Feasibility and outcomes after dose reduction of immunochemotherapy in young adults with Burkitt lymphoma and leukemia: results of the BURKIMAB14 trial.

High dose-intensive or infusional intermediate-dose immunochemotherapy is highly effective treatment for Burkitt lymphoma irrespective of human immunodeficiency virus (HIV) infection. However, toxicities of these regimens are relevant, especially in older adults and elderly patients. The prospective multicenter BURKIMAB14 trial included four to six blocks of immunochemotherapy according to stage (localized: 1 and 2 non-bulky; advanced: 2 bulky, 3, 4) and age, with dose reduction in patients >55 years old. Dose-intensity of chemotherapy was reduced in patients ≤55 years old after achieving complete metabolic response (CMR). Their outcomes were compared with those of similar patients included in the former BURKIMAB08 trial, in which there was no dose reduction. CMR was attained in 86 of 107 (80%) patients (17/19 in localized stages and 69/88 in advanced stages). Patients from the BURKIMAB14 trial ≤55 years old showed similar overall survival (OS), fewer infections and cytopenias than patients from the BURKIMAB08 trial. Patients >55 years old had a significantly higher treatment- related mortality despite dose reduction of chemotherapy. With a median follow-up of 3.61 years the 4-year OS probability was 73% (range, 63-81%). Age (≤55 vs. >55 years) and stage (localized vs. advanced) had prognostic significance. No significant differences in OS were observed in HIV-positive versus HIV-negative patients. The results of BURKIMAB14 are similar to those of other dose-intensive immunochemotherapy trials. Age >55 years and advanced stage, but not HIV infection, were associated with poor survival. Dose reduction of chemotherapy in young adults in CMR is safe and does not impact outcomes (clinicaltrials gov. Identifier: NCT05049473).

IL28B genetic variation and cytomegalovirus-specific T-cell immunity in allogeneic stem cell transplant recipients.

A single nucleotide polymorphism (SNP), 3 kbp upstream of the IL28B gene (rs12979860; C/T), has been shown to influence the dynamics of cytomegalovirus (CMV) replication in allogeneic stem cell transplant recipients (Allo-SCT). We investigated whether this SNP had any effect on the dynamics of CMV-specific T-cell immunity in these patients. CMV pp65/IE-1 IFN-γ CD8+ and CD4+ T cells were enumerated by flow cytometry in 85 patients with no prior CMV DNAemia (group A) and in 57 after the onset of CMV DNAemia (group B). Donor IL28B genotype was determined by real-time PCR and plasma levels of IL-28B were quantitated by ELISA. CMV-specific T-cell counts and plasma IL-28B levels in patients in group A were not significantly different among the IL28B genotype groups. Patients harboring the donor IL28B T/T genotype appeared to expand CMV-specific IFN-γ CD8+ cells to a higher level in response to viral replication than their C/T and C/C counterparts. Fewer patients in the T/T group received pre-emptive antiviral therapy (P = 0.05). Overall, a significant inverse correlation was observed between median IL-28B levels measured prior to the CMV DNAemia onset and the level of CMV-specific CD8+ T cells enumerated after detection of CMV DNAemia (σ = -0.471; P = 0.013). In summary, the data suggested that the protective effect attributed to the rs12979860 SNP minor T allele could be mediated, at least in part, by eliciting robust CMV-specific T-cell responses. J. Med. Virol. 89:685-695, 2017. © 2016 Wiley Periodicals, Inc.

Outcome of Second Allogeneic Hematopoietic Cell Transplantation after Relapse of Myeloid Malignancies following Allogeneic Hematopoietic Cell Transplantation: A Retrospective Cohort on Behalf of the Grupo Español de Trasplante Hematopoyetico.

Allogeneic stem cell transplantation (allo-HCT) represents the most effective immunotherapy for acute myeloid leukemia (AML) and myeloid malignancies. However, disease relapse remains the most common cause of treatment failure. By performing a second allo-HCT, durable remission can be achieved in some patients. However, a second allo-HCT is of no benefit for the majority of patients, so this approach requires further understanding. We present a retrospective cohort of 116 patients diagnosed with AML, myelodysplastic syndromes, and myeloproliferative disorders who consecutively underwent a second allo-HCT for disease relapse. The median age was 38 years (range, 4 to 69 years). Sixty-three patients were alive at last follow-up. The median follow-up of the whole cohort was 193 days (range, 2 to 6724 days) and the median follow-up of survivors was 1628 days (range, 52 to 5518 days). Overall survival (OS) at 5 years was 32% (SE ± 4.7%). Multivariate analysis identified active disease status (P < .001) and second allo-HCT < 430 days (the median of the time to second transplantation) after the first transplantation (P < .001) as factors for poor prognosis, whereas the use of an HLA-identical sibling donor for the second allo-HCT was identified as a good prognostic factor (P < .05) for OS. The use of myeloablative conditioning (P = .01), active disease (P = .02), and a donor other than an HLA-identical sibling (others versus HLA-identical siblings) (P = .009) were factors statistically significant for nonrelapse mortality in multivariate analysis. Time to second transplantation was statistically significant (P = .001) in the relapse multivariate analysis, whereas multivariate analysis identified active disease status (P < .001) and time to second transplantation (P < .001) as poor prognosis factors for disease-free survival. This study confirms active disease and early relapse as dismal prognostic factors for a second allo-HCT. Using a different donor at second allo-HCT did not appear to change outcome, but using an HLA-identical sibling donor for a second transplantation appears to be associated with better survival. Further studies are warranted.

Incidence and dynamics of active cytomegalovirus infection in allogeneic stem cell transplant patients according to single nucleotide polymorphisms in donor and recipient CCR5, MCP-1, IL-10, and TLR9 genes.

Single nucleotide polymorphisms (SNPs) in genes involved in the activation or regulation of innate and adaptive immune responses may modulate the susceptibility to and the natural history of certain chronic viral infections. The current study aimed to investigate whether donor and recipient SNPs in the chemokine receptor 5 (rs1800023), monocyte chemoattractant protein 1 (rs13900), interleukin-10 (rs1878672), and Toll-like receptor 9 (rs352140) genes would exert any influence on the rate of incidence and features of CMV DNAemia in the allogeneic stem cell transplantation setting. This was a retrospective observational multicenter study. The cohort consisted of 102 non-consecutive allogeneic stem cell transplant recipients. SNP genotyping was performed by allele-specific real-time PCR. CMV surveillance was performed by the pp65 antigenemia assay/and or by real-time PCR. Seventy-three patients developed CMV DNAemia within the first 100 days after transplantation (71.5%). Neither donor nor recipient SNPs were associated significantly with the rate of incidence of active CMV infection, nor with the need for pre-emptive antiviral therapy. Both the duration of CMV DNAemia and the plasma CMV DNA peak load during episodes were significantly higher in patients harboring the donor (but not the recipient) chemokine receptor 5 A/A genotype, than in their A/G and G/G counterparts (P = 0.022 and P = 0.045, respectively). The data reported suggest that SNPs in chemokine receptor 5 may influence the dynamics of CMV infection in the Allo-SCT setting.

Enumeration of NKG2C+ natural killer cells early following allogeneic stem cell transplant recipients does not allow prediction of the occurrence of cytomegalovirus DNAemia.

The role of Natural killer (NK) cells in the control of cytomegalovirus (CMV) infection in allogeneic stem cell transplant recipients has not been precisely characterized. The current study is aimed at investigating the potential role of NK cells expressing the activating receptor NKG2C in affording protection against the development of CMV DNAemia in patients exhibiting detectable CMV-specific CD8(+) T-cell responses early following transplantation. A total of 61 nonconsecutive patients were included in the study. Peripheral levels of CD56(bright) CD16(-/low) and CD56(dim) CD16(+) NKG2C(+) NK cells and CMV pp65/IE-1-specific IFN-γ-producing CD8(+) T-cells were enumerated by flow cytometry at days +30 and +60 after transplant. Neither the absolute number of NKG2C(+) NK cells, nor that of CD56(bright) CD16(-/low) and CD56(dim) CD16(+) NKG2C(+) NK-cell subsets at day 30 differed significantly between patients with or without subsequent CMV DNAemia. No significant correlation was found between levels of both NKG2C(+) NK-cell populations and the peak CMV DNA load within subsequent episodes of CMV DNAemia. The data indicate that enumeration of NKG2C(+) NK cells early after transplant is unlikely to be helpful in identifying those patients at highest risk of developing CMV DNAemia. Moreover, the data do not support a direct implication of NKG2C(+) NK cells in preventing the development of CMV DNAemia.

An evaluation of the role of NKG2C+ natural killer cells in protection from cytomegalovirus DNAemia early following allogeneic stem cell transplantation.

The role of natural killer (NK) cells in affording protection against human cytomegalovirus (CMV) in allogeneic stem cell transplant recipients is largely unknown. The current study was aimed at determining whether NKG2C+ NK cells confer protection from CMV DNAemia early following transplantation in patients lacking mono and polyfunctional CMV pp65 and IE-1-specific CD4+ and CD8+ T-cell responses, as measured by flow cytometry for intracellular cytokine staining. Fourteen out of the 36 patients included in this study developed CMV DNAemia between days +30 and +60 after transplant. Three patients did so after day +60. Peripheral blood levels of CD56(bright) CD16(-/low) and CD56(dim) CD16+ NKG2C+ NK cells measured at day +30 and at day +60 in patients who had or had not subsequent CMV DNAemia did not differ significantly. In addition, no significant correlation was found between CD56(bright) CD16(-/low) (σ = -0.229; P = 0.39) and CD56(dim) CD16+ (σ = -0.285; P = 0.28) NKG2C+ NK-cell levels and initial plasma CMV DNA loads. In summary, the data presented do not support a direct implication of NKG2C+ NK cells in preventing the development of CMV DNAemia or modulating the magnitude of CMV replication at early stages during episodes of CMV DNAemia in allogeneic stem cell transplant patients with unreconstituted CMV-specific T-cell responses.

First-line treatment with rituximab-hyperCVAD alternating with rituximab-methotrexate-cytarabine and followed by consolidation with 90Y-ibritumomab-tiuxetan in patients with mantle cell lymphoma. Results of a multicenter, phase 2 pilot trial from the GELTAMO group.

UNLABELLED: The prognosis for fit patients with mantle cell lymphoma has improved with intensive strategies. Currently, the role of maintenance/consolidation approaches is being tested as relapses continue to appear. In this trial we evaluated the feasibility, safety and efficacy of rituximab-hyperCVAD alternating with rituximab-methotrexate-cytarabine followed by consolidation with (90)Y-ibritumomab tiuxetan. Patients received six cycles followed by a single dose of (90)Y-ibritumomab tiuxetan. Thirty patients were enrolled; their median age was 59 years. Twenty-four patients finished the induction treatment, 23 achieved complete remission (77%, 95% confidence interval 60-93) and one patient had progressive disease (3%). Eighteen patients (60%), all in complete remission, received consolidation therapy. In the intent-to-treat population, failure-free, progression-free and overall survival rates at 4 years were 40% (95% confidence interval 20.4-59.6), 52% (95% confidence interval 32.4-71.6) and 81% (95% confidence interval 67.28-94.72), respectively. For patients who received consolidation, failure-free and overall survival rates were 55% (95% confidence interval 31.48-78.52) and 87% (95% confidence interval 70-100), respectively. Hematologic toxicity was significant during induction and responsible for one death (3.3%). After consolidation, grade 3-4 neutropenia and thrombocytopenia were observed in 72% and 83% of patients, with a median duration of 5 and 12 weeks, respectively. Six (20%) patients died, three due to secondary malignancies (myelodysplastic syndrome and bladder and rectum carcinomas). In conclusion, in our experience, rituximab-hyperCVAD alternated with rituximab-methotrexate-cytarabine and followed by consolidation with (90)Y-ibritumomab tiuxetan was efficacious although less feasible than expected. The unacceptable toxicity observed, especially secondary malignancies, advise against the use of this strategy. TRIAL REGISTRATION: clinical.gov identifier: NCT2005-004400-37.

A polymorphism in the TYMP gene is associated with the outcome of HLA-identical sibling allogeneic stem cell transplantation.

Thymidine phosphorylase (TYMP), an enzyme involved in nucleotide synthesis, has been implicated in critical biological processes such as DNA replication, protection against mutations, and tissue repair. In this work, we retrospectively evaluated the influence of a polymorphism in the TYMP gene (rs112723255; G/A) upon the outcome of 448 patients subjected to allogeneic stem cell transplantation (allo-SCT) from an human leukocyte antigen (HLA)-identical sibling donor. The TYMP genotype of patients correlated with overall survival-carriers of the minor allele (A) being at an increased risk of dying after transplantation (hazard ratio, HR = 1.9; P = 0.004). This effect was mostly due to differences in transplant toxicity-related mortality (HR = 2.5; P = 0.029). In addition, the TYMP genotype of donors was associated with the risk of chronic graft-versus-host disease (GVHD)-carriers of the minor allele being at an increased risk of developing this complication ([HR] = 1.7; P = 0.039). The impact of such polymorphism on the risk of chronic GVHD is limited to patients transplanted in early stage disease (HR = 2.2; P = 0.019). The combination of a donor harboring the minor allele with a patient homozygous for the major allele was associated with the highest risk of chronic GVHD (HR = 2.8; P = 0.008). These findings provide the first evidence of the significant impact of the TYMP genotype upon the clinical outcome of patients treated with HLA-identical sibling allo-SCT.

Clinical outcomes after CPX-351 in patients with high-risk acute myeloid leukemia: A comparison with a matched cohort from the Spanish PETHEMA registry.

BACKGROUND: CPX-351 is approved for the treatment of therapy related acute myeloid leukemia (t-AML) and AML with myelodysplastic related changes (MRC-AML). The benefits of this treatment over standard chemotherapy has not been addressed in well matched cohorts of real-life patients. METHODS: Retrospective analysis of AML patients treated with CPX-351 as per routine practice. A propensity score matching (PSM) was used to compare their main outcomes with those observed in a matched cohort among 765 historical patients receiving intensive chemotherapy (IC), all of them reported to the PETHEMA epidemiologic registry. RESULTS: Median age of 79 patients treated with CPX-351 was 67 years old (interquartile range 62-71), 53 were MRC-AML. The complete remission (CR) rate or CR without recovery (CRi) after 1 or 2 cycles of CPX-351 was 52%, 60-days mortality 18%, measurable residual disease <0.1% in 54% (12 out of 22) of them. Stem cell transplant (SCT) was performed in 27 patients (34%), median OS was 10.3 months, and 3-year relapse incidence was 50%. Using PSM, we obtained two comparable cohorts treated with CPX-351 (n = 52) or IC (n = 99), without significant differences in CR/CRi (60% vs. 54%) and median OS (10.3 months vs. 9.1 months), although more patients were bridged to SCT in the CPX-351 group (35% vs. 12%). The results were confirmed when only 3 + 7 patients were included in the historical cohort. In multivariable analyses, SCT was associated with better OS (HR 0.33 95% CI: 0.18-0.59), p < 0.001. CONCLUSION: Larger post-authorization studies may provide evidence of the clinical benefits of CPX-351 for AML in the real-life setting.

Functional profile of cytomegalovirus (CMV)-specific CD8+ T cells and kinetics of NKG2C+ NK cells associated with the resolution of CMV DNAemia in allogeneic stem cell transplant recipients.

Immune mechanisms involved in control of cytomegalovirus (CMV) infection in the allogeneic stem cell transplantation setting have not been fully disclosed. CMV pp65 and IE-1-specific CD8(+) T cells expressing IFN-γ, TNF-α, and CD107a, alone or in combination, and NKG2C(+) NK cells were prospectively enumerated during 13 episodes of CMV DNAemia. The expansion of monofunctional and polyfunctional CD8(+) T cells was associated with CMV DNAemia clearance. The size and functional diversity of the expanding CD8(+) T-cell population was greater in self-resolved episodes than in episodes treated with antivirals. These differences were related to the magnitude of expansion of cognate antigen IFN-γ CD4(+) T cells. The resolution of CMV DNAemia was associated frequently with a marked expansion of both CD56(dim) /CD16(+) NK cells and NKG2C(+) CD56(bright) /CD16(-) NK cells. The data lend support to the role of polyfunctional CD8(+) T cells in controlling CMV replication in the allogeneic stem cell transplantation setting, and suggest that NKG2C(+) NK cells may be involved critically in the resolution of CMV DNAemia episodes.

Allogeneic stem cell transplantation after reduced intensity conditioning in patients with relapsed or refractory Hodgkin's lymphoma. Results of the HDR-ALLO study - a prospective clinical trial by the Grupo Español de Linfomas/Trasplante de Médula Osea (GEL/TAMO) and the Lymphoma Working Party of the European Group for Blood and Marrow Transplantation.

BACKGROUND: Although Hodgkin's lymphoma is a highly curable disease with modern chemotherapy protocols, some patients are primary refractory or relapse after first-line chemotherapy or even after high-dose therapy and autologous stem cell transplantation. We investigated the potential role of allogeneic stem cell transplantation in this setting. DESIGN AND METHODS: In this phase II study 92 patients with relapsed Hodgkin's lymphoma and an HLA-identical sibling, a matched unrelated donor or a one antigen mismatched, unrelated donor were treated with salvage chemotherapy followed by reduced intensity allogeneic transplantation. Fourteen patients showed refractory disease and died from progressive lymphoma with a median overall survival after trial entry of 10 months (range, 6-17). Seventy-eight patients proceeded to allograft (unrelated donors, n=23). Fifty were allografted in complete or partial remission and 28 in stable disease. Fludarabine (150 mg/m(2) iv) and melphalan (140 mg/m(2) iv) were used as the conditioning regimen. Anti-thymocyte globulin was additionally used as graft-versus-host-disease prophylaxis for recipients of grafts from unrelated donors. RESULTS: The non-relapse mortality rate was 8% at 100 days and 15% at 1 year. Relapse was the major cause of failure. The progression-free survival rate was 47% at 1 year and 18% at 4 years from trial entry. For the allografted population, the progression-free survival rate was 48% at 1 year and 24% at 4 years. Chronic graft-versus-host disease was associated with a lower incidence of relapse. Patients allografted in complete remission had a significantly better outcome. The overall survival rate was 71% at 1 year and 43% at 4 years. CONCLUSIONS: Allogeneic stem cell transplantation can result in long-term progression-free survival in heavily pre-treated patients with Hodgkin's lymphoma. The reduced intensity conditioning approach significantly reduced non-relapse mortality; the high relapse rate represents the major remaining challenge in this setting. The HDR-Allo trial was registered in the European Clinical Trials Database (EUDRACT, https://eudract.ema.europa.eu/) with number 02-0036.

Coexistence of Langerhans cell histiocytosis, Rosai-Dorfman disease and splenic lymphoma with fatal outcome after rapid development of histiocytic sarcoma of the liver.

The coexistence of skin-limited Langerhans cell histiocytosis (LCH) and Rosai-Dorfman disease (RDD) is an exceptional finding. The association of lymphomas and histiocytosis is also infrequent. We report the case of a 68-year-old man which presented an exceptional association of cutaneous LCH and RDD and splenic marginal zone lymphoma. He was stable for few years. Suddenly, the patient was admitted into Hematology Department with a remarkable enlargement of spleen and liver without enlargement of lymphadenopathies or skin lesions flare. He died 24 h later despite treatment with systemic chemotherapy combined with prednisone. Pre-mortem biopsy showed infiltration with histiocytic sarcoma. We think that a transdifferentiation phenomenon could explain our case, although we could not show a clonal relationship between the cutaneous and the liver diseases. We also want to pay attention to the fact that a fast transformation to a more aggressive disease can occur long time after the presentation of the first lesion, a problem that stresses the importance of performing a close and permanent follow-up of these patients.

BCL2 translocation in high grade B cell lymphoma (NOS, DH/TH) is associated with reduced progression free survival.

High Grade B Cell Lymphoma, NOS, and High Grade B Cell Lymphoma with Dual Hit or Triple Hit have been recently recategorized in the 2016 revision of the WHO classification of lymphoid neoplasms. In this study we have characterized the genetic, histopathological, and clinical features of a series of this type of lymphoid neoplasia (17 HGBCL NOS and 53 HGBCL DH/TH).HGBCL NOS showed better response to first line treatment than HGBCL with DH/TH but no significant differences in PFS or OS were found between the two categories. Survival analysis in the whole cohort of cases found that only the presence of BCL2 translocation was significantly associated with PFS. Other clinical features such as IPI, LDH or stage were equivalent in both categories. Furthermore, both high grade and DLBCL morphological patterns showed equivalent PFS and OS in this set of High grade BCL NOS/DH/TH.Key pointsBCL2 translocation in High Grade B Cell Lymphoma NOS and High Grade B Cell Lymphoma with DH/TH is associated with reduced progression free survival.Both high grade and DLBCL morphological patterns showed equivalent outcome regarding PFS and OS in HGBCL.

An assessment of the effect of human herpesvirus-6 replication on active cytomegalovirus infection after allogeneic stem cell transplantation.

Human herpesvirus-6 (HHV-6) may enhance cytomegalovirus (CMV) replication in allogeneic stem cell transplant (allo-SCT) recipients either through direct or indirect mechanisms. Definitive evidence supporting this hypothesis are lacking. We investigated the effect of HHV-6 replication on active CMV infection in 68 allo-SCT recipients. Analysis of plasma HHV-6 and CMV DNAemia was performed by real-time PCR. Enumeration of pp65 and IE-1 CMV-specific IFNgamma CD8(+) and CD4(+)T cells was performed by intracellular cytokine staining. HHV-6 DNAemia occurred in 39.8% of patients, and was significantly associated with subsequent CMV DNAemia in univariate (P=.01), but not in multivariate analysis (P=.65). The peak of HHV-6 DNAemia was not predictive of the development of CMV DNAemia. Timing and kinetics of active CMV infection were comparable in patients either with or without a preceding episode of HHV-6 DNAemia. The occurrence of HHV-6 DNAemia had no impact on CMV-specific T cell immunity reconstitution early after transplant. The receipt of a graft from an HLA-mismatched donor was independently associated with HHV-6 (P=.009) and CMV reactivation (P=.04). The data favor the hypothesis that a state of severe immunosuppression leads to HHV-6 and CMV coactivation, but argue against a role of HHV-6 in predisposing to the development of CMV DNAemia or influencing the course of active CMV infection.

Unrelated transplantation for poor-prognosis adult acute lymphoblastic leukemia: long-term outcome analysis and study of the impact of hematopoietic graft source.

Adults with high-risk acute lymphoblastic leukemia (HR-ALL) have a poor outcome with standard chemotherapy and usually undergo unrelated stem cell transplantation (SCT) if a matched sibling donor is not available. We analyzed the outcome of adult patients with unrelated SCT for HR-ALL and studied the possible effect of the hematopoietic stem cell source of the transplant. A total of 149 adult patients (median age, 29 years, range, 15-59 years) with HR-ALL underwent unrelated SCT in 13 Spanish institutions between 2000 and 2007. Patients in first complete remission (CR1) at transplantation had at least one adverse prognostic factor (advanced age, adverse cytogenetics, hyperleukocytosis, or slow response to induction therapy). ALL was in CR1 in 81 patients (54%), in second CR (CR2) in 37 patients (25%), in third CR (CR3) in 11 patients (7%), and with overt disease in 20 patients (13%). The hematopoietic source was unrelated cord blood (UCB) in 62 patients and an unrelated donor (UD) in 87 patients. The patients undergoing UCB-SCT and UD-SCT were comparable in terms of the main clinical and biological features of ALL, except for a higher frequency of patients with more overt disease in the UCB-SCT group. There was no statistically significant difference in overall survival (OS) or disease-free survival (DFS) at 5 years between the 2 groups. Treatment-related mortality (TRM) was significantly lower in the UCB-SCT group (P = .021). The probability of relapse at 1 year was 17% (95% confidence interval [CI], 7%-27%) for the UD-SCT group and 27% (95% CI, 14%-40%) for the UCB-SCT group (P = .088), respectively. Only disease status at transplantation (CR1, 41% [95% CI, 18%-64%] vs CR2, 51% [95% CI, 17%-85%] vs advanced disease, 66% [95% CI, 46%-86%]; P = .001) and the absence of chronic graft-versus-host disease (74% [95% CI, 46%-100%] vs 33% [95% CI, 17%-49%]; P = .034) were significant factors for relapse. All unrelated transplantation modalities were associated with high treatment-related mortality for adult HR-ALL patients without a sibling donor. UCB-SCT and UD-SCT were found to be equivalent options. Disease status at transplantation and chronic GVHD were the main factors influencing relapse in both transplantation modalities.

Kinetics of cytomegalovirus (CMV) pp65 and IE-1-specific IFNgamma CD8+ and CD4+ T cells during episodes of viral DNAemia in allogeneic stem cell transplant recipients: potential implications for the management of active CMV infection.

The dynamics of CMV pp65 and IE-1-specific IFNgamma-producing CD8(+) (IFNgamma CD8(+)) and CD4(+) (IFNgamma CD4(+)) T cells and CMV DNAemia were assessed in 19 pre-emptively treated episodes of active CMV infection. Peripheral counts of IFNgamma CD8(+) and IFNgamma CD4(+) T cells inversely correlated with CMV DNAemia levels (P = <0.001 and P = 0.003, respectively). A threshold value of 1.3 cells/microl predicting CMV DNAemia clearance was established for IFNgamma CD8(+) T cells (PPV, 100%; NPV, 93%) and for IFNgamma CD4(+) T cells (PPV, 100%; NPV, 75%). Undetectable T-cell responses were usually observed at the time of initiation of pre-emptive therapy. Either a rapid (within 7 days) or a delayed (median 31 days) expansion of both T-cell populations concomitant with CMV DNAemia clearance was observed in 5 and 8 episodes, respectively. An inconsistent or a lack of expansion of both T-cell subsets was related to a persistent CMV DNAemia. Robust and maintained CMV-specific T-cell responses after CMV DNAemia clearance and cessation of antiviral therapy were associated with a null incidence of relapsing infections at least during the following month. Data obtained in the present study may be helpful in the design of therapeutic strategies for the management of active CMV infections in the allo-SCT recipient.