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Lymphocyte-variant hypereosinophilic syndrome (L-HES) is a rare disease driven by immunophenotypically aberrant T cells producing eosinophilopoetic cytokines such as interleukin-5 (IL-5). Treatment is challenging because L-HES is relatively steroid resistant and not amenable to tyrosine kinase inhibitors. We searched the literature for clinical trials and observational studies, including case reports, of patients treated for L-HES. In all, 25 studies were selected; two were randomised controlled trials of IL-5 blockade, which included some patients with L-HES, and the rest were observational studies. Corticosteroids are often used as first-line therapy, but patients with L-HES have lower response rates than other types of HES. Treatments that reduce symptoms and steroid dependence in some patients include interferon-alpha (IFN-α), anti-IL-5 monoclonal antibodies, cyclosporine and mycophenolate. These drugs target T-cell activation and proliferation, or IL-5 directly. Although effective, IFN-α and cyclosporine were commonly reported to cause side-effects resulting in discontinuation. Alemtuzumab can induce remissions, but these are generally short lived. The anti-IL-5 monoclonal antibodies mepolizumab and benralizumab are effective and well tolerated, but with a high rate of relapse once withdrawn. Hydroxyurea, methotrexate, imatinib were unsuccessful in most patients studied. More prospective clinical trials are needed for patients with L-HES.

Standard first-line therapy choice for essential thrombocythaemia (ET) requiring cytoreduction, supported by randomized trials, is low-dose aspirin with hydroxycarbamide, but the role of recombinant interferon-alfa (IFNα)-2a/2b and pegylated (PEG)-IFN-α-2a/2b is increasingly highlighted. Longer-term outcome data, however, remains somewhat scarce, particularly in the 'real world'. We hereby report on a large, well-annotated cohort of ET patients from a single referral centre undergoing therapy with either IFNα or (PEG)-IFN-α-2a/2b and demonstrate high rates of complete haematological responses, good tolerability and safety, low rates of thromboembolic events in compliant patients and confirm feasibility of long-term therapy in a significant proportion of patients.

Summary We investigated the current role of interferon‐alpha (IFNα) in hairy cell leukaemia (HCL) in a retrospective analysis of patients with HCL. A cohort of 74 patients with HCL was divided in to three groups: (A) patients aged >65 years with first‐line treatment; (B) patients with comorbidities with first‐line treatment; (C) patients who were purine analogues resistant. In total, 94% achieved a response, with a complete response rate of 24%. After a median (range) follow‐up of 60 (7–236) months, 55 patients (78%) are still responding. The 5‐year progression‐free survival was 95%, 68%, and 96% in groups A, B and C respectively. A proportion of patients were monitored through their B‐Raf proto‐oncogene, serine/threonine kinase (BRAF)‐V600E status. IFNα remains a possible option in select patients with HCL, where minimal residual disease negativity is achievable.

Patients with hairy cell leukaemia (HCL) have highly favourable outcomes after purine analogue therapy. However, most patients subsequently relapse and require re-treatment. A minority of patients develop purine analogue-refractory disease. Targeted therapies have improved outcomes for such patients. Recently, the BRAF V600E mutation was identified in most patients with classical HCL, resulting in constitutive mitogen-activated protein kinase pathway activation; impressive responses are achieved in heavily pre-treated patients with BRAF inhibition. The CD22-targeted immunoconjugate moxetumomab pasudotox and BTK inhibitor ibrutinib also achieve responses in relapsed and refractory patients. HCL variant and the IGHV4-34 molecular variant of HCL lack BRAF mutation and have inferior outcomes with standard purine analogue therapy. The addition of rituximab to purine analogues achieves very high rates of minimal residual disease-negative complete remission and improves outcomes for patients with HCL variant. Given the rarity of HCL, optimal integration of novel therapies into treatment algorithms will require well-designed, collaborative studies.

Summary Congenital dyserythropoietic anaemia type I (CDA‐I) is one of a heterogeneous group of inherited anaemias characterised by ineffective erythropoiesis. CDA‐I is caused by bi‐allelic mutations in either CDAN1 or C15orf41 and, to date, 56 causative mutations have been documented. The diagnostic pathway is reviewed and the utility of genetic testing in reducing the time taken to reach an accurate molecular diagnosis and avoiding bone marrow aspiration, where possible, is described. The management of CDA‐I patients is discussed, highlighting both general and specific measures which impact on disease progression. The use of interferon alpha and careful management of iron overload are reviewed and suggest the most favourable outcomes are achieved when CDA‐I patients are managed with a holistic and multidisciplinary approach. Finally, the current understanding of the molecular and cellular pathogenesis of CDA‐I is presented, highlighting critical questions likely to lead to improved therapy for this disease.

Summary High-dose chemotherapy followed by autologous haematopoetic stem cell transplantation (ASCT) is a standard frontline therapy for multiple myeloma (MM). Unfortunately, there are no randomized clinical studies examining the role of a second ASCT in patients who relapse after the initial autotransplant. Analysing all available retrospective studies, it seems that salvage ASCT can safely be performed in most patients with an overall treatment-related mortality rate

International audience; Myeloproliferative neoplasm-related myelofibrosis is associated with cytopenic or proliferative phases, splenomegaly and constitutional symptoms. Few effective treatments are available and small series suggested that interferon could be an option for myelofibrosis therapy. We performed a retrospective study of pegylated-interferon α-2a (Peg-IFNα-2a) therapy in myelofibrosis. Sixty-two patients treated with Peg-IFNα-2a at 17 French and Belgian centres were included. Responses were determined based on the criteria established by the International Working Group for Myelofibrosis Research and Treatment. Mean follow-up was 26 months. Sixteen of 25 anaemic patients (64%) (eight concomitantly receiving recombinant erythropoietin) achieved a complete response and transfusion-independence was obtained in 5/13 patients (38*5%). Constitutional symptoms resolved in 82% of patients. All five leucopenic patients normalized their leucocyte counts, whereas a normal platelet count was obtained in 5/8 thrombocytopenic patients. Splenomegaly was reduced in 46*5% of patients, and complete resolution of thrombocytosis and leucocytosis were observed in 82*8% and 68*8% of patients, respectively. Side effects (mostly haematological) were mainly of grade 1-2. The only factor independently associated with treatment failure was a spleen enlargement of more than 6 cm below the costal margin. In conclusion, Peg-IFNα-2a induced high response rates with acceptable toxicity in a large proportion of patients with primary and secondary myelofibrosis, especially in early phases.

We analysed the long-term outcome of 35 children and adolescents (

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Summary Maintenance therapy was explored in multiple myeloma (MM) patients after conventional thalidomide, dexamethasone and pegylated liposomal doxorubicin (ThaDD). Patients with newly or relapsed MM obtaining at least minor response after 6 ThaDD courses, were randomised to receive α-interferon (IFN) 3 MU 3 times a week or thalidomide 100 mg daily until relapse. Both groups also received pulsed dexamethasone 20 mg 4 d a month. Fifty-one patients were randomized in the IFN-dexamethasone (ID) arm and 52 in the thalidomide-dexamethasone (TD) arm. The characteristics of two groups were similar. A significantly better 2-years progression-free survival (PFS; 63% vs. 32%; P = 0·024) and overall survival (84% vs. 68%; P = 0·030) was observed in the thalidomide arm. In high-risk patients and in those achieving less than very good partial response after induction, TD fared better in term of PFS. Main side effects were peripheral neuropathy and constipation in TD group, fatigue, anorexia and haematological toxicity in ID arm. There was a 21% probability of discontinuation at 3 years in the thalidomide arm and 44% in the IFN arm (P = 0·014). Low-dose thalidomide plus pulsed low-dose dexamethasone after conventional thalidomide combination-based therapy was also feasible in the long term, enabling significantly better residual disease control if compared with a standard maintenance therapy.

We report the case of a 28-year-old female followed for congenital dyserythropoiesis type I which required repeated transfusions. Alpha-2a interferon treatment was started because of post-transfusion chronic viral hepatitis type C. Following this treatment, haemoglobin level increased and reached normal value during the 24 weeks of interferon treatment. When interferon therapy was stopped, haemoglobin level returned to previous values, requiring more transfusions. Resumption of interferon therapy resulted again in a complete normalization of haemoglobin level. Erythrokinetic studies demonstrated a striking reduction of the ineffective erythropoiesis, and electron microscopy study a reduction in nuclear structure abnormalities. To our knowledge, this is the first report of the efficacy of interferon in congenital dyserythropoiesis.

In patients with myeloid malignancies, cell-mediated immunity is often suppressed, being most profound in those with advanced disease. Such immune dysfunction, as demonstrated in many patients with chronic lymphocytic leukaemia (CLL) and myelodysplastic syndrome (MDS), may, at least in part, be due to altered expression of the CD3-zeta chain, which is an important component of the T-cell receptor (TCR). We speculated that impaired expression of the TCR-zeta chain would be evident in peripheral blood T cells of patients with chronic myeloid leukaemia (CML) and that such an abnormality would result in an increased ex vivo susceptibility to apoptosis. In this study, we demonstrated that, compared with normal controls, zeta chain expression was significantly downregulated in all of the T-cell subsets (P0.009) in more than 90% of CML patients. In addition, there was a significantly lower expression of the CD3-epsilon chain (P0.001) in patients than in controls. In those patients with abnormal zeta chain expression, the proportion of lymphocytes with spontaneous DNA fragmentation, as determined by terminal deoxynucleotide transferase-mediated dUTP-biotin nick-end labelling (TUNEL) assays, was also significantly higher (P0.002) than controls. From all of the patients tested, it was possible to upregulate partially zeta chain expression and hence to reduce the susceptibility to apoptosis by cross-linking the T cells with interleukin (IL)-2, interferon (IFN)-alpha or immobilized CD3. In addition, such cross-linked T cells showed a significantly higher capacity to proliferate than the native CML T cells.

Although interferon alpha (IFN-alpha) is able to induce haematological remission in 60-80% of patients with chronic myeloid leukaemia (CML) in early chronic phase, major cytogenetic remissions are only achievable in 30-40%. Recent clinical data suggest that the addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) to IFN-alpha therapy can significantly improve the cytogenetic response in some patients, although the mechanism remains unknown. We hypothesized that the combination of GM-CSF and IFN-alpha induces the differentiation of dendritic cells, which subsequently stimulates a specific anti-leukaemic response. Monocytes from CML patients were cultured in GM-CSF and interleukin (IL)-4 (GM/IL-4)or in GM-CSF and IFN-alpha (GM/IFN-alpha). After 7 d, the number of cells exhibiting typical antigen-presenting cell (APC) morphology was equal in both groups, and fluorescence in situ hybridization (FISH) analysis confirmed that the APCs generated with GM/IFN-alpha were of leukaemic origin. Phenotypically, both sets of APCs expressed typical surface markers; however, CD86, CD83, CD11c, HLA-ABC and HLA-DR expression was significantly higher in the GM/IFN-alpha APCs, whereas CD1a expression was significantly lower. In mixed lymphocyte reactions (MLR), GM/IFN-alpha APCs stimulated the proliferation of allogeneic T cells significantly better than GM/IL-4 APCs. However, both groups of APCs stimulated autologous T-cell proliferation equally. Finally, we assessed the ability of GM/IFN-alpha APCs to induce a leukaemia-specific cytotoxic T-cell response. Some samples generated cytotoxic T lymphocytes (CTLs) that specifically lysed bcr-abl-positive target cells. These data show that the combination of GM-CSF and IFN-alpha, when used in vitro, induces the differentiation of malignant APCs with potent T-cell stimulatory capacity. Although there is no in vivo evidence to support these findings, it is possible that, when administered to CML patients, GM-CSF in combination with IFN-alpha results in the generation of highly stimulatory leukaemic APCs.

We report a case of congenital dyserythropoietic anaemia, type I, with severe pre- and postnatal manifestations. Exchange transfusions were required for fetal anaemia (3.5 g/dl) at 28 and 30 weeks of gestation. Transfusions were administered at birth (Caesarean section at week 35) and at regular intervals thereafter. At 14 months, alpha-interferon therapy was initiated (106 units three times a week). This resulted in stabilization of the haemoglobin at or above 11 g/dl and a reduction in the percentage of erythroblasts with ultrastructurally abnormal heterochromatin. After 9 months, the dose of alpha-interferon was decreased to 106 units twice a week. No relapse of anaemia was noted during an additional 4 months of follow-up.

This pilot study evaluated the efficacy of a new combination chemotherapy with a newly developed nitrosourea derivative ranimustine and evaluated the efficacy of interferon alpha (IFN-alpha) maintenance in previously untreated patients with multiple myeloma (MM). The induction therapy (ROAD-IN) was a 6-week regimen consisting of chemotherapy with ranimustine, vincristine (Oncovin), melphalan (Alkeran) and dexamethasone starting on day 1 and IFN-alpha, which was administered three times weekly for 3 weeks starting on day 22. This was repeated for three cycles. The responders were subsequently randomized into two groups that received or did not receive IFN-alpha as maintenance therapy. Of the 164 patients registered, 161 were evaluated. An objective response to induction therapy was seen in 75% of patients; complete remission (CR) in 38 (24%) and partial remission (PR) in 82 (51%). The median survival for all patients was 3.6 years from registration. The survival of responders (CR + PR) was significantly better than that of non-responders (median survival 4.3 years vs. 1.4 years; 7-year survival rate 32% vs. 9%; P < 0.0001). The IFN-alpha maintenance did not show any advantage for either response duration or survival. This pilot study demonstrated that a comparatively short period of induction therapy with the ROAD-IN regimen produced a rather high response rate and a similar survival rate to those achieved with other longer induction regimens, and that good responders to the initial therapy survived significantly longer than non-responders.

Hepatitis C virus (HCV) infection is common in multi-transfused thalassaemic patients, and, in combination with transfusional iron overload, can result in progressive liver disease. Therapy with interferon-alpha causes a sustained loss of HCV in only 15-25% of patients, and there is as yet no established effective therapy for those who fail to respond. We have conducted a pilot study of combination anti-viral therapy for patients who failed to respond, or relapsed after an initial response to single-agent interferon-alpha. Patients were treated for 6 months with interferon-alpha 2b, given subcutaneously three mega units thrice weekly, together with ribavirin, orally 1 g daily. 11 patients were enrolled, their median age was 24.9 years. 8/10 evaluable patients had cirrhosis on biopsy, five were infected with HCV type 1 and all but one had initial HCV RNA titres > 10(6) genomes/ml. Five patients (45.5%) had a sustained virological response with loss of serum HCV RNA for > 6 months after finishing therapy. There was no clear association between response to therapy and age, histology, HCV genotype, or HCV RNA titre. Transfusion requirements were significantly increased during the treatment phase, probably due to ribavirin-induced haemolysis, and this necessitated intensification of iron chelation therapy. Serum ferritin levels decreased significantly in those who responded. These results suggest that combination therapy is potent in clearing HCV infection, and may provide effective second-line therapy for thalassaemic patients who have failed to respond to interferon-alpha monotherapy.

Peripheral blood T cells from 83 patients with multiple myeloma (MM) were examined for the production of interferon-gamma (INF-gamma) and interleukin-2 (IL-2) using three-colour flow cytometry. Comparisons were made between the percentage of cytokine-positive lymphocytes in normal donors and in patients during remission or relapse. Patients were divided into those who were on maintenance therapy with interferon-alpha2b (intron A) and those who had no further treatment after high-dose melphalan (HDM) with or without autologous bone marrow (ABMR) or peripheral blood stem cell rescue (PBSCR). The percentage of INF gamma+/CD3+, INF gamma+/CD45RO+/CD3+ and IL-2+/CD8+ was higher in patients on INF alpha2b during remission and relapse compared with normal donors (P

Mobilization of Philadelphia chromosome (Ph) negative blood progenitors was attempted in 23 newly diagnosed chronic myeloid leukaemia (CML) patients using a regimen of cyclophosphamide (CY) 5 g/m 2 and rHUG-CSF 1150 μg/m 2 daily. This regimen was well tolerated with no major adverse events reported. More than 2 x 10 6 /kg CD34 + cells were collected in 21 patients (91%). Predominantly Ph-negative mobilization (0-25% Ph-positive) was seen in 30% of cases overall and was confined to patients with a Sokal prognostic score < 1 (7/11 with Sokal score

UNLABELLED Seventeen patients with high-risk myelodysplastic syndromes (HR-MDS) received lymphoblastoid-interferon alpha (Ly-IFN alpha) for 3 months at escalating doses from 0.5 to 3 MU s.c. 3 times per week. Three patients stopped the treatment after 2 months because of cardiac failure (one patient) and cerebral haemorrhage (two patients); six had a partial response (PR) and continued Ly-IFN alpha; six were resistant and stopped Ly-IFN alpha; two evolved to acute myelogenous leukaemia (AML). Among the six partial responders, four achieved a complete response (CR) during subsequent Ly-IFN alpha treatment (CR duration 3, 4+, 15+ and 29 months) and two did not achieve any further improvement (PR duration 3 and 9 months). Two resistant patients had an unexpected clinical improvement soon after Ly-IFN alpha discontinuation and achieved a PR of 6+ and 14+ months respectively. No toxicity related to Ly-IFN alpha treatment was observed and no reduction of dosage was needed. IN CONCLUSION (1) Ly-IFN alpha seems to be effective in some patients with HR-MDS; (2) the best treatment duration seems to be of a least 6 months.

The RT-PCR technique for the identification of the PML-RAR alpha fusion mRNA is widely used for the detection of minimal residual in acute promyelocytic leukaemia (APL). A positive result after remission induction is highly predictive of early relapse, but the vast majority of patients have no detectable disease by this technique after chemotherapy consolidation, despite the fact that many later relapse. We report a quantitative PCR technique for the PML-RAR alpha cDNA which was used to show that less than 1000 PML-RAR alpha molecules are obtained from 1 microgram of diagnostic bone marrow RNA derived from approximately 1 million APL blasts. The lack of sensitivity of currently employed RT-PCR methods may therefore be explained by their poor yield of PML-RAR alpha cDNA. Minor modifications to the reverse transcription procedure improved this yield 3 fold. Furthermore, expression of the leukaemia-specific transcript increased by approximately one order of magnitude after incubation of the patient's cells for 24 h in vitro with 100 iu/ml alpha interferon.

The efficacy of interferon-alpha 2b (IFN alpha) to prolong progression-free (PFS) and/or overall survival (OS) in early B-CLL (Binet stage A) was examined in a risk-adapted phase III study. 99 previously untreated B-CLL patients were recruited. 44 patients with expected high risk for disease progression, defined by non-nodular bone marrow infiltration and lymphocyte doubling timeor = 12 months or serum thymidine kinase levelsor = 5 U/I, were randomized to either receive IFN alpha (group 1, n = 21) or not (group 2, n = 23). 55 low-risk patients were observed to evaluate this risk stratification (group 3). During a median observation time of 36 months, four patients in the IFN alpha group achieved a partial remission (PR), no patient had stable disease (SD), and 17 patients experienced progressive disease (PD). The four responders had less extensive disease at study entry and tended to exhibit a rise in serum IgG levels. In group 2, no PR, seven SD and 16 PD, whereas in group 3, no PR, 37 SD and 18 PD occurred. PFS in group 1 (6.7 months) was not different from group 2 (13.3 months, P = 0.22), but PFS of groups 1 and 2 differed from group 3 (37 months, Por = 0.001). OS was 44.9 months (group 1), 43.1 months (group 2) and 57.9 months (group 3). OS was not significantly different for group 1 v 2, but was significant between groups 1 and 3 (P = 0.023). The higher percentage of PD in group 2 compared to group 3 (70% v 29%) shows that the selected risk factors allow the definition of CLL stage A patients at risk for disease progression within about a year. In conclusion, our data indicate that IFN alpha does not prolong PFS or OS in stage A CLL patients with high risk for disease progression.

Abnormal adhesive interaction between bone marrow stroma and progenitors, one of the causes of unregulated proliferation in chronic myelocytic leukaemia (CML), may be caused by some alterations in adhesion molecules on CML progenitors. We investigated the expression of adhesion molecules (CD44, VLA-5, VLA-4, LFA-1, ICAM-1, L-selectin and c-kit) on bone marrow CD34++ cells from 16 CML patients by three-colour flow cytometry. The mean percentage of cells expressing L-selectin in the CD34++CD38+(or)++ fraction from untreated CML patients was significantly lower, and that in the CD34++CD38- fraction tended to be lower than that from normal controls. Among 11 CML patients treated with interferon-alpha (IFN-alpha), the mean percentage of the cells expressing L-selectin in the CD34++CD38- fraction from three patients with a low percentage of Ph1(+) cells in bone marrow was significantly higher than that from five patients with a high percentage of Ph1(+) cells. In addition, L-selectin expression rate was inversely correlated to the percentage of Ph1(+) cells. There was no significant difference between the untreated patients and normal controls with regard to the expression rates of the other adhesion molecules in each CD34++ fraction except LFA-1. These data suggest that decreased L-selectin expression in CML CD34++ cells reflects one of the features of malignant CML progenitors.

The genes crucially determining the therapeutic response of chronic myelogenous leukaemia (CML) to interferon-alpha (IFN-alpha) are unknown. Recently, two independent IFN-alpha signalling pathways were identified: the classic pathway mediates induction of 2'-5' oligoadenylate synthetase (2-5 OAS), p68 kinase and IFN regulatory factor-2 (IRF-2), whereas the alternate pathway leads to activation of IFN regulatory factor-1 (IRF-1). We investigated whether deficient or imbalanced expression of components of these two pathways is associated with resistance of CML cells to antiproliferative action of IFN alpha/beta. Constitutive and IFN-induced transcript levels of IFN-dependent genes in mononuclear cells, granulocytes, monocytes, lymphocytes and CD34+ cells of chronic-phase CML and blast crisis patients were assessed by Northern blot techniques and were correlated with subsequent clinical responses to IFN therapy. Our results demonstrated that IFN-alpha or -beta treatment in vitro and in vivo leads to an enhanced expression of IRF-1, IRF-2. RNase L, p68 and 2-5 OAS which was independent of the degree of cellular differentiation and clonal evolution of CML. Neither the magnitude of induction of these genes nor the IRF-1/IRF-2 mRNA balance differed between chronic-phase CML patients responding or failing IFN-alpha therapy. These results indicate that failure of IFN-alpha treatment is not due to defects in mRNA induction of the above-mentioned candidate genes for the direct antiproliferative response to IFN type I.

The participation of minor centres in randomized trials has been questioned because of inferior quality of participation. We have studied this issue in a multicentre trial on myeloma, in which 574 patients were included from 99 participating centres in Sweden, Norway and Denmark from 1 June 1990 until 4 November 1992. Two hundred and eight patients were entered from university hospitals (n = 13), 172 from major county hospitals (n = 25), defined by a population base ofor = 100,000 inhabitants, and 194 from minor county hospitals (n = 61) with a population base of100,000 inhabitants. The accrual rate was similar for the three hospital categories, averaging 54% of all reported cases, corresponding to 38% of the expected number of newly diagnosed cases. The adherence to the study protocol from an administrative point of view was judged by the completeness of follow-up forms and the delay in the notification of deaths, and from a clinical point of view by the dose intensity for the principal drugs of the study, melphalan and interferon. For all studied measures of quality, the values were similar for the three hospital categories. We conclude that with due informative and educational support, minor centres can make a considerable contribution to the patient material of a large randomized trial without impairing the quality of the study.

Two hundred and nineteen cases of Ph+ve CML and 15 Ph-ve, BCR+ve CML cases have been analysed to determine the breakpoint site and its relationship to clinical features, cytogenetic response, duration of chronic phase and survival. 119 cases have had RNA analysis performed to determine the type of BCR/ABL transcript and have also been analysed in a similar way. Presenting features at diagnosis including age, sex, white-cell count and platelet count showed no significant difference for those with 5' and 3' breakpoints and those with either b2a2 or b3a2 BCR/ABL transcripts. However, in a subgroup of patients whose presenting white-cell count was < 100 x 10(9)/l, those with b3a2 transcript did have a significantly higher platelet count. Analysis by Sokal risk grouping showed no difference for 5' or 3' breakpoints but a trend for lower stage among those with b2a2 transcripts. No correlation was found either for genomic breakpoint site or BCR/ABL RNA transcript in terms of duration of chronic phase or survival. When stratified by randomized therapy, either interferon-alpha or standard chemotherapy, no difference was noted in relation to genomic breakpoint site or BCR/ABL transcript. Cytogenetic response was not related to the molecular findings.

Pruritus is a major clinical problem in patients with polycythaemia vera (PV). Conventional symptomatic treatment is unsatisfactory. Recently, a favourable effect of interferon-alpha on pruritus in patients with PV has been reported. Also, interferon-alpha suppresses the increased haemopoiesis in PV. However, long-term treatment with interferon-alpha may be hampered by side-effects and the inconvenience of chronic subcutaneous injection therapy. We conducted a long-term study (median follow-up 13 months) of the efficacy and tolerability of interferon-alpha in 15 patients (mean age 68 years) with PV and severe pruritus. Six patients were evaluable after I year. Pruritus significantly improved in 12/15 patients. Haematological control improved, as evidenced by a decreased number of phlebotomies from a mean of 4.3 in the year before the study to 1.8 while on interferon-alpha. Leucocyte and platelet numbers also decreased significantly. Five patients (33%) did not tolerate interferon-alpha. The effects of interferon-alpha could not be ascribed to an inhibitive effect on histamine production or to the disappearance of the abnormal erythroid progenitor clone, because erythropoietin-independent erythroid colony formation persisted during interferon-alpha treatment. We conclude that long-term interferon-alpha treatment is feasible and effectively relieves pruritus in patients with PV, but side-effects are an important concern. The optimal dose regimen that is well tolerated, relieves pruritus, and offers satisfactory haematological control at the same time remains to be established.

The bcl-2 oncoprotein, which is involved in the t(14,18) translocation, protects cells against apoptosis. We examined the effects of interferon-alpha (IFN-alpha) on bcl-2 protein expression and apoptosis in B-chronic lymphocytic leukaemia (B-CLL) cells. None of 12 patients with B-CLL examined expressed the t(14,18) translocation; however, all these, and seven other patients, expressed significant levels of bcl-2 protein. In vitro, IFN-alpha (500 U/ml over 18 h) increased bcl-2 expression on CLL cells (to 200 +/- 23% of control MCF, as determined by indirect immunofluorescence and flow cytometry, n = 10, P < 0.001). All of eight patients who received IFN-alpha (3 megaunits subcutaneously three times a week) demonstrated an increase in bcl-2 expression on circulating malignant cells. CLL cells undergo apoptotic cell death when cultured in vitro (35.6 +/- 10.3% DNA fragmentation after 18 h, n = 10). In the presence of IFN-alpha, however, DNA fragmentation was reduced to 6.6 +/- 5.8% (n = 10, P < 0.001). IFN-alpha also protected CLL cells against apoptosis induced by hydrocortisone and gamma irradiation (reducing DNA fragmentation from 63.9 +/- 12.6% to 10.8 +/- 4.5% and from 80 +/- 2.9% to 5.4 +/- 1.6%, respectively, P < 0.001 for both). The protective effect of IFN-alpha was dose dependent, and maintained for up to 24 h. Our data demonstrate that bcl-2 expression and apoptosis of CLL cells can be influenced by cytokines. In addition, it seems unlikely that the observed clinical responses to IFN-alpha in patients with CLL are due to a direct effect on the malignant cells.

Summary. Thirteen patients with congenital coagulation disorders and chronic hepatitis C were treated with alpha-interferon (IFN). Serum transaminases (ALT) and hepatitis C virus (HCV)-RNA in plasma and peripheral blood mononuclear cells (PBMC) were followed during and after treatment. During IFN treatment ALT levels normalized in 8/13 patients. In all patients HCV-RNA disappeared from PBMC. In 9/13 HCV-RNA also became undetectable from plasma; in six of these nine this occurred earlier in PBMC than in plasma; in the remaining three the disappearance of HCV-RNA occurred simultaneously in plasma and PBMC. All but two patients relapsed within 3 weeks after cessation of IFN, one relapsed after 6 weeks and one patient remains in remission after 6 months. HCV-RNA reappeared either earlier in plasma (3/12) or simultaneously in plasma and PBMC (9/12). Viral replication in PBMC thus can easily be suppressed by IFN, whereas longer treatment is needed for the eradication of HCV-RNA in plasma. The detection of HCV-RNA in PBMC cannot be used as a prognostic marker for the identification of patients with chronic hepatitis C who will have a sustained response to IFN treatment.

Interferon-alpha (IFN-alpha) treatment has been shown to be highly effective in inhibiting human megakaryocytopoiesis and controlling thrombocytosis in patients with myeloproliferative disorders. These observations suggest that IFN-alpha might play some role in the biological feature of the megakaryocytic lineage and led us to investigate the presence of specific receptors for IFN-alpha on human megakaryocytic cells, i.e. the Dami cell line, and to study the regulation of their expression. Our study demonstrates that [125I]-recombinant human IFN-alpha ([125I]rHu-IFN-alpha) binds to high-affinity specific receptor on these cells. Scatchard analysis of binding data indicates the presence of homogeneous binding sites estimated in the range of 3000-5000, with an apparent equilibrium dissociation constant, Kd, of 1-2 x 10(-9) M. Also, [125I]rHuIFN-alpha binding capacity decreased in Dami cells incubated with unlabelled rHuIFN-alpha. This down-regulation which was dose-dependent appeared to result from a reduction of IFN-alpha cell surface receptors and was observed at doses that elicited antiproliferative effects in Dami cells. Cross-linking of [125I]rHuIFN-alpha to Dami membrane proteins using a bifunctional reagent yielded to a radioactive complex of approximately 150,000 kD on SDS-PAGE. Furthermore, in response to PMA, which induces the differentiation/maturation of the Dami cells as evaluated by surface marker and ploidy analysis, a 3-fold increase of the number of specific membrane receptors for IFN-alpha was observed, without any modification of either the affinity or the M(r) value of the cross-linked complex. Such an increase appeared to be restricted to IFN-alpha receptors; actually it was not observed in [125I]IFN-gamma binding experiments. Transcript analysis indicated that down-regulation and increased expression of the IFN-alpha receptor after PMA treatment are post-transcriptional events.

We describe four patients who developed severe thrombocytopenia which progressed to aplasia after the use of alpha-interferon in maintenance therapy of chronic phase CML after busulphan induction. On reviewing over 400 patients in the MRC CML III trial we found that there is a risk of cytopenia developing after busulphan therapy and a lesser risk of cytopenias developing after alpha-interferon therapy. If the therapies are given in a sequential fashion the risk of cytopenia developing appears to be additive, may be pronounced, and may lead to clinically significant problems. Hydroxyurea alone does not lead to sustained cytopenia. Care should be taken to ensure that counts are stable after the use of busulphan before starting alpha-interferon as maintenance therapy.

We present a Ph-positive chronic myeloid leukaemia patient who lost a complete cytogenetic response (CCR) of 23 months duration at the time of detection of a deletion, not previously observed, of chromosomes 9 and 22 sequences flanking the translocation breakpoint on the derivate 9 chromosome. To our knowledge, this is the first case in which a deletion at the t(9;22) breakpoint has arisen as a secondary genetic alteration produced after formation of the t(9;22) translocation. It remains to be determined whether this genetic abnormality has the same prognostic importance as when observed at diagnosis.

The capacity of alpha-interferon (alpha-IFN) to induce lymphokine activated killer (LAK) cytotoxicity in the absence of interleukin-2 (IL2) has prompted us to test whether or not its ability to reduce dramatically the number of Ph1+ clones in chronic myelogenous leukaemia (CML) patients is in part mediated through the generation of natural killer (NK) or LAK activity. The latter were tested using NK-sensitive (K562) and NK-resistant (Raji) cell lines in a target-cell colony-growth inhibition assay. Effector cells (E) were patient blood mononuclear cells (MC) without in vitro activation prior to their coculture with targets (T). Out of 16 patients tested so far, three failed to undergo cytogenetic remission under alpha-IFN therapy. No NK nor LAK cells could be detected in the MC from two of them while the other displayed NK activity within upper normal limits. 13 patients underwent complete (eight) or partial (five) cytogenetic remission together with significantly high NK and/or LAK activity as compared to normal controls. These observations could favour the hypothesis of an indirect effect of alpha-IFN on leukaemic cells, mediated by cells involved in immune surveillance.

Although 5-fluorouracil (FUra) has been the drug of choice for the treatment of patients with advanced colorectal carcinoma, the response rates are in the range of 15% and the median survival times do not exceed 9 months. Interferon alpha (IFN alpha) has limited antitumour activity in this disease. Recent clinical trials have demonstrated that both the response rate and the survival time of patients with advanced colorectal cancer can be significantly improved by the addition of leucovorin (CF) to FUra. In a randomized phase III trial, the median response to FUra and CF was about 30% with a range of 20-55%, dependent on the dose and schedule of administration of CF. Due to multiplicity of mechanisms of action postulated for IFN alpha, the role of IFN alpha in the modulation of the cytotoxicity and therapeutic efficacy of FUra alone and in combination with CF has been evaluated in patients with advanced colorectal cancer and also in a variety of human cell lines in culture, including human colorectal cell lines, HCT-8, human bladder cell line RT-4 and leukaemia CEM cells. The results obtained in patients demonstrated that indeed the antitumour activity of FUra can be improved by the addition of IFN alpha with a response range from 26% to 76%. The initial clinical use of this combination, however, has been limited in some cases by the severe host toxicity. In vitro results demonstrated that: (1) in vitro cytotoxicity potentiation by IFN alpha is cell-type dependent; (2) in these cells where modulation was possible, alpha IFN was used as a low and noncytotoxic doses (10-50 micrograms/ml for 3-5 d exposure), and (3) the cytotoxicity of IFN alpha was dose dependent, indicating a direct antiproliferative cellular effect.

Malignant carcinoid tumours with the carcinoid syndrome has over the years presented a therapeutic challenge. The patients might not only die from tumour progression but also from symptoms relating to hormone overproduction and the specific cardiac disease, e.g. right heart fibrosis and failure. Surgery has been the treatment of choice in local disease, but when liver metastases have developed other treatment procedures must be considered. Conventional chemotherapy has been of little beneficial value, with response rates of only 10-30%, whereas a new somatostatin analogue, octreotid, is effective in controlling clinical symptoms but not tumour progression. Interferon treatment was introduced in 1982 by our group, and we are now presenting treatment results of 130 patients with histologically verified malignant carcinoid tumours and liver metastases. One hundred and eleven patients were treated with a median dose of 6 mega units (MU) of interferon alpha, five times weekly (dose range 3-9 MU), whereas 29 patients received conventional chemotherapy. Forty-seven out of 111 patients (42%) treated with interferon alpha demonstrated a significant biochemical response and 15% demonstrated more than 50% reduction in tumour size. In another 43 (39%) patients stabilization of the carcinoid disease have been noted, whereas 21 (19%) showed progressive disease. The median duration of response was 34 months. Subjective responses with improvement of diarrhoea, flush and/or bronchoconstriction were noticed in 76 patients (68%). The 19 patients treated with chemotherapy demonstrated only 10% biochemical response, lasting for only 3-5 months. The survival analysis demonstrates a median survival of only 8 months in the group of patients treated with chemotherapy, compared to 80+ months (P less than 0.001) in the groups treated with interferon alpha. Interferon adverse reactions of fatigue, weight loss and anaemia were manageable. Neutralizing interferon antibodies were documented in 5-15% of the patients. Interferon alphas are active in patients with malignant carcinoid tumours. Clinical symptoms are significantly reduced following reduction of circulating hormones. Interferon might also have an impact on survival in this group of patients. The side-effects are moderate and managed by dose adjustments.

Recombinant interferon alfa-2a has been shown to be an effective induction agent in essential thrombocythaemia and thrombocythaemia associated with other myeloproliferative disorders, including chronic granulocytic leukaemia, polycythaemia rubra vera and myelofibrosis. Few data exist on the use of the recombinant interferons as maintenance agents in patients with thrombocythaemia. A cohort of 22 previously untreated patients, with essential thrombocythaemia, were treated with recombinant interferon alfa-2a maintenance therapy for a minimum period of 6 months. Effective long-term control of platelet counts, without evidence of haematological toxicity, was achieved in 19/22 patients. No objective haemorrhagic or thrombotic event occurred in 298 patient-months of interferon therapy. Three patients discontinued interferon alpha therapy due to adverse side-effects. Interferon alfa-2a is an effective maintenance agent in essential thrombocythaemia and is discussed in this context.

Interferon alpha was one of the first drugs tested for the treatment of patients with AIDS-related Kaposi's sarcoma based on its known antiviral properties and its abilities to modulate immune function and inhibit neoplastic cell proliferation. In vitro studies demonstrated defective production of interferon by blood cells of HIV-infected individuals and suppression of HIV replication by interferons alpha and beta. Interferons have also been shown to inhibit angiogenesis induced by tumour cells or by allogeneic lymphocytes in mice. The efficacy of recombinant interferon alpha for the treatment of AIDS-related Kaposi's sarcoma has been well documented with antitumour responses seen in approximately 30% of all patients treated in single agent efficacy trials with doses of at least 20 MU/m2. In several uncontrolled studies, response of Kaposi's sarcoma to treatment with interferon alpha was associated with longer survival and few opportunistic infections. Tumour response appears to be correlated with an absence of opportunistic infection and with CD4 cell numbers. Several studies using high interferon alpha doses have demonstrated decreases in serum HIV P24 core antigens which appear to be confined to patients whose tumours also regressed. The use of interferon alpha in HIV-infected patients with or without Kaposi's sarcoma have demonstrated in vivo anti-HIV activity. Studies have recently evaluated the tolerance and therapeutic potential of interferon alpha in combination with the reverse transcriptase inhibitor, zidovudine (azidothymidine AZT). Synergistic suppression of HIV replication in vitro has been demonstrated with the combination of interferon alpha and zidovudine. The description of HIV isolates with reduced sensitivity to zidovudine following prolonged treatment, and the finding that interferon alpha, but not zidovudine, prevents HIV expression in chronically infected cell lines, suggests that this combination might be useful in long-term treatment of patients with HIV infection.

Recent reports have shown that interferon alpha is effective in B-chronic lymphocytic leukaemia (B-CLL). In a previous study from our unit we obtained a 50% response rate with interferon alfa-2b in B-CLL in early stages. Subsequently, we performed the present study randomizing 34 Binet stage AI, B-CLL patients who were not previously treated (eight controls and 26 who were to receive interferon alfa-2b (IFN alpha-2b) (Intron-A) according to a randomized schedule as follows: 1.5 MU/d in eight patients, 1.5 MU three times a week in 10 patients and 3.0 MU three times a week in eight patients). At 3 months complete response (CR) was obtained in one, partial haematologic response (PHR) in nine and minor haematologic response (MHR) in seven patients with an overall response rate 17/26 or 65%. No bone marrow changes regarding the pattern or degree of infiltration was noticed in any of the responding patients except for the complete responder. Treatment was continued in 15 patients (reduced to two-thirds of the initial dose in the PHR and to one third of the initial dose in the MHR) while in 11 patients it was discontinued because of no response, negative response or toxicity. At 6 months sustained response was observed in 10 patients, while in the remaining five an increase of blood lymphocytes was seen at numbers similar or higher to those noted prior to interferon alfa-2b therapy. Two of the 10 patients in whom blood lymphocytes were still reduced to less than 50% of the pretreatment values, developed gradual lymph node enlargement and therapy had to be discontinued. During the following 6 months the interferon alfa-2b dose was further reduced in all remaining responders to 1.5 MU once or twice a week and their counts remained at the same level as at 6 months of therapy. At 12 months, 18 of our patients were still in stage A while seven had progressed (five to stage B and two to stage C). The overall response after 12 months of therapy was sustained in 8/17 responders. We conclude from our study that interferon alfa-2b is effective in untreated B-CLL patients in early stages and therefore should be investigated in combination with conventional chemotherapy. Clinical trials utilizing interferon alfa-2b and chlorambucil in combination in untreated B-CLL patients are currently in progress in our unit.

Summary We have studied circulating progenitor cells in patients with myelofibrosis, the effects of recombinant α2b interferon (IFN) treatment on these cells in vivo and in vitro and the patients’clinical response to IFN treatment. A 75-fold increase in circulating granulocyte macrophage colony forming units (CFU-GM) and a 25-fold increase in multi-lineage colonies (CFU-GEMM) were seen in the patients compared with controls. Patients who had undergone splenectomy had circulating progenitors within the normal range. IFN treatment of two patients resulted in clinical improvement and reduction in spleen size, but was complicated by a fall in platelet count and persistent malaise. Whilst on treatment the circulating progenitor cells increased up to 5-fold. In contrast, the addition of IFN in vitro to the CFU-GM and CFU-GEMM culture plates resulted in a dose-dependent inhibition of colony growth which was unaffected by the removal of T-cells and monocytes. Thus we confirm that circulating progenitors are raised in patients with myelofibrosis, IFN may be of benefit clinically, reducing spleen size but may increase levels of these cells in vivo. This is in contrast to the inhibitory effect of IFN in vitro on CFU-GM and CFU-GEMM growth.