High-dose acyclovir and pre-emptive ganciclovir to prevent cytomegalovirus disease in myeloablative and non-myeloablative allogeneic stem cell transplantation

High-dose aciclovir in CMV infection prophylaxis after allogeneic HSCT: a single-center long-term experience

There is only limited data on cytomegalovirus (CMV) prophylaxis with high-dose (HD) aciclovir after allogeneic hematopoietic stem cell transplantation (allo-HSCT). We performed a retrospective analysis on a total of 179 patients who underwent their allo-HSCT with HD-aciclovir prophylaxis at our center. A clinically significant CMV infection (cs-CMVi) was observed in 56 (31%) cases with a median time of 49 (range 25-147) days after HSCT. A significantly higher CMV infection rate was observed in seropositive recipients with a seronegative donor (74%) compared to seropositive recipients with a seropositive donor, and seronegative recipients with seropositive and seronegative donors (24%, 18%, 7% respectively; p < 0.001). The CMV serostatus was the only significant risk factor for CMV infection in our analysis. CMV disease developed in three patients with CMV-related death in two cases. During HD-aciclovir prophylaxis, we did not observe any medical condition attributable to HD-aciclovir's adverse effects. Compared to published results, we observed a low incidence of cs-CMVi with HD-aciclovir prophylaxis in several patient subgroups, especially in seropositive recipients with a seropositive donor. With respect to the determined threshold, HD-aciclovir prophylaxis seems to have good efficacy in an intermediate cs-CMVi risk patients, but prospective randomized trials would be needed for definite conclusions.

Effectiveness of letermovir for cytomegalovirus prophylaxis in allogeneic hematopoietic stem cell transplant recipients: A global systematic review

OBJECTIVE(S)

Letermovir (LET), a novel antiviral, has largely supplanted more traditional preemptive therapy (PET) for cytomegalovirus (CMV) prophylaxis in allogeneic hematopoietic stem cell transplant (allo-HCT) patients. Use of LET demonstrated efficacy against placebo in phase III randomized controlled trials, but is considerably more expensive than PET. This review aimed to evaluate the real-world effectiveness of LET in preventing clinically significant CMV infection (csCMVi) for allo-HCT recipients and related outcomes.

DESIGN

A systematic literature review was performed using an a priori protocol using PubMed, Scopus, and ClinicalTrials.gov from January 2010 to October 2021.

SETTING AND PARTICIPANTS

Studies were included if they met the following criteria: LET compared with PET, CMV-related outcomes, patients aged 18 years or older, and English language-only articles. Descriptive statistics were used to summarize study characteristics and outcomes.

OUTCOME MEASURES

CMV viremia, csCMVi, CMV end-organ disease, graft-versus-host-disease, all-cause mortality.

RESULTS

A total of 233 abstracts were screened, with 30 included in this review. Randomized trials demonstrated efficacy of LET prophylaxis in preventing csCMVi. Observational studies demonstrated varying degrees of effectiveness of LET prophylaxis compared with use of PET alone. All studies with a comparator group resulted in lower rates of csCMVi for patients using LET. Included studies varied widely by CMV viral load threshold cutoff and CMV test units, limiting synthesis of results owing to high heterogeneity.

CONCLUSION

LET reduces risk of csCMVi, but lack of standardized clinical definitions on how to evaluate csCMVi and related outcomes largely prevent synthesis of results. Clinicians must consider this limitation in the context of evaluating the effectiveness of LET to other antiviral therapies, especially for patients at risk of late-onset CMV. Future studies should focus on prospective data collection through registries and concordance of diagnostic definitions to mitigate study heterogeneity.

The clinical and economic impact of cytomegalovirus infection in recipients of hematopoietic stem cell transplantation

BACKGROUND

CMV infection (CMV-I) remains an important complication of hematopoietic stem cell transplantation (HSCT).

METHODS

This was a retrospective, single-center cohort study in HSCT recipients. Primary outcomes were adjusted cost and all-cause mortality. Secondary analyses investigated CMV risk factors and the effect of serostatus.

RESULTS

Overall, 690 transplant episodes were included (allogeneic [n = 310]; autologous [n = 380]). All received preemptive CMV antiviral therapy at first detectable DNAemia. CMV-I occurred in 34.8% of allogeneic and 2.1% of autologous transplants; median time to onset was 45 days. In allogeneic HSCT recipients, the primary risk factor for CMV-I was CMV donor/recipient (D/R) serostatus. In a Markov multi-state model for allogeneic HSCT recipients, the hazard ratio for CMV-I and relapse was 1.5 (95% CI 0.8-2.8) and for CMV-I and mortality 2.4 (95% CI 0.9-6.5). In a multivariable model for all patients, CMV-I was associated with increased total cost (coefficient = 0.21, estimated incremental daily cost USD $500; P = 0.02). Cost was attenuated in allogeneic HSCT recipients (coefficient = 0.13, USD $699 vs $613, or $24 892 per transplant episode; P = 0.23). CMV disease (CMV-D) complicated 29.6% of CMV-I events in allogeneic HSCT recipients, but was not associated with an incrementally increased adjusted risk of mortality compared with CMV-I alone. CMV-I (56.4%) and CMV-D (19.8%) were significantly overrepresented in D-/R+ serostatus HSCT recipients, and mortality was higher in R+ HSCT recipients.

CONCLUSIONS

Despite early preemptive antiviral treatment, CMV-I impacts clinical outcomes and cost after HSCT, but the impact on cost is less pronounced in allogeneic HSCT recipients compared with autologous HSCT recipients.

Cyclophosphamide improves engraftment in patients with SCD and severe organ damage who undergo haploidentical PBSCT

Peripheral blood stem cell transplantation (PBSCT) offers a curative option for sickle cell disease (SCD). Although HLA-matched sibling transplantation is promising, the vast majority of patients lack such a donor. We sought to develop a novel nonmyeloablative HLA-haploidentical PBSCT approach that could safely be used for patients with severe organ damage. Based on findings in our preclinical model, we developed a phase 1/2 trial using alemtuzumab, 400 cGy total body irradiation, and escalating doses of posttransplant cyclophosphamide (PT-Cy): 0 mg/kg in cohort 1, 50 mg/kg in cohort 2, and 100 mg/kg in cohort 3. A total of 21 patients with SCD and 2 with β-thalassemia received a transplant. The mean hematopoietic cell transplant-specific comorbidity index of 6 reflected patients with cirrhosis, heart failure, and end-stage renal disease. The engraftment rate improved from 1 (33%) of 3 in cohort 1 to 5 (63%) of 8 in cohort 2 and 10 (83%) of 12 in cohort 3. Percentage of donor myeloid and CD3 chimerism also improved with subsequent cohorts. There was no transplant-related mortality, and overall survival was 87%. At present, 0% in cohort 1, 25% in cohort 2, and 50% in cohort 3 remain free of their disease. There was no grade 2 to 4 acute or extensive chronic graft-versus-host disease (GVHD). Therefore, PT-Cy improves engraftment and successfully prevents severe GVHD after nonmyeloablative conditioning in patients with SCD who are at high risk for early mortality. Additional strategies are necessary to decrease the graft rejection rate and achieve a widely available cure for all patients with SCD. This trial was registered at www.clinicaltrials.gov as #NCT00977691.

Immunotherapy with Donor T Cells Sensitized with Overlapping Pentadecapeptides for Treatment of Persistent Cytomegalovirus Infection or Viremia

We conducted a phase I trial of allogeneic T cells sensitized in vitro against a pool of pentadecapeptides (15-mer peptides) spanning the sequence of CMVpp65 for adoptive therapy of 17 allogeneic hematopoietic cell transplant recipients with cytomegalovirus (CMV) viremia or clinical infection persisting despite prolonged treatment with antiviral drugs. All but 3 of the patients had received T cell-depleted transplants without graft-versus-host disease (GVHD) prophylaxis with immunosuppressive drugs after transplantation. The CMVpp65-specific T cells (CMVpp65CTLs) generated were oligoclonal and specific for only 1 to 3 epitopes, presented by a limited set of HLA class I or II alleles. T cell infusions were well tolerated without toxicity or GVHD. Of 17 patients treated with transplant donor (n = 16) or third-party (n = 1) CMVpp65CTLs, 15 cleared viremia, including 3 of 5 with overt disease. In responding patients, the CMVpp65CTLs infused consistently proliferated and could be detected by T cell receptor Vβ usage in CMVpp65/HLA tetramer + populations for period of 120 days to up to 2 years after infusion. Thus, CMVpp65CTLs generated in response to synthetic 15-mer peptides of CMVpp65 are safe and can clear persistent CMV infections in the post-transplantation period.

Nonmyeloablative HLA-matched sibling allogeneic hematopoietic stem cell transplantation for severe sickle cell phenotype

IMPORTANCE

Myeloablative allogeneic hematopoietic stem cell transplantation (HSCT) is curative for children with severe sickle cell disease, but toxicity may be prohibitive for adults. Nonmyeloablative transplantation has been attempted with degrees of preparative regimen intensity, but graft rejection and graft-vs-host disease remain significant.

OBJECTIVE

To determine the efficacy, safety, and outcome on end-organ function with this low-intensity regimen for sickle cell phenotype with or without thalassemia.

DESIGN, SETTING, AND PARTICIPANTS

From July 16, 2004, to October 25, 2013, 30 patients aged 16-65 years with severe disease enrolled in this nonmyeloablative transplant study, consisting of alemtuzumab (1 mg/kg in divided doses), total-body irradiation (300 cGy), sirolimus, and infusion of unmanipulated filgrastim mobilized peripheral blood stem cells (5.5-31.7 × 10(6) cells/kg) from human leukocyte antigen-matched siblings.

MAIN OUTCOMES AND MEASURES

The primary end point was treatment success at 1 year after the transplant, defined as a full donor-type hemoglobin for patients with sickle cell disease and transfusion independence for patients with thalassemia. The secondary end points were the level of donor leukocyte chimerism; incidence of acute and chronic graft-vs-host disease; and sickle cell-thalassemia disease-free survival, immunologic recovery, and changes in organ function, assessed by annual brain imaging, pulmonary function, echocardiographic image, and laboratory testing.

RESULTS

Twenty-nine patients survived a median 3.4 years (range, 1-8.6), with no nonrelapse mortality. One patient died from intracranial bleeding after relapse. As of October 25, 2013, 26 patients (87%) had long-term stable donor engraftment without acute or chronic graft-vs-host disease. The mean donor T-cell level was 48% (95% CI, 34%-62%); the myeloid chimerism levels, 86% (95% CI, 70%-100%). Fifteen engrafted patients discontinued immunosuppression medication with continued stable donor chimerism and no graft-vs-host disease. The normalized hemoglobin and resolution of hemolysis among engrafted patients were accompanied by stabilization in brain imaging, a reduction of echocardiographic estimates of pulmonary pressure, and allowed for phlebotomy to reduce hepatic iron. The mean annual hospitalization rate was 3.23 (95% CI, 1.83-4.63) the year before, 0.63 (95% CI, 0.26-1.01) the first year after, 0.19 (95% CI, 0-0.45) the second year after, and 0.11 (95% CI, 0.04-0.19) the third year after transplant. For patients taking long-term narcotics, the mean use per week was 639 mg (95% CI, 220-1058) of intravenous morphine-equivalent dose the week of their transplants and 140 mg (95% CI, 56-225) 6 months after transplant. There were 38 serious adverse events: pain and related management, infections, abdominal events, and sirolimus related toxic effects.

CONCLUSIONS AND RELEVANCE

Among 30 patients with sickle cell phenotype with or without thalassemia who underwent nonmyeloablative allogeneic HSCT, the rate of stable mixed-donor chimerism was high and allowed for complete replacement with circulating donor red blood cells among engrafted participants. Further accrual and follow-up are required to assess longer-term clinical outcomes, adverse events, and transplant tolerance.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00061568.

Valganciclovir as pre-emptive therapy for cytomegalovirus infection in allogeneic haematopoietic stem cell transplant recipients

BACKGROUND

In haematopoietic stem cell transplant (HSCT) recipients, cytomegalovirus (CMV) infection contributes significantly to morbidity and mortality in both the early and late post-transplant period. Ganciclovir (GCV) is the treatment of choice for CMV, but requires intravenous administration, a fact that complicates its long-term use. Oral valganciclovir (VGCV) and intravenous GCV were recently shown to have similar efficacy for pre-emptive CMV treatment in solid organ transplant recipients, but relatively limited data are available in HSCT recipients. The objectives of this study were to compare the efficacy of VGCV versus intravenous GCV or foscarnet (FOS) for pre-emptive therapy of active CMV infection in allogeneic HSCT and to determine the incidence of adverse effects and relapses.

METHODS

This was a 2-year prospective, comparative cohort study in which 237 episodes of pre-emptive therapy for active CMV infection were collected in 166 allogeneic HSCT recipients out of 717 included in the Spanish Network for Research on Infection in Transplantation (RESITRA/REIPI) database. Intravenous GCV was the first-line treatment in 112 episodes, intravenous FOS in 38 episodes, and oral VGCV in 87 episodes.

RESULTS

VGCV was used as pre-emptive therapy for active CMV infection in 87 episodes. Excluding episodes considered as relapse, VGCV was as successful (91.4% [74/81]) as GCV (83.7% [87/14]) or FOS (75.8% [25/33]). In the VGCV arm, 7 (8.6%) cases were considered treatment failures: 4 (4.9%) because of adverse events, 1 (1.2%) due to persistent viral activity and 2 (2.5%) based on clinical decision. There were also 6 (7.4%) cases of recurrent infection. No statistically significant differences were found when compared to GCV or FOS.

CONCLUSIONS

In allogeneic HSCT recipients, VGCV seemed effective and safe in the pre-emptive therapy of active CMV infection.

Immune reconstitution and cytomegalovirus infection after allogeneic stem cell transplantation: the important impact of in vivo T cell depletion

We analyzed cytomegalovirus (CMV) infection risk factors and immune reconstitution kinetics in 89 patients after allogeneic stem cell transplantation (allo-SCT). The use of alemtuzumab for in vivo T cell depletion (TCD) had, besides the donor/recipient CMV serostatus, the strongest influence on the CMV infection risk in univariate and multivariate analyses. In comparison to without use of in vivo TCD, the CMV infection risk [hazard ratio (HR)] was 4.82-fold after TCD with alemtuzumab, but only 1.40-fold after TCD with antithymocyte globulin (ATG). Alemtuzumab strongly depressed CD4(+) and CD8(+) T cell reconstitution, whereas ATG only delayed CD4(+) T cell reconstitution. Considering the reconstitution kinetics of CD4(+) and CD8(+) T cells, CMV-specific CD8(+) T cells, NK cells and the IgG concentration, only a low day +60 NK cell count (< or =161 versus >161/microl) was significantly associated with CMV infection development (HR 2.92, p = 0.034). CMV-specific CD8(+) T cells were detected in 57% of patients with a CMV-seropositive donor, but in none of the patients with a CMV-seronegative donor on day +30 (p = 0.01). Our data indicate that the type of in vivo TCD (alemtuzumab or ATG) differentially influences both the CMV infection risk and CD4(+)/CD8(+) T cell reconstitution kinetics in patients after allo-SCT.

Fludarabine-based reduced intensity conditioning transplants have a higher incidence of cytomegalovirus reactivation compared with myeloablative transplants

Two hundred and ten adult CMV seropositive patients undergoing myeloablative conditioning (MAC) [n=127] or reduced intensity conditioning (RIC) [n=83] transplants (HCT) were serially monitored for CMV reactivation and disease, using a qualitative polymerase chain reaction (PCR) followed by quantitation with pp65 antigen or quantitative PCR. CMV reactivation occurred in 53 RIC (63.9%) and 61 MAC (48%; P=0.03) transplants at a median of 47 days (range: 24-1977). Risk factors identified included acute GVHD (P=0.001), RIC regimen (P=0.03), unrelated donor (P=0.02), use of anti-thymocyte globulin/alemtuzumb (P=0.02) and use of bone marrow in MAC transplants (P=0.011). On multivariate analysis, RIC transplants and acute GVHD remained independent predictors. Treatment with antiviral drugs resulted in CMV negativity rates of 86.8% in MAC and 88.6% in RIC transplants. CMV disease occurred in 10.8% of RIC and 4.7% of MAC transplants (P=0.15). At a median follow-up of 26 months (range: 3-88), 48.1% of RIC and 50.3% of MAC transplants are alive. The higher incidence of CMV reactivation among RIC transplants suggests the need for novel prophylactic or pre-emptive strategies in this high-risk group of patients.

Related donor hematopoietic stem cell transplantation for Fanconi anemia without radiation: a single center experience in Turkey

Eight children with FA underwent allogeneic HSCT without using irradiation for the conditioning regimen. Patients received two different conditioning regimens: first two patients received BU 1.5 mg/kg/day for four days and CY 10 mg/kg/day for four days and the other regimen was: Flu 30 mg/m(2)/day for five days, CY 10 mg/kg/day for two days, and ATG-Fresenius 9-10 mg/kg/day for four days. GVHD prophylaxis consisted of CsA + MTX for the first two patients and only CsA for the others. All patients received HLA-identical stem cells from related donors. Primary engraftment was demonstrated in all patients. No patient developed acute GVHD and one patient had chronic GVHD. Only one patient who received BU based regimen died because of VOD. Overall, seven patients (87.5%) are alive with stable full donor chimerism at a median follow-up time of 2.5 yr (range: 1.7-8.9 yr). None of the patients developed secondary malignancy. Based on our data, we conclude that Flu-based, non-irradiation conditioning regimen was safe with low organ toxicity and stable engraftment in FA patients undergoing HSCT from matched related donors.

Robust expansion of viral antigen-specific CD4+ and CD8+ T cells for adoptive T cell therapy using gene-modified activated T cells as antigen presenting cells

Cytomegalovirus (CMV) reactivation after stem cell transplantation can be treated with CMV-specific T cells, but current in vitro techniques using dendritic cells as antigen-presenting cells are time-consuming and expensive. To simplify the production of clinical grade CMV-specific T cells, we evaluated gene-modified activated T cells [antigen presenting T cells (T-APCs)] as a reliable and easily produced source of APCs to boost CD4+ and CD8+ T-cell responses against the immunodominant CMV antigen pp65. T-APCs expressing the full-length immunodominant CMV pp65 gene were used to stimulate the expansion of autologous T cells. After 10 to 14 days, the T cell lines were tested for antigen specificity by using the flow cytometric intracellular detection of interferon-gamma after stimulation for 6 hours with a pp65 peptide library of 15-mers, overlapping by 11 amino acids. Under optimal conditions, this technique induced a median 766-fold and a 652-fold expansion of pp65-specific CD4+ and CD8+ responder cells, respectively, in 15 T cell lines. In 13 of 15 T cell lines, over 10 antigen-specific CD4+ plus CD8+ T cells were generated starting with only 5x10 peripheral blood mononuclear cells, representing an over 3-log increase. These data indicate that T-APCs efficiently boost pp65-specific CD4+ and CD8+ T cell numbers to clinically useful levels. The approach has the advantage of using a single leukocyte collection from the donor to generate large numbers of CMV-specific T cells within a total 3-week culture period using only one stimulation of antigen.

Infections after allogeneic hematopoietic stem cell transplantation with a nonmyeloablative conditioning regimen

Hematopoietic cell transplantation (HCT) following nonmyeloablative conditioning (NMSCT) may be associated with a reduced risk of infection compared to standard allogeneic HCT. We retrospectively analyzed incidence and risk factors of infection in 62 patients undergoing NMSCT with low-dose TBI +/- fludarabine and postgrafting CsA and MMF. The proportion of patients with any infection was 77%, but the majority of infectious events occurred beyond day 30. Donor other than sibling, older age, early disease and male gender were significant risk factors. The incidence of bacteremia was 55% at 1 year and the number of bacteremic episodes was 0.9 per patient (0.08 before day 30). The risk of bacteremia increased with older age and the use of a donor other than an HLA-identical sibling, but not with neutropenia. The incidence of infections other than bacteremia correlated with the use of corticosteroids. The risk of CMV infection increased with high-risk CMV serology, and risk of CMV disease with high-risk CMV serology, older age, first transplantation and a diagnosis of lymphoma. In conclusion, after NMSCT, infections are not frequent in the first 30 days post transplant but careful long-term monitoring is necessary thereafter.

A pilot study of nonmyeloablative allogeneic hematopoietic stem cell transplant for advanced systemic mastocytosis

Systemic mastocytosis (SM) is a disease characterized by tissue infiltration of neoplastic mast cells originating from hematopoietic stem cells. Patients with advanced SM have a poor prognosis, and there is no mast cell ablative therapy available for most patients who carry an activating point mutation in the c-kit gene. We report results of a prospective study evaluating the safety, engraftment, and possibility of inducing a graft-versus-mast cell (GvMC) effect after allogeneic nonmyeloablative hematopoietic cell transplantation (HCT) from an HLA-identical sibling. Three patients with advanced SM were transplanted. All achieved complete donor T cell chimerism followed by clinical evidence for GvMC effect. However, all patients experienced disease progression with the longest response duration of 39 months. The GvMC effect can be observed after nonmyeloablative HCT with limited efficacy. Effective cytoreductive therapy prior to HCT may be required for long-term disease control and cure.

Cytomegalovirus (CMV) infections in children undergoing hematopoetic stem cell transplantation

Cytomegalovirus (CMV) is one of the major causes of morbidity and mortality after hematopoetic stem cell transplantations (HSCT). The purpose of the study was to analyze risk factors of CMV disease in children undergoing HSCT. A total of 110 children who undergone hematopoetic stem cells transplantation were analyzed. In 16 patients (14.5%) CMV antigenemia in white blood cells was diagnosed. Most patients with CMV infection had undergone alloHSCT; one patient had undergone autologous transplantation. Second CMV reactivation in 4 of 16 patients was observed. Acute GvHD occurred in 11/15 patients. Early onset of CMV infection in 13/16 patients and late onset in 3/16 patients were diagnosed. CMV serological status of the donor and recipient before transplantation in children with CMV antigenemia was analyzed. The risk factors of CMV infection in analyzed group of children were type of transplant, recipient seropositivity before transplantation, and presence and intensity of GvHD. In most cases reactivation of CMV infection was diagnosed. CMV infection can also occur in the late post-transplantation period. CMV reactivation can occur in patients after autologous HSCT.

Low incidence of infectious complications after nonmyeloablative compared with myeloablative allogeneic stem cell transplantation

Allogeneic stem cell transplantation (SCT) using a myeloablative (MA) conditioning regimen is limited to relatively young patients because of increased transplant-related mortality in elderly patients. Nonmyeloablative (NMA) conditioning regimens have been developed aiming to reduce transplant mortality. In this study, we set out to evaluate the post-transplant occurrence of infectious complications in recipients of grafts from human leukocyte antigen (HLA)-identical sibling donors treated with either NMA or MA conditioning regimens. Data of 78 consecutively treated patients were analyzed. An NMA conditioning regimen was used in 40 patients and an MA regimen in 38 patients. A significantly lower rate of episodes of febrile neutropenia (0% vs. 34%, P<0.01) and post-transplant Epstein-Barr virus reactivations (0% vs. 18%, P<0.05) was found in SCT recipients treated with an NMA conditioning regimen compared with an MA conditioning regimen. Furthermore, fewer invasive fungal infections (2% vs. 12%, not significant) were diagnosed in the NMA group. The incidence of cytomegalovirus (CMV) reactivations and bacterial infections was low in both groups (CMV reactivations: 13% in both groups; bacterial infections: 10% in the NMA group vs. 8% in the MA group), while CMV disease developed in only 1 patient. Overall, compared to our MA regimen, we found a very low rate of infectious complications after NMA SCT.

Persisting posttransplantation cytomegalovirus antigenemia correlates with poor lymphocyte proliferation to cytomegalovirus antigen and predicts for increased late relapse and treatment failure

Numerous clinical studies link cytomegalovirus (CMV) infection with incomplete posttransplantation T-cell recovery. We hypothesized that the inability of transplant recipients to handle CMV reactivation might correlate with a defective graft-versus-leukemia response and increased posttransplantation morbidity. Between May 1995 and August 2001, 82 patients who were CMV seropositive and survived the first 100 days after transplantation were identified for a day 100 landmark analysis of the effect of CMV reactivation patterns on eventual transplantation outcome. All patients underwent a myeloablative HLA-identical sibling donor T cell-depleted stem cell transplantation with scheduled donor T-cell add-back on day 45. Median follow-up was 1032 days. Forty-two patients who had either no reactivation or only 1 positive test with quick clearance were designated as a CMV immune competent group. Forty patients designated as CMV immune deficient (ID) had at least 2 positive tests. Apart from younger age (33 versus 38 years; P =.05) in the ID group, the 2 groups were balanced for clinical characteristics. In multivariate analysis, ID patients had a significantly higher incidence of leukemia relapse (58% versus 21%; P =.03) and worse disease-free survival (31% versus 66%; P =.04). There was no significant difference in week 1 to 14 posttransplantation lymphocyte counts between the 2 groups. In 67 patients tested 3 to 6 months after transplantation, a proliferative response to CMV antigen (stimulation index > or =2) occurred in 27 of 36 immune competent patients compared with 15 of 31 ID patients (P =.006). These results show that recurrent CMV reactivation in the first 100 days after transplantation predicts for reduced disease-free survival and increased leukemic relapse beyond 100 days and correlates with inferior proliferative responses to CMV. The higher relapse rate may reflect poor immune reconstitution in ID patients or an adverse effect of prolonged antiviral treatment.

The risk of cytomegalovirus infection in non-myeloablative peripheral stem cell transplantation compared with conventional bone marrow transplantation

Non-myeloablative allogeneic peripheral stem cell transplantation (NST) is a novel therapeutic strategy for patients with hematologic malignancies. Whether non-myeloablative transplants are associated with increased risk of cytomegalovirus (CMV) infections is unknown. To clarify this issue, we compared the outcome of CMV infection following 24 allogeneic non-myeloablative peripheral blood stem cell transplants and 40 conventional bone marrow transplants (CBT). The NST regimen consisted (mg/kg). Twelve patients (50%) in the NST group and 17 (43%) in the CBT group developed positive antigenemia before day 100 (p=0.60). The time to the first appearance of positive antigenemia was not different between these two groups (p=0.40), and two groups showed similar initial and maximal antigenemia values (p=0.56 and p=0.68, respectively). Only one case of CMV colitis developed in the CBT group whereas CMV disease did not develop in the NST group. Although statistically insignificant, the treatment response against CMV antigenemia using ganciclovir was in favor of NST group. In conclusion, there was no difference in the risk of CMV infection between NST group and CBT group. Further prospective and controlled study is needed to clarify the impact of non-myeloablative procedure on the outcome of CMV infection.

High-dose acyclovir and pre-emptive ganciclovir in prevention of cytomegalovirus disease in pediatric patients following peripheral blood stem cell transplantation

Cytomegalovirus (CMV) disease remains an important cause of morbidity and mortality in patients undergoing hematopoietic stem cell transplantation (HSCT). We evaluated high-dose acyclovir (HDACV) and pre-emptive ganciclovir to prevent CMV disease in 76 children who underwent peripheral blood stem cell transplantation (PBSCT) and were at risk for CMV reactivation and disease (both recipient and donor seropositive) from May 1998 to April 2003. All received HDACV from day -9 to 6 months post transplant in conjunction with weekly CMV pp65 antigenemia monitoring. The incidence of antigenemia in this cohort was 19.7%, at a median of 22 days post-PBSCT. The frequencies were 26.4 and 4.4% in allogeneic and autologous groups, respectively (P=0.03). Patients with nonmalignant disease had higher CMV antigenemia than those with malignant disease (30.8 vs 8.1%, P=0.02). Age at PBSCT, sex, graft-versus-host disease (GVHD) prophylaxis regimen and presence of acute GVHD did not affect the risk of CMV antigenemia. None of the patients who had positive pp65 antigenemia developed CMV disease during the study period. We conclude that pp65 antigenemia-guided HDACV and pre-emptive ganciclovir may prevent CMV disease in children undergoing PBSCT.

Infectious complications following nonmyeloablative allogeneic hematopoietic stem cell transplantation

Nonmyeloablative hematopoietic stem cell transplantation (NST) has been explored in hematological malignancies and solid tumors in an attempt to minimize treatment-related toxicity. Whether this approach is associated with reduced risk of infectious complications is unclear. The aim of the current study was to evaluate the infectious complications in a series of 32 consecutive adult patients who received NST at our institution. Peripheral blood stem cell grafts (n=30) or marrow grafts (n=2) were infused from human leukocyte antibody (HLA)-matched sibling (n=30), partially matched related (n=1), or unrelated (n=1) donors. Neutropenia developed in two-thirds of patients and lasted 16 days. Acute graft-versus-host disease (GVHD) grade II to IV was observed in 25% of patients, whereas 35% of patients had signs of extensive chronic GVHD. Twenty-two patients (69%) had at least one significant infectious episode. Bacteremia occurred in 19% of patients (n=5 gram-positive, n=1 gram-negative microorganisms). Cytomegalovirus (CMV) infection was observed in 10 out of 28 (36%) evaluable patients; 4 of these had recurrent or persistent CMV antigenemia requiring a second-line treatment, but eventually the viremia cleared. No patients experienced CMV disease. Fungal infections were documented in five (16%) patients, comprising invasive fungal infections in two cases and mucosal fungal infections in three. Four patients died of transplant-related causes, and three of these died before day +100. Infection was considered the primary cause of death in one patient (pulmonary aspergillosis) and contributed to death in another two. The actuarial probability of nonrelapse mortality at 100 days was 10% (95% confidence interval, 3-26%). Our preliminary results suggest that NST is associated to a low incidence of bacteremia or fungal and viral infections. Whether these findings would translate into an improved overall survival needs to be confirmed in larger prospective studies.

Low incidence of CMV viremia and disease after allogeneic peripheral blood stem cell transplantation. Role of pretransplant ganciclovir and post-transplant acyclovir

To establish the incidence of CMV viremia after allogeneic blood stem cell transplantation, we studied 51 consecutive allogeneic peripheral blood stem cell (PBSC) transplant recipients. A total of 12 recipients were at moderate risk for CMV disease and 39 were at high risk. Conditioning regimens varied, but GvHD prophylaxis consisted of tacrolimus and mini-methotrexate in all patients. All patients received prophylactic ganciclovir from admission until day -2 and prophylactic acyclovir from day -1 until day 180 after transplantation. CMV viremia was treated with ganciclovir. Using a PCR-based technique, the cumulative incidence of CMV viremia was 31+/-14% by day 100 and 35+/-14% by day 150. Donor type, CMV risk group, underlying disorder, conditioning regimen, GvHD, and steroid use were not associated with the risk for CMV viremia. No cases of CMV disease occurred. We hypothesize that the low rate of CMV viremia and the absence of CMV disease in this cohort of PBSCT transplant recipients, which contrasts with other reports, may be related to the prophylactic use of high-dose acyclovir and possibly to pretransplant use of ganciclovir.