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Ligation of the cell-surface Fas molecule by its ligand (Fas-L) or agonistic anti-Fas monoclonal antibodies results in the cleavage and activation of the cysteine protease procaspase 8 followed by the activation of procaspase 3 and by apoptosis. In some leukemia cell lines, cytotoxic drugs induce expression of Fas-L, which may contribute to cell killing through the ligation of Fas. The involvement of Fas, Fas-L, and caspase 8 was studied in the killing of B-cell chronic lymphocytic leukemia (B-CLL) cells by chlorambucil, fludarabine, or gamma radiation. Spontaneous apoptosis was observed at 24-hour incubation, with additional apoptosis induced by each of the cytotoxic treatments. Although Fas mRNA expression was elevated after exposure to chlorambucil, fludarabine, or gamma radiation, Fas protein levels only increased after irradiation. Therefore, Fas expression may be regulated by multiple mechanisms that allow the translation of Fas mRNA only in response to restricted cytotoxic stimuli. None of the cytotoxic stimuli studied here induced Fas-L expression. An agonistic anti-Fas monoclonal antibody (CH-11) did not significantly augment apoptosis induction by any of the death stimuli. A Fas-blocking antibody (ZB4) did not inhibit spontaneous, chlorambucil-, fludarabine-, or radiation-induced apoptosis. However, procaspase 8 processing was induced by all cytotoxic stimuli. These data suggest that the Fas/Fas-L signaling system does not play a major role in the induction of apoptosis in B-CLL cells treated with cytotoxic drugs or radiation. However, Fas-independent activation of caspase 8 may play a crucial role in the regulation of apoptosis in these cells.

The aim of this study was to characterize individual-segment and overall patterns of V(H) gene usage in adult B-lineage acute lymphoblastic leukemia (ALL). Theoretical values of V(H) segment usage were calculated with the assumption that all V(H) segments capable of undergoing rearrangement have an equal probability of selection for recombination. Leukemic clones from 127 patients with adult B-lineage acute leukemias were studied by fingerprinting by means of primers for the framework 1 and joining segments. Clones from early preimmune B cells (245 alleles identified) show a predominance of V(H)6 family rearrangements and, consequently, do not conform to this hypothesis. However, profiles of V(H) gene family usage in mature B cells, as investigated in peripheral blood (6 samples), B-cell lymphomas (36 clones) and chronic lymphocytic leukemia (56 clones), are in agreement with this theoretical profile. Sequence analyses of 64 V(H) clones in adult ALL revealed that the rate of V(H) usage is proportional to the proximity of the V(H) gene to the J(H) locus and that the relationship can be mathematically defined. Except for V(H)6, no other V(H) gene is excessively used in adult ALL. V(H) pseudogenes are rarely used (n = 2), which implies the existence of early mechanisms in the pathway to B-cell maturation to reduce wasteful V(H)-(D(H))-J(H) recombination. Finally, similar to early immunoglobulin-H rearrangement patterns in the mouse, B cells of ALL derive from a pool of cells more immature than the cells in chronic lymphoid B-cell malignancies.

Background: We report our updated experience of allogeneic transplantation in lympho-proliferative disorders using a reduced-intensity conditioning regimen combining BEAM (plus fludarabine in three cases) with pre-transplant CAMPATH. Post-transplant donor lymphocytes have been infused for persisting disease or relapse, and both chimerism and minimal residual disease have been monitored utilizing molecular techniques., Methods: Thirty patients with median age 47.6 years underwent allogeneic transplantation for relapsed or high-risk lymphoproliferative disease using HLA-identical (sibling n = 25, unrelated n = 2) or one antigen mismatched sibling donors (n = 3). Twenty-one had NHL, three had HD and six had CLL/PLL. Stem-cell source was PBSC (n = 24), BM (n = 5) or both (n = 1) with a median CD34 dose of 4.5 x 10(6)/kg. GvHD prophylaxis was with CYA and MTX., Results: Engraftment was prompt in the majority of patients, with a median of 15 days to both ANC > 0.5 and platelets > 20. There have been three transplant-related deaths secondary to viral pneumonitis or bacterial pneumonia. Seven patients developed Grade I-II acute GvHD post-transplant. Of 28 evaluable patients, 18 achieved a CR at assessment 2-3 months post-transplant and a further patient converted from PR to CR following DLI, to give an overall CR rate of 68%. Three patients had early progressive disease and six have relapsed from CR or progressed from PR (two of whom have achieved CR following DLI therapy). Overall survival is 67% and event-free survival 48% at 3 years. With a median follow-up of 1.3 years 57% of patients are currently alive and lymphoma-free. A molecular remission has been achieved in nine of 12 informative patients., Discussion: These encouraging results show that this reduced-intensity conditioning regimen is effective, with a low-toxicity profile compared with conventional TBI-based conditioning, and certainly merits further evaluation in this setting.

Patients with Ph+ chronic myelogenous leukemia who relapse after a first allogeneic stem cell transplant still have a possibility of long-term survival. To assess the value of the individual therapeutic options, the factors predicting outcome should be identified. We investigated data from 500 patients who relapsed before July 1996; follow-up was updated during 1998. The actuarial survival from relapse was 34.2% (95% confidence interval [CI]: 29. 9%-38.5%) at 5 years and 23.4% (95% CI: 18.9%-27.9%) at 10 years. Survival after relapse was significantly related to 5 factors: time from diagnosis to transplant (< 2 years vs >/= 2 years), disease phase at transplant (first chronic phase vs other), disease stage at relapse (cytogenetic or chronic phase vs advanced phase), time from transplant to relapse (< 1 year vs >/= 1 year), and donor type (HLA-identical sibling vs volunteer unrelated donor). The effects of individual adverse risk factors were cumulative: The probability of survival at 10 years decreased stepwise from 42% (0 factors), 32% (1 factor), 14% (2 factors), 3% (3 factors), to 0% (4 or 5 factors). Novel strategies for high-risk patients are warranted. We conclude that these 5 factors should be taken into account when comparing results of salvage therapies in patients with Ph+ chronic myeloid leukemia relapsing after allogeneic stem cell transplant.

Graft-versus-host disease (GVHD) is a major cause of mortality and morbidity after allogeneic bone marrow transplantation, but can be avoided by removing T lymphocytes from the donor bone marrow. However, T-cell depletion increases the risk of graft rejection. This study examined the use of CD52 monoclonal antibodies to eliminate T cells from both donor marrow and recipient to prevent both GVHD and rejection. Seventy patients receiving HLA-identical sibling transplants for acute myelogenous leukemia (AML) in first remission were studied. An IgM (CAMPATH-1M) was used for in vitro depletion of the graft and an IgG (CAMPATH-1G) for in vivo depletion of the recipient before graft infusion. No posttransplant immunosuppression was given. Results were compared with two control groups: (1) 50 patients who received bone marrow depleted with CAMPATH-1M, but no CAMPATH-1G in vivo; and (2) 459 patients reported to the International Bone Marrow Transplant Registry (IBMTR) who received nondepleted grafts and conventional GVHD prophylaxis with cyclosporin A (CyA) and methotrexate (MTX). The incidence of acute GVHD was 4% in the treatment group compared with 35% in the CyA/MTX group (P <.001). Chronic GVHD was also exceptionally low in the treatment group (3% v 36%; P <.001). The problem of graft rejection, which had been frequent in the historic CAMPATH-1M group (31%), was largely overcome in the treatment group (6%). Thus, transplant-related mortality of the treatment group (15% at 5 years) was lower than for the CyA/MTX group (26%; P =.04). There was little difference in the risk of leukemia relapse between the treatment group (30% at 5 years) and the CyA/MTX group (29%). Survival of the treatment group at 6 months was better than the CyA/MTX group (92% v 78%), although at 5 years the difference was not significant (62% v 58%) and neither was the difference in leukemia-free survival (60% v 52%). We conclude that T-cell depletion is a useful strategy to prevent GVHD, provided that measures are taken to ensure engraftment. Using CAMPATH-1G to deplete residual host lymphocytes is a simple and practical method to do this. At least in AML, the beneficial reduction in GVHD can be achieved without an increased risk of relapse.

In comparison with HLA-matched sibling bone marrow transplants, unrelated donor transplants are associated with increased graft-versus-host disease and graft failure. This is likely in part due to HLA incompatibilities not identified by current matching strategies. High resolution DNA-based typing methods for HLA class II loci have improved donor selection and treatment outcome in unrelated donor bone marrow transplantation. By using DNA-based typing methods for HLA-A and -B on a cohort of 100 potential bone marrow donor/patient pairs, we find that serological typing for HLA class I is limited in its ability to identify incompatibilities in unrelated pairs. Furthermore, the incompatibilities identified are associated with the presence at high frequency of alloreactive cytotoxic T-lymphocyte precursors. DNA typing also indicates that HLA-C mismatches are common in HLA-A and -B serologically matched pairs. Such mismatches appear to be significantly less immunogenic with respect to cytotoxic T-lymphocyte recognition, but are expected to influence natural killer cell activity. Thus, improved resolution of HLA class I shows many previously undisclosed mismatches that appear to be immunologically functional. Use of high resolution typing methods in routine matching is expected to improve unrelated donor selection and transplant outcome.

Lymphocyte activation remains an area of intense interest to immunologists and cell biologists and the dynamics of expression of surface molecules during the process are widely studied. The CD69 C-type lectin is reportedly the earliest activation antigen on lymphocytes and can be detected within hours of mitogenic stimulation. Recently reports have described differential activation dynamics with respect to different antigenic or mitogenic stimuli. This study has investigated the dynamics of CD69 expression over time after mitogenic, allogeneic, cytokine and target cell mediated activation of T-cell and NK cell subsets. It is apparent that the dynamics of CD69 expression differ with respect to the cell type and the method of stimulation. Mitogenic stimulation resulted in the most rapid expression of CD69 on both T- and NK cells while alloantigen stimulation induced a far slower response. Target cell stimulation of NK cells gave paradoxical results in that the CD69 + ve subset increased as a proportion of the total NK cells but did not increase in number. This was due to the selective binding of CD69 - ve NK cells to the target cells and their subsequent loss from the lymphoid gate. We confirmed this by showing that CD69 + ve NK cells do not lyse K562 target cells. This observation demonstrates the caution needed in the analysis of flow cytometric data based solely upon relative proportions of cells within discrete subsets.

The presentation cytogenetic result was correlated with outcome for 999 patients with acute myeloblastic leukemia (AML) having bone marrow transplantation (BMT) in first complete remission (CR1). The karyotype at diagnosis was classified according to the modified Chicago classification. Allogeneic BMT (AlloBMT) was performed in 500 patients and autologous BMT (ABMT) in 499 patients. For both groups, an abnormal chromosome (abn) 5 and/or 7 or a hypodiploid karyotype had a poor outcome, whereas t(15;17), pseudodiploidy, hyperdiploidy and diploidy were associated with a standard prognosis. Abn (16) and t(8;21) were also of standard prognosis for ABMT, but favorable for AlloBMT. When comparing AlloBMT and ABMT in patients with favorable or standard cytogenetics, AlloBMT was of benefit for remission duration and leukemia-free survival (LFS). Patients with an unfavorable karyotype had a similar outcome, regardless of type of BMT. By multivariate analysis, cytogenetics at diagnosis had the strongest prognostic value for relapse, LFS, and survival in AlloBMT. In ABMT, cytogenetics influenced relapse and LFS. We concluded that the karyotype at diagnosis had important prognostic implication in AML grafted in CR1.

A retrospective case-matched analysis was performed comparing 189 myeloma patients treated with allogeneic bone marrow transplantation (allo-BMT) with an equal number of patients who received autologous stem cell transplantation (ASCT). Matching was performed with respect to gender and number of treatment lines before transplantation. The groups were comparable with the exception of median age (43 years for allo-BMT v 49 years for ASCT, P = .0001) and median posttransplant follow-up (46 months for allo-BMT v 30 months for ASCT, P = .0003). The overall survival was significantly better for ASCT than for allo-BMT, with a median survival of 34 months and 18 months, respectively (P = .001). However, this survival advantage was only observed in men, but not in women. The statistically significant survival advantage for ASCT was seen in most subgroups, ie, chemotherapy-responsive patients, patients who had received two or more treatment lines before transplantation, patients in partial remission, patients with an IgG-subtype, patients older than 46 years of age, patients with stage II disease, and patients with a low or high serum-beta-2-microglobulin at diagnosis. The main reason for the poorer survival in allo-BMT patients was higher transplant-related mortality (41% v 13% for ASCT, P = .0001), which was not compensated for by a lower rate of relapse and progression. However, in patients alive at 1 year posttransplant, there was a trend for better long-term survival (P = .09) and significantly better progression-free survival (P = .02) for allo-BMT as compared with ASCT. We conclude that the median survival is superior for ASCT. However, allo-BMT has a lower relapse rate, which results in a similar long-term outcome for both approaches, but a longer follow-up is needed to assess the final outcome.

Cytomegalovirus (CMV) infection is a major cause of morbidity and mortality after allogeneic bone marrow transplantation (BMT). Our aim was to study the prophylactic effect of high-dose intravenous acyclovir given around the time of BMT followed by oral acyclovir on CMV infection and survival. 310 BMT recipients at risk of developing CMV infection were randomised to one of three regimens in a double-blind and double-dummy design: intravenous acylclovir (500 mg/m2, three times a day) for 1 month followed by oral acyclovir (800 mg four times a day for a further 6 months) (intravenous/oral group); intravenous acyclovir followed by oral placebo (intermediate group); or low-dose oral acyclovir (200 or 400 mg, four times a day) followed by placebo ("controls"). Analysis was by intention-to-treat. Intravenous acyclovir significantly reduced the probability of and delayed the onset of CMV infection. There was no further reduction in infection risk with the addition of long-term oral acyclovir. Time to CMV viraemia was delayed in the intravenous/oral acyclovir group compared with controls. Extending the prophylaxis with oral acyclovir significantly improved survival: 79 of 105 recipients were still alive at 7 months compared with 60 of 102 controls (p = 0.012). Although the intravenous/oral acyclovir group did significantly better than controls in terms of survival, the difference between the intravenous/oral acyclovir group and the intermediate group was of borderline statistical significance (p = 0.054). Adverse events that were possibly treatment related were similar in all three groups. The most commonly reported events were nausea, vomiting, elevated creatinine, and renal failure. High-dose intravenous followed by oral acyclovir improved survival and was of benefit in prophylaxis against the effects of CMV after BMT. Interpretation of CMV infection was made difficult because an intermediate treatment (intravenous acyclovir followed by oral placebo) was as effective as high-dose intravenous/oral acyclovir.

Haemopoietic growth factors are accepted as accelerating haemopoietic recovery after bone-marrow grafting, yet no large randomised trials have been published that convincingly show benefit. Lenograstim (glycosylated recombinant human granulocyte colony-stimulating factor) was given to 315 patients after bone-marrow transplantation in a prospective randomised placebo-controlled multicentre trial. 1 day after bone-marrow infusion, 163 patients received lenograstim 5 micrograms/kg per day by 30-min infusion, and 152 patients received placebo daily for 28 days or until neutrophil recovery. 137 patients had lymphoma, 35 myeloma, 85 acute lymphoblastic leukaemia, and 58 a solid tumour. Patients were stratified by age and by type of bone-marrow transplantation (BMT). Neutrophil recovery to above 10(9)/L for 3 consecutive days was seen earlier in lenograstim-treated patients (16 vs 27 days, p < 0.001). Time to neutrophil recovery above 0.5 x 10(9)/L was reduced (14 vs 20 days, p < 0.001). The difference was significant both in autograft (20 vs 14 days, p < 0.001) and allograft (20 vs 14 days, p < 0.01) patients, in children (20 vs 13 days, p < 0.001), and adults. Lenograstim-treated patients had fewer days of infection, and of antibiotic administration, and also spent less time in hospital. However, clinical and microbiological sepsis was similar in both groups. There was no significant toxicity ascribed to lenograstim. Survival was the same at days 100 and 365. In patients undergoing autologous or allogeneic BMT for neoplastic disease, lenograstim significantly reduced duration of neutropenia and led to earlier hospital discharge.

Donor-specific bone marrow infusion after organ grafting can induce tolerance in animals. In this randomised controlled study we show it has no benefit in patients undergoing liver transplantation. Of 25 patients, 9 received bone marrow 5 days after a 10 day course of antithymocyte globulin. Immunosuppression was maintained with cyclosporin only. An average of 3.0 rejection episodes per patient was seen in the bone marrow group compared to 3.1 in the controls. Chimerism was not found in peripheral blood or bone marrow of recipients using erythrocyte antigen markers, PCR for donor class II DNA or Y-probe in-situ hybridisation in one female recipient of male liver and bone marrow.

We studied the clinical course of 130 chronic myeloid leukemia (CML) patients (89 males and 41 females) in the European Bone Marrow Transplantation Group (EBMT) registry who received transplants before January 1, 1988 and who subsequently had evidence of recurrent leukemia. All patients had received a pretransplant conditioning regimen including total body irradiation (TBI). The first evidence of relapse was cytogenetic only in 74 (57%) patients and hematologic in 56 (43%). The overall actuarial survival from relapse was 36% at 6 years, with a significantly higher proportion of survivors among female patients (53% v 30%; P < .002). In univariate analysis, the 6-year probability of survival was 52% for patients with cytogenetic relapse and 30% for patients relapsing in chronic phase (CP), while no patient who relapsed in advanced phase (AP or BC) survived more than 3.5 years from relapse (P < .0001). The actuarial survival of patients relapsing before 6 months, between 6 and 12 months, and later than 12 months after transplant was 27%, 26%, and 45%, respectively (P < .002). Among patients with cytogenetic relapse, partial or complete disappearance of Ph-positive cells occurred in 40% of untreated patients and in 42% of those treated with interferon (IFN). However, IFN therapy significantly delayed progression toward hematologic disease. Cytogenetic responses were observed in 25% of patients who received IFN for relapse into CP, while only one minor cytogenetic response was reported in patients on conventional chemotherapy. For patients presenting with cytogenetic relapse as well as for those in hematologic relapse, IFN therapy significantly improved the 2-year probability of survival. However, long-term survival for IFN-treated patients in either group was not different from long-term survival in comparable patients not receiving IFN therapy. Twenty-nine patients of this series underwent a second bone marrow transplant (BMT) and the projected survival at 4 years after the second transplant is 28%. In multivariate Cox regression analysis, four factors remained significantly associated with survival: disease phase at relapse (P < .0001), duration of time interval from BMT to relapse (P = .0001), interferon therapy at relapse (P = .0024), and patient sex (P = .0032). This retrospective study provides evidence that some patients who relapse after BMT may benefit from treatment with IFN; a second BMT may offer the chance of cure. Data from this analysis may be useful in designing future prospective trials on posttransplant CML relapse.

Cytomegalovirus (CMV) remains the most common single infective cause of death following allogeneic bone marrow transplantation (BMT) from major histocompatibility complex (MHC)-identical siblings, whereas Epstein-Barr virus (EBV)-related disease is infrequent. We show here that MHC-unrestricted cytotoxic effector cells in the peripheral blood of BMT recipients are highly effective at killing EBV-infected target cells, but are inactive against CMV-infected target cells. Differential cytotoxicity is associated with disparate target structure expression. Although both EBV- and CMV-infected target cells express viral antigens, it is only those infected with EBV that express the adhesion molecule lymphocyte function-associated antigen 1 (LFA1; CD11a/18). Thus, EBV-infected target cells are able to interact with the principal LFA1 ligand, intercellular adhesion molecule 1 (ICAM1; CD54), which is expressed on posttransplant peripheral blood mononuclear (PBM) effector cells. CMV-infected target cells cannot utilize this ligand. Posttransplant cytotoxicity against EBV-infected target cells is abolished by target and effector cell blockade with monoclonal antibodies (MoAbs) to LFA1 and ICAM1, respectively, demonstrating the functional relevance of this additional ligand interaction. These results provide an illustration both of the importance and of the limitations of MHC-unrestricted cytotoxicity in vivo and may explain the frequency of CMV disease and the relative rarity of EBV-related disease following allogeneic transplantation from MHC-matched siblings. The increased immunosuppression used following MHC-mismatched/matched unrelated-donor BMT may cause this MHC-unrestricted defense mechanism to fail and may contribute to the greatly increased incidence of EBV lymphoproliferative syndrome in these patients.

There is substantial evidence that the volume of medical procedures in a hospital has an inverse relationship with mortality. We analyzed data for 1313 recipients of HLA-identical sibling bone marrow transplants for early leukemia (acute leukemia in first remission or chronic myelogenous leukemia in first chronic phase) to determine whether transplant outcome differed in small and large centers. Transplants were performed in 86 bone marrow transplant centers active between the years 1983 and 1988, which participated in the International Bone Marrow Transplant Registry. Twenty-one (24%) centers performed five or fewer allogeneic transplants per year during the study period; five (6%) performed more than 40 per year. After adjustment for differences in patient and disease characteristics, the relative risks of treatment-related mortality (1.53, P less than .01) and treatment failure (1.38, P less than .04) were higher among patients who received transplants at centers doing five or fewer transplants per year than among those at larger centers. Among patients receiving transplants in centers performing more than five transplants a year, there was no statistically significant correlation between number of transplants and outcome.

Major histocompatibility complex-unrestricted lymphokine-activated killer (LAK) cells have been proposed as therapy for a variety of hematologic malignancies. Because these cells recognize and kill their targets independently of their antigen specific CD3 receptor, it is unclear how they might discriminate between normal and malignant cells. We now propose one such mechanism for the selective killing of myeloid leukemia blasts. While both CD2+ and CD2- activated killer cells may inhibit the clonogenic growth of myeloid leukemia cells, only the CD2+ subset effectively inhibits the growth of normal myeloid (granulocyte-macrophage and granulocyte) progenitors. This difference appears to reflect differential requirements for cell adhesion molecule recognition between normal and malignant progenitor cells. Inhibition of the growth of normal granulocyte-macrophage colonies by CD2+ LAK cells is blocked by antibodies to the CD2-lymphocyte function-associated antigen 3 (LFA-3) (CD58) cell adhesion system. In contrast, these antibodies have no effect on CD2+ LAK-mediated inhibition of malignant cell clonogenic growth. Instead, antibodies to the LFA-1 (CD11a/CD18)-intercellular adhesion molecule 1 (ICAM-1) (CD54) adhesion system reduce inhibition. These differences correspond to differential expression of the CD54 cell adhesion molecule by normal and malignant myeloid progenitor cells because less than 15% of normal CD34 positive cells are CD54+ while greater than 85% of CD34+ acute myeloid leukemia blasts express the CD54 antigen. LFA-3, the ligand for CD2, is strongly expressed by erythrocytes, and these cells competitively inhibit killing of normal but not malignant clonogenic cells in an analogous way to the effects of monoclonal antibody to the CD2-LFA-3 adhesion system. The operation of this effect in vivo may be a basis for selective cytotoxicity by CD2+ LAK against clonogenic myeloid blast cells, and could be exploited further with infusion of appropriate monoclonal antibodies.

Cytokine-secreting, major histocompatibility complex-unrestricted activated killer (AK) cells are toxic to a wide range of virus-infected or malignant target cells and may be generated endogenously, eg, after bone marrow transplantation, or by infusion of cytokines such as recombinant interleukin-2 (rIL-2). Although AK cells secrete cytokines such as gamma-interferon and tumor necrosis factor, which are themselves able to recruit fresh cytokine-secreting AK cells, activation in both settings is short-lived, implying the existence of homeostatic regulatory mechanisms. We now demonstrate one mechanism by which rapid homeostasis is achieved. We show that IL-4 is produced in patients with both endogenously and exogenously generated AK cells. The cytokine was detected in serum after marrow transplantation, and IL-4 transcripts appeared in circulating lymphocytes during rIL-2 infusion. Although IL-4 inhibited the induction phase of AK cell function, it had no significant inhibitory effect on the ability of AK cells from these individuals to respond to restimulation. Nonetheless, neutralization of the IL-4 induced during cell activation doubled the half-life of AK function, once activating stimuli were removed, from 18 to 44 hours and produced a 2-log increase in AK cell secretion of tumor necrosis factor and gamma-interferon. These data suggest that IL-4 induced in vivo during lymphocyte activation abbreviates AK cell responses once the triggering stimuli have been removed. Neutralization of endogenous IL-4 in vivo by appropriate monoclonal antibodies might prolong the duration of AK function.

Infection is a common problem for bone marrow transplant (BMT) recipients during the period of neutropenia that immediately follows the procedure. Gram-negative infections present a particular hazard in these immunocompromised hosts. To augment host defenses against one such pathogen, Pseudomonas aeruginosa, we immunized bone marrow transplant donors and/or recipients with a polyvalent O-polysaccharide-toxin A conjugate vaccine. When either donor or recipient alone was vaccinated before transplant, no increase in specific antibody titers to any of the vaccine components was observed in the recipient. However, when both donor and recipient were vaccinated before transplant, increases in antibody titers to all polysaccharide components occurred to levels shown to be protective in animal models of gram-negative sepsis. Specific antibodies were primarily of the IgG1 and IgG2 subclass even though IgG2 subclass deficiency is common after BMT. The requirement for both donor and recipient immunization reflects the need for primed donor B lymphocytes in the marrow inoculum to be transferred into an antigen-containing environment so that maximum B-cell proliferation and antibody secretion can occur. Adoptive transfer of antibody responses to Pseudomonas aeruginosa and other common bacterial pathogens has the potential to reduce infection-related morbidity and mortality after allogeneic bone marrow transplantation.

After bone marrow transplantation (BMT), mortality from viral infections such as cytomegalovirus (CMV) remains high. Gamma-Interferon (gamma IFN) and tumor necrosis factor (TNF) are produced constitutively after BMT and have anti-viral properties. To study the effects of these cytokines on CMV interaction with host cells, we have used patient marrow fibroblasts since marrow stroma is a target for CMV infection correlating with myelosuppression in vivo. Both gamma IFN and TNF are constitutively produced by recipient CD3+ and CD16+ lymphocytes, but not by their marrow fibroblasts. Secretion by peripheral blood mononuclear cells is increased if they are cultured with host fibroblasts infected with CMV in vitro and the levels of gamma IFN and TNF produced are within the range that protects fresh fibroblasts from CMV infection. Constitutive secretion of cytokines by lymphocytes declines by 8 weeks after BMT, a time when the risk of CMV disease increases sharply. The in vitro phenomenon that we have described needs to be evaluated in correlative studies on individual BMT recipients to determine whether such a cytokine-mediated defense mechanism against CMV may operate in vivo.

Eight patients with acute leukaemia undergoing allogeneic bone-marrow transplantation from ABO-incompatible donors received red-cell-depleted donor marrow without any procedure to diminish their anti-ABO antibody titres. Successful marrow red-cell removal (mean 98.8%) was achieved by means of a large-volume separation technique on Ficoll-Metrizoate in the IBM 2991 blood-cell processor. Clinically significant ABO-haemolytic reaction was prevented in all patients, and there was neither failure of engraftment nor rejection. This approach used alone is satisfactory for most ABO-incompatible marrow-transplant recipients, although combining this with some method of recipient antibody depletion, such as plasma exchange, is recommended in the occasional patient with high anti-ABO titres.

For more than 15 years preclinical studies have suggested that acute graft-versus-host disease (aGvHD) might be prevented by the removal of immunocompetent T lymphocytes from the donor marrow inoculum. To test this observation in man 14 patients were given marrows virtually (greater than 99%) depleted of identifiable donor marrow T lymphocytes by the use of a "cocktail" of specific anti-T-cell monoclonal antibodies (MBG6 and RFT8) and rabbit complement. Patients were not given immunosuppressive prophylaxis after bone-marrow transplantation. Moderate to severe (grades II-IV) GvHD was totally prevented. 2 of 13 evaluable patients showed mild (grade I) skin GvHD only. Although peripheral blood recovery was slower than that obtained with other forms of GvHD prophylaxis, no fatal infections occurred. All patients survived the early post-transplant period.

Seventeen patients who received allogeneic bone-marrow transplants from matched or slightly mismatched (in four patients) siblings were observed for at least 60 days or until acute graft-versus-host disease (GvHD) developed. All donor marrows after preliminary manipulation were incubated with 1 mg of the murine monoclonal antibody OKT3 before infusion in an attempt to deplete them of immunocompetent T lymphocytes (opsonisation). In three of the seventeen patients acute GvHD of grade II or greater developed. Two of these patients died, but they had disseminated cytomegalovirus infection as well as GvHD. Eleven patients showed no evidence of acute GvHD, and four had transient limited skin rashes (grade I GvHD). Opsonisation of T lymphocytes has reduced the incidence of severe acute GvHD in this unit from 79% in an earlier group of 14 patients to 18% when added to prophylactic methotrexate.

After marrow transplantation, major histocompatibility complex (MHC)-unrestricted natural killer (NK) lymphocytes are among the first cells to appear in the circulation. After T-cell-depleted bone marrow transplantation (TD-BMT), these cells have an activated pattern of target cell killing; they also secrete lymphokines including gamma-interferon (gamma-IFN), interleukin-2 (IL-2), and tumor necrosis factor (TNF) and may have a significant role as a primary defense against viral reactivation and in the elimination of residual host malignancy. We studied 43 patients with hematologic malignancy, treated by allogeneic TD-BMT, autologous nondepleted BMT, or chemotherapy alone to investigate (a) the mechanisms underlying the generation of these activated killer cells, (b) the range of conditions under which they are produced, and (c) their surface phenotype. We showed that gamma-IFN-secreting activated killer cells with the capacity to kill MHC-nonidentical NK-resistant targets are generated 4 to 6 weeks after either allogeneic TD-BMT or autologous BMT but do not appear after treatment with chemotherapy. Production therefore is not owing to T-cell depletion per se or to host donor alloreactivity, nor is it caused by stimulation by alloantigens contained in blood product support since no significant difference exists between allograft and chemotherapy patients in the number of units of blood platelet support given in the posttreatment period. Because most patients had no evidence of stimulation from virus reactivation/infection, the phenomenon of activation therefore appears to represent posttransplant immune disregulation following repopulation of the host immune system with lymphoid subsets derived exclusively from blood and marrow. Activated killing is predominantly mediated by the CD16+ CD3- subset, but substantial activity remains in the CD16- CD3+ cell fraction. Monoclonal antibodies (MoAbs) that block interaction with class-I MHC molecules at the level of target cell (W6/32 anti-HLA class I) or effector cell (CD8) do not inhibit killing by CD16- CD3+ cells. Activated killer cells may contribute to the lower risk of relapse after marrow transplantation as compared with intensive chemotherapy.

Thirty patients with acute myelogenous leukaemia (A.M.L.) in full haematological remission were allocated alternately to two groups of fifteen patients each. All patients received immunotherapy, given weekly as intradermal and subcutaneous injections of killed allogeneic A.M.L. cells, plus Glaxo B.C.G. given by Heaf gun at a separate site. One group also received a mixture of A.M.L. cells and B.C.G. on 4 occasions early in remission. Four patients in this group have remained in remission for 92 to 134 weeks, whereas all patients in the other group had relapsed by 68 weeks. The findings suggest that cells mixed with B.C.G. may be effective in prolonging remission.

Acyclovir is a new antiviral agent which is highly active against herpesviruses in vitro and in laboratory animals. Twenty-three cancer patients with cutaneous and/or systemic herpes zoster or herpes simplex infections were treated with parenteral acyclovir. All had received previous specific treatment for their malignant disease and ten had undergone bone-marrow transplantation. The drug seemed to arrest the progress of the infections and was most effective when given early. Although two patients showed transient increases in blood-urea, possibly the result of acyclovir, the drug was remarkably non-toxic in the doses used.

Two patients with relapsed acute lymphoblastic leukaemia of thymic phenotype (Thy-ALL) resistant to all conventional chemotherapy achieved complete remission when treated with 2'-deoxycoformycin, a selectively lymphocytotoxic compound that acts by inhibition of the enzyme adenosine deaminase. These observations show that malignant thymocytes are dependent on adenosine-deaminase activity and suggest that it may be possible to use deoxycoformycin in other patients with Thy-ALL to induce remission or to kill Thy-ALL blasts in bone marrow harvested before autologous bone-marrow transplantation, leaving normal haemopoietic stem cells intact.

To test the effect of transplantation of T-cell-depleted bone marrow on recipient immune function the results of pre-transplantation immunisation with tetanus toxoid and hepatitis-B vaccine were studied in 38 donor-recipient pairs. Immunisation of the donor alone resulted in transfer of an antibody response to the recipient; immunisation of both donor and recipient resulted in potentiation of the antibody response in both magnitude and duration. These findings indicate that donor T-cell-depleted marrow can transfer humoral immunity to the recipient and that appropriate pre-transplant immunisation schedules may be of benefit to the recipient.

Mitoxantrone, a synthetic and newly available intercalating agent, was shown to have activity in relapsed or refractory acute leukaemia, which is apparently schedule dependent. A 5-day treatment programme demonstrated impressive activity, with a 50% response rate and 24% complete remissions. Toxicity in these preliminary studies was limited compared to that expected with the anthracycline antibiotics. Mitoxantrone is an active and relatively non-toxic agent which merits further assessment prior to its incorporation in first-line therapy of acute leukaemia.

Activated killer cells, unrestricted by major histocompatibility (MHC) antigens circulate in the peripheral blood of patients who have undergone autologous and allogeneic bone marrow transplant (BMT) and may contribute to the reduced risk of leukemic relapse observed after these procedures. Interleukin-2 (IL-2) in vitro augments this cytotoxicity and used therapeutically might thereby promote the eradication of minimal residual disease. In order to assess whether these effects on cytotoxicity can be reproduced in vivo, we studied changes in number, phenotype, and MHC unrestricted cytotoxicity of peripheral blood mononuclear cells obtained from patients with hematologic malignancy receiving IL-2 infusions. Patients with acute myeloid leukemia and multiple myeloma were treated after cytotoxic chemotherapy or autologous BMT. IL-2 infusions produced an initial lymphopenia, followed by a progressive recovery in mononuclear cell numbers and a rebound lymphocytosis after the termination of treatment. This affected all lymphocyte subsets; in particular CD25 (IL-2 receptor) positive cell numbers rose sevenfold. Cells with the ability to kill a natural killer (NK)-resistant, lymphokine activated killer cell (LAK)-sensitive target appeared in the circulation during 16 of 19 infusions and mean LAK activity rose from 5.9% to 15.5% during infusion (E:T ratio, 50:1; P less than .001). During IL-2 infusion, cells present in the peripheral blood inhibited the growth of myeloid leukemia blasts in agar after overnight co-culture. Depletion experiments showed that LAK activity was mediated by cells of both CD3- CD16+ (NK derived) and CD3+ CD16- (T derived) subsets. LAK precursor activity in peripheral blood also significantly increased during IL-2 infusion. Increases in major histocompatibility complex (MHC) unrestricted cytotoxicity can be produced by IL-2 infusions in vivo and may result in improved relapse-free survival following chemotherapy or BMT.

To study the importance of transferred immunity against cytomegalovirus (CMV) in allogeneic, HLA-matched, T-cell-depleted bone-marrow transplantation, the incidence, severity, and outcome of CMV infections were studied in 40 CMV-seropositive recipients in relation to the donors' immunity against CMV. There was no significant difference in the incidence of CMV infections between recipients of seropositive (n = 27) and seronegative (n = 13) marrow. However, the incidence of CMV pneumonitis (8/13 compared with 4/27; p less than 0.001) and the mortality attributable to CMV infection (6/13 compared with 1/27, p less than 0.01) were significantly greater in the group with seronegative donors than in those with seropositive donors. Multivariate regression analysis showed that recipients of seronegative marrow had a fifteen-fold greater risk of CMV pneumonitis and a fifty-fold increase in risk of a fatal CMV infection than recipients of seropositive marrow. Thus, after T-cell depletion CMV-seropositive marrow protects seropositive recipients against severe CMV infections; whenever possible, therefore, such recipients should be given marrow from seropositive donors. Ultimately, active immunisation of CMV-seronegative donors might help to protect seropositive recipients of T-cell-depleted marrow transplants against severe CMV infections.

Highly purified human recombinant interleukin 2 (IL-2) markedly accelerated lethal GVHD in the H-2-identical B10.BR----CBA combination, but had no effect when the donor cells were depleted of mature (Thy-1.2-positive) T lymphocytes, indicating a strong immunopotentiating effect of IL-2 on mature T cells causing GVHD. In the same donor-host combination, IL-2 did not influence the recovery from the post-transplantation bone marrow aplasia. The results suggest that IL-2 could be considered for adjuvant hormonal therapy to enhance immune recovery in recipients of T-cell-depleted allogeneic marrow.

Seventeen patients with acute leukaemia refractory to conventional chemotherapeutic agents were treated with the adenosine deaminase inhibitor, 2'-deoxycoformycin (dCF). Of the twelve patients with acute lymphoblastic leukaemia of the thymic phenotype (Thy-ALL), seven went into complete remission after one or two courses of therapy. Two other (Thy-ALL) patients showed good partial response, and three were resistant to dCF. The five patients with acute leukaemia of other phenotypes had progression of disease despite treatment with dCF. Response to dCF can be predicted from the pattern of change in cellular nucleotide levels in blood and/or bone marrow blasts which have been treated in vitro with dCF and deoxyadenosine. The main adverse effects of dCF therapy were renal and liver dysfunction, conjunctivitis, and haemolysis.

Cell-cultures of cytomegalovirus (CMV) were fixed after 24 hours' incubation and examined by a monoclonal antibody based immunofluorescence method for the detection of CMV-specific early antigens. 385 urine, saliva, or blood samples from 63 immunocompromised patients were inoculated onto cell-cultures. Comparison with the results of conventional cell-cultures in patients who remained uninfected showed that the new technique had a specificity of 100%. The sensitivity was 80%. This immunofluorescence method gave positive results 27h after inoculation of the specimens instead of the mean of 17 X 5 days with the conventional method based on detection of cytopathic effect. 3 saliva samples, from patients who had previously excreted CMV, reacted in the immunofluorescence method but CMV, reacted in the cell-cultures-perhaps because the assay identified defective, interfering particles in these samples. The monoclonal antibodies were also used successfully in another immunofluorescence system to diagnose cytomegalovirus pneumonitis in 3 patients by testing material obtained by bronchoalveolar lavage.

Acute myelofibrosis (AM) or malignant myelosclerosis is a myeloprofilerative syndrome in which bone marrow fibrosis is associated with a proliferation of immature myeloid cells. In four patients with typical AM, investigated by the platelet-peroxidase reaction at ultrastructural level, the blast cells were found to be megakaryoblasts. One patient, treated with the drug combination DAT, achieved a complete remission of 5 mo duration. This study supports the view that megakaryoblastic leukemia is the most frequent underlying cause of AM and proposes that it should be classified as a form of acute myeloid leukemia.

Bone-marrow transplantation has been used in patients with acute lymphoblastic leukaemia (ALL) thought to be at high risk of relapse if managed with chemotherapy. Data from 444 ALL patients with one or more high-risk features at diagnosis were analysed to evaluate outcome after HLA-identical bone-marrow transplantation during first or during second remission. The 4-year actuarial probability of leukaemia-free survival was 45% (95% confidence interval 36-54%) for transplants in first remission compared with 22% (15-29%) for those in second remission (p less than 0.0002). The 4-year probabilities of relapse were 26% (14-38%) and 56% (45-67%) respectively (p less than 0.0001). For high-risk ALL, transplantation in first remission had clearly superior results to transplantation in second remission. Further studies are needed to determine whether patients with high-risk ALL should receive transplants during first remission or should initially receive chemotherapy, with transplantation being reserved for patients who relapse.

72 patients severely immunocompromised by their underlying disease (marrow aplasia, acute leukaemia, or solid tumour) or by the treatment they were receiving, or both, were randomised to receive antifungal prophylaxis with either oral ketoconazole or conventional doses of oral amphotericin B and nystatin. All patients also had gut decontamination with non-absorbable antibiotics, skin antisepsis, sterile food, and oral cotrimoxazole. Protection against fungal infection was significantly superior with ketaconazole. When patients who had received allogeneic bone-marrow transplant were studied separately, there was no significant difference between the two treatments, probably because there was a fall-off in ketoconazole absorption from the end of the third week after the transplant. However, ketoconazole greatly reduced the likelihood of fungal infection in non-transplant patients.

Interleukin-2 (IL-2) therapy may improve immune reconstitution and reduce the risk of leukemic relapse in the setting of minimal residual disease by augmenting cytotoxic effector mechanisms directed at residual malignant cells. In addition, IL-2 in vitro promotes the release of cytokines including gamma-interferon (gamma-IFN) and tumor necrosis factor (TNF), which also possess antileukemic activity and can enhance granulocyte function. To determine if IL-2 infusion induces release of gamma-IFN and TNF in vivo in sufficient quantity to mediate these effects, we have measured serum levels of these cytokines and secretion by lymphocytes obtained from patients receiving this cytokine in a phase 1 trial. Serum gamma-IFN was undetectable pre-IL-2 and increased to 1.5 to 17 U/mL during IL-2 infusion (P less than .05). Culture of patient lymphocytes for 48 hours produced 1.2 U gamma-IFN/2 x 10(6) cells/mL pre-IL-2 rising to 50 U/2 x 10(6) cells/mL when the lymphocytes were obtained during therapy (P less than .05). Lymphocyte subset analysis showed that both CD3+ and CD16+ cells secreted gamma-IFN in response to IL-2. TNF secretion by lymphocytes also rose during IL-2 infusion from a mean of 5 U/mL to 14.4 U/mL (P less than .01) although no rise was seen in serum levels. The material secreted by IL-2-stimulated lymphocytes is bioactive as addition of supernatants from lymphocytes obtained during IL-2 therapy to cultures of myeloid blasts significantly inhibited clonogenic growth. IL-2-induced secretion of these cytokines mediated this inhibition as it could be partially blocked by either anti-gamma-IFN or anti-TNF antibodies. Preincubation of granulocytes with the same supernatants produced enhanced oxidative metabolism, measured by chemiluminescence in response to N-formyl-methionyl-leucyl-phenylalanine (FMLP). This effect also could be partially abrogated by anti-gamma-IFN and anti-TNF antibodies. Therefore, secondary cytokine secretion may boost granulocyte function and contribute to the antileukemic effects of IL-2 infusion in patients following bone marrow transplantation or chemotherapy.