Summary:We investigated the use of 'prophylactic' donor lymphocyte infusions (DLI) containing 1 ؋ 10 7 CD3 ؉ cells, given at 30, 60 and 90 days post-allogeneic blood and marrow transplantation (BMT), following conditioning with fludarabine 30 mg/m 2 /4 days and melphalan 70 mg/m 2 /2 days. GVHD prophylaxis consisted of cyclosporin A (CsA) 2 mg/kg daily with early tapering by day 60. Our goals were the rapid achievement of chimerism and disease control, providing an immunological platform for DLIs to treat refractory patients with hematological malignancies. Twelve heavily pre-treated patients with life expectancy less than 6 months were studied; none were in remission. Diagnoses were AML (n ‫؍‬ 4), MDS (n ‫؍‬ 1), ALL (n ‫؍‬ 3), CML (n ‫؍‬ 3) and multiple myeloma (n ‫؍‬ 1). Response rate was 75%. Three patients are alive at a median of 450 days (range, 450-540). Two patients are in remission of CML in blast crisis and AML for more than 14 months. Median survival is 116 days (range, 25-648). Six patients received 12 DLIs; three patients developed acute GVHD after the first infusion and were excluded from further DLIs, but no GVHD occurred among patients receiving subsequent DLIs. One patient with CML in blast crisis went into CR after the first DLI. The overall incidence of acute GVHD was 70%. Primary causes of death were infections (n ‫؍‬ 3), acute GVHD (n ‫؍‬ 3), chronic GVHD (n ‫؍‬ 1) and disease relapse (n ‫؍‬ 2). We observed high response and chimerism rates at the expense of an excessive incidence of GVHD. DLI given at day ؉30 post BMT caused GVHD in 50% of the patients, and its role in this setting remains unclear. The therapeutic benefit of allogeneic BMT is in part related to an immunological graft-versus-leukemia (GVL) effect that frequently evolves in the context of graft-versus-host disease (GVHD). The ability of donor lymphocytes to induce remission in patients relapsing after allogeneic transplantation illustrates the potency of this effect.1 Establishing donor-recipient tolerance with less toxic regimens may provide the basis for further immunological manipulations in order to maximize the GVL effect. However, rapidly evolving diseases may not be amenable to this strategy, considering that the immune-mediated elimination of malignant cells may take weeks or months to occur. This fact suggests the need for strategies to reinforce the immune-mediated phenomena in the post-transplant period.Groups in Jerusalem and Houston pioneered the use of sub-lethal doses of fludarabine-based conditioning regimens. These regimens have been shown to be less toxic and to provide enough immunosuppression to prevent graft rejection and establish stable mixed or complete chimerism.2,3 The combination of melphalan and fludarabine has enabled allogeneic stem cell engraftment in the majority of patients treated, at least in the setting of HLA-identical transplantation. Patients with refractory relapses of advanced leukemias appear to benefit the least.

Allogeneic stem cell transplantation has been increasingly performed for a variety of hematologic diseases. Clinically significant acute graft-versus-host disease (GVHD) occurs in 9 to 50% of patients who receive allogeneic grafts, resulting in high morbidity and mortality.

Cytomegalovirus (CMV) reactivation remains one of the main infectious complications following hematopoietic stem cell transplantation (HSCT). In this study, we explored the role of anti-CMV antibody titers in HSCT from alternative donors and to compare the risk of CMV reactivation between posttransplant cyclophosphamide-based haploidentical HSCT and antithymocyte globulin-based unrelated donor (URD) HSCT. We included 98 CMV-positive patients, 30 undergoing haploidentical HSCT and 68 undergoing URD HSCT. The majority of patients had a malignant disease (84%), received a myeloablative conditioning regimen (78%), and received a bone marrow graft (90%). The median pretransplantation anti-CMV IgG level was 109 U/mL. With median follow-up of 2.2 years, a total of 72 CMV reactivations occurred in 50 patients. There was no difference in CMV reactivation pattern between haploidentical HSCT recipients and URD HSCT recipients. In multivariable analysis until the first event, the incidence of CMV reactivation was higher in patients with anti-CMV IgG levels >100 U/mL (hazard ratio [HR], 2.38; P = .005) and in patients diagnosed with grade II-IV acute graft-versus-host disease (GVHD) (HR, 10.8; P = .003) after day +50 and lower in patients who received higher doses of CD34 cells (HR, .44; P = .006). In multivariable analysis for recurring events, the incidence of CMV reactivation was higher in patients receiving reducedintensity conditioning (HR, 1.69: P = .04) and in patients with acute GVHD (HR, 1.88; P = .02), and lower in those who received higher doses of CD34 cells (HR, .55; P = .01). In summary, we have shown that pretransplantation anti-CMV IgG titers are correlated with CMV reactivation risk. More studies are needed to assess how this information can be incorporated in HSCT. The use of high-dose cellular grafts, a modifiable risk factor, also protects against CMV reactivation.

Allogeneic transplantation is a well recognized treatment strategy of leukemia. However, its use in advanced leukemia patients is a subject of some debate especially when donors are not HLA-identical siblings because of the toxicity and cost of the procedure. We reviewed retrospectively the outcome of patients (pts) who received allogeneic transplantation for advanced acute leukemia in our center between 09/86 and 11/97. Thirty-six pts (study group) who lacked a matched sibling donor received partially matched related donor (n=14: PMRD group) or matched unrelated donor transplantation (n=22: MUD group). Fifteen pts had AML and 21 ALL. Seventeen pts (47%) were in CR>1, 13 pts (36%) had refractory disease and six pts (17.7%) were in untreated relapse. The outcome was compared to that of 56 patients (AML: 45.5 %, ALL: 55.5 %, CR>1: 49.9 %, refractory disease: 37.5 %, untreated relapse 19.6 %) who received allogeneic transplantation from a matched sibling donor (control group). Various conditioning regimens and GVHD prophylaxis were used. The actuarial incidence of grade II to IV acute GVHD was significantly higher in the study group (57%) than in the control group (34%) (p=0.047). The actuarial risk of relapse at three years was 21% +/- 22% in the study group versus 65% +/- 16% in the control group (p= 0.04). The actuarial probability of transplant-related mortality at 3 years is 64 +/- 16% for the study group and 25 +/- 11% for the control group (p=0.001). The leading cause of death in the study group was infection (30%) followed by acute GVHD and relapse. Relapse was the major cause of death in the control group (54%), followed by infection, interstitial pneumonia, veno-occlusive disease and GVHD. The OS and probability of leukemia-free survival at 3 years were 28 % +/- 15% (95% CI) and 27% +/- 15% (95% CI) in the study group. The overall survival and probability of LFS at 3 years were respectively 28 +/- 12% (95% CI) and 23 +/- 12% (95% CI) in the control group (p = 0.08 and p=0.11 respectively). In multivariate analysis, transplant-related mortality was higher in the study group (p=0.04) and lower if both donor and recipient were seronegative for CMV (p=0.007). OS was significantly higher for seronegative couples (p=0.0001), and when CR was achieved before BMT (p=0.0022). These results suggest that all efforts in this field should be directed on lowering the transplant related mortality for non geno-identical transplants and the relapse rate in geno-identical transplants.