Cytomegalovirus infections in allogeneic stem cell recipients after reduced-intensity or myeloablative conditioning assessed by quantitative PCR and pp65-antigenemia

Predictors of cytomegalovirus reactivation after allogeneic hematopoietic cell transplantation: Insights from a real-world experience

BACKGROUND

We aimed to investigate factors associated with cytomegalovirus (CMV) viremia and CMV disease and its impact on post-transplant outcomes including overall survival (OS) following allogeneic hematopoietic stem cell transplantation (Allo-SCT).

METHODS

We conducted a single-center retrospective study including 452 Allo-SCT recipients (matched unrelated donor, MUD 61%; haploidentical, haplo 39%) from 2016 to 2021. Data were analyzed using SPSS v28. Descriptive (chi-square and t-test), Kaplan-Meier and regression analyses were conducted.

RESULTS

The median age was 57 years. Sixty-one percent were males and 84.3% were Caucasians. CMV serostatus was positive in 59.1% of recipients. The median follow-up was 24.4 months. CMV viremia and CMV disease were observed in 181 (40%) and 32 (7%) patients, respectively. Among CMV seropositive recipients, 65% developed CMV viremia and 11% were noted to have CMV disease compared to 4% and 1% in seronegative recipients, respectively (p < 0.001). Patients with CMV disease had significantly lower OS than those without CMV disease (median 14.1 months vs. not reached, p = 0.024); however, OS was not associated with CMV viremia (median not reached in both groups, p = 0.640). Letermovir prophylaxis was used in 66% (n = 176/267) of CMV seropositive recipients, but no impact was observed on the incidence of CMV viremia or CMV disease and OS.

CONCLUSIONS

CMV disease leads to significantly inferior survival after an allogeneic hematopoietic cell transplantation. Recipient CMV seropositive status was associated with the risk of CMV viremia and CMV disease, and this was not abrogated with the use of Letermovir prophylaxis.

Factors Associated With Cytomegalovirus Infection in Pediatric Allogeneic Hematopoietic Stem Cell Transplant Recipients: A Prospective Single-Center Study

OBJECTIVES

The human cytomegalovirus is a notorious pathogen in the pediatric transplant setting. Although studies on factors in complicity with cytomegalovirus infection abound, the roles of age, sex, allogeneic hematopoietic stem cell transplant modality, and type of underlying disease (malignant vs nonmalignant) with regard to cytomegalovirus infection and viral load in children are seldom explored. Our aim was to examine the significance of these factors on cytomegalovirus infection and viral load in Serbian pediatric recipients of allogeneic hematopoietic stem cell transplant.

MATERIALS AND METHODS

Thirty-two pediatric recipients of allogeneic hematopoietic stem cell transplant to treat various malignant and nonmalignant disorders were prospectively monitored for cytomegalovirus infection. The real-time quantitative polymerase chain reaction was used for pathogen detection and quantitation. Demographic and virologic parameters were statistically analyzed with SPSS statistics software (version 20).

RESULTS

Cytomegalovirus DNA was detected in 23 patients (71.9%). Infection occurred significantly more often (P = .015) in patients with haploidentical donors. The opposite was noted for matched sibling grafts (P = .006). Viral load was higher in female patients (P = .041) and children with malignant diseases (P = .019).There was no significant relationship between viral infection or load and medical complications.

CONCLUSIONS

Transplant recipients presented with a high incidence of cytomegalovirus viremia. The modality of allogeneic hematopoietic stem cell transplant was associated with the frequency of cytomegalovirus infection. Age, sex, type of underlying disease, and medically relevant events were not conducive to occurrences of viremia. Notably, we observed substantial viral loads in female patients and patients with neoplastic diseases. Studies comprising larger populations are needed to better understand these results.

Clinical impact of multiple DNA virus infections in nondepleted haploidentical and unrelated allogeneic hematopoietic stem cell transplantation

Few studies have compared the clinical impact of multiple DNA-virus infections in haploidentical hematopoietic stem cell transplantation (haplo-HSCT) with posttransplant cyclophosphamide (PTCy) and unrelated donor allogeneic hematopoietic stem cell transplantation (UD-HSCT) with thymoglobulin, so we retrospectively analyzed viral infections in the first 6 mo posttransplant in these scenarios. Fifty-nine patients underwent to haplo-HSCT, and 68 to UD-HSCT. The most frequent infection was cytomegalovirus (CMV) (76.3% in haplo-HSCT and 69.1% in UD-HSCT) (P = .878) and in the group of patients with CMV reactivation, maximal CMV viral load over 2500 UI/ml correlated with worse overall survival-hazard ratio (HR) 1.93 (95% confidence interval [CI] 1.04-3.59) P = .03. The cumulative incidence of multiple DNA virus within 180 d of posttransplant was 78.7% for one virus and 28.4% for two or more viruses with no difference regarding the type of transplant. Viral infections, age, and acute graft versus host disease (GVHD) grades II-IV were risk factors for worse overall survival in multivariate analyses: one virus HR 2.53 (95% CI 1.03-6.17) P = .04, two or more viruses HR 3.51 (95% CI 1.37-9) P < .01, age HR 1.03 (95% CI 1.02-1.05) P < .01 and acute GVHD II-IV HR 1.97 (95% CI 1.13-3.43) P = .01. Also, age over 50 y HR 4.25 (95% CI 2.01-8.97) P < .001, second CMV reactivation or having both CMV and BK polyomavirus (BKV) HR 2.65 (95% CI 1.26-5.56) P = .01 and acute GVHD grades II-IV HR 2.23 (95% CI 1.12-4.43) P = .022 were risk factors for nonrelapse mortality in the multivariate analyses. In conclusion, multiple DNA-virus infections are frequent in both haplo-HSCT and UD-HSCT and a risk factor for worse overall survival.

The association of conditioning regimen with cytomegalovirus reactivation after allogeneic hematopoietic stem cell transplantation

Background and Objectives:

Infections is yet one of the life-threatening complications of the hematopoietic stem cell transplantation (HSCT). The myeloablative and immunosuppressive conditioning regimens, which are administered before HSCT, dampen the defense capacity of the recipients’ immune systems. In this condition, opportunistic infections, especially viral infections such as cytomegalovirus (CMV) can be reactivated and cause morbidity and mortality in HSCT patients. Here, we aimed to find out any possible relationship between types of conditioning regimen and CMV reactivation in allogeneic HSCT patients.

Materials and Methods:

We retrospectively analyzed the data of 145 CMV-seropositive cases out of total 201 allo-HSCT patients, including age, gender, underlying disease, conditioning regimen, prophylaxis regimen and occurrence of acute graft-versus-host disease (aGVHD) to evaluate their roles in CMV reactivation.

Results:

Our result showed that conditioning regimen containing Busulfan and Fludarabine (P=0.003) or Cyclophospha-mide (P=0.02) significantly decrease the early CMV reactivation. Patients who developed aGVHD (P=0.003) and those who received anti-thymocyte globulin (ATG) as prophylaxis regimen (P=0.002), had 1.84 and 2.63 times higher risks of CMV reactivation, respectively.

Conclusion:

Our findings suggest the conditioning regimen, aGVHD and ATG as influencing factors for early CMV reactivation post-HSCT which should be considered in the future studies.

Clinical features of cytomegalovirus retinitis after solid organ transplantation versus hematopoietic stem cell transplantation

PURPOSE

To investigate and compare the clinical features of cytomegalovirus (CMV) retinitis after solid organ transplantation (SOT) and hematopoietic stem cell transplantation (HSCT) and to determine the poor prognostic factors.

METHODS

Patients consulted to the ophthalmology department for CMV viremia after transplantation between March 2008 and February 2018 and followed for more than 6 months were analyzed. Medical records regarding demographic, serologic, and ocular characteristics were compared between the SOT and HSCT groups. Factors associated with poor visual outcomes were determined with logistic regression.

RESULTS

CMV retinitis developed in 11.3% of patients with CMV viremia following transplantation. In the SOT group (25 eyes/18 patients) and the HSCT group (33 eyes/21 patients), CMV retinitis occurred at 5.8 months and 3.7 months post-transplantation, respectively. Mortality was significantly higher in the HSCT group (52.4% vs. 5.6%, P < 0.001). During the mean 11.7 months of follow-up, visual acuity tended to be aggravated (P = 0.087) despite antiviral treatment, which was especially notable in the SOT group (P = 0.028). Six eyes (10.3%) underwent vitrectomy due to retinal detachment, most of which (5 eyes) were in the SOT group. Multivariate logistic regression analysis showed that the presence of concurrent CMV disease (OR = 14.11, P = 0.009) and foveal involvement (OR = 114.85, P = 0.001) were poor prognostic factors.

CONCLUSION

Clinical manifestations of CMV retinitis differed between the HSCT and SOT group. Concurrent CMV diseases and foveal involvement were associated with poor visual outcomes in CMV retinitis following transplantation.

Immune Reconstitution and Infection Patterns after Early Alemtuzumab and Reduced Intensity Transplantation for Nonmalignant Disorders in Pediatric Patients

Hematopoietic stem cell transplantation (HSCT) is a therapeutic option for many nonmalignant disorders (NMD) and is curative or prevents disease progression. Reduced-intensity conditioning (RIC) in HSCT for NMD may reduce regimen-related acute toxicities and late complications. Myeloablation is often replaced by immune suppression in RIC regimens to support donor engraftment. The pace of immune reconstitution after immune suppression by RIC regimens is influenced by agents used, donor source, and graft-versus-host disease prophylaxis/treatment. In a multicenter trial (NCT 00920972) of HSCT for NMD, a RIC regimen consisting of alemtuzumab, fludarabine, and melphalan was substituted for myeloablation. Alemtuzumab was administered early (days -21 to -19) to mitigate major lymphodepletion of the incoming graft and the risk of graft rejection. Immune reconstitution and infectious complications were prospectively monitored for 1-year post-HSCT. Seventy-one patients met inclusion criteria for this report and received marrow or peripheral blood stem cell transplants. Immune reconstitution and infections are reported for related donor (RD) and unrelated donor (URD) transplants at 3 time-points (100days, 6 months, and 1 year post-HSCT). Natural killer cell recovery was rapid, and numbers normalized in both cohorts by day +100. Mean CD3, CD4, and CD8 T-lymphocyte numbers normalized by 6 months after RD HSCT and by 1 year in the URD group. CD4 and CD8 T-lymphocyte counts were significantly higher in patients who received RD HSCT at 6 months and at 1 year, respectively, post-HSCT compared with patients who received URD HSCT. The pace of CD19 B-cell recovery was markedly different between RD and URD cohorts. Mean B-cell numbers were normal by day 100 after RD HSCT but took 1 year post-HSCT to normalize in the URD cohort. Despite these differences in immune reconstitution, the timing and nature of infections did not differ between the groups, presumably because of comparable T-lymphocyte recovery. Immune reconstitution occurred at a faster pace than in prior reports using RIC with T-cell depletion. The incidence of infections was similar for both cohorts and occurred most frequently in the first 100days post-HSCT. Viral and fungal infections occurred at a lower incidence in this cohort, with "early" alemtuzumab compared with regimens administering serotherapy in the peritransplantation period. Patients were susceptible to bacterial infections primarily in the first 100days irrespective of donor source and had no increase in mortality from the same. The overall mortality rate from infections was 1.4% at 1 year. Close monitoring and prophylaxis against bacterial infections in the first 100days post-HSCT is necessary but is followed by robust immune reconstitution, especially in the T-cell compartment.

Differences of cytomegalovirus diseases between kidney and hematopoietic stem cell transplant recipients during preemptive therapy

BACKGROUND/AIMS

Cytomegalovirus (CMV) surveillance and preemptive therapy is a widely-used strategy for preventing CMV disease in transplant recipients. However, there are limited data on the incidence and patterns of CMV disease during the preemptive period. Thus, we investigated the incidence and pattern of tissue-invasive CMV disease in CMV seropositive kidney transplantation (KT) and hematopoietic stem cell transplantation (HCT) recipients during preemptive therapy.

METHODS

We prospectively identified patients with tissue-invasive CMV disease among 664 KT (90%) and 496 HCT (96%) recipients who were D+/R+ (both donor and recipient seropositive) during a 4-year period.

RESULTS

The incidence rates of CMV disease were 4.1/100 person-years (4%, 27/664) in KT recipients and 5.0/100 person-years (4%, 21/496) in HCT recipients. Twenty-six (96%) of the KT recipients with CMV disease had gastrointestinal CMV, whereas 17 (81%) of the HCT recipients had gastrointestinal CMV and 4 (19%) had CMV retinitis. Thus, CMV retinitis was more common among HCT recipients (p = 0.03). All 27 KT recipients with CMV disease suffered abrupt onset of CMV disease before or during preemptive therapy; 10 (48%) of the 21 HCT recipients with CMV disease were also classified in this way but the other 11 (52%) were classified as CMV disease following successful ganciclovir preemptive therapy (p < 0.001).

CONCLUSIONS

The incidence of CMV disease was about 4% in both KT and HCT recipients during preemptive therapy. However, CMV retinitis and CMV disease as a relapsed infection were more frequently found among HCT recipients.

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.

The risk factors for cytomegalovirus reactivation following stem cell transplantation

Objective:

Opportunistic infections like cytomegalovirus (CMV) are among the primary causes of morbidity and mortality in patients undergoing hematipoetic stem cell transplantation (HSCT). This infection is frequently seen in early postengraftment period. So we determined to find the risk factors associated with CMV reactivation.

Methods:

We retrospectively evaluated the medical records of 126 consecutive patients who underwent allogenic-HSCT from peripheral blood stem cells from August 2011 to February 2013 in Shariati Hospital. We included HSCT patients with 15 years of age or older, who survived at least 100 days after transplantation. CMV reactivation was detected based on the weekly PP65 assessment. Patients with 10 or more positive cells per 50,000 cells were defined as having high-level antigenemia.

Findings:

From 126 patients which included in this study, 76 were male (60%). CMV antigenemia was documented in 43 patients (34%). The median time to CMV infection was 40 days (range: 3–77) after transplantation. The incidence of high-level antigenemia during the first 100 days following HSCT was 11%.

Conclusion:

We found that the significant risk factor for CMV antigenemia in multivariate analysis was prior graft-versus-host disease (GVHD) experience and higher donor age. For high-level antigenemia, GVHD or duration of its treatment was significant determinant.

Impact of pretransplant donor and recipient cytomegalovirus serostatus on outcome for multiple myeloma patients undergoing reduced intensity conditioning allogeneic stem cell transplantation

Scope of the study was to investigate the impact of pre-transplant CMV serostatus of the donor and/or recipient on the outcome of patients undergoing allogeneic hematopoietic stem cell transplantation (Allo-SCT) for Multiple Myeloma (MM). To our knowledge no data are available in the literature about this issue. We retrospectively followed 99 consecutive patients who underwent reduced-intensity conditioning (RIC) Allo-SCT for MM in our cancer center at Marseille between January 2000 and January 2012. Based upon CMV serostatus, patients were classified as low risk (donor [D]-/recipient [R] -) 17 patients (17.1%), intermediate risk (D+/R) 14 patients (14.1%), or high risk - either (D-/R+) 31 patients (31.3%) or (D+/R+), 37 patients (37.3%). Cumulative incidence of CMV reactivation was 39% with a median time of 61 days (26-318). Three patients (3%) developed CMV disease. Two factors were associated with CMV reactivation: CMV serostatus group (low: 0% vs. intermediate: 29% vs. high: 50%; p=0.001) and the presence of grade II-IV acute GvHD (Hazard Ratio: HR=2.1 [1.1-3.9]). Thirty-six of the 39 patients (92%) with CMV reactivation did not present positive detection of CMV after a 21-day median duration preemptive treatment with ganciclovir. Cumulative incidence of day 100 grade II-IV acute GvHD, 1-year chronic GvHD and day 100 transplantation related mortality (TRM) were 37%, 36% and 9%, respectively. CMV reactivation and serostatus were not associated with increased GvHD and TRM or short survival. Only the presence of acute GvHD as a time dependent variable was significantly associated with increased TRM (p=0.005). Two-year overall and progression free survival were 56% and 34%, respectively. Donor and recipient CMV serostatus and acute GvHD are independent factors for increased CMV reactivation in high-risk MM patients undergoing RIC Allo-SCT. However, we did not find any influence of CMV reactivation on post transplantation outcome. CMV monitoring and pre-emptive treatment strategy could in part explain these results. Novel prophylactic measures such as immunotherapy and drug prophylaxis need to be considered in this group of patients, warranting further prospective studies.

Cytomegalovirus pneumonia in hematopoietic stem cell recipients

Cytomegalovirus (CMV) is a frequently encountered infection following hematopoietic cell transplantation, and tissue invasive pneumonia is a dreaded complication of the virus in this population. In this review of CMV pneumonia, we address epidemiology, pathogenesis, diagnostics, current therapy, and strategies to prevent the development of CMV. We also review emerging treatment and prevention options for this challenging disease.

Tandem autologous-allogeneic nonmyeloablative sibling transplantation in relapsed follicular lymphoma leads to impressive progression-free survival with minimal toxicity

Autologous stem cell transplantation (ASCT) prolongs survival in patients with relapsed follicular lymphoma. ASCT is usually not curative, however. Myeloablative allogeneic transplantation has produced long-term survival at a cost of significant transplantation-related mortality (TRM), whereas reduced-intensity transplantation entails less TRM but has a higher relapse rate. We thus initiated a protocol consisting of ASCT followed by nonmyeloablative allogeneic transplantation (NMT) for relapsed follicular lymphoma to mimic myeloablative allogeneic transplantation without the associated toxicity. The NMT was non-T cell-depleted, and all donors were HLA-identical siblings. We report results in 27 patients with a median age of 49 years (range, 34-65 years). Five patients demonstrated histological progression toward an aggressive lymphoma. The patients had received a median of 3 lines of previous therapy. Disease status before ASCT included 8 patients in complete remission, 14 in partial remission, and 5 refractory. Five patients developed grade II-IV acute graft-versus-host disease, and 20 patients developed chronic graft-versus-host disease requiring systemic therapy. With a median follow-up of 39 months after NMT, overall survival and progression-free survival were 96% at 3 years. We conclude that the combined ASCT-NMT strategy appears to be safe, with excellent progression-free survival even in refractory and transformed cases. This novel approach warrants further investigation in larger prospective studies.

Comparison of reduced intensity and myeloablative conditioning regimens for stem cell transplantation in patients with malignancies: a meta-analysis

OBJECTIVE

The reduced intensity conditioning (RIC) stem cell transplantation is widely employed for the treatment of many hematologic malignancies, but the survival effectiveness is still unclear. This study conducted an updated meta-analysis to determine whether any significant difference could be found by using RIC vs. myeloablative conditioning (MAC) regimen for transplantation in patients with malignancies.

METHODS

We electronically searched the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase, and relevant articles (1987.01-2009.12). Comparative studies were carried out on clinical therapeutic effect of RIC and MAC on the survival outcomes and the transplantation-related complications.

RESULTS

We obtained 1776 records, and 29 studies totaling 6235 patients have been assessed. Compared with MAC regimen, the RIC regimen had a higher overall survival (OS) at one-yr and no difference at two-yr later after transplantation. RIC regimen had significantly lower rates of disease-free survival (DFS) after two-yr follow-up, lower incidences of ≥ II degree acute graft-versus-host disease (aGVHD), and lower TRM [OR, 0.61, 95% CI (0.53, 0.69)], but with a higher relapse rate [OR, 1.88(1.41, 2.51)]. No significant difference was found in rates of cytomegalovirus (CMV) infection and chronic GVHD between the regimens.

CONCLUSIONS

This meta-analysis confirmed that compared with MAC condition regimen, the RIC regimen had a consistently equivalent or even better rate in OS, but with lower DFS at longer follow-up.

Early CMV viremia is associated with impaired viral control following nonmyeloablative hematopoietic cell transplantation with a total lymphoid irradiation and antithymocyte globulin preparative regimen

The reconstitution of immune function after hematopoietic cell transplant (HCT) plays an important role in the control of viral infections. Both donor and recipient cytomegalovirus (CMV) serostatus has been shown to contribute to effective immune function; however, the influence of a nonmyeloablative preparative (NMA) regimen using total lymphoid irradiation (TLI) and antithymocyte globulin (ATG) on antiviral immune reconstitution has not yet been described. In 117 recipients of NMA HCT patients following ATG and TLI, not unexpectedly, CMV viremia was seen in approximately 60% of the seropositive patients regardless of donor serostatus, and recipient seropositivity significantly increased the odds of CMV viremia after transplant in a multivariate analysis. The administration of ATG and TLI resulted in a strikingly earlier viremia in the posttransplant period when compared to the previously reported timing of viremia following myeloablative preparative regimens, especially for transplant recipients who were seropositive for CMV with seronegative donors. Furthermore, early viremia in the setting of a CMV naïve donor was associated with a delay in functional antiviral control. These observations demonstrate the dynamic nature of immunity in relation to CMV antigen exposure in the complex environment resulting from NMA conditions where both donor and residual recipient immune response affect viral control.

Pre-transplant cytomegalovirus (CMV) serostatus remains the most important determinant of CMV reactivation after allogeneic hematopoietic stem cell transplantation in the era of surveillance and preemptive therapy

Between January 2001 and June 2008, 315 adult patients (median age 43 years, range 16-65) including 203 males and 112 females undergoing hematopoietic stem cell transplantation (HSCT) had serial monitoring for cytomegalovirus (CMV) followed by initiation of preemptive therapy. The majority (62.1%) had a conventional myeloablative transplant with 116 (36.9%) having a reduced-intensity conditioning (RIC) transplant, using either matched sibling/family (63.3%) or unrelated donors (36.7%). Graft source was peripheral blood stem cells in 257 (81.5%), bone marrow in 41 (13.1%), and cord blood in 16 (5.4%). T-cell depletion with anti-thymocyte globulin or alemtuzumab was used in 35%. Based upon CMV serostatus, patients were classified into low risk (donor [D]-/recipient [R]-), intermediate risk (D+/R-), or high risk (D-/R+ or D+/R+). Serial weekly monitoring for CMV viremia was performed using a qualitative polymerase chain reaction (PCR) and when positive, quantification was done using either pp65 antigen or a quantitative PCR. CMV reactivation was seen in 123 patients (39.1%) at a median of 50 days post HSCT (range 22-1978). CMV serostatus was the most important risk factor with incidence of 53% in the high-risk group (53.3%) compared with 10.2% in the intermediate risk and 0% in the low-risk group (P<0.0001). Other significant risk factors identified included use of alemtuzumab during conditioning (P=0.03), RIC transplants (P=0.06), and the presence of acute graft-versus-host disease (GVHD) (P<0.0001). On a multivariate analysis, CMV serostatus, RIC transplants, and acute GVHD remained independent predictors of CMV reactivation. All were treated with antiviral therapy with responses seen in 109 (88.6%). Sixteen patients (13%) developed CMV disease at a median of 59 days post HSCT (range 26 days-46 months), 8 of whom died. At a median follow up of 43 months (range 6-93), 166 patients (52.6%) are alive with a significantly higher survival among patients without CMV reactivation (57.2%) as compared with patients with CMV reactivation (45.5%; P=0.049). CMV reactivation and disease remains a major problem in high-risk patients undergoing allogeneic HSCT. Novel prophylactic measures such as immunotherapy and drug prophylaxis need to be considered in this specific group of patients.

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.

Incidence of Viral and fungal infections following busulfan-based reduced-intensity versus myeloablative conditioning in pediatric allogeneic stem cell transplantation recipients

Reductions in the duration and nadir of neutropenia have translated into a significant decrease in bacteremia in adult recipients of allogeneic stem cell transplantation (allo-SCT) with reduced-intensity conditioning (RIC) during the first 30 days after transplantation. It remains to be determined whether RIC allo-SCT also will result in a decrease in systemic viral infections (SVIs) and invasive fungal infections (IFIs), which are more dependent on alterations in cellular immunity. We compared the incidence of SVIs and IFIs in children receiving busulfan-based RIC allo-SCT and in children receiving myeloablative conditioning (MAC) allo-SCT for various malignant and nonmalignant diseases. Allo-SCT recipients at risk for cytomegalovirus (CMV) received ganciclovir/foscarnet, and most of the patients received antifungal prophylaxis with liposomal amphotericin B until day +100. Eighty-six patients (median age, 7.5 years; 70% with malignant disease, 30% with nonmalignant disease; 80% average risk, 20% poor risk) were evaluated. The probability of developing grade II-IV acute graft-versus-host disease (aGVHD) was 29.1% (95% confidence interval [CI]=16.7%-41.6%) in RIC allo-SCT versus 40.3% (95% CI=23.9%-56.6%) in MAC allo-SCT (P=.23), and that of chronic GVHD (cGVHD) was 28.9% (95% CI=14.7%-43.0%) in RIC allo-SCT versus 28.4% (95% CI=10.5%-46.3%) in MAC allo-SCT (P=.73). The overall probability of developing an SVI was 58%, and that of developing an IFI was 15%. These probabilities did not differ significantly by conditioning intensity. In a multivariate Cox regression model, the following were identified as independent risk factors for invasive fungal infection: older age (hazard ratio [HR]=1.3; 95% CI=1.1-1.6; P=< .01), poor risk status (HR=6.5; 95% CI =1.1-37.4; P=.03), and CMV-positive recipient (high vs low CMV risk group, HR=26.7; 95% CI=3.4-210.8; P=< .01). Overall infection-related mortality was only 1.1% (1/86) for SVIs and 2.3% (2/86) for IFIs. Our data indicate that RIC allo-SCT does not carry a lower risk of SVIs and IFIs than MAC allo-SCT in pediatric recipients.

Regimen-related mucosal injury of the gut increased the incidence of CMV disease after allogeneic bone marrow transplantation

Cytomegalovirus (CMV) infection is 1 of the major causes of morbidity in patients undergoing allogeneic stem cell transplantation (allo-SCT). The incidences of CMV antigenemia and CMV disease in 43 patients who received allogeneic bone marrow transplantation (BMT) using a reduced-intensity conditioning (RIC) regimen, which mainly consisted of fludarabine (Flu), busulfan (Bu), and total body irradiation (TBI), were compared with those in 68 patients who received a myeloablative conditioning (MAC) regimen, and risk factors for CMV antigenemia and CMV disease were identified. Before engraftment, grade 3-4 mucosal injury because of the conditioning regimen was significantly decreased in RIC patients (stomatitis: P = .02; diarrhea: P < .01). Rate of engraftment, incidences of acute graft-versus-host disease (aGVHD), and rate of corticosteroid administration were not different in RIC patients and MAC patients. Although the incidences of CMV antigenemia were not significantly different in RIC patients and MAC patients (64.1% versus 57.8%, log rank, P = .59), the incidence of CMV disease was significantly decreased in RIC patients (5.4% versus 20.3%, log rank, P = .04). CMV seropositivity in the patients (P < .01) and corticosteroid administration (P < .01) were revealed by multivariate analysis to be significant risk factors for CMV antigenemia. Grade II-IV aGVHD (P = .02) and grade 3-4 diarrhea before engraftment (P = .04) were revealed to be risk factors for CMV disease. The present study is the first study to show that severe diarrhea before engraftment is a significant risk factor for CMV disease. In summary, risk of CMV disease was significantly decreased in patients without severe mucosal injury of the gut because of the conditioning regimen before engraftment.

Comparable incidence and severity of cytomegalovirus infections following T cell-depleted allogeneic stem cell transplantation preceded by reduced intensity or myeloablative conditioning

Reports on infectious complications following reduced intensity conditioning (RIC) before allogeneic stem cell transplantation (allo-SCT) are equivocal. This prospective follow-up study compared the impact of cytomegalovirus (CMV) infections following RIC with fludarabine, ATG and busulphan or conventional myeloablative conditioning (MAC). Forty-eight RIC and 59 MAC patients were enrolled. The occurrence and severity of CMV infections within 100 days following allo-SCT were assessed, using plasma CMV DNA load kinetics. CMV DNAemia was observed in 21 RIC (60%) and in 19 MAC (44%) patients at risk for CMV. The mean CMV DNAemia free survival time was comparable following RIC and MAC: 70 days (95% (confidence interval) CI: 59-80 days) and 77 days (95% CI: 68-86 days), respectively (P=0.24). Parameters indicative for the level of CMV reactivation, including the area under the curve of CMV DNA load over time as well as the onset, the peak values and duration of CMV infection episodes, the numbers and duration of CMV treatment episodes and recurrent infections, were not different in both groups. During follow-up, none of the patients developed CMV disease. RIC with fludarabine, ATG and busulphan demonstrated safety comparable to conventional MAC with regard to frequency and severity of CMV infections within 100 days following T cell-depleted allo-SCT.

Patients at high risk for CMV infection and disease show delayed CD8+ T-cell immune recovery after allogeneic stem cell transplantation

Human cytomegalovirus (CMV) is a major cause of death after transplantation. The frequency of pp65-specific T cells was examined in 38 HLA-A2+ stem cell recipients during the first year after transplantation. Patients were divided into four groups based on donor/recipient serostatus: d+/r+ (n=17), d+/r- (n=7), d-/r+ (n=9) and d-/r- (n=5). Peripheral blood mononuclear cells were stimulated with the CMVpp65 peptide NLVPMVATV, and the specific T-cell frequency was assessed by interferon gamma (IFN-gamma) ELISPOT assay. Responding T cells were characterized by flow cytometry revealing a terminal differentiated effector phenotype. Surveillance of CMV infection was carried out by real-time polymerase chain reaction (n=26) or immunofluorescence (n=12). Infection was present in 7/9 d-/r+ high-risk patients, and CMV disease occurred exclusively in this group with delayed or absent virus-specific T-cell recovery. In contrast, 16/24 intermediate-risk patients showed CMV-specific T cells. Our data suggest that CMV infection and disease rates are elevated in high-risk patients with delayed CMV-specific T-cell immune reconstitution and lower in those with early recovery of T-cell immunity. We recommend preferring CMV seropositive donors for CMV seropositive recipients, as this should lead to durable CMV-specific T-cell responses soon after transplantation with consecutive protection from CMV disease.

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.

Infections with human herpesvirus 6 variant B delay platelet engraftment after allogeneic haematopoietic stem cell transplantation

The clinical significance of human herpesvirus (HHV-6) infections after allogeneic stem cell transplantation (SCT) remains controversial. We analysed cryoconserved plasma samples from 82 patients after allogeneic SCT by quantitative polymerase chain reaction for HHV-6 variants A and B. Platelet engraftment was delayed in patients with HHV-6B infections but not with HHV-6A infections detected before day +28. In multivariate analysis early HHV-6B infections and the type of conditioning were associated with platelet engraftment. In conclusion, the two variants of HHV-6 should be studied separately; early infections with HHV-6B may contribute to delayed platelet engraftment after allogeneic SCT.