Genetic variability of cytomegalovirus glycoprotein O in hematopoietic stem cell transplant recipients

K. Roubalova, O. Strunecky, A. Vitek, S. Zufanova, B. Prochazka. Genetic variability of cytomegalovirus glycoprotein O in hematopoietic stem cell transplant recipients.
Transpl Infect Dis 2011: 13: 237–243. All rights reserved Abstract: Genetic variation of cytomegalovirus (CMV) strains can correlate with their pathogenicity for immunocompromised patients. Glycoprotein O (gO), together with glycoprotein L and glycoprotein H, mediate the fusion of the viral envelope with the cell membrane and promotes virus penetration, envelopment, and release. The variability of gO might play a role in CMV cell tropism. The goal was a retrospective analysis of gO variability in a cohort of hematopoietic stem cell transplant (HSCT) recipients to determine the distribution of gO genotypes and to investigate their impact on clinical outcome and manifestation of CMV infection. Methods. In archived blood samples from 51 adult allogeneic HSCT recipients with active CMV infection, gO was analyzed by sequencing the N‐terminal domain of the UL74 gene using the dye deoxy termination method. Results. The gO1 and gO2 clades were most common (39% and 20%, respectively, and gO3 was associated with higher risk of symptomatic infection (P=0.026 in multivariant analysis). Despite being associated with higher antigenemia levels (P=0.02), gO4 had the best survival and lower rate of CMV recurrence. No significant differences were found in clinical manifestation and outcome of CMV disease between patients with various gO clades. Because CMV strains sharing an identical gO sequence differed in glycoprotein B genotypes, sequencing the N‐terminal part of the gO gene does not seem to be optimal for the identification of strains. Conclusions. gO genotyping may contribute to the biological characterization of CMV strains in HSCT recipients.     

Central nervous system aspergillosis in allogeneic stem cell transplant recipients

Invasive aspergillosis (IA) is relatively common in allogeneic stem cell transplant (SCT) recipients. Although lungs are the most common site, central nervous system (CNS) involvement is also observed in this setting. We have retrospectively studied 14 cases of CNS aspergillosis found in a cohort of 455 allogeneic SCT recipients (incidence 3%). All patients, except one, had experienced acute graft-versus-host disease treated with high-dose methylprednisolone, and eight patients (57%) had also received ATG. The median time to the diagnosis of CNS aspergillosis was 124 days (range 49-347 days) from SCT. Pulmonary aspergillosis had been diagnosed earlier in four patients (29%). The most common initial symptoms of CNS aspergillosis were convulsions, hemiparesis, and mental alteration. Neuroradiological studies revealed single (two patients) or multiple (seven patients) focal lesions of 0.2-9 cm in diameter. Despite clinical suspicion in many patients, a confirmed diagnosis of CNS aspergillosis was made during life in only one patient. A total of 12 patients (86%) received amphotericin B. Despite therapy, all patients died 0-27 days (median seven days) after the initial CNS symptoms. CNS aspergillosis is not uncommon in allogeneic SCT recipients. Clinical manifestations are usually dramatic and progress quickly. Earlier and more effective treatment of IA is needed to prevent dissemination of infection into the CNS.     

Recurrent trichosporonosis with central nervous system involvement in an allogeneic hematopoietic stem cell transplant recipient

Trichosporon is an ubiquitous yeast that has emerged as an opportunistic pathogen in the immunocompromised host. We describe a case of invasive trichosporonosis in an allogeneic hematopoietic stem cell transplant (allo‐HSCT) recipient while on caspofungin antifungal prophylaxis. She developed disseminated trichosporonosis in the pre‐engraftment period and was successfully treated with voriconazole. She later developed 2 further episodes of invasive trichosporonosis involving the central nervous system. This case highlights the challenges of managing trichosporonosis in allo‐HSCT recipients and suggests the need for lifelong therapy in some patients.     

Antifungal prophylaxis in hematopoietic stem cell transplant recipients

Infections remain a major complication of hematopoietic stem cell transplantation, with recent trends indicating that fungal pathogens have become one of the most common causes of death. Attention has turned to the use of prophylactic antifungal medications to prevent infection with both Candida and Aspergillus species. Recent studies, which are reviewed within, indicate success in preventing infections caused by azole-susceptible Candida species, accompanied by improved transplant-related mortality rates in high-risk patients. Further studies are necessary to develop strategies to prevent infection with Aspergillus species.     

异基因造血干细胞移植后中枢神经系统移植物抗宿主病的研究进展

正异基因造血干细胞移植(allogeneic hematopoietic stem cell transplantation,allo-HSCT)是对多种血液病治疗有效、甚至是唯一可治愈的治疗手段。研究[1～4]显示,allo-HSCT后中枢神经系统并发症(central nervous system complication,CNSC)发病率在8%～42%,而病死率在40%～70%,严重影响移植后患者长期生存。CNSC可分为药物毒性、感染性、代谢性、脑血管性、免疫性、肿瘤性并发症及微血管血栓病变,而中枢神经系统移植物抗宿主病(central nervous system graftversus-host disease,CNS-GVHD)是免疫性CNSC中的一种特殊类型[3]。由于脑组织难于获取,CNS-GVHD很     

Adenovirus infections in hematopoietic stem cell transplant recipients.

We report a 12% incidence of adenovirus infections among 532 recipients of hematopoietic stem cell transplant (HSCT) from January 1986 through March 1997. The median time from day of stem cell infusion to first positive culture was 41 days. Recipients of allogeneic stem cells, as opposed to autologous stem cell recipients, were more likely to have a culture positive for adenovirus (16% vs. 3%; P<.0001). Pediatric patients were also more likely than adults to have a positive culture (23% vs. 9%; P<.0001). Among stem cell recipients with partially matched related donors, pediatric recipients appear to be at significantly greater risk for infection than adult recipients (P<.001). Positive cultures were associated with evidence of invasion in 64% of cases (41 of 64). A multiple logistic regression analysis showed that isolating adenovirus from more than 1 site correlated with greater risk for invasive infections (P=.002). Invasive infections were associated with poorer chance of survival.     

Infections of the central nervous system in transplant recipients

Central nervous system (CNS) infections, accounting for 4–29% of CNS lesions in transplant recipients, are a significant post‐transplant complication. Focal CNS infectious lesions or brain abscesses have been documented in 0.36–1% of the transplant recipients. Mycelial fungi, particularly Aspergillus, are by far the most frequent etiologies of post‐transplant brain abscesses. Bacteria, with the exception of Nocardia, are rarely associated with brain abscesses in transplant recipients. Time of onset and concurrent extraneural lesions have implications relevant towards invasive diagnostic procedures in transplant recipients with brain abscesses. Meningoencephalitis in transplant recipients is predominantly due to viruses, e.g., herpesviruses, and less frequently due to Listeria monocytogenes, Toxoplasma gondii, and Cryptococcus. Despite a wide, and at times perplexing array of opportunistic pathogens that can cause CNS infections, the temporal association of the infection with the time elapsed since transplantation, risk factors, clinical manifestations, and neuroimaging characteristics of the lesion can allow a reasoned and rational approach towards the recognition, diagnosis, and appropriate management of CNS infections in transplant recipients.     

Varicella zoster central nervous system vasculitis after allogeneic hematopoietic stem cell transplant successfully treated with cyclophosphamide

We report the first case of varicella zoster central nervous system vasculitis, to our knowledge, which responded to intravenous pulses of cyclophosphamide in an immunocompromised child with severe and progressive disease, without sequelae.     

Current antiviral strategies for controlling cytomegalovirus in hematopoietic stem cell transplant recipients: prevention and therapy

Cytomegalovirus (CMV) remains a cause of significant morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Ganciclovir prophylaxis, or preemptive treatment based on detection of antigenemia or CMV DNA by PCR, effectively prevents CMV disease during the first 100 days after transplant in allograft recipients. In recipients of T-cell depleted transplant or if severe acute graft-versus-host disease is present, ganciclovir prophylaxis or preemptive treatment should be started with an induction course of ganciclovir (5 mg/kg BID) and given at least 5 days per week and continued until day 100 after transplant. Although prevention of CMV disease before day 100 is highly effective, there is a continued risk of late-onset CMV disease after day 100. In CMV-seropositive recipients, the incidence of late CMV disease may be as high as 17%. Strategies to prevent late CMV infection and disease are needed. In seronegative recipients, seronegative or leukocyte-reduced blood products are effective in preventing acquisition of CMV through blood products. Controversy exists about the optimal strategy of preventing CMV disease in seropositive autologous HSCT recipients. The outcome of CMV pneumonia remains poor despite treatment with ganciclovir in combination with CMV hyperimmune globulin or intravenous immunoglobulin. Owing to continued clinical significance of CMV in the HSCT setting, new and more effective anti-CMV drugs with improved pharmacokinetic properties are urgently needed.     

Analysis of rotavirus antigenemia in hematopoietic stem cell transplant recipients

Systemic rotavirus infection, such as rotavirus antigenemia, has been found in immunocompetent rotavirus gastroenteritis patients. However, the pathogenesis of rotavirus infection in immunocompromised transplant recipients remains unclear. Enzyme-linked immunosorbent assay was used to measure rotavirus antigen levels in serially collected serum samples obtained from 62 pediatric patients receiving allogeneic hematopoietic stem cell transplants (HSCT). Rotavirus antigen was detected in 43 (6.8%) of 633 serum samples (8 of 62 patients). The duration of rotavirus antigenemia ranged between 1 and 10 weeks, and diarrhea was concurrent with rotavirus antigenemia in Cases 3, 6, 7, and 8. The level of viral antigen in the transplant recipients (0.19 ± 0.20) was significantly lower than that observed in serum samples collected from immunocompetent patients on either day 1 (0.49 ± 0.18, P = 0.0011) or day 3 (0.63 ± 0.09, P = 0.0005). A patient who received a graft from a human leukocyte antigen (HLA)-mismatched donor was at significant risk for rotavirus antigenemia (P = 0.024; odds ratio = 9.44) in comparison to patients who received grafts from HLA-matched donors. Although the duration of antigenemia was clearly longer in HSCT patients than in immunocompetent rotavirus gastroenteritis patients, the levels of viral antigen were not as high. Therefore, mismatched HLA may be a risk factor for rotavirus antigenemia after HSCT.     

Outcome of alveolar hemorrhage in hematopoietic stem cell transplant recipients

Alveolar hemorrhage (AH) is a frequent, serious complication of hematopoietic stem cell transplantation (HSCT). To study the incidence of AH, its clinical course and outcomes in HSCT patients, a retrospective review of the records of all adult patients who underwent bronchoscopy between January 1, 2002 and December 31, 2004 was carried out and those who underwent bronchoscopy after HSCT identified. A total of 223 patients underwent bronchoscopy after HSCT for diffuse pulmonary infiltrates with respiratory compromise. Eighty-seven (39%) patients had AH. Of these, 53 had AH without any identified organism while 34 had an organism along with hemorrhage on bronchoalveolar lavage (BAL). Six-month survival rate of patients with AH was 38% (95% confidence interval: 27-48%). In 95 of the 223 patients, an organism was isolated from BAL. These patients had poor outcomes compared to patients in whom no organism was identified. Patients with both AH and an organism had the worst prognosis. Mortality of patients with AH is improving and long-term survival of patients with AH is feasible. Isolation of a microbial organism in BAL is a strong predictor of poor outcome.     

UL54 foscarnet mutation in an hematopoietic stem cell transplant recipient with cytomegalovirus disease

We present a case of foscarnet (FOS) resistance arising from a UL54 mutation after a short duration of FOS exposure, which has not been previously described in a stem cell transplant recipient, to our knowledge. We discuss the use of FOS to treat other viral infections and the implications this may have for the development of resistance mutations and treatment of cytomegalovirus disease.     

Acquired factor VII deficiency in hematopoietic stem cell transplant recipients

Acquired factor VII (FVII) deficiency in the absence of vitamin K deficiency, oral anticoagulant therapy, synthetic liver dysfunction, or DIC is rare, with only a handful of cases thus far reported. In the period from 1990 to 1996 we identified eight patients with acquired FVII deficiency, all of whom presented with prolongation of the prothrombin time (PT) in the first 2 weeks following stem cell transplantation (SCT). The mean plasma FVII clotting activity (FVII:c) was 22% (range 8-35%) with an approximately equivalent reduction in FVII antigen (FVII:Ag) level. Mean plasma levels of fibrinogen and factors II, V, IX, and X were normal. Protein C activity was significantly depressed in only one of the three patients in whom it was measured. Several patients experienced bleeding complications, and hemorrhage directly accounted for death in two cases. Veno-occlusive disease of the liver developed in three patients. We conclude that FVII deficiency should be considered in the differential diagnosis of prolonged PT in patients who have recently undergone SCT. The mechanism of this acquired deficiency state remains to be defined.     

Oral valganciclovir as preemptive therapy is effective for cytomegalovirus infection in allogeneic hematopoietic stem cell transplant recipients

Between March 2007 and January 2008, the safety and efficacy of oral valganciclovir (VGC) preemptive therapy for cytomegalovirus (CMV) infection was evaluated in ten consecutive patients who received allogeneic hematopoietic stem cell transplantation (HSCT). Patients were screened once or twice per week after engraftment using CMV pp65 antigenemia assay. When more than 2 CMV antigen-positive cells per 50,000 leukocytes were detected, preemptive therapy with oral VGC was initiated at a dose of 900 mg twice daily for 3 weeks. Nine patients (90%) completed the 3-week VGC treatment except for one patient who developed febrile neutropenia. There was no other significant toxicity. CMV antigen-positive cells were rapidly decreased in all nine patients and became undetectable by the end of the VGC treatment. None of the patients developed CMV disease. CMV infection relapsed in four of the ten patients (40%) after the VGC treatment. These observations suggest that preemptive therapy with VGC is effective for preventing CMV disease in allogeneic HSCT patients. Further studies with a large number of patients will be necessary to determine the optimal initial- and maintenance-dose of VGC.     

Invasive fungal disease in allogeneic hematopoietic stem cell transplant recipients: an autopsy-driven survey

Abstract: Invasive mycoses are pre-eminent causes of morbidity and mortality in the allogeneic stem cell transplant setting. In spite of novel diagnostic modalities, the timely and specific identification of invasive mycoses still remains challenging. We analyzed the case history of 97 consecutive patients receiving 103 allogeneic stem cell transplants between January 2003 and October 2006 performed by a single team at 2 transplant centers in Budapest, Hungary. All patients with febrile neutropenia not responding to broad-spectrum antibacterial therapy received amphotericin B deoxycholate empirically. In cases of proven or probable invasive aspergillosis, intravenous voriconazole was instituted. Patients who failed to improve on initial therapy were treated with an antifungal combination, while responders were switched to oral voriconazole. A total of 38 patients died following allografting. Both centers had an autopsy rate of 100% due to central health care regulations. An infectious cause of death could be identified in 15 cases, invasive fungal disease being the most prevalent and accounting for 10 fatalities. Six patients died of invasive aspergillosis, while invasive candidiasis and mucormycosis led to a fatal outcome in 2 cases each. Despite the regular use of galactomannan antigen detections and imaging, an ante mortem diagnosis of proven/probable invasive fungal disease could only be established in 4 of 10 autopsy-verified cases (aspergillosis: 3, candidiasis: 1, mucormycosis: 0). In the remaining 6 patients, deep mycoses were missed clinically and were revealed only by postmortem histology. Present diagnostic and therapeutic strategies still seem to be suboptimal for the management of invasive fungal diseases in the high-risk allogeneic stem cell transplant population.