Effect of cytomegalovirus infection on 1-year mortality rates among recipients of allogeneic bone marrow transplants

Cytomegalovirus (CMV) infection and risk of mortality in allogeneic hematopoietic stem cell transplantation (Allo-HSCT): A systematic review, meta-analysis, and meta-regression analysis

Controversy surrounds the potential association between cytomegalovirus (CMV) infection and increased risk of mortality after allogeneic hematopoietic stem cell transplantation (Allo-HSCT). A systematic literature search was conducted using the PubMed, EMBASE, and Web of Science databases, assessing the association between CMV infection, as documented by the pp65 antigenemia assay or by polymerase chain reaction (PCR) using blood specimens, and overall mortality (OM) and nonrelapse mortality (NRM) in the allo-HSCT setting. Pooled effects were estimated using the generic inverse variance random effects model. Heterogeneity was evaluated by Cochrane's Q test and I² statistics. The source of heterogeneity was investigated by meta-regression and subgroup analyses. Twenty-six of 1367 studies fulfilled eligibility criteria. CMV infection identified by PCR monitoring was significantly associated with an increased risk of OM and NRM (hazard ratio 1.47, 95% confidence interval [1.20-1.81], P ≤ .001; hazard ratio 1.68, 95% confidence interval [1.14-2.49], P = .05, respectively). In this setting, the use of preemptive antiviral therapy (PET) resulted in a twofold increased risk of OM and NRM. The estimated effect sizes were associated with allo-HSCT modalities. Although our analyses point to an association between CMV infection and an increased risk of OM and NRM in allo-HSCT recipients, the high heterogeneity across studies prevented drawing of robust conclusions on this matter.

CMV in Hematopoietic Stem Cell Transplantation

Due to its negative impact on the outcome of stem cell transplant (SCT) and solid organ transplant patients (SOT) CMV has been called “the troll of transplantation”. One of the greatest advances in the management of SCT has been the introduction of the preemptive strategy. Since its introduction, the incidence of the viremia, as expected, remains unchanged but there has been a marked decline in the incidence of early CMV disease. However, in spite of the advances in prevention of CMV disease, CMV is still today an important cause of morbidity and mortality. Late CMV disease is still occurring in a significant proportion of patients and the so-called indirect effects of CMV are causing significant morbidity and mortality. Fortunately there have been several advances in the development of new antivirals, adoptive immunotherapy and DNA-CMV vaccines that might transform the management of CMV in the near future.

Cytomegalovirus Infection in Pediatric Hematopoietic Stem Cell Transplantation: Risk Factors for Primary Infection and Cases of Recurrent and Late Infection at a Single Center

Cytomegalovirus (CMV) infection is a significant source of morbidity and mortality in allogeneic stem cell transplantation (SCT). We identified a cohort of 91 pediatric SCT patients at risk (defined as either donor and/or recipient seropositivity) for CMV infection at our institution. We retrospectively categorized at-risk SCT recipients as those who (1) were at risk of CMV infection in the post-SCT period, (2) had documented CMV infection before SCT, (3) experienced recurrence of post-SCT CMV viremia, or (4) experienced late post-SCT CMV viremia; categories were not mutually exclusive. We analyzed the impact of SCT-related factors on incidence of CMV infection and outcome, and we described the outcome of each of these cohorts. In univariate analysis, recipient CMV seropositivity, use of umbilical cord blood graft, and acute graft-versus-host disease (GVHD) predicted post-SCT CMV viremia, and the effects of acute GVHD (odds ratio, 4.018; 95% confidence interval, 1.032 to 15.643) and CMV seropositivity (odds ratio, 16.525; 95% confidence interval, 2.041 to 133.803) were confirmed in multivariate analysis. Patients with recurrence of post-SCT CMV viremia had a 50% all-cause mortality rate, compared with 12% in all 91 patients. Patients with pre-SCT CMV infection had a high incidence of post-SCT CMV infection but could successfully undergo SCT with antiviral prophylaxis and pre-emptive CMV treatment. All patients with late CMV infection had prior GVHD. Theses findings identify risk factors for post-SCT CMV infection and provide novel descriptions of childhood SCT recipients with pre-SCT, recurrent, and late CMV infection, which may contribute to risk stratification strategies for CMV at-risk patients in pediatric allogeneic SCT.

Cytomegalovirus load at treatment initiation is predictive of time to resolution of viremia and duration of therapy in hematopoietic cell transplant recipients

BACKGROUND

Preemptive antiviral therapy relies on viral load measurements and is the mainstay of cytomegalovirus (CMV) prevention in hematopoietic cell transplant (HCT) recipients. However, optimal CMV levels for the initiation of preemptive therapy have not been defined.

OBJECTIVES

The objectives of our work were to evaluate the relationship between plasma CMV DNA levels at initiation of preemptive therapy with time to resolution of viremia and duration of treatment.

STUDY DESIGN

Retrospective analysis of HCT recipients undergoing serial CMV PCR testing between June 2011 and June 2014 was performed.

RESULTS

221 HCT recipients underwent preemptive therapy for 305 episodes of CMV viremia. Median time to resolution was shorter when treatment was initiated at lower CMV levels (15 days at 135-440 international units (IU)/mL, 18 days at 441-1000 IU/mL, and 21 days at >1000 IU/mL, P<.001). Prolonged viremia lasting >30 days occurred less frequently when treatment was initiated at 135-440 IU/mL compared to 441-1000 IU/mL and >1000 IU/mL (1%, 15%, 24%, P<.001). Median treatment duration was also shorter in the lower viral load groups (28, 34, 37 days, P<.001).

CONCLUSION

Initiation of preemptive therapy at low CMV levels was associated with shorter episodes of viremia and courses of antiviral therapy. These data support the utility of initiating preemptive CMV therapy at viral loads as low as 135 IU/mL in HCT recipients.

Intensive strategy to prevent CMV disease in seropositive umbilical cord blood transplant recipients

Seropositive umbilical cord blood transplant (UCBT) recipients are at increased risk for CMV complications. To reduce CMV complications, we adopted an intensive strategy that consisted of ganciclovir administered before transplantation (5 mg/kg intravenously daily from day -8 to day -2), high-dose acyclovir (2 g, 3 times daily) after transplantation, and biweekly monitoring with a serum CMV PCR for preemptive therapy. Hazard rates and cumulative incidence of CMV complications along with days treated were compared in high-risk CMV-seropositive UCBT recipients who received the intensive strategy and a historical cohort who received a standard strategy. Of 72 seropositive patients, 29 (40%) received standard prophylaxis and 43 (60%) the new intensive approach. The hazard rate (HR) for CMV reactivation was lower for patients receiving the intensive strategy (HR 0.27, 95% confidence interval 0.15-0.48; P < .001) and led to fewer cases of CMV disease by 1 year (HR 0.11, 95% confidence interval 0.02-0.53; P = .006). In patients who reactivated, the intensive strategy also led to fewer days on CMV-specific antiviral therapy (median 42% [interquartile range 21-63] vs 70% [interquartile range 54-83], P < .001). Use of an intensive CMV prevention strategy in high-risk CMVseropositive UCBT recipients results in a significant decrease in CMV reactivation and disease.

Surveillance of cytomegalovirus (CMV) DNAemia in pediatric allogeneic stem cell transplantation: incidence and outcome of CMV infection and disease

Cytomegalovirus (CMV) remains a serious problem after hematopoietic stem cell transplantation (HSCT). To investigate the incidence of CMV infection and outcome we retrospectively analyzed 70 consecutive pediatric allogeneic HSCTs monitored by CMV polymerase chain reaction (PCR), with at least 1-year follow-up or until death. All patients at risk for CMV infection (CMV-seropositive patients and CMV-seronegative recipients transplanted from CMV-seropositive donors) received hyperimmune anti-CMV globulins whereas in the group of HSCT patients with both donor and recipient CMV negativity, polyvalent immunoglobulins were given, both at a dose of 400 mg/kg. All patients received acyclovir at prophylactic doses for at least 6 months. Patients were monitored twice a week by CMV PCR. Patients with 2 positive results for CMV DNAemia received ganciclovir for 14 days and continued until 2 consecutive negative results were obtained. The incidence of CMV DNAemia was 12.8% (9/70) in the whole group, with significant higher risk for patients with CMV-seropositive recipient status, 8 out of 22 (36%), vs. patients with seronegative status, 1 out of 48 (2%) (P=0.0002). Three out of 9 patients with DNAemia developed CMV disease despite adequate preemptive treatment. The transplant-related mortality was higher in the CMV-seropositive recipient group (P=0.05). Age, use of hyperimmune anti-CMV globulins at a high dose, and the low incidence of graft-versus-host disease might be contributing factors to this low incidence.

Donor CMV serologic status and outcome of CMV-seropositive recipients after unrelated donor stem cell transplantation: an EBMT megafile analysis

Cytomegalovirus (CMV) has been a major cause of morbidity and mortality after allogeneic stem cell transplantation (SCT). The importance of the recipient's serologic status is paramount. However, the importance of the donor's serologic status in CMV-seropositive recipients is controversial. We analyzed the influence of the donor's CMV status in a large cohort of patients. A total of 7018 patients seropositive for CMV reported to the European Group for Blood and Marrow Transplantation (EBMT) were included; 5910 patients had undergone HLA-identical sibling SCT and 1108 patients had undergone unrelated donor SCT. Univariate and multivariate proportional hazards models were constructed for survival, event-free survival, transplant-related mortality, and relapse incidence. Patients receiving grafts from CMV-seropositive HLA-identical sibling donors had the same survival as patients grafted from seronegative donors (hazard ratio [HR], 1.04; P =.37; 95% confidence interval [CI], 0.95-1.14). However, unrelated donor stem cell (SC) transplant recipients receiving grafts from CMV-seropositive donors had an improved 5-year survival (35% versus 27%; HR = 0.8; P =.006), an improved event-free survival (30% versus 22%; HR = 0.8; P =.01), and a reduced transplant-related mortality (49% versus 62%; HR = 0.7; P <.001). There was no influence on the relapse incidence. The effects of donor CMV status remained in multivariate analyses. The effect of donor status was different among different disease categories. In patients with chronic myelogenous leukemia (CML), T-cell depletion abrogated the beneficial effect of donor status, suggesting that the effect is mediated through transfer of donor immunity. Our data suggest that donor CMV status influences outcome of unrelated SCT. For a CMV-seropositive patient, a seropositive donor might be preferable.

Prevention of cytomegalovirus disease in recipients of allogeneic stem cell transplants

The main risk factors for cytomegalovirus (CMV) disease in recipients of allogeneic stem cell transplants (SCT) are recipient CMV seropositivity and acute graft-versus-host disease. Currently, two antiviral strategies, prophylactic or preemptive antiviral treatment, are used for prevention of CMV disease. Preemptive treatment is most favorable when short-term (14-day) treatment is applied. Several methods are available for monitoring of CMV reactivation. PCR-based CMV DNA detection assays are the most sensitive methods; however, the clinical benefit of this high sensitivity is unclear. Even more, there is lack of clarity whether PCR tests can better be performed with plasma, whole blood, or peripheral blood leukocyte samples. Recovery of a CMV-specific CD8(+) cytotoxic-T-lymphocyte (CTL) response is necessary for preventing CMV reactivation and disease. Reconstitution of absolute CMV-specific CTL counts to values above 10 x 10(6) to 20 x 10(6) CTLs/liter is associated with protection from CMV disease. In the near future, preemptive therapy might be withheld in patients with CMV reactivation who are shown to have adequate CMV-specific cytotoxic T-cell levels. Antiviral therapy with (val)acyclovir has been studied only as prophylactic treatment for prevention of CMV infection. High-dose oral valacyclovir is more effective than acyclovir when used in addition to preemptive treatment of CMV reactivation with ganciclovir or foscarnet. Three antiviral drugs have been tested for preemptive therapy of CMV reactivation and/or treatment of CMV disease. Although intravenous ganciclovir is considered the drug of choice, foscarnet has similar efficacy and less toxicity, especially hematologic toxicity. Cidofovir has not been tested extensively, but so far the results are disappointing. Oral valganciclovir for preemptive treatment of SCT recipients is currently being studied. In addition to antiviral therapy, adoptive immunotherapy with CMV-specific cytotoxic T cells as prophylactic or preemptive therapy is a very elegant strategy; however, generation of these cells is expensive and time-consuming, and therefore the therapy is not available at every transplantation center. Magnetic selection of CMV-specific CD8(+) T cells from peripheral blood by using HLA class I-peptide tetramers may be very promising, making this strategy more accessible.

Influence of antithymocyte globulin dose on outcome in cytomegalovirus-seropositive recipients of partially T cell-depleted stem cell grafts from matched-unrelated donors

The adverse impact of positive-recipient Cytomegalovirus (CMV) serostatus on the outcome of matched-unrelated donor (MUD) grafts has been stressed. We evaluated whether CMV-seropositive MUD recipients transplanted after 1999 still showed inferior outcome compared with CMV-seronegative recipients. Two important changes in transplantation procedure were introduced in 1999: (1) reduction of antithymocyte globulin dose, (2) introduction of sequence-based typing of HLA-DRB1. Thirty-six patients received partial T cell-depleted grafts before 1999, and 44 after 1999. CMV-seropositive patients transplanted before 1999 showed a highly significant inferior outcome compared with seronegative recipients. In contrast, no difference in outcome was observed between the two groups of patients transplanted after 1999.

Pre-emptive treatment of CMV DNAemia in paediatric stem cell transplantation: the impact of recipient and donor CMV serostatus on the incidence of CMV disease and CMV-related mortality

Cytomegalovirus (CMV) DNAemia was detected by PCR in 30/125 (24%) consecutive paediatric patients undergoing allogeneic stem cell transplantation. All patients with CMV DNAemia received pre-emptive ganciclovir until two consecutive negative results were obtained. CMV-IgG-positive patients (R+) had a significantly increased risk of DNAemia as compared to CMV-IgG-negative (R-) patients (62% vs 8%) P<0.0001. The incidence of DNAemia was 71% (10/14) in R+ transplanted from seronegative donors (D-) compared to 54% (13/32) in those transplanted from seropositive donors (D+). Of 30 (40%) children with DNAemia, 12 developed CMV disease despite pre-emptive treatment. The overall incidence of disease was 0% (0/59) for R-/D-, 9% (3/23) for R+/D+, 7% (2/29) for R-/D+ and 57% (8/14) for R+/D-. In patients with DNAemia, 4/20 (20%) patients with D+ and 8/10 (80%) with D- became symptomatic. In the multivariate analysis of both groups, patients at risk (R+ and/or D+) and patients with DNAemia, a negative donor serostatus was the only factor associated with a significantly increased incidence of disease. Seven of 9 patients with lethal CMV disease had received CMV-IgG-negative grafts. The data suggest that in CMV seropositive recipients donor CMV seropositivity is associated with a reduced incidence of CMV disease and a favourable outcome following pre-emptive treatment.

Human cytomegalovirus induces a direct inhibitory effect on antigen presentation by monocyte-derived immature dendritic cells

The hypothesis that productive infection of monocyte-derived immature dendritic cells (DCs) by the human cytomegalovirus (HCMV) is associated with decreased immunostimulatory capacity was tested in this study. DCs were infected with 60-80% efficiency by HCMV strain TB40/E. Infected versus uninfected cells were analysed by fluorescence-activated cell sorting and by immunocytochemistry for surface expression of major histocompatibility complex (MHC) and co-stimulatory molecules as well as cytokine secretion during the 3 d after infection. The immunostimulatory capacity of these cells was measured by mixed leucocyte reaction. In spite of the fact that HCMV infection of DCs induced an increased release of tumour necrosis factor-alpha (TNF-alpha) and a decreased interleukin 10 (IL-10) production, expression of MHC class I and II, as well as CD40 and CD80 molecules, were downregulated on infected DCs. The mixed leucocyte reaction showed significantly reduced immunostimulatory capacity of infected DC cultures. Simultaneous detection of MHC antigens and virus antigens by double immunofluorescence revealed that downregulation occurred only on infected cells, but not on uninfected bystander cells. These findings demonstrate on a single cell level, together with the marked downregulation of MHC and co-stimulatory molecules in the presence of high TNF-alpha and low IL-10 levels, a direct inhibitory effect of HCMV on antigen presentation by immature DCs independent of soluble mediators.

Influence of cytomegalovirus seropositivity on outcome after T cell-depleted bone marrow transplantation: contrasting results between recipients of grafts from related and unrelated donors

We analyzed the effect of cytomegalovirus (CMV) serostatus on overall survival (OS) and transplant-related mortality (TRM) in 253 consecutively treated patients receiving partially T cell-depleted (TCD) bone marrow from either matched related donors (MRDs; n=205) or matched unrelated donors (MUDs; n=48). Short-course, low-dose preemptive therapy with ganciclovir was provided as soon as a positive antigenemia assay result was obtained. Ganciclovir prophylaxis, which was identical to preemptive therapy, was given to patients with acute graft-versus-host disease (GVHD) grades II-IV who had to be treated with high-dose steroids. In recipients of transplants from MRDs, inferior OS and increased TRM were predicted by extensive chronic GVHD (P<.001). High-risk disease status and older age adversely influenced OS (P=.001) and TRM (P=.002), respectively; older age resulted in a trend toward decreased OS (P=.066). In recipients of transplants from MUDs, OS and TRM were strongly influenced by patient CMV seropositivity (P=.013 and.007, respectively). In conclusion, CMV seropositivity is not an adverse risk factor for OS and TRM in recipients of transplants from MRDs. However, in recipients of transplants from MUDs, patient CMV seropositivity strongly affects OS and TRM.

Extended antigenemia surveillance and late cytomegalovirus infection after allogeneic BMT

Late CMV disease remains a major concern in allogeneic BMT recipients. Few surveillance data are available on the occurrence of CMV infection and recurrences after day +100. We evaluated the occurrence of antigenemia (AG) recurrences until day +365 in 76 patients who received pre-emptive ganciclovir (GCV) therapy prompted by AG > or = 2 positive cells. Sixty-two episodes of AG recurrences were detected in 33 of the 52 patients who had positive AG. Survival analysis showed a 45.4% probability of AG recurrence on day +100, 64.8% on day +180 and 71.2% on day +365. The median time for AG recurrences was 113 (35 to 343) days. Thirty-five of the 62 episodes (56.4%) occurred after day +100. More than 70% of the patients responded to a 2-week course of GCV and no CMV disease was observed shortly after discontinuation of GCV. The Cox proportional model showed a significant effect of AG recurrences on patient's follow-up only when the patient developed chronic GVHD (P = 0.012). Extended surveillance favored early introduction of GCV and late CMV pneumonia occurred in only one of the 76 patients (1.3%). AG recurrences are frequent after day +100 and extended surveillance until day +365 is recommended for patients who develop chronic GvHD.

Valacyclovir for the prevention of cytomegalovirus infection after allogeneic stem cell transplantation: a single institution retrospective cohort analysis

A retrospective single center study was performed to evaluate the safety and efficacy of valacyclovir for prevention of cytomegalovirus (CMV) infection (reactivation) after allogeneic stem cell transplantation (SCT). We compared a group of 31 patients at risk for CMV reactivation (donor, recipient or both seropositive for CMV) who received valacyclovir at an oral dose of 1 g three times a day for CMV prophylaxis with a matched cohort of 31 patients who did not receive the drug or any other form of CMV prophylaxis. Valacyclovir was used as primary prophylaxis in 12 patients and as secondary prophylaxis (after a prior CMV reactivation was effectively treated with either ganciclovir or foscarnet and without CMV antigenemia at the start of valacyclovir) in the remaining 19 patients. The two treatment groups were well matched for the donor-recipient CMV serological status and other pre-transplant characteristics. CMV reactivation was detected by blood antigenemia testing using a commercially available immunofluorescence assay for CMV lower matrix protein pp65 in circulating leukocytes. For primary prophylaxis, 3/12 patients who received valacyclovir reactivated CMV compared to 24/31 patients in the control group (P < 0.001). For secondary prophylaxis, 5/19 valacyclovir patients reactivated compared to 16/24 control patients (P < 0.05). Valacyclovir was well tolerated except for infrequent and mild gastrointestinal side-effects. There was no difference in the incidence of CMV disease in the two groups. Prophylaxis with valacyclovir appears to be safe and efficacious in preventing both primary and secondary CMV reactivation in at-risk patients after allogeneic SCT. Larger prospective randomized studies will be required to confirm these observations.

Infection in the neutropenic and stem cell transplant patient

The spectrum of infectious complications in neutropenic patients after stem cell or bone marrow transplant is not very different from that seen in other neutropenic patients, with the possible exception of fungal infections. The prevention and therapy of these infections remain a major challenge. The management of neutropenic patients after stem cell or bone marrow transplant has markedly benefited from the development of new antiviral agents and the use of granulocyte/macrophage colony stimulating factors.