in a patient with cured Hodgkin's disease

We report a 54-year-old patient with Hodgkin's disease who achieved a complete remission after combined modality treatment. Three years later the patient developed a severe hemorrhagic syndrome, concomitant with the onset of a factor VIII inhibitor in plasma. The control of very proteiform bleedings was extremely difficult, even with plasmaphereses, as well as with immunosuppressive and substitutive therapies. Two years later, a secondary acute nonlymphocytic leukemia (ANLL) was diagnosed. Two courses of chemotherapy with fludarabine, cytosine arabinoside and G-CSF (FLAG) were able to obtain a complete remission. Hemorrhagic complications were mainly linked to thrombocytopenia and continued until recovery of thrombopoiesis. Factor VIII inhibitor levels and related clinical symptoms decreased progressively. In conclusion, we suggest that FLAG succeeded in inhibiting an abnormal lymphoid clone responsible for factor VIII inhibitor production, suggesting a possible role for intensive chemotherapy in similar situations, which are often refractory to conventional immunosuppressive and depletive therapy.

Does the type of BCR/ABL junction predict the survival of patients with Ph1-positive chronic myeloid leukemia?

The prognostic value of the site of DNA rearrangement within the M-BCR on chromosome 22 or of the type of transcript has been debated in the last years. The majority of the studies do not support the hypothesis of a predictive value of such molecular parameters. Results coming from a multicentric, prospective trial, based on alpha-IFN therapy, seem to indicate a better karyotypic response in 3' rearranged patients. The possibility of evoking a cytotoxic immune response directed towards peptides originating from each of the different BCR/ABL junctions constitute an important challenge for the future.

Interleukin-11 (IL-11) and IL-9 counteract the inhibitory activity of transforming growth factor beta 3 (TGF-beta 3) on human primitive hematopoietic progenitor cells

BACKGROUND

TGF-beta 3 has been proven to be a potent suppressor of human hematopoietic progenitor cells and its effects on hematopoiesis are only inhibitory.

METHODS

In this paper we investigated the antiproliferative activity of TGF-beta 3 on highly purified bone marrow (BM) CD34+ cells and more immature CD34+/4-hydroperoxycyclophosphamide (4-HC) resistant cells. Primitive hematopoietic progenitors were stimulated by early acting stimulatory factors such as SCF, IL-11, IL-9 and the intermediate-late acting growth factors IL-3 and granulocyte-macrophage colony-stimulating factor (GM-CSF), alone and in combination.

RESULTS

The addition of TGF-beta 3 to cultures of CD34+ cells containing IL-11, IL-9 or SCF alone resulted in 86% or more inhibition of total colony formation. Conversely, IL-3 and GM-CSF-stimulated colony growth was inhibited by 57% and 58%, respectively (p < 0.02). IL-11 and IL-9 acted synergistically or additively with IL-3 and GM-CSF on the clonogenic growth of BFU-E derived from CD34+ cells, in both the presence and absence of TGF-beta 3. Co-incubation of CD34+ cells with 2 synergistic factors (e.g. IL-11 and SCF or IL-9 and SCF), with or without TGF-beta 3, resulted in the enhancement of both CFU-GM and BFU-E growth. The percentage of CD34+ cells inhibited by TGF-beta 3 was significantly reduced when IL-11 or IL-9, but not SCF, was added to the other cytokines (e.g. IL-11 and IL-3-stimulated cultures were inhibited by 42%, compared to 57% and 90% for the CSF alone; p < 0.05). Similarly, the addition of IL-11 or IL-9 to SCF decreased the suppressive activity of TGF-beta 3 (e.g. IL-11 and SCF in combination were inhibited by 52.4%, compared to 90% or more when the same cytokines were used separately; p < 0.001). These effects were mainly observed on CD(34+)-derived BFU-E although IL-9 appeared to override TGF beta-3 on both CFU-GM and BFU-E. When tested on CD34+/4-HC resistant progenitors, IL-11, IL-9 and SCF increased the number of clonogenic cells responsive to IL-3 and GM-CSF. However, TGF-beta 3 demonstrated a greater inhibitory activity on earlier cells than on the more mature CD34+ cell fraction, and none of the study cytokines completely abrogated the activity of TGF-beta 3.

CONCLUSIONS

These data confirm that TGF-beta 3 exerts its suppressive effect on hematopoietic progenitor cells according to the differentiation state of the target cells and the presence of other cytokines interacting with the cells. The permissive growth factors IL-11 and IL-9 seem to be able to partially counteract the negative regulation of TGF-beta 3.

AZT+methotrexate in high-grade HIV-related non-Hodgkin lymphomas: interim report on feasibility and tolerance

BACKGROUND

3' azido-3' deoxythymidine (AZT) is a thymidine analogue useful in the treatment of AIDS. We have previously demonstrated that AZT can possess significant antineoplastic activity when combined with de novo thymidylate synthesis inhibitors, such as 5-fluorouracil or methotrexate (MTX). We report here on the feasibility and tolerance of the combination AZT+MTX in the treatment of HIV-related non-Hodgkin lymphomas (NHL).

PATIENTS AND METHODS

IV-positive patients with high-grade NHL were treated, at weekly intervals, with three consecutive courses of MTX 1 g/m2 plus increasing doses of oral AZT (2, 4 and 6 g/m2) and folinic acid rescue.

RESULTS

From July 1992 to June 1994, 16 patients were enrolled in the trial after giving informed consent. Grade III-IV neutropenia was observed after 22% of the courses, but was prevented by G-CSF administration in 34/59 courses. Grade III-IV anemia was observed after 15% of the courses. No non hematological toxicity was observed.

CONCLUSIONS

The combination AZT+MTX was extremely well tolerated in this series of HIV-related NHL patients. If these results are confirmed in terms of antineoplastic efficacy, the protocol will deserve wider application.

Fludarabine + Ara-C + G-CSF: cytotoxic effect and induction of apoptosis on fresh acute myeloid leukemia cells

It has been reported that the adenine nucleoside analogue fludarabine is able to increase the phosphorylation and the cytotoxicity of cytosine arabinoside (Ara-C) in different leukemic models, both in vitro and in vivo. In poor prognosis acute myeloid leukemia (AML), the combination of fludarabine with Ara-C and granulocyte colony-stimulating factor (G-CSF) has proven to be a highly effective regimen. In this study we aimed to further investigate the effects of this drug combination. In vitro, on fresh AML cells from ten patients, our results confirm an additive cytotoxic effect displayed by fludarabine + Ara-C, as demonstrated by isobologram analysis of the data. The addition of G-CSF significantly increased the efficacy of the drug combination. These effects appeared to be related to an increased incorporation of [3H]Ara-C into cellular DNA in the presence of fludarabine + G-CSF. Furthermore, the quantitative evaluation of programmed cell death (apoptosis) showed that fludarabine + Ara-C + G-CSF induce apoptosis to a higher degree than either compound alone. This finding suggests that cooperative induction of apoptosis could be the potential mechanism of action of this drug combination.

Autoimmune neutropenia after unrelated bone marrow transplantation

A 26-year-old male with Ph+ chronic myeloid leukemia, recipient of an HLA-compatible marrow from a matched unrelated donor, showed good platelet engraftment coupled with poor neutrophil recovery. On day +33 the presence of surface-bound anti-neutrophil antibodies was detected by immunofluorescence. At variance with previously reported cases, the WBC count improved without any specific treatment, and the test became negative on day +42.

Prognostic value of serum IL-10 and soluble IL-2 receptor levels in aggressive non-Hodgkin's lymphoma

We investigated the prognostic significance of interleukin-10 (IL-10) and soluble interleukin-2 receptor (sIL-2r) levels in the pretreatment serum of 105 individuals with newly-diagnosed aggressive non-Hodgkin's lymphoma (NHL). Commercially available enzyme-linked immunoassay kits were used for cytokine and receptor measurements. Detectable levels of IL-10 were found in 42 (40%) patients at diagnosis, with no correlation with clinico-haematological parameters, but in no control samples (P < 0.001). Pretreatment concentrations of sIL-2r were markedly increased in individuals with NHL when compared to controls (2614 +/- 893 U/ml v 219 +/- 65 U/ml, P < 0.001), patients with stage III/IV presenting higher values than those with stage II disease (3885 +/- 1196 U/ml v 1732 +/- 646 U/ml, P < 0.001). No single parameter was associated with the achievement of complete remission, but the combination of elevated IL-10 and of sIL-2r greater than 3000 U/ml selected a subset of patients with a high probability of failing induction therapy (P < 0.001). Life-table analysis also indicated that patients with these characteristics have a significantly shorter event-free survival. In a multivariate analysis the combination of IL-10 with sIL-2r was found to have greater predictive strength than the combination of IL-10 with beta 2-microglobulin. We conclude that IL-10 and sIL-2r measurements can be expected to improve existing methods of risk assignment in aggressive NHL.

All-trans retinoic acid potentiates megakaryocyte colony formation: in vitro and in vivo effects after administration to acute promyelocytic leukemia patients

In this study, we evaluated the in vitro growth of normal hematopoietic progenitors (CFU-GM, BFU-E, CFU-GEMM, CFU-meg) stimulated by optimal sources of colony stimulating activity in the absence or presence of 10(-6) M all-trans retinoic acid (ATRA). ATRA alone did not show any colony-stimulating ability when added in culture to partially purified bone marrow populations. On the other hand, it significantly increased the number of CFU-GM (p = 0.003) and both the number (p = 0.009) and size (p = 0.002) of CFU-meg in the presence of appropriate colony-stimulating activity. Since ATRA had only modest stimulatory effects on purified CD34+ cells, the megakaryocyte colony-stimulating activity of ATRA was mainly due to an increased production of endogenous cytokines by bone marrow accessory cells. In parallel experiments, the in vitro growth of the different hematopoietic progenitors was evaluated in 28 patients affected by acute non-lymphoid leukemia (ANLL), mainly acute promyelocytic leukemia (APL). Bone marrow cells were harvested after remission induction obtained: (i) in ten APL patients treated with ATRA followed by one chemotherapy cycle (CHT) (3/7: Daunorubicin+Ara-C): group A ('ATRA/CHT'); (ii) eight APL patients treated with one CHT cycle alone (3/7 as above): group B ('APL-CHT'); (iii) in ten ANLL-non-APL patients after one CHT cycle (3/7 as above): group C ('ANLL-CHT'). The number of the different hematopoietic progenitors, and in particular CFU-GM and CFU-meg, was significantly higher in APL patients treated with ATRA plus CHT (group A) compared to APL (group B) or ANLL-non-APL (group C) patients treated with CHT alone (CFU-GM: p = 0.01; CFU-meg: p = 0.03). Our data demonstrate that ATRA is able to potentiate both normal and APL megakaryocytopoiesis and suggest that the in vivo administration of ATRA could be beneficial in other pathological conditions, where the megakaryocyte progenitor cell compartment is impaired.

Expression and functional role of c-kit ligand (SCF) in human multiple myeloma cells

In this study we investigated the proliferation of three well-documented MM lines and 10 bone marrow samples from myeloma patients in response to rh-SCF alone and combined with Interleukin-6 (IL-6), IL-3 and IL-3/GM-CSF fusion protein PIXY 321. Neoplastic plasma cells were highly purified (> 90%) by immunomagnetic depletion of T, myeloid, monocytoid and NK cells. The number of S-phase cells was evaluated after 3 and 7 d of liquid culture by the bromodeoxyuridine (BRDU) incorporation assay. The proliferation of RPMI 8226 and U266 cell lines was also assessed by a clonogenic assay. All the experiments were performed in serum-free conditions. RPMI 8226 cell line was not stimulated by SCF which also did not augment the proliferative activity of IL-6, IL-3 and PIXY-321. Conversely, SCF addition resulted in 2.4-fold increase of the number of U266 colonies and in a higher number of U266 and MT3 cells in S-phase (24.5 +/- 2% SEM v 14.5 +/- 1% SEM and 32 +/- 3% SEM v 21 +/- 4% SEM, respectively; P < 0.05). The c-kit ligand also enhanced the proliferation of MT3 and U266 cells mediated by the other cytokines. Anti-SCF polyclonal antibodies completely abrogated the proliferative response of MT3 cells to exogenous SCF and markedly reduced the spontaneous growth of the same cell line. Reverse transcriptase-polymerase chain reaction amplification (RT-PCR) did detect SCF mRNA in MT3 and RPMI 8226 cells. Moreover, secreted SCF was found, in a biologically active form, in the supernatant of the two cell lines by the MO7e proliferation assay. When tested on fresh myeloma samples, SCF increased the number of S-phase plasma cells (4.7 +/- 1.6% v 3.4 +/- 1.3% in control cultures: P = 0.02). Significant proliferation was also induced by IL-6 (7 +/- 2.3% of BRDU+ cells; P = 0.006), IL-3 (5.3 +/- 1.3%; P = 0.01) and PIXY-321 (5.4 +/- 1.6%; P = 0.02). The addition of SCF significantly enhanced the proliferation of myeloma cells responsive to IL-6. In summary, our results indicate that SCF is expressed in MM cells and stimulates the proliferation of neoplastic plasma cells.

Negligible hemostatic toxicity of intermediate-dose Erwinase in adult patients with acute lymphoblastic leukemia: preliminary data

The hemostatic toxicity of low dose L-asparaginase from Erwinia carotovora (Erwinase) has been reported to be negligible in adult patients with acute lymphoblastic leukemia (ALL); conversely, no consistent data have been obtained when Erwinase is administered at intermediate doses. We report preliminary clinical and laboratory hemostatic data from 10 adult patients with ALL treated during induction phase with intermediate doses of Erwinase (20,000 IU/m2s.c. every other day, for a total of six administrations). No thrombotic or hemorrhagic events were registered and the mean values of PT, aPTT, fibrinogen, antithrombin and D-dimer did not change during treatment. Only one patient showed a decrease of antithrombin (48% on day 8) requiring temporary suspension of Erwinase therapy. These data suggest that intermediate doses of Erwinase also have negligible hemostatic toxicity in adult patients with ALL.

Detection of soluble interleukin-2 receptor and interleukin-10 in the serum of patients with aggressive non-Hodgkin's lymphoma. Identification of a subset at high risk of treatment failure

BACKGROUND

This study explores the ability of the combined detection of soluble IL-2 receptor (sIL-2r) and interleukin-10 (IL-10) to predict treatment failure in patients with aggressive non-Hodgkin's lymphoma (NHL) and to evaluate the modifications in cytokine measurements induced by the therapeutic administration of recombinant human granulocyte-macrophage colony-stimulating factor (GM-CSF).

METHODS

Serum levels of sIL-2r and IL-10 were measured serially in 93 patients with newly diagnosed aggressive NHL treated with four courses of a multiagent chemotherapy regimen. GM-CSF was administered subcutaneously in 39 of these patients from day +5 to day +18 after each chemotherapy course.

RESULTS

Pretreatment levels of sIL-2r were greatly elevated in patients with NHL compared with control subjects (P < 0.001), significantly correlating with the Ann Arbor stage (P < 0.001) and beta 2-microglobulin (beta 2-m) concentrations (r = 0.552, P = 0.004). IL-10 was detected in 37 patients at diagnosis, with no correlation with clinicohematologic parameters, and was not detected in the control sample (P < 0.001). Cytokine and receptor levels progressively declined to normal ranges in responding patients, whereas they remained elevated in nonresponders. During administration of GM-CSF, the authors observed an increase of sIL-2r, whereas lower elevations were recorded for IL-10. However, on completion of the induction treatment, cytokine/receptor levels were comparable in patients with the same type of response, whether or not they had received GM-CSF. In the five patients who were investigated at relapse, the levels of sIL-2r, beta 2-m, and lactic dehydrogenase were found to be elevated. IL-10 concentrations were high in three of these patients: two already had detectable levels at presentation, whereas one tested positive only on recurrence. No single parameter was associated with response to therapy, but the combination of elevated IL-10 and sIL-2r concentrations greater than 3000 U/ml resulted in a subset of eight patients who failed induction chemotherapy (P < 0.001). In addition, six of eight patients with high IL-10 and beta 2-m concentrations greater than 3.3 mg/l had an unfavorable outcome (P = 0.003). A multivariate regression model was used to identify sIL-2r (P = 0.004) and beta 2-m (P = 0.043) as the covariates that amplified the prognostic ability of IL-10.

CONCLUSIONS

sIL-2r and IL-10 measurements provide valuable information for better management of patients with NHL as markers to monitor disease activity and as prognostic indicators.

Pre-treatment with all-trans retinoic acid accelerates polymorphonuclear recovery after chemotherapy in patients with acute promyelocytic leukemia

All-trans retinoic acid (ATRA) is currently being used as remission induction treatment for acute promyelocytic leukemia (APL). Conventional chemotherapy is added both during and after ATRA treatment, in order to avoid the occurrence of hyperleukocytosis, and to improve the duration of complete remission. In this study we analysed the hematopoietic recovery of 18 consecutive APL patients after standard Idarubicin or Daunorubicin +/- Cytosine-Arabinoside regimens. 9 of the patients were at the onset of the disease, (CHT group) while 9 had been pre-treated with ATRA 45 mg/sqm/day for at least 3 months (ATRA group). 500 PMN/mmc were reached after 20.8 day from the end of treatment in CHT group and after 12.0 days in ATRA group (p = 0.007). Platelets recovery was faster, even though not significantly in ATRA group. Interestingly, PMN recovery in ATRA group was even shorter (p = 0.004) than that obtained in CHT group, after the first course of chemotherapy (treatment in CR vs treatment in CR). If these results are confirmed in a larger study, a protective effect of ATRA on normal residual hemopoiesis should be postulated.