Successful ribavirin therapy for severe adenovirus hemorrhagic cystitis after allogeneic marrow transplant from close HLA donors rather than distant donors

Overcoming post-transplant graft failure and adenovirus infection in a patient with FLT3-TKD-mutated mixed-phenotype acute leukemia: A case report

Mixed-phenotype acute leukemia (MPAL) with FLT3-TKD mutations is a rare and challenging subtype of leukemia. Effective management strategies are crucial for improving patient outcomes. A 31-year-old man with FLT3-TKD-mutated MPAL achieved hematological remission through the JALSG ALL202-O protocol and gilteritinib, followed by cord blood transplantation (CBT). Post-transplant complications included adenovirus-induced hemorrhagic cystitis, managed with bladder irrigation and ribavirin, and engraftment failure, necessitating a second CBT on Day 35. Subsequent adenoviral conjunctivitis resolved with vidarabine. The patient achieved neutrophil engraftment by Day 76 and was discharged on Day 173 without relapse. This case highlights the importance of vigilant supportive care and tailored therapy in managing MPAL with FLT3 mutations, especially in the context of post-transplant complications.

The infectivity of progeny adenovirus in the presence of neutralizing antibody

Human adenoviruses (Ads), common pathogens that cause upper respiratory and gastrointestinal infections, are blocked by neutralizing antibodies (nAbs). However, Ads are not fully eliminated even in hosts with nAbs. In this study, we assessed the infectivity of progeny Ad serotype 5 (Ad5) in the presence of nAb. The infectivity of Ad5 was evaluated according to the expression of the Ad genome and reporter gene. Infection by wild-type Ad5 and Ad5 vector continued to increase until 3 days after infection even in the presence of nAb. We established an assay for determining the infection levels of progeny Ad5 using a sorting system with magnetic beads and observed little difference in progeny Ad5 counts in the presence and absence of nAb 1 day after infection. Moreover, progeny Ad5 in the presence of nAb more effectively infected coxsackievirus and adenovirus receptor (CAR)-positive cells than CAR-negative cells. We investigated the function of fiber proteins, which are the binding partners of CAR, during secondary infection, observing that fibre proteins spread from infected cells to adjacent cells in a CAR-dependent manner. In conclusion, this study revealed that progeny Ad5 could infect cells even in the presence of nAb, differing from the common features of the Ad5 infection cycle. Our findings may be useful for developing new therapeutic agents against Ad infection.

Hemorrhagic Cystitis Secondary to Adenovirus and BK Virus Infection in a Diffuse Large B-Cell Lymphoma Patient with Recent CAR T-Cell Therapy

Patients who undergo chimeric antigen receptor T-cell therapy (CAR T-cell therapy) are immunosuppressed due to multiple factors. While adenovirus and BK virus are well-known pathogens in the context of hematopoietic stem cell transplant, there are no detailed reports of these infections in the setting of CAR T-cell therapy. We describe a 70-year-old male who recently underwent CAR T-cell therapy for diffuse large B-cell lymphoma. He presented with intractable gross hematuria and dysuria. Workup revealed adenovirus viremia and viruria and BK virus viruria. He was treated for adenovirus hemorrhagic cystitis with intravenous cidofovir 1 mg/kg/day, every three days for three weeks, with good clinical response. We also discuss the mechanisms of immunosuppression in CAR T-cell therapy as well as the principles of treatment of adenovirus and BK virus infections in the immunosuppressed patient.

[Use of ribavirin in viruses other than hepatitis C. A review of the evidence]

Ribavirin is a molecule with antiviral activity against different viruses. In clinical practice, it has made its niche almost exclusively for the treatment of the hepatitis C virus. However, there are other diseases in which it could be of benefit and it has the advantage of being suitable for oral, intravenous and inhaled administration. We conducted a review of the indications of the main drug agencies (Spanish, European and American) and other possible indications, mainly haemorrhagic fevers and coronavirus.

Nursing Management of Haemorrhagic Cystitis in Patients Undergoing Haematopoietic Stem Cell Transplantation: a Multicentre Italian Survey

Background

Haemorrhagic cystitis (HC) is a severe complication occurring after haematopoietic stem cell transplantation (HSCT) in 13–40% of patients, caused by infectious and/or non-infectious factors that increase the in-hospital length of stay and the risk of mortality of transplanted recipients. Although different management interventions have been suggested in the literature, available knowledge on interventions performed by Italian nurses in their daily practices has not been documented to date.

Aim of the study

The aim of this study is to describe HC preventive and treatment interventions in patients undergoing HSCT as performed by Italian nurses in their daily practice.

Material and methods

A multicentre survey was conducted in 2018 by inviting all 110 Italian HSCT centres belonging to the Italian Group for Bone Marrow Transplantation (GITMO). Data collection was performed with an online questionnaire submitted to GITMO reference nurses working in each HSCT centre. Descriptive statistics were performed.

Results

A total of 38 Italian centres participated. The preventive intervention most applied in daily care was the mesna administration (n=37; 97.4%), followed by intravenous hyperhydration (n=33; 86.8%) and forced diuresis with furosemide (n=24; 63.1%). Preventive continuous bladder irrigation (CBI) was performed in 13 centres (34.2%). Transfusions of blood products (n=32; 84.2%), CBI (n=31; 81.6%) and intravenous hydration (n=28; 73.7%) were the most applied treatments, beyond the administration of analgesics (n=38; 100.0%) and antispasmodics (n=26; 68.4%).

Conclusion

A great variability both in the HC prevention and treatment interventions applied in daily practice across centres have emerged suggesting that no strong recommendations in the field are available to date. Therefore, there is a need to increase the evidence available in the field by providing methodological studies of higher quality, multicentre and prospective.

Genitourinary Tract Infections

Similarly to the general population, genitourinary tract infections are common conditions in theimmunocompromised host. They can be furthermore divided into infections of the urinary tract and genital tract infections. Transplant recipients are more likely to have infections of the urinary tract infections while persons with human immunodeficiency virus (HIV) are at higher risk for the second group of infections, especially sexually transmitted infections (STIs). Manifestations of these diseases can be associated with more complications and can be more severe. We provide an overview of manifestations, diagnosis, and management of these disorders.

Adenovirus: Epidemiology, Global Spread of Novel Serotypes, and Advances in Treatment and Prevention

Adenoviruses (AdVs) are DNA viruses that typically cause mild infections involving the upper or lower respiratory tract, gastrointestinal tract, or conjunctiva. Rare manifestations of AdV infections include hemorrhagic cystitis, hepatitis, hemorrhagic colitis, pancreatitis, nephritis, or meningoencephalitis. AdV infections are more common in young children, due to lack of humoral immunity. Epidemics of AdV infection may occur in healthy children or adults in closed or crowded settings (particularly military recruits). The disease is more severe and dissemination is more likely in patients with impaired immunity (e.g., organ transplant recipients, human immunodeficiency virus infection). Fatality rates for untreated severe AdV pneumonia or disseminated disease may exceed 50%. More than 50 serotypes of AdV have been identified. Different serotypes display different tissue tropisms that correlate with clinical manifestations of infection. The predominant serotypes circulating at a given time differ among countries or regions, and change over time. Transmission of novel strains between countries or across continents and replacement of dominant viruses by new strains may occur. Treatment of AdV infections is controversial, as prospective, randomized therapeutic trials have not been conducted. Cidofovir is the drug of choice for severe AdV infections, but not all patients require treatment. Live oral vaccines are highly efficacious in reducing the risk of respiratory AdV infection and are in routine use in the military in the United States, but currently are not available to civilians.

Therapeutic Basis of Vidarabine on Adenovirus-Induced Haemorrhagic Cystitis

When adenovirus causes haemorrhagic cystitis in immunocompromised patients, vidarabine is used for its treatment because therapeutic choice is limited. Although vidarabine has been reported to be effective for these patients, its therapeutic basis has not yet been established. Vidarabine dose-dependently inhibited viral replication as assessed by a yield reduction assay. Viral protein synthesis was dose-dependently inhibited by vidarabine but not at all by acyclovir, and the degree of inhibition by vidarabine was different for each of the viral proteins, ranging from 0–40% of the untreated control. These results indicated the specificity and mechanism of action of vidarabine against adenovirus. The concentration of vidarabine and its metabolite in the bladder is suggested to exhibit effective anti-adenoviral activity in suppressing the replication of adenovirus. Thus, our results support vidarabine therapy as a possible candidate for adenovirus-induced haemorrhagic cystitis in immunocompromised patients.

A Rare Case of Hemorrhagic Cystitis in Allogeneic Hematopoietic Stem Cell Transplant Patient

Post bone marrow transplant patients are susceptible to atypical infections, especially viral pathogens. The risk increases many folds in cases of allogeneic transplantation, which also receive GVHD prophylaxis. Viral pathogens like cytomegalovirus and herpes are the common ones encountered during follow-up period. However, in recent times there have been reports of a variety of disease manifestations of rare viruses like polyoma virus and adenovirus. These viral infections may play a crucial role in morbidity and mortality in immunocompromised patients. We hereby elaborate the follow-up course of a 36-year-old post allogeneic transplant patient of acute myeloid leukemia who developed adenovirus related haemorrhagic cystitis. Treatment with oral ribavirin lead to dramatic improvement in symptomatology within a week. This cases re-emphasizes the fact that after ruling out the commoner pathogens, it's of utmost importance to strongly consider the atypical pathogens in such cases.

Adenovirus pneumonia presenting with nodular shadows on chest X-ray in two unrelated allogeneic bone marrow transplant recipients

Adenoviruses are increasingly recognized as important pathogens following allogeneic stem cell transplantation. We herein report two cases of disseminated adenovirus infection that presented with nodular shadows on chest X-ray after allogeneic bone marrow transplantation from unrelated donors. Both patients died of respiratory failure. Autopsies revealed adenovirus infection of multiple organs. Adenovirus infection should be suspected when nodular lung lesions of unknown origin appear in allogeneic stem cell transplant recipients.

Management of refractory hemorrhagic cystitis following hematopoietic stem cell transplantation in children

HC is a complication associated with HSCT, but occurs rarely in solid organ recipients. The reported incidence varies from <10% to more than 70%. HC is characterized by hemorrhagic inflammation in urinary tract mucosa with symptoms varying from asymptomatic microscopic hematuria to frank hematuria with clot formation and urinary tract obstruction. Early onset HC may be explained by toxicity of chemo- and/or radiotherapy, while multiple factors including viral infections and their interplay seem to be involved in late onset HC. So far, only incidence of cyclophosphamide-associated HC has been reduced with preventive treatment. Likely, once HC is established, the treatment principles are similar regardless of the etiology and depend on the intensity of HC. Prevention of urinary tract obstruction, transfusion support, analgesic, and spasmolytic therapy are generally accepted in HC management. Treatment beyond this conservative approach entails higher risk for side effects, and thus treatment escalation proportional to HC intensity is warranted. No standard and evidence-based treatment escalation algorithm has been widely adopted yet. As severe HC following HSCT is a potentially life-threatening complication, a multidisciplinary and individual approach is required in children suffering from this devastating complication.

Hematuria due to adenoviral infection in bone marrow transplant recipients

Late-onset hemorrhagic cystitis (HC) caused by adenovirus (AdV) infection is a common complication in hematopoietic stem cell transplantation (HSCT) recipients. However, limited information exists regarding adenovirus-associated HC. We report a retrospective study of 84 hematopoietic stem cell transplant recipients that evaluated the incidence and risk factors for AdV-induced HC. The development of HC was strongly related to adenoviral infection (P = .004). Among 13 patients who developed late-onset HC, AdVs were identified as a causative agent in 10 cases. AdV preferentially affected younger (P = .013) and male patients. Affected subjects had been transplanted for either malignant (7/10) or nonmalignant disorders (3/10). Most cases of AdV-hematuria were self-limited single or recurrent mild hemorrhagic episodes (P = .000), occurring at a median of 41 days after transplantation and lasting an average of 4 days. Viral load in patients with AdV-induced HC was similar to infected subjects who did not develop HC (2.5 × 10(3) vs 3.4 × 10(3) copies/mL). We HC occurring before 200 days was associated with a greater risk of a fatal outcome (P = .002) but occurrence of AdV infection did not affect a patient's survival. Our study confirmed the suggestion that non-AdV coinfections may worsen the course of AdV-HC.

Common Viral Pneumonia

Common respiratory viruses are now recognised as true opportunistic respiratory pathogens in patients with haematological malignancies. The epidemiology of these viruses has not been extensively studied in immunocompromised hosts, but is probably closely related to viral activity in immunocompetent hosts, who constitute the virus reservoir for immunocompromised patients. In these patients, common respiratory viruses may cause severe infections with higher rates of progression to pneumonia and mortality compared to immunocompetent individuals. Prolonged high-titre viral shedding is common in patients with haematological malignancies and may enhance not only viral transmission, but also the selection of resistant strains. Influenza and respiratory syncytial virus (RSV) infections have been particularly well studied. They are associated with pneumonia rates of about one-third for influenza and 30–40% for RSV. Both viruses are responsible for mortality rates ranging from 15% to 30%. The exact mechanisms of pneumonia related to these viruses remains unknown, but bacterial and fungal co-infections are frequent and must be carefully investigated. Parainfluenza viruses (PIV) and RSV have also been linked to late airflow obstruction in haematopoietic stem cell transplant recipients. Neuraminidase inhibitor therapy has been suggested for influenza, ribavirin for RSV, and cidofovir for adenovirus infections. However, there is no evidence supporting the use of these drugs, and randomised controlled trials are urgently needed to better define the optimal management of common viral pneumonia in patients with haematological malignancies. The absence of proven effective treatments highlights the critical importance of prevention. Viral transmission may be interrupted by contact isolation with droplet precautions for infected patients and by having patients and health care workers with suspected infection, and their relatives, refrain from visits and work. Immunisation remains the cornerstone of influenza prevention and is recommended for patients with haematological malignancies, their relatives, and health care workers.

[Urologic aspects of Polyomavirus infection]

JC virus (JCV) and BK virus (BKV) are human Polyomaviruses of the papovavirus family, which also includes a simian vacuolating virus 40 (SV40). Human Polyomaviruses were first isolated in 1971 from the brain (JCV) and urine (BKV) of two different patients. Human Polyomaviruses have a limited and specific tissue tropism infecting the renal tubular cells, the urothelium, the B cells and the brain cells. The virus infects the majority of the human population with seroconversion occurring during adolescence. The detection of the virus may be cytological, pathological, virological or immunological. Following a typically subclinical primary infection, Polyomavirus establishes a life-long persistent infection, especially in the urinary tract. BKV is known to reactivate and cause severe disease in immunosuppressed patients. The presence of Polyomavirus outside conditions of immunosuppression raises the question of its meaning and its therapeutic management. Given the ubiquitous nature of the virus and its strong association with cancer in animal models, they may play an etiological role in human malignancies. Here, we describe the biology of human Polyomaviruses, review their non-malignant and malignant potentials, and discuss the therapeutic aspect.

Urinary excretion of ganciclovir contributes to improvement of adenovirus-associated hemorrhagic cystitis after allogeneic bone marrow transplantation

A nine-yr-old girl developed AdV-associated HC after bone marrow transplantation. Intravenous GCV markedly reduced urinary AdV DNA loads and improved clinical findings. This appeared to result partly from a high concentration of GCV in urine. GCV may be effective for AdV-induced HC without definitive disseminated infection.

Original research: Intravenous ribavirin--review of the FDA's Emergency Investigational New Drug Database (1997-2008) and literature review

Intravenous (IV) ribavirin does not have US Food and Drug Administration (FDA) approval, although oral and aerosol formulations have been approved. Intravenous ribavirin can, however, be authorized for use as a result of an Emergency Investigational New Drug (EIND) application as investigational treatment for patients with serious viral infections, including emerging or rare infections for which no alternative treatment is available. This retrospective study evaluated clinical experience with IV ribavirin based on a review of the FDA's EIND database and a literature review. The main outcome measures were disease condition, clinical outcomes, and adverse events (AEs). First, the FDA's EIND database was evaluated for these variables among patients authorized to receive investigational IV ribavirin. Second, published literature on IV ribavirin was reviewed for diseases treated, reported clinical outcomes, and AEs. Adverse events reported in the literature were compared with AEs listed in approved product labeling (aerosol and oral formulations). From February 1997 to December 2008, 608 IV ribavirin EIND requests were made for 19 disease conditions. Adenovirus, respiratory syncytial virus, and parainfluenza infections comprised 84.7% of IV ribavirin EINDs. Inadequate reporting of clinical outcomes and AEs in the EIND database prevented analysis of either outcome. Data interpretation in the literature was limited by multiple factors, including retrospective design, small sample sizes, differences in reporting outcomes and AEs, lack of generalizability, and potential confounders such as concomitant medications, selection bias, and reporting bias. Reported AEs were consistent with labels of approved aerosol and oral formulations, except for lip and gingival swelling. However, estimates of frequency, severity, and causality of AEs associated with IV ribavirin could not be determined because of study limitations. Our study findings suggest that the literature is inconclusive on the potential benefit for continued use of IV ribavirin. A review of the literature and the FDA's EIND database suggests that prospective, controlled trials of IV ribavirin in patients with adenovirus, parainfluenza, or serious respiratory syncytial virus infections could be feasible.

Viruses and kidney disease: beyond HIV

SUMMARY

Human immunodeficiency virus (HIV)-infected patients may acquire new viral co-infections; they also may experience the reactivation or worsening of existing viral infections, including active, smoldering, or latent infections. HIV-infected patients may be predisposed to these viral infections owing to immunodeficiency or risk factors common to HIV and other viruses. A number of these affect the kidney, either by direct infection or by deposition of immune complexes. In this review we discuss the renal manifestations and treatment of hepatitis C virus, BK virus, adenovirus, cytomegalovirus, and parvovirus B19 in patients with HIV disease. We also discuss an approach to the identification of new viral renal pathogens, using a viral gene chip to identify viral DNA or RNA.

Differential susceptibility of adenovirus clinical isolates to cidofovir and ribavirin is not related to species alone

Background

We have previously reported that human adenovirus (HAdV) reference strains clearly show species-dependent resistance to ribavirin, whereas different species of HAdV are equally sensitive to cidofovir. All the serotypes tested were susceptible to cidofovir, whereas only serotypes from species C were sensitive to ribavirin. Here, we aimed to extend these investigations to clinical isolates.

Methods

In vitro, we tested 126 isolates obtained from 65 patients included in a European survey of HAdV infection.

Results

Among the 126 isolates tested, all presented cidofovir 50% inhibitory concentration (IC50) in the same range as the HAdV 5 reference strain. Regarding ribavirin, all isolates from species C (79 tested) showed an IC50 comparable with previously reported results for reference strains; however, 24/32, 2/6 and 3/3 tested isolates from species A, B and D, respectively, were shown to have a ribavirin IC50 comparable with the HAdV 5 reference strain (species C), contrary to previous observations for reference strains of the same species. Among patients who were treated with cidofovir for disseminated HAdV infection, ≥4 sequential isolates could be obtained from 9 patients; no variation in cidofovir susceptibility could be detected.

Conclusions

Cidofovir is active in vitro in all HAdV clinical isolates. Ribavirin was revealed to be active on most HAdV isolates from species A, B and D, and in all isolates from species C. Finally, no resistance to cidofovir became apparent in sequential isolates obtained from treated patients.

Viruses

Viral infections are an important and often unrecognized component of disease in immunocompromised patients. The diagnosis and management of viral infections have expanded largely because of new quantitative molecular diagnostic assays. Well-recognized pathogens such as herpes simplex virus (HSV), cytomegalovirus (CMV), and respiratory viruses have been joined by newly recognized pathogens such as BK virus, human herpesvirus-6 (HHV-6), and human metapneumovirus in this highly susceptible patient population. The role of Epstein-Barr virus (EBV) and Human herpesvirus-8 (HHV-8) in lymphoproliferative diseases also continue to be clarified. As a result, the management of viral infections in patients with hematologic malignancies continues to be a growing challenge for the clinician.

Viral lower urinary tract infections

Lower urinary tract infections (UTIs) are common among the general population and are most often caused by bacterial pathogens. Viruses are an uncommon cause of UTIs in an immunocompetent host; however, viruses are increasingly recognized as the cause of lower UTI, especially hemorrhagic cystitis, among immunocompromised patients. BK virus, adenovirus, and cytomegalovirus are predominant pathogens involved in hemorrhagic cystitis after stem cell and solid organ transplantation, and their early diagnosis and treatment may prevent significant morbidity of hemorrhagic cystitis. The diagnosis of viral lower UTI is based on molecular techniques, and real-time polymerase chain reaction is often the method of choice because it allows for quantification of viral load. Cidofovir is becoming a drug of choice in viral UTIs because it is active against the most common viral pathogens. This review discusses the epidemiology, pitfalls in diagnosis, and current treatment of viral UTIs.

Adenovirus infection after allogeneic stem cell transplantation

Adenovirus infection after allogeneic hematopoietic stem cell transplantation (HSCT) is an emerging pathogen causing relevant morbidity and mortality, with preponderance in children. During the last years, basic research on the biology of the virus and host immune response ameliorated the diagnostic, surveillance, and therapeutic strategies. Risk factors for infection commonly have an impact on T-cell reconstitution, such as T-cell depleted graft, unrelated or HLA-mismatched donor transplantation, and GvHD. Weekly surveillance by PCR in stool and blood till day 100 or longer post-HSCT and pre-emptive therapy with cidofovir are the mainstay of the current approach to adenoviral infections post-HSCT. Since a sufficient host T-cell response is essential to clear the virus, diagnostic procedures for detection of virus-specific T-cells have recently been developed to assess the risk of the infection. Furthermore, adoptive immunotherapy is a new treatment option for patients with absent specific T-cell response and present systemic adenoviral infection.

Risk factors and treatment of hemorrhagic cystitis in children who underwent hematopoietic stem cell transplantation

A retrospective cohort of 163 children with 171 hematopoietic stem cell transplantation (HSCT) performed during Mar. 1992-Dec. 2005 were analyzed to evaluate the incidence, risk factors, management, and outcome of hemorrhagic cystitis (HC). Fourteen patients (8.2%) developed HC (6 boys, median age 6.6 years) at 0-166 days after HSCT (median 25 days), and lasted for 3-96 days (median 26 days). Older age at transplant (median 11.0 vs. 6.4 years, P = 0.013), allogeneic transplant (OR = 4.4, P = 0.02), cyclophosphamide-containing conditioning (OR = 4.87, P = 0.008), moderate-to-severe acute graft-versus-host disease (GVHD) (OR = 3.56, P = 0.025) and hepatic GVHD (OR = 3.62, P = 0.017) were associated with higher risks of HC in univariate but not multivariate analyses. While estrogen was ineffective in most patients, intravesical formalin, which was used in five patients, was found to be a very effective yet safe treatment for intractable HC. Patients with HC had longer hospital stay (median 175 vs. 88 days, P = 0.004). HC resolved after treatments in all cases but eight of the 14 patients subsequently died of other complications of HSCT. In conclusion, HC is a serious complication of allogeneic HSCT. Treatment with intravesical formalin appears effective and safe and can be considered early in severe HC to reduce the risk of morbidity and mortality.

Viral lower urinary tract infections

Lower urinary tract infections (UTIs) are common among the general population and are most often caused by bacterial pathogens. Viruses are an uncommon cause of UTIs in an immunocompetent host; however, viruses are increasingly recognized as the cause of lower UTI, especially hemorrhagic cystitis, among immunocompromised patients. BK virus, adenovirus, and cytomegalovirus are predominant pathogens involved in hemorrhagic cystitis after stem cell and solid organ transplantation, and their early diagnosis and treatment may prevent significant morbidity of hemorrhagic cystitis. The diagnosis of viral lower UTI is based on molecular techniques, and real-time polymerase chain reaction is often the method of choice because it allows for quantification of viral load. Cidofovir is becoming a drug of choice in viral UTIs because it is active against the most common viral pathogens. This review discusses the epidemiology, pitfalls in diagnosis, and current treatment of viral UTIs.

Hemorrhagic cystitis in adults after unrelated cord blood transplantation: a single-institution experience in Japan

Hemorrhagic cystitis (HC) is the main complication after hematopoietic stem cell transplantation (SCT). Adenovirus (AdV) is the leading cause of late-onset HC after SCT in Japan. The incidence and outcome of HC were studied in 77 adults who underwent unrelated cord blood transplantation (CBT). Thirty-two patients developed HC in a median of 19 days (range, 11-170 days) after CBT. The cumulative incidence of HC was 41.8% at 1 year. Ten patients developed gross hematuria. The cumulative incidence of moderate-to-severe HC was 13.2% at 1 year. Only 1 patient developed severe HC; AdV was detected in a urine sample from that patient. AdV was also detected in a urine sample from another patient with moderate HC after CBT. AdV in both patients was identified as AdV type 11. The cumulative incidence of AdV-induced HC was 2.8% at 1 year. The incidence of AdV-induced severe HC after CBT may be relatively low among Japanese adults. The role of other viruses, including BK virus, in the pathogenesis of HC after CBT needs to be examined.

Human CD4+ T cells stimulated by conserved adenovirus 5 hexon peptides recognize cells infected with different species of human adenovirus

The immune response against human adenovirus (HAdV) has gained interest because of the application of HAdV-based vectors in gene therapy and the high incidence of infections in pediatric recipients of allogeneic stem cell grafts. Because antiviral medication is frequently ineffective, the option of adoptive transfer of HAdV-specific donor-derived T cells in these immunocompromised patients is investigated. To generate good manufacturing practice-compatible reagents, a panel of 63 long, overlapping, peptides of the hexon protein was screened for recognition by T cells. Five conserved peptides of 30 amino acids were identified that were recognized by the majority of adult donors. CD4+ T cells from long-term cultures of PBMC, stimulated with this set of five peptides, recognized cells infected with HAdV serotypes belonging to different species. These data demonstrate that adult human T cells preferentially recognize conserved sequences of amino acid residues from a structural protein of HAdV. In the context of gene therapy, this observation may limit the beneficial effect of switching to HAdV-based vectors derived from less common serotypes of HAdV in an attempt to circumvent pre-existing immunity. However, this cross-reactivity benefits the application of HAdV-specific T cells for adoptive immunotherapy in immunocompromised transplant recipients.

A rapid quantitative PCR-based assay for testing antiviral agents against human adenoviruses demonstrates type specific differences in ribavirin activity

Human adenovirus (HAdV) infections are increasingly frequent and potentially fatal as a disseminated disease in highly immunocompromised patients. Determining the in vitro sensitivity of HAdV to antiviral agents is not an easy task because HAdV CPE reduction assays are difficult to interpret and may take more than 1 week. We developed a phenotypic assay for testing the antiviral activity during the first round of replication using HAdV DNA concentration as an objective readout within 30 h. After evaluating the assay with cidofovir, we focused on determining the antiviral of ribavirin against different HAdV serotypes because clinical response of HAdV infections towards ribavirin treatment varied considerably. Several HAdV prototypes (1, 2, 5, 11, 31, 34, 48) associated with disseminated infections and clinical isolates were tested. Predominating HAdV of species C were more sensitive to ribavirin (HAdV-2 and -5: EC(50)<10 microM, EC(99) 111 and 104 microM, respectively) than HAdV of other species, for example HAdV-31 (EC(50) 56 microM, EC(99)>500 microM). Differential ribavirin sensitivity of HAdV types may contribute to the variable outcome of ribavirin therapy. Rapid screening of antiviral agents with the rapid qPCR-based assay against a multitude of HAdV serotypes may also facilitate development of future antiviral agents.

Cidofovir for the treatment of adenoviral infection in pediatric hematopoietic stem cell transplant patients

BACKGROUND

Adenovirus (ADV) infections are associated with significant morbidity and mortality after hematopoietic stem cell transplantation (HSCT). The virus is endemic in the general pediatric population and frequently causes severe disease in immunocompromised patients, especially children. We report our experience with cidofovir (CDV) for treatment of ADV infection in 57 HSCT patients, median age 8 years (range 0.5-26).

METHODS

Peripheral blood was prospectively screened weekly on all patients for ADV by quantitative real-time PCR for the first 100 days post-HSCT or longer if clinically indicated. Cultures for viral pathogens were performed from other involved sites. Upon detection of ADV by PCR, culture or tissue histopathology, CDV was given intravenously at 5 mg/kg weekly for 2 consecutive weeks, then every 2 weeks until 3 consecutive ADV-negative samples were documented from all previously invoved sites.

RESULTS

The clinical manifestations of ADV infection were: diarrhea (53%), fever (21%), hemorrhagic cystitis (12%), and pneumonitis (11%). Eight patients (14%) presented with disseminated disease. CDV treatment resulted in complete resolution of clinical symptoms in 56 (98%) patients in whom the virus became undetectable by all methods. One patient died due to ADV pneumonitis. No cases of dose-limiting nephrotoxicity were observed. CONCLUSIONS. Cidofovir appeared safe and effective for the treatment of ADV infection in this predominantly pediatric HSCT population. Vigilant surveillance and early treatment with CDV can prevent the poor outcomes associated with ADV disease. A larger prospective study is needed to further determine the role of CDV in the treatment of ADV after HSCT.

Cidofovir bladder instillation for the treatment of BK hemorrhagic cystitis after allogeneic stem cell transplantation

We report a case of severe hemorrhagic cystitis after allogeneic transplantation in association with high BK viral load. After failure of aggressive hydration, platelet and blood transfusions, continuous bladder irrigation, and tapering of the immune suppression, we instilled cidofovir into the bladder, which resulted in decreased BK viral load and significant clinical improvement. Our case suggests that local cidofovir therapy for viral hemorrhagic cystitis is effective and well tolerated with no observed side effects.

Adenovirus infections in transplant recipients

Adenoviruses are increasingly recognized as contributors to morbidity and mortality among stem cell and solid-organ transplant recipients. Clinical presentations range from asymptomatic viremia to respiratory and gastrointestinal disease, hemorrhagic cystitis, and severe disseminated illness. The limited clinical data available support the use of cidofovir for many of these illnesses. Prospective studies are needed to better understand the pathogenesis of and therapeutic options for adenoviral infections in this patient population.

Antiviral therapy for adenovirus infections

The treatment of severe adenovirus keratoconjunctivitis and life-threatening adenovirus infections in immunocompromised patients is still unsatisfactory. We here review the mode of action and antiviral data for cidofovir and ribavirin, obtained in cell culture, animal models or patients. Several nucleoside or nucleotide analogues have been described that target the adenovirus polymerase, whereas other antiviral targets have been poorly investigated. Furthermore, optimal therapeutic response may be achieved by combining antiviral therapy with immunotherapeutic approaches, as currently being explored.

Incidence, clinical outcome, and management of virus-induced hemorrhagic cystitis in children and adolescents after allogeneic hematopoietic cell transplantation

We analyzed the incidence, etiology, risk factors, and clinical management of hemorrhagic cystitis (HC) in 102 children who underwent allogeneic stem cell transplantation: 28 from matched siblings, 57 from unrelated donors, and 17 from mismatched relatives. Conditioning regimens consisted of high-dose chemotherapy (n=83) or total body irradiation (n=19). In all children, urine and plasma were prospectively screened for human polyomavirus (HPV; BK virus [BKV] and JC virus [JCV]) or adenovirus (AdV) DNA with a polymerase chain reaction-based assay. Viral DNA was detected in the urine of 56 children (54.9%): BKV in 48 (47%), JCV in 4 (3.9%), and AdV in 4 (3.9%). HC occurred in 26 children (25.5%), and viruria was detected in all of them: BKV in 21 (80.8%), AdV in 4 (14.4%), and JCV in 1 (3.8%). All patients with AdV viruria developed HC. The cumulative incidence of HC in patients with HPV viruria was 0.43. The only significant risk factor for HC in patients with HPV-positive urine was conditioning with high-dose chemotherapy. Twenty-two children were treated with cidofovir, with no significant toxicity. In all treated patients but 1, the clinical symptoms were moderate, and no HC-related death was observed. We conclude that virus-induced HC is a frequent complication after allogeneic hematopoietic cell transplantation. Treatment with cidofovir is feasible, and further studies are warranted to evaluate its activity in HC mediated by BKV or JCV.

Improved outcome for children with disseminated adenoviral infection following allogeneic stem cell transplantation

Adenovirus (AdV) infections are a frequent cause of morbidity and mortality following allogeneic stem cell transplantation (SCT), and disseminated infection is associated with high mortality, particularly in paediatric SCT. Here, we describe an approach to reduce mortality from adenoviraemia by combining prospective monitoring for the occurrence of adenoviraemia using a sensitive polymerase chain reaction method, early antiviral therapy and prompt withdrawal of immunosuppression. A total of 155 consecutive paediatric SCT procedures were prospectively monitored, of which 113 (73%) transplants involved donors other than matched siblings and 126 (83%) employed T-cell depletion. Adenoviraemia was detected in 26/155 (17%) transplants and developed exclusively in patients who had received T-cell-depleted grafts. Withdrawal of immunosuppression coupled with early antiviral therapy led to resolution of adenoviraemia in 19/26 (81%) patients with only five patients succumbing to disseminate AdV infection. Survival from adenoviraemia was associated with lymphocyte recovery to above 0.3x10(9)/l. Mortality was closely linked with the absence of lymphocyte recovery because of profound T-cell depletion of the graft with CD34+ magnetic-activated cell sorting. Mortality from disseminated AdV infection was 5/26 (19%) in this study, which is significantly lower than previously reported.

Adenovirus infection in children after allogeneic stem cell transplantation: diagnosis, treatment and immunity

Human adenoviruses (HAdV) are a frequent cause of potentially fatal infections in patients after allogeneic stem cell transplantation, especially in children. Monitoring of serum/plasma by real-time quantitative PCR is a sensitive tool for the recognition of patients at risk of a potentially fatal infection and for the evaluation of the efficacy of treatment. Data from a retrospective study and from a prospective study demonstrate that recovery of immunity after transplantation is essential for the elimination of HAdV infection. The feasibility of several approaches for the manipulation of immunity in the immunocompromised host to prevent a fatal course of the infection is discussed.

Prospects for adenovirus antivirals

Adenoviruses cause a number of self-limiting but often highly infectious diseases that affect multiple organs, most commonly those associated with respiratory, genitourinary and gastrointestinal tracts and the ocular surface. Many factors have driven a search for effective topical and systemic antivirals to adenoviruses. These include patient morbidity, economic losses and chronic visual disturbances associated with epidemic keratoconjunctivitis; and the startling recent trend of high morbidity and rising mortality associated with systemic adenoviral infections in the immunosuppressed, particularly paediatric bone marrow transplant recipients. The development of effective antivirals has proven to be a complex task, owing to the fact that multiple and often genetically divergent adenovirus serotypes can cause similar diseases. Currently, there remains no licensed systemic or topical treatment in the USA or Europe. However, many compounds have been explored for activity against adenoviruses, and some have been evaluated clinically in either a topical setting for ocular disease or in the setting of systemic treatment in the face of life-threatening adenovirus infections. This article outlines such compounds, discusses the potential for their clinical development, and highlights some problems that may be faced in evaluating their efficacy clinically.

In Vitro Susceptibility of Adenovirus to Antiviral Drugs is Species-Dependent

Adenovirus infections are a frequent and serious complication following allogeneic haematopoietic stem cell transplantation (HSCT). The antiviral drugs cidofovir and ribavirin have been used as first-line therapy for disseminated infections with variable results. In the present study, in vitro susceptibility to these two drugs was evaluated on HEp-2 cells in adenovirus reference strains representing serotypes of each of the six species and in clinical isolates. Susceptibility to cidofovir was comparable between species with inhibition of replication of all tested serotypes in a narrow dose range (IC50= 17–81 μM). However, susceptibility to ribavirin was highly dependent on the species. Serotypes from species A, B, D, E and F were all resistant to ribavirin (IC50=396 to >500 μM). Only replication of serotypes from species C was inhibited by ribavirin (IC50=48–108 μM). This species-dependent susceptibility of adenovirus to ribavirin was confirmed in clinical isolates. When tested on other cell lines (PLC, A549 and 293), all species were revealed to be resistant to ribavirin. If our in vitro findings are predictive of virological responses in vivo, these results suggest that ribavirin would not be effective for management of non-C species adenovirus infections after HSCT.

Treatment of adenovirus infections in the immunocompromised host

Adenovirus infections are increasing as causes of morbidity and mortality in severely immunocompromised patients. The currently available antiviral agents, ribavirin and cidofovir, have yielded mixed results in case reports and small case series. Similar to cytomegalovirus disease, established adenovirus disease is often difficult to treat. Therapy may yield poor results, even when effective antiviral drugs are used. New strategies, including pre-emptive therapy, should be tested in prospective, clinical trials. New agents and adoptive transfer of specific T-cells to adenovirus might improve the current situation.

Hemorrhagic cystitis after allogeneic hematopoietic stem cell transplantation: donor type matters

Hemorrhagic cystitis (HC) remains a common complication of allogeneic blood and marrow transplantation. Previous analyses of risk factors for this complication were performed in heterogenous populations, with dissimilar diagnosis and conditioning regimens. We postulated that HC is more prevalent in matched unrelated donor (MUD) and unrelated cord blood (UCB) transplantations than in matched related donor (MRD) transplantations. We performed a retrospective study on 105 acute lymphocytic leukemia patients treated with 12 Gy total body irradiation-based regimens and allogeneic transplants (MUD, n = 38; UCB, n = 15; mismatched related, n = 20; MRD, n = 32). HC occurred in 16% of patients receiving MRD transplants, 30% of recipients of mismatched related, and 40% of MUD or UCB transplants (hazard ratio 2.9, 95% CI 1.0-7.9 for the comparison of MRD versus MUD). The excessive rate of HC among MUD and UCB patients became evident after the first 30 days after transplantation. Recipients younger than 26 years had a significantly higher incidence of HC (HR 2.5, 95% CI 1.1-5.8). This donor type and age effect was independent of platelet engraftment, development of graft-versus-host disease (GVHD), source of stem cells, use of anti-thymocyte globulin (ATG) or cyclophosphamide in the regimen, steroid use, or stem cell source. We concluded that HC is more prevalent in MUD and UCB transplantations. (Blood. 2004;103:4674-4680)

A case of severe hemorrhagic cystitis following bone marrow transplantation

Hemorrhagic cystitis (HC) is a common adverse effect caused by the preparative regimens for bone marrow transplantation. Unfortunately, an effective therapy for HC has not yet been established. Here we report a case of severe HC in which the upper as well as the lower urinary tract were severely affected, resulting in right ureteral obstruction and a contracted bladder. Hyperbaric oxygen therapy was effective in suppressing the severe HC, but the cause of HC could not be identified. Five years after the bone marrow transplantation the patient underwent augmentation ileocystoplasty with ileal ureteral replacement.

Fiber-modified adenoviruses generate subgroup cross-reactive, adenovirus-specific cytotoxic T lymphocytes for therapeutic applications

Adenovirus (Ad) infections are responsible for considerable morbidity and mortality, particularly in pediatric hematopoietic stem cell transplant (HSCT) recipients. To date there is no therapy. The present study was motivated by the potential for using adoptive immunotherapy as either prophylaxis or treatment for Ad infections and associated diseases. The authors have developed a protocol to reactivate Ad-specific memory T cells from peripheral blood mononuclear cells (PBMCs) using a clinical-grade adenoviral vector. Such lines contain a specific CD4 and CD8 T-cell component and are capable of recognizing and lysing target cells infected with wild-type Ad serotypes from different Ad groups. Furthermore, the frequency of Ad-specific precursors can be determined in PBMCs ex vivo and used as a means to assess changes in Ad-specific T-cell memory responses after infusion. This is the first report of a simple and reproducible method to activate and expand Ad-specific cytotoxic T lymphocytes (CTLs), which should be protective against the range of different Ad subtypes that affect transplant recipients.

Successful cidofovir treatment of adenovirus-associated hemorrhagic cystitis and renal dysfunction after allogenic bone marrow transplant

We present a patient who developed hemorrhagic cystitis and renal dysfunction after unrelated bone marrow transplantation. Polyoma BK virus and adenovirus 11 were detected in the urine. Vidarabine was administered without effect. Relatively low dose cidofovir was efficacious. Renal function improved, and the urinary secretion of adenovirus stopped.

Molecular monitoring of adenovirus in peripheral blood after allogeneic bone marrow transplantation permits early diagnosis of disseminated disease

Adenovirus (AdV) infection in the course of allogeneic stem cell transplantation (SCT) is associated with high transplant-related morbidity and mortality. Disseminated AdV disease is lethal in most instances. Early detection of AdV infection and identification of patients carrying a high risk of disseminated disease therefore remain a major challenge. In view of the large number of existing AdV types, we have established real-time polymerase chain reaction (PCR) assays permitting sensitive detection and quantification of all 51 currently known human AdV serotypes. In a series of 132 consecutive pediatric patients undergoing SCT, more than 5000 samples derived from peripheral blood (PB), stool, urine, and throat were screened for adenovirus infection by PCR during the posttransplantation period. Thirty-six patients (27%) tested positive by PCR, revealing AdV types of the subgenera A, B, C, D, and F. Except for enteritis in some patients with AdV positivity in stool, detection of the virus at sites other than PB was not associated with clinical signs of virus disease, and transplant-related mortality was not significantly different from AdV-negative patients. By contrast, 82% of patients who had detectable AdV in PB died from infectious complications (P <.001). Monitoring of PB specimens by real-time PCR permitted early diagnosis of invasive AdV infection in all instances. In patients who developed disseminated AdV disease, detection of the virus in PB preceded onset of clinical symptoms by a median of more than 3 weeks. The observation of AdV in peripheral blood may therefore serve as a basis for early initiation of preemptive antiviral treatment.

Extensive cross-reactivity of CD4+ adenovirus-specific T cells: implications for immunotherapy and gene therapy

Adenovirus (Ad)-specific T-cell responses in healthy adult donors were investigated. Ad5, inactivated by methylene blue plus visible light, induced proliferation and gamma interferon (IFN-gamma) production in peripheral blood mononuclear cells of the majority of donors. Responding T cells were CD4(+) and produced IFN-gamma upon restimulation with infectious Ad5 and Ads of different subgroups. T-cell clones showed distinct cross-reactivity patterns recognizing Ad serotypes from either one subgroup (C), two subgroups (B and C), or three subgroups (A, B, and C). This cross-reactivity of Ad-specific T cells has relevance both for Ad-based gene therapy protocols, as well as for the feasibility of T-cell-mediated adoptive immunotherapy in recipients of an allogeneic stem cell transplantation.

Cidofovir for adenovirus infections after allogeneic hematopoietic stem cell transplantation: a survey by the Infectious Diseases Working Party of the European Group for Blood and Marrow Transplantation

Adenovirus is an important cause of morbidity and mortality after allogeneic hematopoietic stem cell transplantation and there is no established therapy. Cidofovir has in vitro efficacy against adenovirus. We performed a retrospective analysis of 45 patients treated with cidofovir for adenovirus from 10 centers. In total, 16 patients had definite adenovirus disease, 13 probable disease, and 16 asymptomatic infections. A total of 31 (69%) patients were successfully treated with cidofovir, 10 failed, and four were not evaluable owing to early death from other causes. Cidofovir therapy was successful in 10 patients with adenovirus disease, 10 patients with probable disease, and in 10 patients with asymptomatic infections. The overall survival at 28 days and 6 months after initiation of cidofovir therapy was 76 and 46%, respectively. Of the patients, 18 developed toxicity associated with cidofovir: 14 developed renal toxicity and four other types of toxicities. We conclude that cidofovir may be useful against adenovirus after allogeneic hematopoietic stem cell transplantation but additional studies are needed.