Cytomegalovirus infection in marrow transplantation

Efficacy and Safety of Aqueous Interleukin-8-Guided Treatment in Cytomegalovirus Retinitis after Bone Marrow Hematopoietic Stem Cell Transplantation

PURPOSE

To explore the optimal treatment for cytomegalovirus retinitis (CMVR) in patients status-post Allogeneic bone marrow hematopoietic stem cell transplantation (Allo-HSCT), based on aqueous humor indicators.

METHODS

A randomized controlled study with 35 eyes. Eyes were randomized with a 1:1 ratio to standard treatment group (Group 1, with treatment endpoint as aqueous CMV-DNA load＜10³ copy/ml), and interleukin (IL)-8 group (Group 2, with treatment endpoint as aqueous IL-8 level ＜30 pg/ml or CMV-DNA load＜10³ copy/ml) to receive antiviral intravitreal injections. Number of injections, CMVR recurrence rate, complication rate, and vision changes were analyzed and compared.

RESULTS

The mean number of injections in group 2 was less than in group 1 (6 vs 8 respectively, p<0.05). There were no significant differences in CMVR recurrence, complication and vision recovery rate.

CONCLUSION

Incorporating aqueous humor IL-8 level into the criteria of CMVR treatment decision can safely and effectively reduce the number of intravitreal injections needed and can be used as important indicators to assess treatment endpoint.

Overview of human cytomegalovirus pathogenesis

Human cytomegalovirus (HCMV) is a human pathogen that infects greater than 50 % of the human population. HCMV infection is usually asymptomatic in most individuals. That is, primary infection or reactivation of latent virus is generally clinically silent. HCMV infection, however, is associated with significant morbidity and mortality in the immunocompromised and chronic inflammatory diseases in the immunocompetent. In immunocompromised individuals (acquired immune deficiency syndrome and transplant patients, developing children (in utero), and cancer patients undergoing chemotherapy), HCMV infection increases morbidity and mortality. In those individuals with a normal immune system, HCMV infection is also associated with a risk of serious disease, as viral infection is now considered to be a strong risk factor for the development of various vascular diseases and to be associated with some types of tumor development. Intense research is currently being undertaken to better understand the mechanisms of viral pathogenesis that are briefly discussed in this chapter.

Amotosalen-treated donor T cells have polyclonal antigen-specific long-term function without graft-versus-host disease after allogeneic bone marrow transplantation

We have previously shown that amotosalen HCl (S-59 psoralen)-treated donor splenocytes, which have limited proliferative capacity in vitro, can protect major histocompatibility complex-mismatched bone marrow transplant (BMT) recipients from lethal murine cytomegalovirus infection without causing graft-versus-host disease. In this study, we further investigated the effects of amotosalen-treated donor T cells on immune reconstitution after allogeneic BMT. We were surprised to find that amotosalen-treated donor T cells persisted long-term in vivo, comprising 6% to 10% on average of the T-cell compartment of transplant recipients at 4 months after transplantation. Donor T cells derived from amotosalen-treated splenocytes were predominantly polyclonal CD44 hi/int CD8 + memory T cells and were functionally active, synthesizing interferon gamma in response to stimulation with murine cytomegalovirus antigen. Amotosalen-treated donor T cells, reisolated from BMT recipients' spleens >/=4 months after transplantation, proliferated in vitro, thus indicating repair of amotosalen-mediated DNA cross-links. Compared with infusion of untreated donor splenocytes, amotosalen-treated cells enhanced thymopoiesis by bone marrow-derived stem cells in BMT recipients. However, amotosalen treatment abrogated the thymopoietic activity of lymphoid progenitor cells among the donor splenocytes. Thus, infusion of amotosalen-treated donor T cells produced rapid immune reconstitution after major histocompatibility complex-mismatched BMT by transferring long-lived polyclonal memory T cells with antiviral activity and also by enhancing bone marrow-derived thymopoiesis. This is a novel approach to adoptive immunotherapy in allogeneic BMT.

The human cytomegalovirus

Human cytomegalovirus (HCMV), a betaherpesvirus, represents the major infectious cause of birth defects, as well as an important pathogen for immunocompromised individuals. The viral nucleocapsid containing a linear double-stranded DNA of 230 kb is surrounded by a proteinaceous tegument, which is itself enclosed by a loosely applied lipid bilayer. Expression of the HCMV genome is controlled by a cascade of transcriptional events that leads to the synthesis of three categories of viral proteins designated as immediate-early, early, and late. Clinical manifestations can be seen following primary infection, reinfection, or reactivation. About 10% of infants are infected by the age of 6 months following transmission from their mothers via the placenta, during delivery, or by breastfeeding. HCMV is a significant post-allograft pathogen and contributes to graft loss independently from graft rejection. Histopathologic examination of necropsy tissues demonstrates that the virus enters via the epithelium of the upper alimentary, respiratory, or genitourinary tracts. Hematogenous spreading is typically followed by infection of ductal epithelial cells. Infections are kept under control by the immune system. However, total HCMV clearance is rarely achieved, and the viral genome remains at selected sites in a latent state. Virological and molecular detection of HCMV, as well as serological demonstration of a specific immune response, are used for diagnosis. Treatment of HCMV infections is difficult because there are few options. The presently available drugs produced a significant clinical improvement, but suffer from poor oral bioavailability, low potency, development of resistance in clinical practice, and dose-limiting toxicities.

Randomized clinical trial of ganciclovir vs acyclovir for prevention of cytomegalovirus antigenemia after allogeneic transplantation

Cytomegalovirus (CMV) disease remains a major cause of morbidity following allogeneic stem cell transplantation (SCT). In a prospective randomized trial, we tested prophylactic therapy with ganciclovir or acyclovir for patients at high risk of disease. Ninety-one CMV seropositive recipients of related (n = 53) and unrelated (n = 38) donor transplants were enrolled. All patients received intravenous (i.v.) ganciclovir 5 mg/kg every 12 h days -7 to -2, followed by acyclovir 10 mg/kg i.v. every 8 h from day -1 until neutrophil engraftment. Patients were then randomly assigned to either ganciclovir (n = 45) or acyclovir (n = 46) until day 100 post transplant. Any degree of antigenemia was treated with ganciclovir 5 mg/kg i.v. twice a day for 2 weeks, followed by 5 mg/kg i.v. each weekday for 6 weeks. At day 100, the cumulative incidence of antigenemia was 31% (95% CI 17-45%) for ganciclovir and 41% (95% CI 26-56%) (P = 0.22) for acyclovir prophylaxis, respectively. The assigned prophylaxis cohort did not predict for CMV antigenemia. The cumulative incidence of CMV disease at 12 months was 13% (95% CI 3-23%) and 17% (95% CI 6-28%) (P = 0.59) for the ganciclovir- and acyclovir-treated groups, respectively. An absolute neutrophil count (ANC) <or=1500 x 10(6)/l at randomization (P < 0.01) and grade II-IV acute graft-versus-host-disease (P = 0.01), but not the assigned prophylaxis cohort (P = 0.62), were independent risk factors for CMV disease. The incidence of fungal infections and renal insufficiency was similar across treatment groups; however, bacterial infections and secondary neutropenia occurred more frequently in the ganciclovir group. With our study powered to detect a 60% reduction in antigenemia with ganciclovir prophylaxis, we did not find a statistically significant difference between ganciclovir and acyclovir when used as part of an overall strategy for prevention of CMV antigenemia and disease in SCT, although fewer side-effects occurred with acyclovir treatment.

Beta-herpesvirus challenges in the transplant recipient

Cytomegalovirus (CMV) has major consequences after allogeneic stem cell and solid organ transplantation. CMV may cause significant morbidity and mortality, and monitoring to detect reactivation to reduce disease or management of end organ disease is associated with increased resource utilization. Two other members of the beta-herpesvirus family, human herpesvirus (HHV) type 6 and HHV-7, are increasingly recognized as important pathogens in transplant recipients, either by direct infection (e.g., encephalitis, hepatitis, or pneumonitis) or via interaction with CMV. In addition to direct effects of CMV infection, such indirect effects as an increased risk for bacterial and fungal infections or impaired graft acceptance and function are important research topics. Diagnosis and treatment of CMV infection is currently more advanced than for HHV-6 and HHV-7.

Virological, clinical, and ophthalmologic features of cytomegalovirus retinitis after hematopoietic stem cell transplantation

We identified 10 patients who developed cytomegalovirus (CMV) retinitis after HSCT during a 14-year period. The median day of diagnosis of CMV retinitis after transplantation was day 251 (range, days 106--365). CMV retinitis was associated with CMV serostatus of donor or recipient (P=0.01), CMV reactivation before day 100 (P=0.007), delayed lymphocyte engraftment (P<0.05), and chronic graft versus host disease (GVHD; P<0.001). In allogeneic recipients of HSCT who were alive at day 100 after transplantation and had chronic clinical extensive GVHD, the incidence of GVHD was 1.4% (8 of 577). Five of 10 patients had other manifestation of CMV disease before retinitis occurred (4 with gastrointestinal disease and 1 with interstitial pneumonia; median time, 70 days before onset of CMV retinitis; range, 58--279 days), and 4 others had CMV excretion. CMV retinitis was bilateral in 4 patients; 9 of 10 patients had ocular symptoms (i.e., decreased vision and floaters). Six of 7 patients responded well to ganciclovir or foscarnet systemic treatment, 1 improved only after switching to cidofovir, and 1 patient who received a transplant in 1983 did not respond to acyclovir treatment. In conclusion, CMV retinitis is an uncommon late complication after HSCT that occurs mainly in seropositive allograft recipients with previous CMV reactivation and chronic GVHD, and with delayed engraftment of lymphocytes.

Cytomegalovirus infection and non-neutropenic fever after autologous stem cell transplantation: high rates of reactivation in patients with multiple myeloma and lymphoma

In a retrospective study, we examined the association between cytomegalovirus (CMV) infection and non-neutropenic fever immediately following autologous peripheral blood stem cell transplantation for a variety of haematological malignancies and solid tumours. Sixty non-neutropenic febrile episodes (41 in CMV-seropositive and 19 in CMV-seronegative patients) were evaluated. CMV reactivation, documented by CMV antigenaemia, was detected in 16 out of 41 (39%) seropositive patients compared with 0 out of 19 seronegative patients. In 12 of these 16 patients, CMV infection was considered the sole cause of fever. Thirteen patients had maximum antigenaemia levels > 5 cells/slide. Specific antiviral treatment led to the resolution of the fever in all, but two, patients, who developed fatal CMV pneumonia. Patients with multiple myeloma and lymphoma, possibly owing to a combination of disease-related characteristics and prior immunosuppressive treatment, had high rates of CMV reactivation and may require more frequent diagnostic evaluation and prompt therapeutic intervention.

Increased Incidence of Cytomegalovirus Disease After Autologous CD34-Selected Peripheral Blood Stem Cell Transplantation

High-dose therapy with autologous peripheral blood stem cell (PBSC) rescue is widely used for the treatment of malignant disease. CD34 selection of PBSC has been applied as a means of reducing contamination of the graft. Although CD34 selection results in a 2 to 3 log reduction in contaminating tumor cells without significantly delaying engraftment, many other types of cells are depleted from the CD34-enriched grafts and immune reconstitution may be impaired. In the present study, 31 cytomegalovirus (CMV)-seropositive patients who received myeloablative therapy followed by the infusion of CD34-selected autologous PBSC were assessed for the development of CMV disease in the first 100 days posttransplant. Seven patients (22.6%) developed CMV disease and 4 patients (12.9%) died from complications of their infection. In a contemporaneous group of 237 CMV-seropositive patients receiving unselected, autologous PBSC, only 10 patients (4.2%) developed CMV disease, with 5 deaths (2.1%). In a multivariate logistic regression analysis, the use of CD34-selected autologous PBSC after high-dose therapy was associated with a marked increase in the incidence of CMV disease and CMV-associated deaths.

Increased Incidence of Cytomegalovirus Disease After Autologous CD34-Selected Peripheral Blood Stem Cell Transplantation

High-dose therapy with autologous peripheral blood stem cell (PBSC) rescue is widely used for the treatment of malignant disease. CD34 selection of PBSC has been applied as a means of reducing contamination of the graft. Although CD34 selection results in a 2 to 3 log reduction in contaminating tumor cells without significantly delaying engraftment, many other types of cells are depleted from the CD34-enriched grafts and immune reconstitution may be impaired. In the present study, 31 cytomegalovirus (CMV)-seropositive patients who received myeloablative therapy followed by the infusion of CD34-selected autologous PBSC were assessed for the development of CMV disease in the first 100 days posttransplant. Seven patients (22.6%) developed CMV disease and 4 patients (12.9%) died from complications of their infection. In a contemporaneous group of 237 CMV-seropositive patients receiving unselected, autologous PBSC, only 10 patients (4.2%) developed CMV disease, with 5 deaths (2.1%). In a multivariate logistic regression analysis, the use of CD34-selected autologous PBSC after high-dose therapy was associated with a marked increase in the incidence of CMV disease and CMV-associated deaths.

Preventing opportunistic infections in bone marrow transplant recipients

In 1996, a Center for Disease Control and Prevention (CDC)-sponsored working group began developing guidelines for preventing opportunistic infections (OIs) in bone marrow transplant (BMT) recipients. The purposes of the guidelines are to: a) summarize current data regarding the epidemiology of OIs in BMT recipients; b) produce an evidence-based statement of recommended strategies for preventing OIs in BMT recipients; c) decrease the incidence, morbidity, and mortality of OIs in BMT recipients; and d) define directions for future OI prevention research. Each recommendation is given two ratings: one indicating the strength of the recommendation, and another indicating the strength of evidence supporting the recommendation. The target audience for the guidelines includes transplant and infectious disease physicians and BMT unit and clinic staff. The BMT OI guidelines include sections on viral, bacterial, fungal, protozoal, and helminth infections, immunization, infection control, and blood and stem cell safety. The disease-specific sections address preventing exposure and disease among both adult and pediatric recipients of allogeneic and autologous BMTs. The immunization section addresses: a) immunization of BMT recipients, their household contacts, and health care workers; b) travel immunizations for BMT recipients; and c) passive immunization with immune globulin products. The infection control sections address room ventilation, isolation and barrier precautions, and prevention of nosocomial and other infections (e.g. infections acquired from visitors, plants, food, pets, construction sites, etc.). The blood safety section contains recommendations on preventing transmission of infections to BMT recipients from infected donated cells. After the guidelines are made available for public comment, they will be finalized and published in the Morbidity and Mortality Weekly Report and placed on the CDC web site.