Reduced-intensity conditioning reduces the risk of severe infections after allogeneic peripheral blood stem cell transplantation

Dose intensity for conditioning in allogeneic hematopoietic cell transplantation: can we recommend "when and for whom" in 2021?

Allogeneic hematopoietic stem-cell transplantation is a potentially curative therapy for various hematologic diseases. An essential component of this procedure is the pre-transplant conditioning regimen, which should facilitate engraftment and reduce or eliminate tumor cells. The recognition of the substantial association of a graft-versus- tumor effect and the high toxicity of the commonly used conditioning regimen led to the introduction of more differentiated intensity strategies, with the aim of making hematopoietic stem-cell transplantation less toxic and safer, and thus more applicable to broader populations such as older or unfit patients. In general, prospective and retrospective studies suggest a correlation between increasing intensity and nonrelapse mortality and an inverse correlation with relapse incidence. In this review, we will summarize traditional and updated definitions for conditioning intensity strategies and the landscape of comparative prospective and retrospective studies, which may help to find the balance between the risk of non-relapse mortality and relapse. We will try to underscore the caveats regarding these definitions and analyses, by missing complex differences between intensity and toxicity as well as the broad influences of other factors in the transplantation procedure. We will summarize evidence regarding several confounders which may influence decisions when selecting the intensity of the conditioning regimen for any given patient, according to the individual risk of relapse and non-relapse mortality.

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.

Splenomegaly May Increase the Risk of Rejection in Low-Risk Matched Related Donor Transplant for Thalassemia, This Risk Can Be Partially Overcome by Additional Immunosuppression during Conditioning

Severe thalassemia syndromes (ST) are highly curable by bone marrow transplant (BMT), but rejection may still occur. We retrospectively analyzed our fully matched related donor transplants to establish if isolated splenomegaly is an independent risk factor for rejection and if this risk can be reduced by modifying the conditioning protocol. In this study, we compared rejection rates between patients with and without splenomegaly in 189 consecutive low-risk ST transplants across 2 sequential conditioning regimens: regimen A (August 2013 to December 2016): busulfan (14 mg/kg oral, not adjusted to serum levels), cyclophosphamide (200 mg/kg), and anti-thymocyte globulin (ATG) (Genzyme (Sanofi, Paris, France) 4 mg/kg or Fresenius (Grafalon, Neovii Biotech GmbH, Gräfelfing Germany) 16 mg/kg on days -12 to -10), and regimen B: same backbone as regimen A except fludarabine total dose of 150 mg was added upfront and ATG dose was increased to 7 mg/kg in case of splenomegaly and/or sex-mismatched transplants (January 2017 to September 2018). Compared with regimen A, in regimen B, both overall rejection rates (RRs) (16% versus 6.5%, P = .023) and treatment-related mortality (TRM) (9.9% versus 2.8%, P = .038) improved significantly. By Cox regression analysis, the improvement in RR between the 2 protocols was particularly significant in patients with splenomegaly (RR 54.5% versus 6.5%, P = .00015; TRM 18.2% versus 6.5%, P = .25) (hazard ratio, 4.13; confidence interval, 1.61 to 10.6; P = .003). The increased risk of rejection related to splenomegaly can be overcome by adding fludarabine to the standard ATG-Busulfan- Cyclophosphamide (ATG-Bu-Cy) protocol without significantly increasing transplant-related morbidity and mortality or resorting to splenectomy pre-BMT.

Monocenter study on epidemiology, outcomes, and risk factors of infections in recipients of 166 allogeneic stem cell transplantations during 1 year

OBJECTIVES

During allogeneic hematopoietic stem cell transplantation (allo-SCT), infections significantly contribute to morbidity and mortality. A monocentric prospective analysis was performed to assess epidemiology, risk factors, and outcomes of infections during the peri-transplant period.

METHODS

Data were recorded prospectively using a predefined questionnaire.

RESULTS

In 2015, 163 consecutive patients, 37.4% female, median age 59 (range 18-79) years received 166 allo-SCT. Median duration of leukopenia <10⁹ /L was 14.5 days (range 4-43 days). Fever of unknown origin (FUO) occurred in 118/166 patients (71.1%). Severe sepsis developed in 95, and septic shock developed in 26 patients. Intensive diagnostic workup helped to identify causative microorganisms only in a small number of infectious courses. All but 13 patients needed antibiotic therapy, each according to the standard operating procedures of the department. Cumulative incidence of death by infection after 1 year was 16.6% (95% CI: 11.3-22.7). The only risk factor for FUO in neutropenia was duration of neutropenia </≥14 days (55.4% vs 85.5%, P < .001).

CONCLUSION

Results of an elaborate diagnostic workup of infections in the peri-transplant period are scarce. Attention to risk factors might help to identify patients at risk for severe infections.

Infections in Allogeneic Stem Cell Transplantation

Allogeneic hematopoietic stem cell transplantation (allo-HSCT) has become a widely used modality of therapy for a variety of malignant and nonmalignant diseases. Despite advances in pharmacotherapy and transplantation techniques, infection remains one of the most severe and frequently encountered complications of allo-HSCT.

This chapter will address the risk factors for development of infection following allo-HSCT, including those related to the host, the conditioning regimen, and the graft, as well as the timing of opportunistic infections after allo-HSCT. The most common bacterial, viral, fungal, and parasitic infections, as well as issues surrounding their diagnostics and treatment, will be discussed. Finally, this chapter will address vaccination and other preventative strategies to be utilized when caring for patients undergoing allo-HSCT.

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.

Factors associated with pulmonary toxicity after myeloablative conditioning using fractionated total body irradiation

Purpose

Pulmonary toxicities, including infectious pneumonia (IP) and idiopathic pneumonia syndrome (IPS), are serious side effects of total body irradiation (TBI) used for myeloablative conditioning. This study aimed to evaluate clinical factors associated with IP and IPS following TBI.

Materials and Methods

Fifty-eight patients with hematologic malignancies who underwent TBI before allogeneic hematopoietic stem cell transplantation between 2005 and 2014 were reviewed. Most patients (91%) received 12 Gy in 1.5 Gy fractions twice a day. Pulmonary toxicities were diagnosed based on either radiographic evidence or reduced pulmonary function, and were subdivided into IP and IPS based on the presence or absence of concurrent infection.

Results

Pulmonary toxicities developed in 36 patients (62%); 16 (28%) had IP and 20 (34%) had IPS. IP was significantly associated with increased treatment-related mortality (p = 0.028) and decreased survival (p = 0.039). Multivariate analysis revealed that the risk of developing IPS was significantly higher in patients who received stem cells from a matched unrelated donor than from a matched sibling donor (p = 0.021; hazard ratio [HR] = 12.67; 95% confidence interval [CI], 1.46–110.30). Combining other conditioning agents with cyclophosphamide produced a higher tendency to develop IP (p = 0.064; HR = 6.19; 95% CI, 0.90–42.56).

Conclusion

IP and IPS involve different risk factors and distinct pathogeneses that should be considered when planning treatments before and after TBI.

Pushing the envelope-nonmyeloablative and reduced intensity preparative regimens for allogeneic hematopoietic transplantation

Allogeneic hematopoietic cell transplantation (HCT) was originally developed to allow delivery of myeloablative doses of chemotherapy and radiotherapy. With better understanding of disease pathophysiology, the graft vs malignancy (GVM) effect of allogeneic hematopoietic transplantation and toxicities associated with myeloablative conditioning (MAC) regimens, the focus shifted to developing less toxic conditioning regimens to reduce treatment-related morbidity without compromising survival. Although HCT with MAC is preferred to reduced intensity conditioning (RIC) for most patients ⩽60 years with AML/myelodysplastic syndrome and ALL, RIC and nonmyeloablative (NMA) regimens allow HCT for many otherwise ineligible patients. Reduced intensity preparative regimens have produced high rates of PFS for diagnoses, which are highly sensitive to GVM. Relapse of the malignancy is the major cause of treatment failure with RIC/NMA HCT. Incorporation of novel agents like bortezomib or lenalidomide, addition of cellular immunotherapy and use of targeted radiation therapies could further improve outcome. In this review, we discuss commonly used RIC/NMA regimens and promising novel regimens.

Incidence, risk factors, and outcome of bloodstream infections during the pre-engraftment phase in 521 allogeneic hematopoietic stem cell transplantations

BACKGROUND

Bloodstream infection (BSI) after allogeneic hematopoietic stem cell transplantation (HSCT) is a well-known complication during the pre-engraftment phase. Knowledge of trends in etiology and antibiotic susceptibility of BSI is important as the time to effective antibiotic treatment is closely associated with survival in bacteremic patients with septic shock.

METHODS

BSI during the pre-engraftment phase was studied retrospectively in 521 patients undergoing HSCT at our center in 2001-2008. Incidence, risk factors, outcome, and microbiology findings were investigated and compared with BSI in a cohort transplanted during 1975-1996.

RESULTS

The incidence of at least 1 episode of BSI was 21%, the total attributable mortality of BSI was 3.3%, and crude mortality at day 120 after transplantation was 21%. The rate of gram-positive and gram-negative BSI was 80% and 13%, respectively. Gram-negative BSI was more frequent both in 2001-2004 and in 2005-2008 compared with 1986-1996 (P = 0.023 for 2001-2004, P = 0.001 for 2005-2008), with fluoroquinolone-resistant Escherichia coli as the predominant finding. BSI with viridans streptococci and E. coli occurred significantly earlier after HSCT than BSI with Enterococcus species, with median time of 4, 8, and 11 days, respectively (P < 0.01 both for viridians streptococci vs. Enterococcus species, and E. coli vs. Enterococcus species). Risk factors for BSI in multivariate analysis were transplantation from unrelated donor and cord blood as stem cell source, whereas peripheral blood as stem cell source was protective.

CONCLUSIONS

Despite low attributable mortality of BSI, crude mortality at day 120 after transplantation was 21%, indicating an association between BSI and other risk factors for death. The risk of gram-negative BSI increased over time in parallel with an increased rate of quinolone resistance. However, the incidence and attributable mortality of gram-negative BSI remained low. Thus, prophylaxis with ciprofloxacin is still deemed appropriate, but continued assessments of the risk and benefits of fluoroquinolone prophylaxis must be performed.

Immune Reconstitution and Early Infectious Complications Following Nonmyeloablative Hematopoietic Stem Cell Transplantation

Non-myeloablative stem cell transplantation (NMT) has been increasingly used in compromised patients who would otherwise have been unable to undergo allotransplant. There is little understanding of the kinetics of immune reconstitution and its influence on infective complications following NMT. The aim of present study was to evaluate lymphocyte subset reconstitution over the first 12 months post-transplant in 15 adult patients receiving NMT with comparison to that of 30 patients grafted with a conventional hemopoietic stem cell transplantation (HSCT). NMT recipients were conditioned with fludarabine-based conditioning regimens. Peripheral blood stem cell (PBSC) was the source of stem cells in 13 NMT recipients and in 24 conventional HSCT recipients. Absolute numbers of helper (CD4+) T cells, naive (CD4+ CD45RA+) and memory (CD4+ CD45RO+) T cells as well as suppressor (CD8+) T cells, CD19+ B cells and NK cells were comparable in the two groups at all time points after transplantation. A median value of 200 CD4+ T cells/microl was achieved at 2 months post-transplant by the NMT and HSCT recipients. The CD4:CD8 ratio remained severely depressed throughout the study period. Almost all CD4+ lymphocytes expressed CD45RO antigen in the both groups of patients B lymphocytes showed low counts throughout the entire study period in both groups. Bacteremia and CMV antigenemia occurred respectively in 13 and 36% of the patients in the NMT group and in 15 and 39% of the patients in the HSCT group. Our preliminary data indicate that patients receiving a NMT have a lymphocyte reconstitution similar to that observed in patients who received a conventional HSCT. The incidence of bacteremia and CMV infection were not significantly different between the groups. Nevertheless, due to the small sample size, these results should be considered suggestive rather than definitive.

Infectious complications following allogeneic stem cell transplantation: reduced-intensity vs. myeloablative conditioning regimens

BACKGROUND

In allogeneic stem cell transplantation (allo-SCT), reduced-intensity conditioning (RIC) is known for producing less regimen-related toxicity. However, whether or not RIC reduces the risk for infection and infection-related mortality (IRM) remains controversial.

METHODS

We retrospectively analyzed infectious episodes and IRMs after allo-SCTs by time period and by the intensity of the conditioning regimen (RIC [n = 81] vs. myeloablative conditioning, MAC [n = 150]).

RESULTS

The cumulative incidence of any kind of infection was lower in the RIC group through the entire period (72% vs. 87%; P = 0.007). The onset of infections was deferred in the RIC group as compared with the MAC group (P = 0.012). Bacteremia occurred less frequently in the RIC group through the entire period (5% vs. 14%; P = 0.044). However, the incidences of cytomegalovirus reactivation and disease, herpes zoster, virus-associated hemorrhagic cystitis, and invasive fungal infection were not different between the two groups. Furthermore, there was no difference in relapse-free survival and IRM between the two conditioning regimens.

CONCLUSION

Careful monitoring and appropriate preventive/therapeutic strategies for infectious complications, comparable to those for allo-SCT recipients with MAC, should also be applied to those with RIC, especially after engraftment.

Efficiency and risk factors for CMV transmission in seronegative hematopoietic stem cell recipients

Cytomegalovirus (CMV) transmission via stem cells or marrow in CMV donor seropositive/recipient seronegative (D+/R-) hematopoietic cell transplantation (HCT) is surprisingly inefficient, and factors associated with transmission in these high-risk HCT recipients are unknown. In a retrospective cohort of D+/R- HCT recipients, cumulative incidence curve estimates were used to determine posttransplantation rates of CMV and multivariable Cox proportional models to assess risk factors associated with transmission. A total of 447 patients from 1995 to 2007 were eligible for enrollment. Overall, 85 of 447 (19.0%) acquired CMV at a median of 49 days (IQR 41-60) posttransplantation. CMV disease before day 100 occurred in 6 of 447 (1.3%) patients and in 7 of 447 (1.6%) after day 100. The donor graft, specifically the total nucleated cell count (adjusted hazard ratio [HR] 2.7; 95% confidence interval [CI], 1.4-4.7, P = .0002), was the only factor associated with CMV transmission in multivariable analyses. Notably, the source stem cells (marrow versus peripheral blood stem cell [PBSC]), screening method, and graft-versus-host disease (GVHD) were not associated with transmission. Thus, a highly cellular graft was the only identifiable risk factor associated with CMV transmission, suggesting that viral genomic content of the donor graft determines transmission efficiency in D+/R- HCT recipients.

Voriconazole versus itraconazole for antifungal prophylaxis following allogeneic haematopoietic stem-cell transplantation

Antifungal prophylaxis for allogeneic haematopoietic stem-cell transplant (alloHCT) recipients should prevent invasive mould and yeast infections (IFIs) and be well tolerated. This prospective, randomized, open-label, multicentre study compared the efficacy and safety of voriconazole (234 patients) versus itraconazole (255 patients) in alloHCT recipients. The primary composite endpoint, success of prophylaxis, incorporated ability to tolerate study drug for ≥100 d (with ≤14 d interruption) with survival to day 180 without proven/probable IFI. Success of prophylaxis was significantly higher with voriconazole than itraconazole (48·7% vs. 33·2%, P <0·01); more voriconazole patients tolerated prophylaxis for 100 d (53·6% vs. 39·0%, P<0·01; median total duration 96 vs. 68 d). The most common (>10%) treatment-related adverse events were vomiting (16·6%), nausea (15·8%) and diarrhoea (10·4%) for itraconazole, and hepatotoxicity/liver function abnormality (12·9%) for voriconazole. More itraconazole patients received other systemic antifungals (41·9% vs. 29·9%, P<0·01). There was no difference in incidence of proven/probable IFI (1·3% vs. 2·1%) or survival to day 180 (81·9% vs. 80·9%) for voriconazole and itraconazole respectively. Voriconazole was superior to itraconazole as antifungal prophylaxis after alloHCT, based on differences in the primary composite endpoint. Voriconazole could be given for significantly longer durations, with less need for other systemic antifungals.

Tetramer monitoring to assess risk factors for recurrent cytomegalovirus reactivation and reconstitution of antiviral immunity post allogeneic hematopoietic stem cell transplantation

BACKGROUND

Reactivation of cytomegalovirus (CMV) is a major cause of morbidity after allogeneic hematopoietic stem cell transplantation (HSCT). In healthy individuals, virus-specific T cells (CMV-CTL) control the reactivation of latent CMV. The monitoring of virus-epitope-binding CD8(+) T cells using major histocompatibility complex-I-peptide complexes (tetramers) has recently been established, allowing assessment of the reconstitution of CMV-CTL post HSCT.

PATIENTS AND METHODS

In order to study immune reconstitution and reactivation control through CMV-CTL, we regularly monitored all patients undergoing allogeneic HSCT in our department for 2 years, who matched at least 1 of 6 commercially available tetramers for common human leukocyte antigen (HLA) types. To verify risk factors for CMV reactivations in our cohorts, clinical characteristics of all patients transplanted within the last 10 years were included in statistical analyses determining the relative risk for single and recurrent CMV reactivations.

RESULTS

As expected, CMV serostatus, HLA match, and donor source significantly influenced the risk of recurrent CMV reactivation. Applying CMV-CTL tetramer monitoring for 2 years allowed the monitoring of 114 (85%) of 134 patients, by testing a set of tetramers representing 6 epitopes from 3 different CMV proteins. The presence of CMV-CTL before day + 50 and their expansion post reactivation seem to protect against recurrent CMV reactivations. The mean number of CMV-CTL by day +100 was >5-fold higher in the recipient CMV-positive/donor-positive (R +/D +) group (91/μL) compared with the R +/ D- (13/μL) and the R -/D +(2/μL) group. Seventy-nine percent of patients from the R +/D + setting recovered >10 CMV-CTL per μL by day + 100, while almost 50% of the other groups failed to mount a CMV-specific response by that time (R +/D -: 58%; R -/D +: 43%).

CONCLUSION

Tetramer monitoring can help to predict (recurrent) CMV reactivation and is a useful approach to monitor individual patients with increased risk for recurrent reactivation post HSCT; thus, it could help to identify patients in need of adoptive transfer of CMV-CTL or to optimize the use of antiviral drugs.

Surveillance of active human cytomegalovirus infection in hematopoietic stem cell transplantation (HLA sibling identical donor): search for optimal cutoff value by real-time PCR

BACKGROUND

Human cytomegalovirus (CMV) infection still causes significant morbidity and mortality after allogeneic hematopoietic stem cell transplantation (HSCT). Therefore, it is extremely important to diagnosis and monitor active CMV infection in HSCT patients, defining the CMV DNA levels of virus replication that warrant intervention with antiviral agents in order to accurately prevent CMV disease and further related complications.

METHODS

During the first 150 days after allogeneic HSTC, thirty patients were monitored weekly for active CMV infection by pp65 antigenemia, nested-PCR and real-time PCR assays. Receiver operating characteristic (ROC) plot analysis was performed to determine a threshold value of the CMV DNA load by real-time PCR.

RESULTS

Using ROC curves, the optimal cutoff value by real-time PCR was 418.4 copies/104 PBL (sensitivity, 71.4%; specificity, 89.7%). Twenty seven (90%) of the 30 analyzed patients had active CMV infection and two (6.7%) developed CMV disease. Eleven (40.7%) of these 27 patients had acute GVHD, 18 (66.7%) had opportunistic infection, 5 (18.5%) had chronic rejection and 11 (40.7%) died - one died of CMV disease associated with GVHD and bacterial infection.

CONCLUSIONS

The low incidence of CMV disease in HSCT recipients in our study attests to the efficacy of CMV surveillance based on clinical routine assay. The quantification of CMV DNA load using real-time PCR appears to be applicable to the clinical practice and an optimal cutoff value for guiding timely preemptive therapy should be clinically validated in future studies.

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.

Lower respiratory tract respiratory virus infections increase the risk of invasive aspergillosis after a reduced-intensity allogeneic hematopoietic SCT

We have analyzed the incidence and risk factors for the occurrence of invasive aspergillosis (IA) among 219 consecutive recipients of an allogeneic hematopoietic SCT after a reduced-intensity conditioning regimen (Allo-RIC). Twenty-seven patients developed an IA at a median of 218 days (range 24–2051) post-Allo-RIC, for a 4-year incidence of 13% (95% confidence interval 4–24%). In multivariate analysis, risk factors for developing IA were steroid therapy for moderate-to-severe graft vs host disease (GVHD) (Hazard Ratio (HR) 2.9, P=0.03), occurrence of a lower respiratory tract infection (LRTI) by a respiratory virus (RV) (HR 4.3, P<0.01) and CMV disease (HR 2.8, P=0.03). Variables that decreased survival after Allo-RIC were advanced disease phase (HR 1.9, P=0.02), steroid therapy for moderate-to-severe GVHD (HR 2.2, P<0.01), not developing chronic GVHD (HR 4.3, P<0.01), occurrence of LRTI by an RV (HR 3.4, P<0.01) and CMV disease (HR 2, P=0.01), whereas occurrence of IA had no effect on survival (P=0.5). Our results show that IA is a common infectious complication after an Allo-RIC, which occurs late post-transplant and may not have a strong effect on survival. An important observation is the possible role of LRTI by conventional RVs as risk factors for IA.

High Incidence of Invasive Aspergillosis Associated with Intestinal Graft-versus-Host Disease following Nonmyeloablative Transplantation

Invasive aspergillosis (IA) remains a major complication following allogeneic hematopoietic stem cell transplant (HSCT). In contrast to conventional HSCT, few investigators have examined risk factors of IA associated with nonmyeloablative (NMA) regimens characterized by outpatient administration, immunosuppression rather than cytoreduction, and short duration of neutropenia posttransplant. We report our results on a cohort of 125 patients treated homogenously who received a 6/6 matched sibling NMA HSCT designed to be performed on an outpatient basis. Conditioning regimen included fludarabine (30 mg/m(2) x 5 days) and cyclophosphamide (300 mg/m(2) x 5 days) followed by reinfusion of a minimum of 4 x 10(6) CD34(+) cells/kg. Acute graft-versus-host disease (aGVHD) prophylaxis consisted of tacrolimus and mycophenolate mofetil (MMF). Overall, 13 patients developed IA (5 proved, 6 probable, 2 possible) 44-791 days (median 229) after NMA HSCT, with a risk of 7% at 1, 11% at 2, and 15% at 3 years. Patients who suffered from IA had poorer overall survival (crude hazard ratio 2.3; 95% confidence interval [CI] 1.0-5.4; P = .045). Intestinal aGVHD or chronic GVHD (cGVHD) was significantly associated with IA at 1 (27% versus 3%, P = .003), 2 (27% versus 8%, P = .01), and 3 years (37% versus 10%, P = .005). The use of daclizumab was also significantly associated with IA at 3 years (47% versus 12%, P = .02). Age, sex, diagnosis, previous autologous transplant, duration of neutropenia, occurrence of cytomegalovirus viremia, duration of steroids or MMF intake, aGVHD, cGVHD, and cumulative number of days spent in hospital were not associated with IA. After multivariate analysis, intestinal GVHD remained the only statistically significant risk factor for IA at 1 (P = .003), 2 (P = .01), and 3 years (P = .005). We conclude that in NMA HSCT, the risk of IA increases over time and is significantly associated with intestinal GVHD. Because there is currently no surrogate in vitro markers of immunocompetence following NMA HSCT, this clinical finding is of particular importance to identify a population at higher risk who should be targeted for antimold prophylaxis.

Invasive fungal infections in allogeneic and autologous stem cell transplant recipients: a single-center study of 166 transplanted patients

OBJECTIVES

Invasive fungal infections (IFIs) remain a major cause of infection-related morbidity and mortality following hematopoietic stem cell transplantation (HSCT).

PATIENTS AND METHODS

We retrospectively analyzed the incidence of IFIs in 166 patients undergoing either allogeneic or autologous HSCT at our institution between January 2000 and December 2003.

RESULTS

Incidence of invasive aspergillosis (IA) and invasive candidiasis among allogeneic HSCT recipients was 23% (16-32%, 95% confidence interval [CI]) and 3% (1-9%, 95% CI), respectively. Duration of neutropenia and reduced-intensity conditioning were the only risk factors for IA in the multivariate model. Patients with IA had significantly reduced overall survival (8% versus 56%, P=0.01) due to higher transplant-related mortality (63% versus 31%, P=0.03). Following autologous HSCT, incidence of IA and invasive candidiasis was 8% (4-19%, 95% CI) and 2% (0.2-11%, 95% CI), respectively. Duration of neutropenia was the only risk factor for the development of IA following autologous HSCT. Overall survival of autologous HSCT recipients with IA was similar to that of patients without IA. Seventeen percent of autologous HSCT recipients were colonized with Candida species. Compared with non-colonized patients these patients had significantly reduced overall survival (72% versus 23%, P=0.004), due to increased treatment-related mortality (23% versus 9%, P=0.02).

CONCLUSION

Diagnosis of IA following allogeneic HSCT and Candida colonization in the setting of autologous HSCT defines patient populations with poor outcome but primarily not as a result of the fungal pathogen. Regarding the incidence of IA, duration of neutropenia is the main risk factor, and dose-reduced conditioning is an additional risk factor for the development of IA following allogeneic HSCT, probably owing to increased recipient age in this patient cohort, requiring further studies in this transplantation setting.

Active CMV disease does not always correlate with viral load detection

The use of quantitative cytomegalovirus (CMV) real-time polymerase chain reaction (RT-PCR) and preemptive ganciclovir therapy is replacing prophylaxis as the management of choice in high-risk patients undergoing stem cell transplantation (SCT). However, there are limited data defining its role in this setting. In the current retrospective single-centre study, quantitative RT-PCR was used to determine CMV in 577 consecutive patients undergoing SCT (172 allogeneic and 405 autologous) over a 5-year period. CMV RT-PCR was performed weekly until cessation of immunosuppression (allogeneic) or for 30 days post-SCT (autologous). Treatment was commenced after two consecutive positive results or a high copy on the first occasion (> 1000 copies/ml, > 3 log). The overall CMV reactivation rate in patients undergoing allogeneic SCT was 30%, with reactivation observed in 72% of high-risk patients (recipient positive patients). CMV end-organ disease was observed in eight patients (1%); of these, four were CMV RT-PCR negative at the time of diagnosis of end-organ CMV disease, with three remaining negative throughout the course of the disease. CMV-related mortality was recorded in three patients. The current data support a preemptive treatment strategy-based CMV RT-PCR, but indicate that in symptomatic patients, a negative CMV PCR result does not exclude CMV end-organ disease.

Complications pulmonaires précoces des allogreffes de cellules souches hématopoïétiques

INTRODUCTION

Pneumonia is one of the main causes of mortality following allogenic stem cell transplantation, especially in the first months after the transplant has been performed.

STATE OF THE ART

Pneumonia is the most common infection occurring after transplant and the infection with the highest mortality. Following the classical, myeloablative approach to transplant, two thirds of the pneumonias that occur are of infectious origin. Their causes roughly follow the timing of the immune reconstitution, and may depend on the type of transplant, the match between donor and recipient, and, overall, the occurrence of graft-versus-host disease. Most bacterial pneumonias occur during the initial neutropenic phase. The 2nd and 3rd month post transplant are mainly complicated by viral pneumonia, especially respiratory virus and adenovirus pneumonia in deeply immunosuppressed patients. Preemptive and prophylactic strategies have considerably reduced the incidence of cytomegalovirus pneumonia. Pneumonia due to encapsulated bacteria, such as Haemophilus influenzae and Streptococcus pneumoniae, usually considered to be late infections, may actually be observed from the second month post-transplant.

PERSPECTIVES

The increasing use of reduced-intensity conditioning regimens has modified the time course of the main adverse events following transplantation, including the timing of the infectious pneumonias. The pneumonias that are specifically related to allogenic transplant are idiopathic interstitial pneumonia, bronchiolitis obliterans, and bronchiolitis obliterans organizing pneumonia, which are all considered to be pulmonary manifestations of graft-versus-host disease, and treated as such. Prophylaxis for many of these infectious pneumonias (i.e., P jiroveci, S pneumoniae, toxoplasmosis) are well standardized.

CONCLUSIONS

Much remains to be done to decrease the incidence of pneumonia in these patients and to understand their mechanisms.

Non-bacterial infections in allogeneic non-myeloablative stem cell transplant recipients

Data on non-bacterial infections during allogeneic non-myeloablative hematopoietic stem cell transplantation (HSCT) are widely different. We evaluated data on 48 consecutive patients who received a conditioning regimen with fludarabine and cyclophosphamide (73%) or fludarabine and total body irradiation (27%) and then underwent allogeneic non-myeloablative HSCT. Cytomegalovirus (CMV) infection was common and occurred in 48% of patients; 3 patients developed CMV disease, and all survived. CMV reactivation was found to be common with both conditioning regimens in our patient population. Invasive aspergillosis occurred in 4 patients (8%) and 3 died. Other serious non-bacterial infections were uncommon. Review of the available literature on non-myeloablative HSCT suggests that the frequency and type of opportunistic infections vary considerably.

Clinical outcomes and direct hospital costs of reduced-intensity allogeneic transplantation in chronic myeloid leukemia

A reduced-intensity conditioning allogeneic stem cell transplantation was given to 19 patients (aged 15-59 years) in the first chronic phase and one patient in the accelerated phase with chronic myeloid leukemia (CML) after a regimen consisting of fludarabine (Flu), busulfan (Bu) and ATG Fresenius. The median follow-up was 27 months. Until day +100, no transplant-related mortality was recorded. The incidence of acute and chronic graft-versus-host disease (GvHD) was 55 and 75%, respectively. Two patients (10%) died from GvHD. Fourteen (70%) patients achieved molecular remission. Additional post-transplant intervention (donor lymphocyte infusion, imatinib) was necessary, however, in 10 patients (50% of the patients; non-achievement of stable molecular remission or later relapses). The total direct cost of the transplantation treatment for all of the patients came to 1,572,880 euro. If the patients had been treated with imatinib and followed-up with the same time period as they were following a transplantation, the direct cost of the imatinib treatment would have been 2,005,117 euro. The transplantation treatment appears to be less expensive after approximately 2 years of follow-up. Flu+Bu+ATG is a low-toxicity regimen for patients with CML. However, a close follow-up is necessary and about 50% of the patients require further therapeutic intervention.

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.

Impact of the intensity of the pretransplantation conditioning regimen in patients with prior invasive aspergillosis undergoing allogeneic hematopoietic stem cell transplantation: A retrospective survey of the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

In this retrospective study, we analyzed the outcomes of 129 patients who underwent an allogeneic hematopoietic stem cell transplantation (allo-HSCT) and had a history of probable or proven invasive aspergillosis (IA), of whom 57 (44%) received a reduced-intensity conditioning (RIC). Overall, 27 patients with IA progressed after the allo-HSCT (cumulative incidence [CumInc] at 2 years, 22%). The variables that increased the 2-year CumInc of IA progression were (1) longer duration of neutropenia after transplantation; (2) advanced status of the underlying disease; and (3) less than 6 weeks from start of systemic anti-Aspergillus therapy and the allo-HSCT. In addition, (4) conventional myeloablative conditioning increased the risk of progression early after transplantation (before day 30) only, while 3 variables increased the risk beyond day 30 were (5) cytomegalovirus disease; (6) bone marrow or cord blood as source of stem cells; and (7) grades II to IV acute graft-versus-host disease (GVHD). A risk model for progression was generated, defined as low (0-1 risk factors, 6% incidence), intermediate (2-3 risk factors, 27% incidence), or high risk (> or = 3 risk factors, 72% incidence [P < .001]). These findings may help in the interpretation and design of future studies on secondary prophylaxis of IA after an allo-HSCT.

Graft-versus-tumor effects on murine mammary carcinoma in a model of nonmyeloablative haploidentical stem cell transplantation

Despite a slight decrease in mortality over the last decade, breast cancer still remains a leading cause of cancer-related death in women. Although anti-tumor effects have been observed after allogeneic stem cell transplantation (SCT), this treatment is not standard care owing to graft-versus-host disease (GVHD) and scarcity of suitable donors. With the aim of reducing treatment-related mortality and increasing donor availability in clinical situations, we developed a preclinical mouse model that combines nonmyeloablative conditioning with the use of haploidentical donor-recipient pairs. To mimic active disease, CB6F1 mice were inoculated with 5 x 10(4) 4T1 mammary carcinoma cells 10 days before transplantation. Keratinocyte growth factor (KGF) was used as GVHD prophylaxis. Syngeneic (CB6F1) SCT did not cure any of the mice and KGF treatment did not influence tumor development. After transplantation with haploidentical (B6CBAF1) bone marrow and splenocytes, however, tumor outgrowth was reduced and long-term disease-free survival (>3 months) was observed in 9/18 (50%) (P=0.0011) of the animals. We conclude that in a model of murine breast cancer, a graft-versus-tumor effect can be induced by a nonmyeloablative haploidentical SCT procedure.

Cytomegalovirus (CMV) infections and CMV-specific cellular immune reconstitution following reduced intensity conditioning allogeneic stem cell transplantation with Alemtuzumab

We studied the incidence and recurrence of Cytomegalovirus (CMV) infection and reactivation in 38 recipients of Alemtuzumab reduced intensity conditioning-stem cell transplantation, and used CMV-HLA tetramer studies to discover if these events correlated with recovery of circulating CMV-specific CD8+ T cells (cytotoxic T lymphocyte (CTLs)). The cumulative incidence of CMV infection was 60% at 1 year (95% CI, 45-78%) with a median reactivation time of 24 days (range 5-95 days). All patients with CMV reactivation received Ganciclovir or Foscarnet, and only one developed CMV disease. More strikingly, only 8/21 patients had relapse of CMV antigenemia. Tetramer analysis in 13 patients showed that 11 reconstituted CMV CTLs (7/11 by day 30 and 10/11 by day 90). The development of CMV infection was accompanied by a >5-fold rise of CMV CTLs. Recurrence of CMV infection occurred only in the patients who failed to generate a CTL response to the virus. Hence, recipients of SCT using Alemtuzumab-RIC are initially profoundly immunosuppressed and have a high incidence of early CMV reactivation. However, in the majority of patients, infection is transient, and antiviral T cell reconstitution is rapid. Monitoring with CMV-specific CTLs may help identify the subset of patients at risk from recurrent infection or disease.

Keratinocyte growth factor ameliorates acute graft-versus-host disease in a novel nonmyeloablative haploidentical transplantation model

Allogeneic stem cell transplantations (SCT) are currently being used as a therapy for hematological malignancies, some solid tumors and nonmalignant bone marrow deficiencies. Nevertheless, clinical applicability is limited due to toxicity of conditioning regimens, graft-versus-host disease (GVHD) and the scarcity of HLA-identical family donors. New concepts are based on nonmyeloablative conditioning to reduce toxicity, prevention or amelioration of GVHD and the use of haploidentical donors to increase donor availability. To combine these requirements, we have developed a nonmyeloablative conditioning regimen, consisting of low-dose total body irradiation and cyclophosphamide-based chemotherapy. In a haploidentical F1 --> F1 mouse model, this nonmyeloablative transplantation protocol resulted in stable full donor chimerism, but also in the development of severe GVHD. Administration of keratinocyte growth factor (KGF) reduced GVHD, evident as reduced weight loss and a lesser degree of dermatitis, compared to saline-treated controls. KGF preserved plasma citrulline and tumor necrosis factor-alpha levels, both indicative for reduced injury to the gastrointestinal tract. This was confirmed by histological findings. At 6 months after transplantation, survival rates were significantly higher in KGF-treated animals as compared to phosphate buffered saline-treated controls. These results indicate that KGF preserves gut integrity and might therefore contribute substantially to reduction of lethal GVHD in (nonmyeloablative) haploidentical transplantation.

Do minitransplants have minicosts? A cost comparison between myeloablative and nonmyeloablative allogeneic stem cell transplant in patients with acute myeloid leukemia

Allogeneic hematopoietic stem cell transplantation (SCT) is a widely used, cost-intensive procedure. Although pretransplant nonmyeloablative (NMA) or reduced-intensity conditioning regimens appear very promising, prospective studies comparing this approach with the conventional myeloablative (MA) approach in specific hematologic diseases are necessary, especially in patients in whom the conventional approach is not contraindicated. Cost may be an important factor in the decision-making process. We compared the costs of MA and NMA transplants in patients with acute myeloid leukemia (AML). We estimated 1-year resource utilization in 12 consecutive MA patients (median age: 39 years) and in 11 consecutive NMA patients (median age: 58 years) who underwent HLA-identical sibling SCT for AML. Resources care expenses were valued using the average daily rate for personnel costs, supplies, and room costs. Other data were directly collected from the patients' charts. Despite a trend for lower costs in NMA patients during the first 6 months, costs during the 6-12-month period were significantly higher after NMA due to late complications and readmissions (P=0.03). Finally, mean 1-year costs were not different in MA and NMA patients (P=0.75). Prospective studies comparing conventional and NMA approaches in homogeneous populations should include economic items.

New findings and key questions in hematopoietic stem cell transplantation

Invasive aspergillosis remains the primary cause of death from infection following allogeneic stem cell transplantation. Most cases occur during the second or third month after transplantation, during graft-versus-host disease or immunosuppression. Strategies for management of these cases include the development of more effective antifungals for prophylaxis, the use of biological markers to improve the early diagnosis of aspergillosis, new approaches to transplantation to reduce the risk of infection, and the emerging area of targeted cellular therapy.

Influence of the intensity of the conditioning regimen on the characteristics of acute and chronic graft-versus-host disease after allogeneic transplantation

The graft-versus-host disease (GVHD) characteristics of 150 consecutive patients undergoing reduced intensity conditioning allogeneic (allo-RIC) transplants and 88 patients undergoing myeloablative conditioning regimen were analysed. All patients received the same GVHD prophylaxis and peripheral blood stem cells from a human leucocyte antigen identical sibling. The cumulative incidence of acute GVHD (aGVHD) was 67% and 44% in the myeloablative and allo-RIC regimen groups, respectively (P < 0.001), and was 39% vs. 29%, respectively (P = 0.043), for grades 2-4 aGVHD. Only conditioning type (myeloablative versus allo-RIC) significantly influenced the incidence of aGVHD in multivariate analysis: Hazard ratio (HR) = 2.16 [95% confidence interval (CI): 1.52-3.07], P < 0.0001. The cumulative incidence of chronic GVHD (cGVHD) was 63% and 71% among myeloablative and allo-RIC patients respectively (P = 0.084). This trend was because of the higher incidence of limited cGVHD, but not extensive cGVHD among allo-RIC recipients [HR = 3.3 (95% CI: 1.42-8.08), P = 0.0017]. Moreover, among patients who developed cGVHD, the cumulative incidence of limited cGVHD was significantly lower in the myeloablative group than in the allo-RIC group (7% vs. 25%, P = 0.007). Duration of immunosuppression was shorter among allo-RIC patients (35.5% vs. 68.8% required systemic immunosuppression 36 months after transplant, P = 0.028). Although prospective controlled trials are required to further evaluate the effect of the conditioning regimen on GVHD, our results suggest that RIC modifies the incidence and characteristics of both acute and cGVHD after allogeneic transplantation, and decreases the immunosuppression requirements in long-term follow up when compared with myeloablative conditioning.

Retrospective multicenter study of allogeneic peripheral blood stem cell transplantation followed by reduced-intensity conditioning or conventional myeloablative regimen

This retrospective study compared the results of reduced-intensity conditioning stem cell transplantation (RIST) and a conventional myeloablative regimen (CST) followed by allogeneic peripheral blood stem cell transplantation. In this respect, 63 RISTs and 41 CSTs were performed at 5 transplantation centers in Korea between April 1998 and December 2002. The RIST group had more adverse pretransplant characteristics. More aggressive diseases, like acute myeloid or lymphoblastic leukemia, were included in the CST group, while the RIST group included more indolent diseases, like chronic myeloid leukemia or myeloma (p < 0.001). The incidence of acute graft-versus-host disease (GVHD) grades 2-4 was 29.1 and 57.9% for the RIST and CST groups, respectively (p = 0.010), yet the incidence of chronic GVHD was similar in the two groups (57.4 vs. 71.9%). With a median follow-up of 13 months (0.5-61 months, 17 months in 52 survivors), the 3-year overall (OS) and disease-free survival (DFS) was similar in the RIST and CST groups (p = 0.965 for OS, p = 0.545 for DFS). In a multivariate analysis, RIST (p = 0.010), good performance status (p = 0.006) and a higher CD34+ cell dose (p = 0.008) were all identified as independent favorable prognostic factors for OS. Accordingly, in the current study, RIST produced equivalent or acceptable results compared with CST in terms of OS. Therefore, a prospective randomized trial of RIST and CST is warranted.

Reduced-Intensity Conditioning Allogeneic Blood Stem Cell Transplantation with Fludarabine and Oral Busulfan with or without Pharmacokinetically Targeted Busulfan Dosing in Patients with Myeloid Leukemia Ineligible for Conventional Conditioning

We prospectively compared outcomes after a fludarabine (Flu) plus oral busulfan (Bu)-containing reduced-intensity conditioning regimen (150 mg/m2 Flu and 10 mg/kg oral Bu), with (n = 32; Flu- T Bu group) or without (n = 30; Flu-Bu group) therapeutic dose monitoring and dose adjustment of Bu. All patients received peripheral blood stem cells from a genoidentical sibling, and study cohorts had similar patient characteristics. Dose adjustments of Bu were required in 20 (63%) patients in the Flu- T Bu group (median final dose, 8.89 mg/kg; range, 6.3-13.34 mg/kg). Donor T-cell and granulocyte engraftments were similar, and early conditioning-related toxicities were mild and similar in both study groups. With a median follow-up of 45 months (51 months in the 37 survivors), posttransplantation outcomes did not differ between cohorts. The strongest predictor of 2-year overall survival and leukemia-free survival was the presence of chronic graft-versus-host disease (77% versus 34% for overall survival and 74% versus 34% for leukemia-free survival; P < .001 for both outcomes). In conclusion, therapeutic dose monitoring of oral Bu in a reduced-intensity conditioning setting does not seem to affect outcome, although further studies may identify very-high-risk patients who benefit from this strategy.

Incidence of Human Cytomegalovirus Infection in Patients with Refractory Solid Tumors Receiving Nonmyeloablative Allogeneic Stem Cell Transplants versus Recipients of Standard SCT for Hematologic Malignancies

Human cytomegalovirus (HCMV) infection is the most frequent infectious complication after conventional allogeneic stem cell transplantation (alloSCT). From December 1998 to December 2002, we prospectively monitored HCMV reactivation in 59 patients affected by solid tumors and undergoing nonmyeloablative alloSCT (NST). Patients were allografted from HLA-identical sibling donors after fludarabine/cyclophosphamide-based conditioning regimens. Seventeen (28.8%) of 59 patients presented with HCMV antigenemia, and 14 received ganciclovir, with successful HCMV clearance in all cases. No patient developed HCMV viremia or disease. The median time to HCMV reactivation was 54 days (range, 16-245 days) after NST. These patients were compared with a cohort of hematologic patients who were treated with conventional myeloablative alloSCT. Matching criteria included HCMV risk group, stem cell source, donor type, and age. In the myeloablative group, HCMV active infection was observed in 47 (85.4%) of 55 patients at a median time of 30 days (range, 13-64 days) after alloSCT, and HCMV infection occurred more frequently ( P < .001) and earlier ( P = .001) than in NST patients. Patients affected with solid tumors undergoing NST had a reduced and delayed incidence of HCMV active infection.

Impact of early NK cell recovery on development of GvHD and CMV reactivation in dose-reduced regimen prior to allogeneic PBSCT

Dose-reduced allogeneic peripheral blood stem cell transplantation (PBSCT) is a therapeutic approach for patients with haematological malignancies who are not eligible for conventional allogeneic PBSCT. We analysed early development of lymphocyte subpopulations and the occurrence of cytomegalovirus (CMV) reactivation and acute graft-versus-host reaction (GvHD) in patients undergoing the protocol according to Slavin vs conventionally treated patients. Lymphocyte status prior to conditioning and at day +30 after allogeneic PBSCT was determined in 24 out of 51 patients who received conventional allogeneic PBSCT (eg cyclophosphamide plus total body irradiation) and compared with 27 patients being treated according to the Slavin protocol (fludarabine, busulphan and ATG). There is a significant delay in CD4 (T helper) cell development and consecutive lower CD4/CD8 ratios and a better reconstitution of CD8 (T cytotoxic) and NK (natural killer) cells after the Slavin protocol. Patients undergoing this protocol and no, or only grade I, acute GvHD show an even better NK cell reconstitution compared to patients with grade II-IV GvHD. A low CD4/CD8 ratio represents a CMV risk factor only in conventionally treated patients with grade 0-I GvHD, while after preparative regimen according to the Slavin protocol, the NK/CD8 ratio might be a marker for the prediction of CMV reactivation in addition to CMV risk status.

The changing face of invasive fungal infections in hematopoietic cell transplant recipients

PURPOSE OF REVIEW

To review recent observations that describe changes in the likelihood of invasive fungal infections, shifts in types of fungal pathogens, and altered manifestations of fungal syndromes after hematopoietic cell transplantation and explore how changes in transplant practices are influencing these epidemiologic shifts.

RECENT FINDINGS

Shifts in invasive fungal infections are occurring as a consequence of changes in transplant practices, including the intensity of conditioning regimens, new immunosuppressive therapies, new antineoplastic therapies administered before hematopoietic cell transplantation, and possibly use of mold-active agents as prophylaxis. Non-fumigatus Aspergillus species and other mold pathogens, such as Fusarium and zygomycosis, are assuming greater prominence and may be increasing.

SUMMARY

Epidemiologic shifts in invasive fungal infections are likely co-travelers with advances in transplant practices. Thus, ongoing studies of epidemiologic shifts in invasive fungal infections are important.

Aspergillus infections in transplant recipients

Aspergillus infections are occurring with an increasing frequency in transplant recipients. Notable changes in the epidemiologic characteristics of this infection have occurred; these include a change in risk factors and later onset of infection. Management of invasive aspergillosis continues to be challenging, and the mortality rate, despite the use of newer antifungal agents, remains unacceptably high. Performing molecular studies to discern new targets for antifungal activity, identifying signaling pathways that may be amenable to immunologic interventions, assessing combination regimens of antifungal agents or combining antifungal agents with modulation of the host defense mechanisms, and devising diagnostic assays that can rapidly and reliably diagnose infections represent areas for future investigations that may lead to further improvement in outcomes.

Elderly age and prior autologous transplantation have a deleterious effect on survival following allogeneic peripheral blood stem cell transplantation with reduced-intensity conditioning: results from the Spanish multicenter prospective trial

Over a 3-year period, 145 patients ineligible for myeloablative conditioning underwent reduced-intensity conditioning (RIC) hematopoietic stem cell transplantation (SCT) from an HLA-identical sibling in a prospective study. The median age was 54 years, 88 patients were male and 61 patients were beyond the early-intermediate phase of their disease. The 100-day probability of developing grade II-IV acute graft-versus-host disease (GVHD) was 34%, and the 1-year probability of developing chronic extensive GVHD was 41%. The 1-year probabilities of transplant-related mortality (TRM), overall (OS) and progression-free survival were 20, 60 and 52%, respectively. Multivariate analyses found a better OS in: (i) patients <60 years; and (ii) recipients of a first SCT; and a higher TRM in: (i) age >60 years, (ii) recipients of a prior autologous SCT, and (iii) an ECOG performance status >1. The 1-year TRM in patients with 0 or 1 and >2 of the above-mentioned adverse prognostic factors were 17 vs 53%, respectively (P<0.001). In summary, our study shows that elderly patients have a higher TRM following an RIC protocol. However, age by itself should not preclude these RIC transplants, since TRM appears to be unacceptably high only in the presence of additional adverse factors.

Impact of unrelated donor status on the incidence and outcome of cytomegalovirus infections after non-myeloablative allogeneic stem cell transplantation

Little is known about the impact of cytomegalovirus (CMV) infections that occur after human leucocyte antigen (HLA)-matched unrelated donor (MUD) non-myleoablative haematopoietic stem cell transplantation (HCT). We analysed the incidence, onset and outcomes of CMV infections in 59 recipients of MUD and in 109 recipients of HLA-matched related donor (MRD) allogeneic HCT following non-myeloablative conditioning containing 2 Gy total body irradiation and fludarabine. In CMV seropositive recipients, antigenaemia occurred in 68% (MUD) and in 49% (MRD, P = 0.08); there were no differences in the maximum levels of CMV antigenaemia and the time to cessation with antiviral therapy. CMV viraemia by culture was more common in MUD compared with MRD HCT recipients in univariate analysis (26% vs. 6%, P = 0.01), however, this difference was not detectable after controlling for other factors. The rates of CMV disease in the first 100 d were similar in MUD (9%) and MRD (5%) HCT recipients. CMV disease tended to occur earlier in the MUD compared with the MRD recipients (median day 41 vs. day 80). Beyond day 100, rates of CMV disease remained similar in both cohorts (cumulative incidence: MUD 21% and MRD 14%). The 30-d and 1-year survivals after CMV disease diagnosis were not significantly different in both groups. Thus, there appeared to be a trend toward increased CMV reactivation in MUD compared with MRD non-myeloablative allogeneic HCT recipients; however, these differences did not reach statistical significance in this cohort and preemptive therapy was similarly effective in preventing CMV diseases.

Rapid induction of complete donor chimerism by the use of a reduced-intensity conditioning regimen composed of fludarabine and melphalan in allogeneic stem cell transplantation for metastatic solid tumors

We evaluated the feasibility and efficacy of a reduced-intensity conditioning (RIC) regimen of fludarabine and melphalan to achieve rapid complete donor chimerism after allogeneic stem cell transplantation (SCT) in patients with metastatic solid tumors. Between January 1999 and January 2003, 8 patients with metastatic breast cancer (BC) and 15 with metastatic renal cell carcinoma (RCC) underwent allogeneic SCT after an RIC regimen of 5 days of fludarabine and 2 days of melphalan. Filgrastim-mobilized stem cells from HLA-identical related or unrelated donors were infused. Prophylaxis for graft-versus-host disease (GVHD) consisted of tacrolimus and methotrexate. All 22 evaluable patients had 100% donor chimerism at day 30 and at all measurement times thereafter. One patient died 19 days after SCT. Nine patients (39%) had grades II to IV acute GVHD and 10 patients (43%) had chronic GVHD. Five patients (22%) died of nonrelapse treatment-related complications. Treatment-related disease response was seen in 10 patients (45%), with 3 complete responses, 2 partial responses, and 5 minor responses. Fludarabine-melphalan is a feasible and effective RIC regimen for allogeneic SCT in metastatic BC and RCC. It induces rapid complete donor chimerism without the need for donor lymphocyte infusion. Tumor regression associated with GVHD is consistent with graft-versus-tumor effect.

T- and B-cell immune reconstitution and clinical outcome in patients with multiple myeloma receiving T-cell-depleted, reduced-intensity allogeneic stem cell transplantation with an alemtuzumab-containing conditioning regimen followed by escalated donor ly

Immune reconstitution after conventional allogeneic transplantation is a major determinant of survival. We conducted a detailed investigation of T- and B-cell immune reconstitution and clinical outcome in 19 patients with multiple myeloma undergoing reduced-intensity stem cell transplantation using in vivo T-cell depletion with alemtuzumab. These patients experienced delayed T-cell recovery, particularly in the naïve (CD45 RA+) CD4 compartment. T-cell receptor spectratype analysis showed a reduced repertoire diversity, which improved rapidly after the administration of donor leucocyte infusions and subsequent conversion to full donor T-cell chimaerism. Post-transplant recovery of CD19+ B cells was also delayed for up to 18 months. Spectratype analysis of IgH CDR3 repertoire revealed a gradual normalization in IgM spectratype complexity by 6-12 months after transplant. There was a high incidence of viral infection, particularly cytomegalovirus reactivation, but the regimen-related mortality was low, perhaps because of the very low incidence of acute graft-versus-host disease (GVHD; grade I-II skin GVHD was seen in 5/19 patients). Over 80% of all patients have relapsed at a median of 283 (range 153-895) d after transplant, suggesting that the initially low rate of GVHD comes at a high price with regard to the desired graft-versus-myeloma effect.