ALBERT

Description: Purpose. Cytomegalovirus (CMV) reactivation after transplant occurs frequently and is generally thought to be associated with an increased transplant-associated mortality. We aimed first to evaluate the cytotoxic effects of CMV on AML in vitro, and further, the clinical outcome of patients with AML with a documented CMV reactivation after transplant. We hypothesized that CMV directly affects AML cells thereby reducing the risk for leukemic relapse in AML-patients after transplant. Patients and Methods. We retrospectively evaluated 236 patients with AML in two cohorts (108 patients in the 1st cohort transplanted from an HLA-identical sibling donor, and 127 patients in a 2nd cohort transplanted from an HLA-identical unrelated donor). All patients were transplanted in Essen. Endpoints of the study were probabilities of relapse and overall survival (OS). For the definition of a CMV reactivation treatment with ganciclovir and the detection of pp65 positive cells in peripheral mononuclear cells at minimum at two different occasions were required. For in vitro studies we used the cell lines Kasumi-1 (AML-M2), SD-1 (ALL) and K562 (CML in blast crises) and infected them with the AD169 CMV strain. 14 days after infection we evaluated the apoptosis rate by measuring annexin V by FACS, the proliferation rate by BRDU assay, the expression of disease-specific marker (AML1/ETO, BCR-ABL), pro-and antiapoptosis marker p21, c-myc by real-time PCR in infected cells and controls. Results. Infection of CMV in Kasumi-1 cells (AML) induced in 99.8% of cells apoptosis. Apoptosis was induced also in SD-1 cells (ALL) in 31.3% of cells after CMV infection, whereas no difference in the apoptosis rate was seen for K562 cells (CML) after CMV infection (6.4%) compared to uninfected controls (9.0%). These results were in concordance with the clinical observation of a CMV reactivation after transplant in AML, ALL, and CML. In 25.9% of AML- patients of cohort 1 and in 29.9% of AML-patients of cohort 2 we detected a CMV reactivation. AML-Patients with a documented CMV reactivation had in both cohorts a markedly reduced risk for leukemic relapse (probability of risk for relapse at 5-year 9.2% versus 52.6% in cohort 1 (p

Description: Abstract 2261 Poster Board II-238 Cytomegalovirus reactivation (HCMV) occurs frequently after hematopoetic stem cell transplantation and is associated with an increased treatment-related mortality. We aimed first to evaluate the cytotoxic effects of CMV on AML in vitro, and further, the clinical outcome of patients with AML with a documented CMV reactivation after transplant. First, we show that HCMV infects acute leukemia cell line Kasumi-1 (AML) and SD-1 (ALL), inhibits their proliferation and induces apoptosis almost in all cells after 14 days. HCMV further inhibits the proliferation of bone marrow progenitor cells derived from healthy volunteers as demonstrated here by the reduction of the number and size of colony forming units in methylcellulose assays. The induction of apoptosis is unusual because HCMV possesses various strategies to prevent apoptosis in infected cells in order to delay their cell death and maintain its own virus replication. Apoptosis via a caspase-dependent pathway occurred although HCMV induced a significant up-regulation of the anti-apoptotic gene cFLIP and anti-stress gene Gadd45a and simultaneously down-regulation of pro-apoptotic genes p53, Bcl-2, Gadd45γ in Kasumi-1 and SD-1 cells, showing that the anti-apoptotic mechanisms of HCMV to prevent cell death failed. Concordantly, the coapplication of the caspase-specific inhibitor zVAD.fmk to HCMV- infected Kasumi-1 cells inhibited the induction of apoptosis to a great extent. In the second part of our study we evaluated the clinical outcome of patients with AML after transplant in whom a HCMV reactivation occurred. We evaluated a homogenous group of 140 patients with AML after myeloablative conditioning, non-T cell depleted allogeneic HSCT from a HLA-identical sibling donor, and compared the clinical results to 60 patients with CML after transplant. CMV reactivation was documented by CMV-related matrix protein pp65 antigenemia test and routinely accompanied by a CMV preemptive therapy with ganciclovir. CMV reactivation in AML patients was associated with reduced risk for relapse (11.6% v 50.5%; p

Description: The impact of early human cytomegalovirus (HCMV) replication on leukemic recurrence was evaluated in 266 consecutive adult (median age, 47 years; range, 18-73 years) acute myeloid leukemia patients, who underwent allogeneic stem cell transplantation (alloSCT) from 10 of 10 high-resolution human leukocyte Ag-identical unrelated (n = 148) or sibling (n = 118) donors. A total of 63% of patients (n = 167) were at risk for HCMV reactivation by patient and donor pretransplantation HCMV serostatus. In 77 patients, first HCMV replication as detected by pp65-antigenemia assay developed at a median of 46 days (range, 25-108 days) after alloSCT. Taking all relevant competing risk factors into account, the cumulative incidence of hematologic relapse at 10 years after alloSCT was 42% (95% confidence interval [CI], 35%-51%) in patients without opposed to 9% (95% CI, 4%-19%) in patients with early pp65-antigenemia (P 〈 .0001). A substantial and independent reduction of the relapse risk associated with early HCMV replication was confirmed by multivariate analysis using time-dependent covariate functions for grades II to IV acute and chronic graft-versus-host disease, and pp65-antigenemia (hazard ratio = 0.2; 95% CI, 0.1-0.4, P 〈 .0001). This is the first report that demonstrates an independent and substantial reduction of the leukemic relapse risk after early replicative HCMV infection in a homogeneous population of adult acute myeloid leukemia patients.