Search

Hemophagocytic lymphohistiocytosis (HLH; hemophagocytic syndrome) is a rare syndrome of potentially fatal, uncontrolled hyperinflammation. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is indicated in primary, recurrent or progressive HLH, but information about its outcomes in the adult population is limited. We obtained data about 87 adult (≥18 years of age) patients retrospectively reported to the EBMT. The median survival time was 13.9 months. The three and five-year overall survival (OS) was 44% (95% CI 33-54%). Among 39 patients with a follow-up longer than 15 months, only three died. Relapse rate was 21% (95% CI 13-30%), while NRM reached 36% (95% CI 25-46%). Younger patients (<30 years of age) had better prognosis, with an OS of 59% (95% CI 45-73%) at three and five years vs 23% (95% CI 8-37%) for older ones. No difference in survival between reduced and myeloablative conditioning was found. To our knowledge, this is the largest report of adult HLH patients who underwent allo-HSCT. Patients who survive the first period after this procedure can expect a long disease-free survival. Both reduced intensity and myeloablative conditioning have therapeutic potential in adult HLH., (© 2022. The Author(s), under exclusive licence to Springer Nature Limited.)

Autologous hematopoietic stem cell transplantation (AHSCT) has emerged as a promising treatment option in severely affected and refractory patients with autoimmune diseases. This is a retrospective survey of patients reported to the EBMT registry between 1998 and 2019, who received AHSCT for TAK. Data from six patients treated with AHSCT for refractory TAK have been identified, five were female (83%), median age 25 (9-39) years. All patients were pretreated with a median of 6 (4-8) lines of therapy, including steroids (six patients), methotrexate (five patients), cyclophosphamide, mycophenolate mofetil or infliximab (four patients), tocilizumab or etanercept (two patients). Conditioning included cyclophosphamide and rabbit anti-thymocyte globulin in all patients. At 6 months post transplantation, remission was obtained in all cases, which persisted at 12 months in five cases. Four patients reactivated TAK at a median time of 27 (7-52) months after AHSCT, and three resumed disease-modifying therapy. At last follow-up, all patients were alive, two patients were in remission (off-therapy), two patients improved compared with baseline, and two patients were in complete and partial remission, respectively, under immunosuppressive treatment. This retrospective case-series demonstrates that AHSCT has the potential to provide significant clinical responses in TAK patients, but large prospective trials are necessary to confirm these preliminary data.

Limited therapeutic options are available after relapse of acute leukaemia following first reduced intensity conditioning haematopoietic stem cell transplantation (RIC1). A retrospective study on European Society for Blood and Marrow Transplantation (EBMT) registry data was performed on 234 adult patients with acute leukaemia who received a second RIC transplantation (RIC2) from 2000 to 2012 as a salvage treatment for relapse following RIC1. At the time of RIC2, 167 patients (71.4%) had relapsed or refractory disease, 49 (20.9%) were in second CR and 18 (7.7%) in third or higher CR. With a median follow-up of 21 (1.5-79) months after RIC2, 51 patients are still alive. At 2 years, the cumulative incidence of non-relapse mortality (NRM), relapse incidence (RI), leukaemia-free survival (LFS) and overall survival (OS) were 22.4% (95% confidence interval (CI): 17-28.4), 63.9% (56.7-70.1), 14.6% (8.8-18.5) and 20.5% (14.9-26.1), respectively. In patients with acute myelogenous, biphenotypic and undifferentiated leukaemia (representing 89.8% of all patients), duration of remission following RIC1 >225 days, presence of CR at RIC2, patient's Karnofsky performance status >80 at RIC2 and non-myeloablative conditioning were found to be the strongest predictors of patients' favourable outcome.

TBI-based preparative regimens are considered as standard conditioning therapy for allogeneic stem cell transplantation (AHSC) in patients with ALL. We investigated toxicity and efficacy of a non-TBI-based regimen consisting of treosulfan, etoposide and cyclophosphamide for ALL within a prospective study. Major inclusion criteria were CR and non-eligibility for TBI. Fifty patients with a median age of 46.5 years (range, 18-64) were included. Donors were HLA-identical sibling (n=8), matched (n=42) or mismatched (n=10) unrelated. The toxicity was moderate, resulting in a cumulative incidence of non-relapse mortality (NRM) at 1 year of 8% (90% confidence interval: 2-15%). Acute GvHD grade II-IV and grade III/IV was noted in 53% and 14%, respectively. Chronic GvHD at one year was seen in 41%. After a median follow-up of 24 months the cumulative incidence of relapse was 36% (90% confidence interval: 24-48) and 51% (90% confidence interval: 37-65) at 1 and 2 years, respectively. The estimated 2-year disease-free and overall survivals were 36 and 48%, respectively. Treosulfan, etoposide and cyclophosphamide followed by AHSC has a favorable toxicity profile with low NRM and therefore represents a potential alternative regimen for ALL in 1. CR (NCT00682305).

Allogeneic hematopoietic cell transplantation (HCT) activity significantly increased in the Eastern Mediterranean area over the past decade. However, comparative outcomes with longer established centers, especially European Blood and Marrow Transplantation (EBMT) centers, have not been reported. We compared outcomes of matched-sibling allogeneic HCT between East Mediterranean Blood and Marrow Transplantation (EMBMT) and EBMT centers for adult patients with AML in first CR using myeloablative conditioning. We matched 431 patients from EMBMT with 431 patients from EBMT centers according to patient, disease and transplant characteristics. EMBMT recipients and donors were more likely to be CMV seropositive. There were no significant differences in the incidence of acute or chronic GVHD, or the 3-year cumulative incidence of non-relapse mortality (NRM) and relapse incidence (RI) between the two groups (NRM: EMBMT=16% vs EBMT=11), (RI: EMBMT=13% vs EBMT=19%). Notably, the 3-year leukemia-free survival (LFS) and OS were similar between the groups (LFS: EMBMT=70±2% vs EBMT=69±3%), (OS: EMBMT=74±2% vs EBMT=73±2%). Despite differences in socioeconomics, health resources and transplant experience, matched-sibling allogeneic HCT outcomes in emerging centers in the EMBMT region appear similar to EBMT centers.

Allogeneic hematopoietic SCT with reduced-intensity conditioning (RIC-HSCT) is increasingly adopted for the treatment of older adults with AML. Our goal was to verify for the first time, if center experience influences outcome of RIC-HSCT. Results of 1413 transplantations from HLA-matched related or unrelated donors for adult patients with AML in first CR were analyzed according to the level of center activity. Transplants were performed in 203 European centers between 2001 and 2007. The 2-year probability of leukemia-free survival (LFS) after RIC-HSCT performed in centers with the lowest activity (< or =15 procedures/7 years) was 43±3% compared with 55±2% in the remainder (P<0.001). The incidence of non-relapse mortality (NRM) was 24±3% and 15±1% (P=0.004), whilst relapse rate was 33±3% and 31±1% (P=0.33), respectively. In a multivariate model, adjusted for other prognostic factors, low RIC-HSCT activity was associated with decreased chance of LFS (hazard ratio (HR)=0.64; P<0.001) and increased risk of NRM (HR=1.47, P=0.04) and relapse (HR=1.41, P=0.01). Center experience is a very important predictor of outcome and should be considered in future analyses evaluating the results of RIC-HSCT. The reasons why centers with low RIC-HSCT activity have worse outcomes should be further investigated.

In 1997, the first consensus guidelines for haematopoietic SCT (HSCT) in autoimmune diseases (ADs) were published, while an international coordinated clinical programme was launched. These guidelines provided broad principles for the field over the following decade and were accompanied by comprehensive data collection in the European Group for Blood and Marrow Transplantation (EBMT) AD Registry. Subsequently, retrospective analyses and prospective phase I/II studies generated evidence to support the feasibility, safety and efficacy of HSCT in several types of severe, treatment-resistant ADs, which became the basis for larger-scale phase II and III studies. In parallel, there has also been an era of immense progress in biological therapy in ADs. The aim of this document is to provide revised and updated guidelines for both the current application and future development of HSCT in ADs in relation to the benefits, risks and health economic considerations of other modern treatments. Patient safety considerations are central to guidance on patient selection and HSCT procedural aspects within appropriately experienced and Joint Accreditation Committee of International Society for Cellular Therapy and EBMT accredited centres. A need for prospective interventional and non-interventional studies, where feasible, along with systematic data reporting, in accordance with EBMT policies and procedures, is emphasized.

We present 60 patients with refractory (n=8) or relapsed (n=52) adult ALL who received allogeneic hematopoietic SCT (HSCT) with (n=41) or without (n=19) prior reinduction chemotherapy. In our center, omission of reinduction is recommended if a suitable donor is promptly available, tumor burden is moderate and disease features suggest a highly aggressive course. Overall survival (OS) of the whole cohort at 1, 2 and 5 years was 42, 33 and 28%, respectively. Leukemia-free survival at 1, 2 and 5 years was 37, 33 and 24%. Deaths were due to relapse (n=25), acute or chronic GVHD (n=7), infections (n=8) or toxicity (n=4). Interestingly, patients who did not receive reinduction before HSCT had better outcomes than patients who received reinduction with OS at 1, 2 and 5 years being 58 vs 34%, 47 vs 25% and 47 vs 18%, respectively (P=0.039). Importantly, even achievement of a second CR after reinduction was not associated with improved survival compared to patients directly proceeding to HSCT. We conclude that patients who undergo HSCT for refractory or relapsed ALL can achieve long-term survival. In selected patients, reinduction chemotherapy can be omitted if immediate HSCT is feasible.

The outcome of patients with acute lymphoblastic leukemia (ALL) receiving therapeutic donor lymphocyte infusions (DLIs) in relapse after stem cell transplantation (SCT) is poor. We analyzed the impact of prophylactic DLIs in ALL on chimerism and sustained complete remission (CR). Eighty-five patients with ALL were allografted between January 1998 and September 2004. Twenty-six of them received prophylactic DLIs and were included in this analysis. A total of 12 of 13 patients, who were treated with mixed chimerism (MC) converted to complete donor chimerism (92%) and 10 of 12 patients had persistent donor chimerism and sustained CR during subsequent follow-up. Overall, 18 of 26 patients developed graft-versus-host disease (GVHD) after DLIs (69%), acute GVHD in 46 and chronic GVHD in 62%. After a median follow-up of 42 months (14-72) after SCT, 18 of 26 patients (70%) are alive, 16 in CR. Probability of event-free survival (EFS) for patients treated with DLIs is 62%, and overall survival is 70% at 3 years. Our preliminary data support a graft-versus-leukemia effect of prophylactic DLIs able to induce stable donor chimerism and ongoing CR after SCT. As the accompanying GVHD rate was considerable, careful selection of patients for prophylactic DLIs is mandatory.

To assess the role of allogeneic stem cell transplantation (SCT) after reduced-intensity conditioning (RIC) in acute leukaemias, we retrospectively compared 25 patients with acute lymphoblastic leukaemia or acute myelogenous leukaemia after RIC to a historical group of 50 matched controls after high-dose conditioning. Engraftment, acute GvHD and severe infections were comparable in both groups. During the observation period, 1/25 patients (4%) after RIC and 14/50 (28%) after standard SCT died due to transplant-related causes; cumulative nonrelapse mortality (NRM) was 4% after RIC and 24% after standard SCT (P=0.029). In total, 15/25 patients (60%) relapsed after RIC and 20/50 (40%) after standard SCT; probability of disease-free survival (DFS) at 3 years was 43% after RIC and 49% after standard SCT (NS). Overall survival (OS) was 40% after RIC and 37% after standard SCT (NS). Stage of disease, cytogenetic risk profile, acute and chronic GvHD, chimerism status at day 90 and severe infections after transplantation were risk factors with significant impact on DFS and/or OS. In retrospective analysis, patients with acute leukaemias who receive RIC because of contraindications against standard SCT have a comparable outcome to standard SCT, but the higher relapse rate warrants further studies.

Experimental data and early phase I/II studies suggest that high-dose chemotherapy followed by autologous hematopoietic stem cell transplantation (HSCT) can arrest progression of severe autoimmune diseases. We have evaluated the toxicity and disease response in 473 patients with severe autoimmune disease treated with autologous HSCT between 1995 and 2003, from 110 centers participating in the European Group for Blood and Marrow Transplantation (EBMT) autoimmune disease working party database. Survival, transplant-related mortality, treatment response and disease progression were assessed. In all, 420 patients (89%; 86+/-4% at 3 years, median follow-up 20 months) were alive, 53 (11%) had died from transplant-related mortality (N=31; 7+/-3% at 3 years) or disease progression (N=22; 9+/-4% at 3 years). Of 370 patients, 299 evaluable for response (81%) showed a treatment response, which was sustained in 213 (71% of responders). Response was associated with disease (P<0.001), was better in patients who received cyclophosphamide during mobilization (relative risk (RR)3.28 (1.57-6.83)) and was worse with increasing age (>40 years, RR0.29 (0.11-0.82)). Disease progression was associated with disease (P<0.001) and conditioning intensity (high intensity, RR1; intermediate intensity, RR1.81 (0.96-3.42)); low intensity, RR2.34 (1.074-5.11)). These data from the collective EBMT experience support the hypothesis that autologous HSCT can alter disease progression in severe autoimmune disease.

Seven out of 29 patients with metastatic renal cell carcinoma (RCC) considered eligible for allogeneic stem cell transplantation underwent nonmyeloablative stem cell transplantation (NST) from HLA-identical donors. Conditioning comprised cyclophosphamide, fludarabine and antithymocyte globulin. Prolonged mixed chimerism (MC) after engraftment converted to complete donor chimerism (CC) after infusion of donor lymphocytes and/or graft-versus-host disease (GvHD) in six patients. Five patients developed severe GvHD. Two of seven patients had a delayed tumor response after conversion to CC. After a median follow-up of 10 months (4-24 months), 5/7 patients are alive, one in very good partial remission (PR), one with stable and three with progressive disease. One of the seven patients died from sepsis in PR and 1/7 died from rapid tumor progression after sustained MC. None of the 22 nontransplanted patients responded to further therapies. Survival after 1 year was 59% in transplanted and 66% in nontransplanted patients (n.s.). A pooled data analysis from the literature suggests a graft-versus-tumor effect after transplant in patients with metastatic RCC, which becomes effective after chimerism conversion. Available data demonstrate high nonrelapse mortality in these patients. NST in RCC still has to be regarded as an investigational approach requiring careful patients' selection and longer follow-up within clinical studies.

Hematopoietic stem cell transplantation as a treatment for autoimmune disease began in 1996 and has subsequently spread worldwide. In Europe phase III trials have opened, while in America phase III trials are being designed and funded by the National Institutes of Health. On 6 June 2002, clinicians and scientists from around the world met at Snowbird, Utah to discuss the results and future directions of stem cell therapy for autoimmune diseases. What follows are general concepts from chairpersons of this meeting.

At Northwestern University, a phase I/II trial of hematopoietic stem cell transplant (HSCT) for systemic lupus erythematosus (SLE) has shown promising results. A phase III HSCT trial is being developed to confirm efficacy of HSCT vs continuing the currently accepted standard of care, intravenous pulse cyclophosphamide.

23 patients with ALL (n=9) and AML (n=14) underwent nonmyeloablative stem cell transplantation (NST) from an HLA-identical donor after conditioning with fludarabine (180 mg/m(2)), busulfan (8 mg/kg) and anti-T-lymphocyte globulin (40 mg/kg). After NST, 20/23 patients engrafted. Ten out of 14 patients with uncontrolled disease reached complete remission. A multiplex-PCR using short tandem repeats was used for chimerism analysis and detected mixed chimerism (MC) in 14/22 evaluable patients (64%) after NST. Prophylactic donor lymphocyte infusions (DLI) were given to 11/14 patients with MC; MC converted to complete donor chimerism (CC) in 6/11 patients within 2-6 weeks. All patients with persistent MC with or without DLI relapsed during further follow-up. MC predicted impending relapse 4-52 weeks before clinical diagnosis. Ten of 23 patients (43%) are alive 2-34 months after stem cell transplantation. 12 of 23 patients (52%), have died from leukaemia after NST. One out of 23 patients has died from severe sepsis. In conclusion, NST leads to stable engraftment and complete remission in patients with advanced acute leukaemias. NST can cure a substantial proportion of these patients, but the relapse rate is still high. Repeated chimerism analysis is a useful tool to detect recipient cells, especially in patients without molecular markers of disease and can be used to monitor immunomodulatory therapies. MC is unstable in these patients and predicts impending relapse. Prophylactic DLI can convert MC to CC, which seemed to lower relapse risk.

Basiliximab, a chimeric interleukin-2 receptor (IL-2-R) antagonist, was evaluated in 17 patients with steroid-refractory acute graft-versus-host disease (GVHD) after allogeneic stem cell transplantation (SCT). Patients were transplanted from a related (n = 6) or unrelated (n = 11) HLA-identical donor because of acute lymphoblastic leukemia (n = 4), acute myeloid leukemia (n = 3), chronic myeloid leukemia (n = 7), myelodysplastic syndrome (n = 1), non-Hodgkin's lymphoma (n = 1), and multiple myeloma (n = 1). Basiliximab was given at a dose of 2 x 20 mg on 2 consecutive days after steroid-refractory acute GVHD had developed. Basiliximab was repeated on day 8 in cases of persistent GVHD. A median of four basiliximab infusions (range 1-12) were given to these patients. None had infusion-associated or cytokine-related side-effects after basiliximab. Twelve of 17 patients (71%) responded to basiliximab, 9/17 (53%) had a complete response (CR) of acute GVHD and 3/17 (18%) had a partial response (PR). Five of 17 patients (29%) did not respond. Chronic GVHD developed in 8/13 evaluable patients and only 2/8 had responded to basiliximab before. Five of 13 evaluable patients have no signs of chronic GVHD and all five had a CR or PR after basiliximab. This is the first report on the safety of basiliximab in patients with steroid-refractory acute GVHD. Our data suggest that basiliximab is effective in a substantial proportion of these patients.

We reviewed data from 24 transplant centers in Asia, Australia, Europe, and North America to determine the outcomes of stem cell collection including methods used, cell yields, effects on disease activity, and complications in patients with autoimmune diseases. Twenty-one unprimed bone marrow harvests and 174 peripheral blood stem cell mobilizations were performed on 187 patients. Disease indications were multiple sclerosis (76 patients), rheumatoid arthritis (37 patients), scleroderma (26 patients), systemic lupus erythematosus (19 patients), juvenile chronic arthritis (13 patients), idiopathic autoimmune thrombocytopenia (8 patients), Behcet's disease (3 patients), undifferentiated vasculitis (3 patients), polychondritis (1 patient) and polymyositis (1 patient). Bone marrow harvests were used in the Peoples Republic of China and preferred worldwide for children. PBSC mobilization was the preferred technique for adult stem cell collection in America, Australia, and Europe. Methods of PBSC mobilization included G-CSF (5, 10, or 16 microg/kg/day) or cyclophosphamide (2 or 4 g/m2) with either G-CSF (5 or 10 microg/kg/day) or GM-CSF (5 microg/kg/day). Bone marrow harvests were without complications and did not affect disease activity. A combination of cyclophosphamide and G-CSF was more likely to ameliorate disease activity than G-CSF alone (P < 0.001). g-csf alone was more likely to cause disease exacerbation than the combination of cyclophosphamide and g-csf (P = 0.003). Three patients died as a result of cyclophosphamide-based stem cell collection (2.6% of patients mobilized with cyclophosphamide). When corrected for patient weight and apheresis volume, progenitor cell yields tended to vary by underlying disease, prior medication history and mobilization regimen. Trends in the approaches to, and results of, progenitor cell mobilization are suggested by this survey. While cytokine-based mobilization appears less toxic, it is more likely to result in disease reactivation. Optimization with regard to cell yields and safety are likely to be disease-specific and prospective disease-specific studies of mobilization procedures appear warranted.

In patients with systemic sclerosis (SSc) treatment-related mortality after autologous stem cell transplantation (ASCT) appears to be increased as compared to patients with hematological malignancies. In our phase I/II study on ASCT in autoimmune diseases a patient with SSc died on day 2 after ASCT. Here we report the results of the autopsy which revealed advanced pulmonary and cardiac fibrosis as the most probable cause of death. In spite of detailed technical examination before enrollment, the cardiopulmonary function tests did not reflect the advanced stage of the disease. We conclude that in selected patients with SSc, biopsies should be performed to reduce mortality after ASCT.

Non-infectious lung complications (NILC) are frequent, influencing morbidity and mortality of patients after allogeneic BMT. Although the term NILC encompasses a number of different entities, an association with GVHD has been noted for almost all of them. Our study was directed towards assessing the incidence and risk factors for developing NILC, as well as the response to treatment and long-term outcome. Forty (14.7%) out of 272 patients surviving for more than 3 months after allogeneic BMT, developed lung complications fulfilling the criteria for NILC. The evaluation was based on clinical investigation, radiologic imaging, lung function tests, broncho-alveolar lavage and biopsies. Risk factors were assessed by univariate and multiple statistical regression models, where chronic GVHD proved to be the only significant risk factor for the development of NILC (P = 0.011). In three patients NILC developed in direct association with donor lymphocyte infusions. The majority of patients responded well to treatment with corticosteroids and immunosuppressive drugs. NILC had no adverse effect on survival. The frequency of NILC was low in autologous (5%) as compared with allogeneic transplants (14.7%) but this difference was not statistically significant. Bone Marrow Transplantation (2000) 25, 1263-1268.

The Chronic Leukemia Working Party of the EBMT has collected data on 118 patients of median age 24 years (range 0.3 to 53 years) who underwent an allogeneic bone marrow transplantation from unrelated donors for treatment of MDS or secondary AML (RA/RARS, n = 24; RAEB, n = 26; RAEB-t, n = 34; CMML, n = 12; sAML, n = 22) between 1986 and 1996. The data were reported by 49 EBMT centers. Thirty-four of 118 patients are alive, relapse was the cause of death in 19 of 84 patients and the remaining patients died of transplant-related mortality. For the whole group the actuarial probability of survival at 2 years is 28%, disease-free survival 28%, relapse risk 35% and transplant-related mortality is 58%. The transplant-related mortality is significantly influenced by the age of the recipient (<18 years 40%, 18-35 years 61%, >35 years 81%). The relapse rate after BMT is influenced by FAB classification of the disease at BMT. Patients with a low blast count (RA, RAEB) have a lower probability of relapse (13%, 15%) compared to patients with RAEB-t or sAML (29%, 45%). Furthermore, we found evidence of a graft-versus-leukemia effect in MDS/sAML. Patients with acute GVHD, grade II-IV, had a probability of relapse of 26% vs 42% in patients with no acute GVHD or grade I only. Allogeneic transplantation with an HLA-matched, unrelated donor may be offered to younger patients (age <35 years) with poor risk myelodysplasia or secondary AML.

Allogeneic bone marrow transplantation (BMT) offers a potential cure for younger patients with myelodysplastic syndromes (MDS) or secondary acute myeloid leukemia (sAML). More than 600 patients from 50 European centers have now been reported to the European Group for Blood and Marrow Transplantation (EBMT). We retrospectively analyzed 131 patients reported to the Chronic Leukemia Working Party of the EBMT who underwent BMT from HLA-identical siblings without prior remission induction chemotherapy. At the time of BMT 46 patients had refractory anemia (RA) or RA with ringed sideroblasts, 67 patients had more advanced MDS subtypes and 18 patients had progressed to sAML. The 5-year disease-free (DFS) and overall survival (OS) for the entire group of patients was 34 and 41%, respectively. Fifty patients died from transplant-related complications, most commonly graft-versus-host disease and/or infections. Relapse occurred in 28 patients between 1 and 33 months after BMT, resulting in an actuarial probability of relapse of 39% at 5 years. DFS and OS were dependent on pretransplant bone marrow blast counts. Patients with RA/RARS, RAEB, RAEB/T and sAML had a 5-year DFS of 52, 34, 19 and 26%, respectively. The 5-year OS for the respective patient groups was 57, 42, 24 and 28%. In a multivariate analysis, younger age, shorter disease duration, and absence of excess of blasts were associated with improved outcome. From these data we conclude that patients with myelodysplasia who have appropriate marrow donors, especially those aged less than 40 years and those with low medullary blast cell count should be treated with BMT as the primary treatment early in the course of their disease. Transplantation early after establishing the diagnosis of MDS may improve prognosis due to a lower treatment-related mortality and a lower relapse risk.

In Germany allotransplantation of bone marrow or peripheral blood stem cells is presently performed by 34 different teams operating more or less independently. Thus, strategies of immunogenetic donor search, use of the various tissue typing techniques and policy on acceptable HLA mismatches in related and unrelated settings may vary considerably from one transplant centre to another. This paper summarises the results of the first German consensus meeting on immunogenetic donor search for bone marrow/peripheral blood stem cell grafting. The main goal of the participating transplant physicians and immunogeneticists was to define national standards for the above issues.

Antibodies to IFN-alpha have been recognized as a novel type of autoantibody developing after allogeneic BMT. Ninety-six patients undergoing BMT for various hematologic disorders were followed for the presence of spontaneous IFN-alpha antibodies until 12 years after transplantation. Seven of them (7.3%) developed IFN-alpha antibodies occurred late after BMT (> or = 15 months), rose to very high titers in some patients, and persisted for years despite combined immunosuppressive treatment. They were oligo- or polyclonal in nature, predominantly IgG with a broad IgG subclass distribution, and neutralized the antiviral and antiproliferative activity of various natural and recombinant IFN-alpha types including the patients' endogenous IFN-alpha in vitro. All antibody-positive recipients suffered from chronic GVHD (n = 5) or chronic viral hepatitis (n = 2), but the only significant association was with prior severe aplastic anemia (3/9, 33%; P = 0.022). There was no discernible HLA association of IFN antibody development. Although the clinical relevance of the IFN-alpha antibodies is uncertain they may interfere with cellular defence mechanisms and immune regulation after BMT.

Six patients treated for relapsed chronic myeloid leukaemia after allogeneic bone marrow transplantation with donor buffy coat transfusions were investigated. In the 5 patients who achieved molecular remission high frequencies of host-reactive interleukin 2-secreting T helper cell precursors (Th-p) were detectable by limiting dilution analysis. In four of the patients the presence of Th-p was associated with a clinical syndrome similar to transfusion GVHD suggesting a T cell response to minor histocompatibility antigens (minor H) expressed by both malignant haemopoiesis and host tissues. In the fifth responding patient no GVHD or bone marrow hypoplasia was observed. The nature of the antigens recognised by these donor Th-p remains unknown. No host-reactive Th-p were detectable in the non-responder and host-reactive cytotoxic T cell precursors (CTL-p) were not consistently detectable in the responding patients.

We investigated the role of interleukin 2 (IL-2)-secreting T helper cell precursors (Th-p) in primary and secondary chronic graft-versus-host disease (GVHD). Twelve patients with chronic GVHD (8 primary and 4 secondary chronic GVHD) and 8 patients without chronic GVHD were investigated using a sensitive limiting dilution assay. High frequencies of host-reactive interleukin 2-secreting T helper cell precursors were detectable in all patients with chronic GVHD irrespective of the mode of onset. Host-reactive IL-2-secreting T helper cell precursors disappeared in patients whose GVHD resolved. Host-reactive IL-2-secreting T helper cell precursors were never found in the control patients without chronic GVHD. Host-reactive cytotoxic T cell precursors (CTL-p) were not consistently detectable in patients with chronic GVHD and were occasionally found in patients without GVHD. No autoreactive IL-2-secreting T helper cell precursors or cytotoxic T cell precursors were detectable in either group. The absence of autoreactive IL-2-secreting T helper cell precursors in patients was confirmed by clonal specificity analysis in 4 patients. These data suggest a role for host-reactive IL-2-secreting T helper cell precursors in the initiation and maintenance of chronic GVHD as previously shown for acute GVHD.

We have performed a non-randomised GVHD prophylaxis trial comparing cyclosporin/methotrexate with in vivo/ex vivo T cell depletion with the monoclonal antibodies Campath 1G/1M in patients with acute leukaemias in first complete remission. We observed significantly less acute and chronic GVHD, neutropenic fever and severe mucositis in the T cell depletion group. The incidence of graft rejection and relapses was no higher than in the cyclosporin/methotrexate group. There is a trend in favour of improved disease-free survival in the in vivo/ex vivo T cell depletion group (80% vs. 62%).

Combined in vivo/ex vivo T cell depletion is effective in the prophylaxis of graft-versus-host disease (GVHD) after allogeneic bone marrow transplantation (BMT), but influences the occurrence of active cytomegalovirus (CMV) infection and disease. Twenty nine patients receiving a T cell-depleted marrow graft (Campath-1M) after intravenous application of the monoclonal antibody Campath-1G prior to conditioning were monitored for virus shedding and antigenaemia from day -7 to day +100. In seropositive patients in this group active CMV infection occurred more frequently (10 of 16) and much earlier (nine of 10 until day +21) than in 27 seropositive patients (10 of 27, P < 0.02) receiving cyclosporin A and methotrexate (CsA/MTX). Early active CMV infection after in vivo/ex vivo T cell depletion correlated strictly with an early increase in blood lymphocyte counts (P < 0.01), with predominance of NK cells and/or CD8+ T cells. Three cases of very early interstitial pneumonitis (IP) occurred after in vivo/ex vivo T cell depletion compared with none in the CsA/MTX group. IP was fatal in the only patient with early active CMV infection, who remained lymphocytopenic till death on day +31. This may indicate that an early immune response against CMV is possible and essential for favourable clinical outcome.

In a patient undergoing allogeneic BMT for chronic phase CML, de novo chronic GVHD developed within 80 days after transplantation. Eighteen months post-BMT, high serum levels of neutralizing interferon-alpha (IFN-alpha) antibodies were detected, which persisted despite continuous immunosuppressive treatment. The antibodies were of oligoclonal or polyclonal origin, predominantly of the IgG1 type, and reacted broadly with various human IFN-alpha types, including the patients endogenous IFN-alpha, but failed to recognize natural IFN-beta and recombinant IFN-gamma. Pathogenesis and clinical impact of the IFN-alpha antibodies are unknown. Antibodies of cytokines are a novel class of autoantibodies that may develop after allogeneic BMT and interfere with cytokine homeostasis and immune regulation.