Cytomegalovirus immune plasma in bone marrow transplant recipients

Cytomegalovirus-specific neutralizing antibodies effectively prevent uncontrolled infection after allogeneic hematopoietic stem cell transplantation

Cytomegalovirus (CMV) infection remains one of the most frequent and life-threatening infectious complications after allogeneic hematopoietic stem cell transplantation (allo-HSCT). Herein, we comprehensively compared the immune cells of patients with uncontrolled and controlled CMV infection post-allo-HSCT and found that B-cells were extraordinarily insufficient because of impaired B-cells reconstitution in the uncontrolled infection group. Furthermore, in the controlled infection group, reconstructed B-cells showed signatures of mature B-cells, high expression of CXCR4 and IFITM1, and enrichment of CMV-associated B-cell receptors, which were lacking in the uncontrolled infection group. Consistently, sera from the uncontrolled infection group failed to inhibit CMV infection via neutralizing virus in vitro because of its lower content of anti-CMV-specific immunoglobulin G (IgG) than the controlled infection group. Overall, these results highlighted the contribution of B cells and anti-CMV-specific neutralizing IgGs to the restraint of CMV infection post-allo-HSCT, suggesting their potential as a supplementary treatment to improve outcomes.

American Society for Transplantation and Cellular Therapy Series: #4 - Cytomegalovirus treatment and management of resistant or refractory infections after hematopoietic cell transplantation

The Practice Guidelines Committee of the American Society of Transplantation and Cellular Therapy (ASTCT) partnered with its Transpl. Infect. Dis. Special Interest Group (TID-SIG) to update its 2009 compendium-style infectious disease guidelines for hematopoietic cell transplantation (HCT). A new approach was employed with the goal of better serving clinical providers by publishing each standalone topic in the infectious diseases series as a concise format of frequently asked questions (FAQ), tables, and figures. Adult and pediatric infectious diseases and HCT content experts developed and answered FAQs. Topics were finalized with harmonized recommendations that were made by assigning an A through E strength of recommendation paired with a level of supporting evidence graded I through III. The fourth topic in the series focuses on the management and treatment of cytomegalovirus (CMV) resistant and refractory infections. The diagnosis, definitions of resistant and refractory CMV, risk factors, virological genotypes and treatment algorithms are reviewed.

Cytomegalovirus Humoral Response Against Epithelial Cell Entry-Mediated Infection in the Primary Infection Setting After Hematopoietic Cell Transplantation

BACKGROUND

The influence of humoral immunity on the prevention of primary cytomegalovirus (CMV) infection after hematopoietic cell transplantation (HCT) is poorly understood.

METHODS

To determine whether neutralizing antibodies (nAbs) against CMV pentameric complex (PC)-mediated epithelial cell entry decrease CMV infection after HCT, samples were analyzed from a randomized controlled trial of CMV intravenous immunoglobulin (IVIG) prophylaxis. Weekly serum from 61 CMV donor-positive/recipient-negative (D+/R-) HCT patients (33 control, 28 CMV IVIG) was tested using a PC-entry nAb assay and quantitative CMV polymerase chain reaction (PCR).

RESULTS

There was a trend toward higher weekly PC-entry nAb titers (P = .07) and decreased CMV infection by PCR at viral load cutoffs of ≥1000 and ≥10 000 IU/mL in the CMV IVIG arm. High nAb titers were not significantly protective against CMV infection later after HCT in both study arms. Among CMV-infected patients, each log2 increase in nAb titer was associated with an average 0.2 log10 decrease in concurrent CMV viral load after infection (P = .001; adjusted for study arm).

CONCLUSIONS

This study provides initial support that CMV IVIG prophylaxis moderately enhances PC-entry nAB activity in D+/R- HCT recipients.

Effectiveness of immunoglobulin prophylaxis in reducing clinical complications of hematopoietic stem cell transplantation: a systematic review and meta-analysis

BACKGROUND

Prophylactic immunoglobulin has been used with varying efficacy to reduce complications in hematopoietic stem cell transplant recipients.

STUDY DESIGN AND METHODS

A systematic review and meta-analysis was conducted of randomized controlled trials that assessed clinical outcomes (overall survival, transplant-related mortality, graft-versus-host disease [GVHD], veno-occlusive disease [VOD], interstitial pneumonitis, disease relapse, cytomegalovirus [CMV] infection and disease, non-CMV infection) of immunoglobulin prophylaxis versus placebo in hematopoietic stem cell transplant recipients. MEDLINE, EMBASE, EBM Reviews, and the Cochrane Central Register of Controlled Trials were searched up to June 2017. Quality of included studies and outcomes were evaluated via Risk of Bias assessment and Grading of Recommendations, Assessment, Development and Evaluation criteria, respectively.

RESULTS

Of 899 citations screened, 27 studies (n = 3934) were included. Immunoglobulin prophylaxis had no impact on survival (risk ratio [RR], 0.94; 95% confidence interval [CI], 0.88-1.01; 11 studies, n = 1962) but decreased risk of acute GVHD (RR, 0.78; 95% CI, 0.65-0.94; eight studies, n = 1097) and CMV disease (RR, 0.52; 95% CI, 0.28-0.97; two studies, n = 167). Meta-analysis revealed increased risk of VOD (RR, 3.04; 95% CI, 1.10-8.41; three studies, n = 384) and disease relapse (RR, 1.26; 95% CI, 1.07-1.49; seven studies, n = 1647). Other outcomes were small in sample size or nonsignificant. Results should be interpreted cautiously given the low quality of studies and evidence of outcomes.

CONCLUSION

Immunoglobulin prophylaxis did not have a significant effect on survival. Positive clinical effects were shown for acute GVHD and CMV disease and negative effects against VOD and disease relapse. No studies examined the effect of immunoglobulin treatment in hypogammaglobulinemic patients despite current guidelines, warranting further studies in this population.

Immunoglobulin prophylaxis against cytomegalovirus infection in patients at high risk of infection following allogeneic hematopoietic cell transplantation

Reports on the efficacy of intravenous immunoglobulin (IVIG) prophylaxis against cytomegalovirus (CMV) infection after allogeneic hematopoietic cell transplantation (HCT) have often sparked controversy. In addition, we are not aware of any study that has examined whether prophylaxis with IVIG affects the incidence of CMV infection in high-risk patients--those who are elderly or have received human leukocyte antigen (HLA) mismatched HCT. In the present open-label, phase II study, we addressed this question. We enrolled 106 patients in the study. The cumulative incidences of CMV infection at 100 days after HCT were similar in the intervention and the control groups (68% and 64%, P=.89; 89% and 87%, P=.79, respectively, for patients 55 years or older and those who received HLA-mismatched HCT). In those who received HLA-mismatched HCT, 1-year overall survival after HCT was 46% in the intervention group and 40% in the control group (P=.31); for age≥55 years, the corresponding values were 46% and 40% (P=.27). Our data showed that prophylaxis with regular polyvalent IVIG did not affect the incidence of CMV infections or survival among older patients or those who receive HLA-mismatched HCT.

Immunoglobulin prophylaxis in hematopoietic stem cell transplantation: systematic review and meta-analysis

PURPOSE

Because the role of immunoglobulins (IVIG) prophylaxis in patients undergoing hematopoietic stem-cell transplantation (HSCT) has not been established in terms of survival and infection prevention, we conducted a meta-analysis evaluating these issues.

METHODS

Systematic review and meta-analysis of randomized-controlled trials comparing prophylaxis with polyvalent IVIG or cytomegalovirus (CMV)-IVIG and control or another preparation or dose. PUBMED, Cochrane Library, LILACS, and conference proceedings were searched. Two reviewers appraised the quality of trials and extracted data. Relative risks (RRs) with 95% CIs were estimated and pooled.

RESULTS

Thirty trials including 4,223 patients undergoing bone marrow transplantation (BMT) were included. There was no difference in all-cause mortality when polyvalent IVIG or CMV-IVIG was compared to control (RR, 0.99; 95% CI, 0.88 to 1.12; and RR, 0.86; 95% CI, 0.63 to 1.16, respectively). There was no difference in clinically documented infections when polyvalent IVIG was compared with control (RR, 1.00; 95% CI, 0.90 to 1.10; five trials). CMV infections were not significantly reduced with either polyvalent IVIG or CMV-IVIG. Interstitial pneumonitis was reduced with polyvalent IVIG in older studies but not in the more recent ones, nor in studies assessing CMV-IVIG. Polyvalent IVIG increased the risk for veno-occlusive disease (RR, 2.73; (95% CI, 1.11 to 6.71). Graft-versus-host disease was not affected.

CONCLUSION

Because there is no advantage in terms of survival or infection prevention, IVIG does not have a role in HSCT.

Immunoglobulin prophylaxis in hematological malignancies and hematopoietic stem cell transplantation

BACKGROUND

Patients undergoing hematopoietic stem cell transplantation (HSCT) and those with lymphoproliferative disorders (LPD) have a higher incidence of infections due to secondary hypogammaglobulinemia. One approach is the prophylactic administration of intravenous immunoglobulins (IVIG). Randomized controlled trials (RCTs) showed conflicting results in terms of type, schedule, dose and hematological patients benefiting from IVIG. We therefore performed a systematic review and meta-analysis to evaluate the role of IVIG in these patients.

OBJECTIVES

To determine whether prophylaxis with IVIG reduces mortality or affects other outcomes in patients with hematological malignancies.

SEARCH STRATEGY

PubMed (January 1966 to December 2007), CENTRAL (The Cochrane Library, up to 2007, issue 1), LILACS and conference proceedings published between 2002-2007 were searched. The terms "immunoglobulins" or "gammaglobulins" or specific gammaglobulins and similar and the terms "hematologic neoplasms" or "hematologic malignancies" or "transplant" or "autotransplant" or "allotransplant" or "bone marrow transplant" or "peripheral stem cell transplant" and similar were selected. References of all included trials and reviews identified were scanned for additional trials.

SELECTION CRITERIA

All RCTs comparing prophylaxis of IVIG with placebo, no treatment or another immunoglobulin preparation, different administration schedules or doses for patients with hematological malignancies were included. One author screened all abstracts identified through the search strategy and two reviewers independently inspected each reference identified by the search and applied inclusion criteria.

DATA COLLECTION AND ANALYSIS

For each trial, results were expressed as relative risks (RR) with 95% confidence intervals (CI) for dichotomous data and weighted mean differences for continuous data. We conducted meta-analysis, where enough similar trials were available, using the fixed- effects model, unless significant heterogeneity was present. We performed sensitivity analyses to assess the effect of individual methodological quality measures on effect estimates, including allocation generation, concealment and blinding.

MAIN RESULTS

Forty trials were included: thirty included HSCT patients and ten included patients LPD. When polyvalent immunoglobulins or hyperimmune cytomegalovirus (CMV)-IVIG was compared to control for HSCT, there was no difference in all-cause mortality. Polyvalent immunoglobulins significantly reduced the risk for interstitial pneumonitis but increased the risk for veno-occlusive disease and adverse events. In LPD, no benefit in terms of mortality IVIG could be demonstrated but there was a decrease in clinically and microbiologically documented infections.

AUTHORS' CONCLUSIONS

In patients undergoing HSCT, routine prophylaxis with IVIG is not supported. Its use may be considered in LPD patients with hypogammaglobulinemia and recurrent infections, for reduction of clinically documented infections.

Antibodies for the prevention and treatment of viral diseases

This paper reviews current use and evolving role of polyclonal and monoclonal antibody products for the prevention and treatment of viral diseases. Antibodies continue to be indicated for prophylaxis either prior to an anticipated exposure especially in situations of travel, or more commonly following an exposure. The predominant indication for use of antibody products is to prevent infection. With the availability of vaccines for the prevention of chickenpox, hepatitis A, hepatitis B, measles, rabies and smallpox, the role of passive immunization is reserved for susceptible individuals and those at high risk for complications of infection. Risks of transmission of infections associated with use of human plasma-derived products have been reduced by improvements in donor screening and virus removal and inactivation procedures. An additional safety concern has been addressed by the removal of thimerosal as a preservative. Within the last 5 years, two antibodies have been licensed for a viral indication, RespiGam and Synagis both for prevention of respiratory syncytial virus infection. RespiGam is a human plasma derived antibody and Synagis is a humanized monoclonal antibody, the first such antibody to be licensed for an infectious disease indication. CytoGam for prevention of cytomegalovirus infection in kidney transplant patients has recently been granted an expanded indication to include use in lung, liver, pancreas and heart transplant patients. As the use of therapeutics becomes more sophisticated, researchers may find better ways of using antibody products.

Status of Cytomegalovirus Prevention and Treatment in 2000

Cytomegalovirus (CMV) infection continues to be a problem in selected populations following hematopoietic stem cell transplantation (SCT). Although there have been no new antiviral agents for management of this infection in recent years, the methods for using the existing agents have improved with newer assays for detection of virus. In addition, our understanding of immunity to CMV has undergone considerable expansion. This paper will address these new aspects relating to CMV infection in the setting of SCT.

In Section I Dr. Zaia reviews the pathogenesis of CMV and the current epidemiology of CMV disease following marrow or blood allo-SCT with emphasis on late-onset disease. The current lab tests available for preemptive management are summarized including the role for conventional shell vial cultures, and a comparison of the CMV antigenemia assay with the new nucleic acid-based assays, including the hybrid capture assay, the NASBA assay, and “real-time” PCR assays. Use of antiviral agents with these tests in the preemptive management of CMV infection is discussed.

Ultimately, what is necessary is restoration of adequate CMV immunity, and that requires understanding the basics of the CMV-specific immune response. In Section II, Dr. Sissons traces the evolution of the CTL response from primary infection into memory and reviews recent advances in the understanding of cytotoxic T cell based immunity to CMV, based on the use of T cell clonotypic analysis and markers of T cell memory and activation, with conventional CTL functional assays.

In Section III Dr. Riddell presents approaches to correction of the problem of CMV pathogenesis, namely direct restoration of the CMV-specific cellular immune deficiency. Attempts at passive therapies will be reviewed with the focus on current problems and approaches to these problems.

In Section IV, Dr. Diamond presents work on the identification of multiple HLA-allele specific cytotoxic T cell epitopes specific for CMV-pp65 and - pp150. Specific epitopes are recognized by CMV-seropositive individuals including healthy donors, SCT recipients, and AIDS patients, indicating their potential usefulness as vaccines. One of these epitopes is recognized by most individuals who express the HLA A*0201 Class I allele. Pre-clinical evaluation in HLA2.1 transgenic mice of vaccine structures utilizing this epitope, and alternative delivery systems are described. Possible methods for vaccination of donor and/or recipient of a SCT as well as their limitations, utilizing synthetic or viral vaccines, are discusseed.

Status of Cytomegalovirus Prevention and Treatment in 2000

Cytomegalovirus (CMV) infection continues to be a problem in selected populations following hematopoietic stem cell transplantation (SCT). Although there have been no new antiviral agents for management of this infection in recent years, the methods for using the existing agents have improved with newer assays for detection of virus. In addition, our understanding of immunity to CMV has undergone considerable expansion. This paper will address these new aspects relating to CMV infection in the setting of SCT.

In Section I Dr. Zaia reviews the pathogenesis of CMV and the current epidemiology of CMV disease following marrow or blood allo-SCT with emphasis on late-onset disease. The current lab tests available for preemptive management are summarized including the role for conventional shell vial cultures, and a comparison of the CMV antigenemia assay with the new nucleic acid-based assays, including the hybrid capture assay, the NASBA assay, and “real-time” PCR assays. Use of antiviral agents with these tests in the preemptive management of CMV infection is discussed.

Ultimately, what is necessary is restoration of adequate CMV immunity, and that requires understanding the basics of the CMV-specific immune response. In Section II, Dr. Sissons traces the evolution of the CTL response from primary infection into memory and reviews recent advances in the understanding of cytotoxic T cell based immunity to CMV, based on the use of T cell clonotypic analysis and markers of T cell memory and activation, with conventional CTL functional assays.

In Section III Dr. Riddell presents approaches to correction of the problem of CMV pathogenesis, namely direct restoration of the CMV-specific cellular immune deficiency. Attempts at passive therapies will be reviewed with the focus on current problems and approaches to these problems.

In Section IV, Dr. Diamond presents work on the identification of multiple HLA-allele specific cytotoxic T cell epitopes specific for CMV-pp65 and - pp150. Specific epitopes are recognized by CMV-seropositive individuals including healthy donors, SCT recipients, and AIDS patients, indicating their potential usefulness as vaccines. One of these epitopes is recognized by most individuals who express the HLA A*0201 Class I allele. Pre-clinical evaluation in HLA2.1 transgenic mice of vaccine structures utilizing this epitope, and alternative delivery systems are described. Possible methods for vaccination of donor and/or recipient of a SCT as well as their limitations, utilizing synthetic or viral vaccines, are discusseed.

Use of intravenous immunoglobulin to prevent or treat infections in persons with immune deficiency

Intravenous immunoglobulin (IVIG) concentrates were originally developed as replacement therapy for individuals with primary deficiencies of the immune system. However, in various well-designed, controlled clinical trials, the ability of IVIG to prevent and possibly treat infections in patients with secondary immune deficiencies has also been considered. In this review, we briefly consider these different applications and suggest whether the data are sufficient to employ IVIG in these clinical settings.

Cytomegalovirus prophylaxis and treatment following bone marrow transplantation

OBJECTIVE

To provide an overview of the role of cytomegalovirus (CMV) in the bone marrow transplant (BMT) population and update the current methods of prevention and treatment of CMV infection and disease, with emphasis on CMV interstitial pneumonia (CMV-IP).

DATA SOURCES

The current medical literature, including abstracts presented at recent national and international meetings, is reviewed. References were identified by searching the MEDLINE database from January 1988 through June 1994. The reference lists of the published studies and reviews obtained from the initial literature search were reviewed as well.

STUDY SELECTION

Data regarding the epidemiology of CMV, the risk factor associated with CMV infection and disease, as well as data on the prevention and the treatment of CMV infection and disease in the BMT population are cited. Specific attention was focused on randomized, placebo-controlled studies pertaining to the prevention of CMV infection and disease in CMV-immunoglobulin G positive recipients undergoing allogeneic BMT. Information from nonrandomized, placebo-controlled studies was included in the absence of stronger data.

DATA EXTRACTION

Information contributing to CMV in the BMT population was reviewed. Data supporting and disputing specific preventive and treatment modalities are presented.

DATA SYNTHESIS

The incidence of CMV seropositivity in the general population is high and while BMT becomes a widely accepted treatment modality, CMV reactivation and subsequent disease, especially CMV-IP, becomes a significant prognostic factor of morbidity and mortality. Even though antiviral agents such as ganciclovir and foscarnet can inhibit the viral replication in vivo, they have not been able to treat CMV-IP effectively. It has been suggested that CMV-IP is an immunopathologic process that can cause irreversible damage, hence, the low efficacy of antiviral therapy and the associated high mortality. Immunomodulating agents such as intravenous immune globulin and cytomegalovirus hyperimmune globulin can increase the efficacy of antivirals in the treatment of CMV-IP. This further supports the postulated immunopathologic process of this disease. The lack of understanding of the pathophysiology of the disease compromised the efforts of treatment and led to the development of preventive interventions with antiviral and immunomodulatory regimens that resulted in a significantly lower incidence of infection and disease. As a result of current data, the Eastern Cooperative Oncology Group has published guidelines for the prevention and treatment of CMV infection and disease.

CONCLUSIONS

The prognosis of CMV disease in the BMT recipients has improved as a result of a wide variety of modifications in the management of BMT recipients. These include an increased understanding of the risk factors associated with CMV infection, routine screening for CMV replication and excretion, and more effective prophylactic regimens. Still, more than half of the patients who develop pneumonia will die, indicating that more studies are needed to increase the understanding of the pathophysiology and refine the preventive and therapeutic regimens against CMV.

Pulmonary infiltrates in the cancer patient. New approaches to an old problem

A variety of etiologies may produce pulmonary infiltrates in a patient with cancer. Infectious etiologies, of an ever-increasing number, are always of paramount concern due to their high mortality in this patient population. Patients may be rendered immunosuppressed for prolonged periods of time and therefore are highly susceptible to infection. We present an overview of the many causes of pulmonary infiltrates in the cancer patient and an approach to diagnosis and treatment.

Humoral immune responses and cytomegalovirus excretion in children with asymptomatic infection

Forty-two seropositive children aged 3 to 5 years attending a kindergarten were followed up for 1 year in order to examine the relationship between humoral immunity and cytomegalovirus (CMV) excretion status. Anti-CMV antibodies were measured at the beginning and end of the study by enzyme-linked immunosorbent assay, neutralizing antibody test, and immunoblot techniques. Among these children, 32 persistently shed virus in urine, 2 intermittently shed CMV, and 4 experienced reactivation during the study. Virus was never isolated from 4 seropositive children. The level of anti-CMV IgG antibody in seropositive children who remained nonshedders was significantly higher than in children who shed virus during follow-up. On immunoblots, all seropositive nonshedders reacted to a CMV-specific 65 kD antigen, whereas most shedders (80%) did not. These findings suggest that humoral immunity plays a role in controlling persistent CMV infection in children with asymptomatic infection. However, the humoral immunity measured by the neutralizing test and the presence of antibodies against CMV-specific envelope antigens (116 kD/55 kD) apparently play a limited role in modifying persistent excretion and regulating reactivation of latent CMV. Immune evasion by CMV to block these antigens may explain these results.

Pancytopenia in allogeneic marrow transplant recipients: role of cytomegalovirus

We describe the clinical course of three cytomegalovirus-antibody-positive allogeneic marrow graft recipients who developed progressive pancytopenia during the third month post-transplant. Bone marrow biopsy cores were hypocellular without evidence of disease recurrence. Haemopoietic progenitor assays demonstrated a decrease of all assayable progenitors. Cytomegalovirus was identified from the blood and urine of all three patients. However, none of the patients developed other manifestations of cytomegalovirus infection such as pneumonitis, hepatitis and enteritis. The therapeutic use of ganciclovir and intravenous immunoglobulins resulted in prompt resolution of both viraemia and viruria in all three patients, and of pancytopenia in two patients.

Biological response modifiers and infectious diseases: actual and potential therapeutic agents

Biological response modifiers (BRMs) are agents which can modify the immune response to cancer or invasion of the organism by infectious agents. An explosive appearance of new BRMs has resulted from the development of recombinant gene technology and the availability of monoclonal antibodies. Colony-stimulating factors first became available for the prevention of neutropenia but may also have a role in the treatment of infections. Interleukin-1 is being tested as a modular of hematopoiesis and may be useful as a helper factor for T- and B-cell function. Immunoglobulins are being used against viral and bacterial infections while interferons can prevent viral upper respiratory infections and suppress or irradicate some viral hepatitides. Other BRMs which show promise include chemical agents and traditional herbal medicines.

Cytomegalovirus: a virus of increasing relevance to oral medicine and pathology

Human cytomegalovirus (HCMV) is a ubiquitous herpesvirus, emerging as an opportunistic pathogen in immunocompromised persons, particularly those infected with human immunodeficiency viruses (HIV). Clinical syndromes caused by HCMV are usually not specifically identifiable without laboratory investigations. However, it is now apparent that HCMV may cause oral ulceration in immunocompromised persons and it may play a role in other diverse conditions in these and other patients.

Cytomegaloviral virus infection in bone marrow transplantation recipients: strategies for prevention and treatment

Cytomegalovirus is major infectious pathogen following allogeneic bone marrow transplantation. In infected recipients, the virus is generally detected between 4 and 10 weeks after transplantation. Historically, CMV disease developed in 30-40% of seropositive recipients, the predominante manifestation being interstitial pneumonitis, which was generally lethal. Therapeutic interventions are discussed with special reference to the use of antiviral therapy for both treatment and prevention of CMV disease. The strategies developed in the bone marrow transplantation population to treat or prevent the development of CMV disease can be extrapolated to other patients groups who are immunosuppressed and at risk for developing clinical manifestations of CMV infection.

Passive immunization against cytomegalovirus in allograft recipients. The Rotterdam Heart Transplant Program experience

We analyzed the results of passive immunization against CMV in 146 heart transplant recipients. The 65 seronegative recipients were prophylactically treated with anti-CMV immunoglobulins during and after the operation. Twenty-nine of these 65 patients received a seropositive donor heart. CMV infection occurred in 21/65 seronegative and in 40/81 seropositive recipients (difference not significant). The incidence of CMV infection in seronegative recipients of a CMV-matched donor heart (3/34) was significantly lower than in seronegative recipients of a positive donor heart and lower than in seropositive recipients, but no significant difference in infection rate was found between the two latter groups (18/29 vs. 40/81). Although primary infection more frequently resulted in CMV disease than secondary infection (11/21 vs. 10/40) no difference in incidence of disease was noted between seronegative and seropositive patients (11/65 vs. 10/81), nor was there a difference in the severity of symptoms following primary or secondary infection. There was a higher incidence of CMV disease in all patients who received a heart from a seropositive donor versus a seronegative donor. However, after transplantation of a heart from a seropositive donor the incidence (27%) of CMV disease observed in our passively immunized seronegative patients was the same as in the patients with naturally acquired seropositivity. There was no difference in the prevalence of coronary artery disease between patients with and without CMV infection or disease. We conclude that using the current passive immunization scheme the occurrence of CMV infection and disease is largely dependent on the serostatus of the donor.

Viral infections in leukemia and bone marrow transplant patients

Infections by herpesviruses are common phenomena in patients being treated for acute leukemia and those undergoing bone marrow transplantation. Reactivation of endogenous latent virus caused by the immunosuppressive and cytotoxic effects of cytoreductive therapies is a common mechanism of infection. With cytomegalovirus (CMV), acquisition of exogenous virus by transfusion of blood products containing virus and from the bone marrow graft in the case of bone marrow transplantation can occur. Serious morbidity can result and occasional mortality. CMV infections in allogeneic BMT recipients have high case fatality rates. Treatment and preventive strategies for herpes simplex virus (HSV), CMV, and varicella zoster virus (VZV) have been developed to reduce morbidity. Acyclovir, either given prophylactically or as treatment of active infection, has been highly successful in reducing illness from HSV and VZV infection. For CMV, provision of CMV-seronegative blood products is the mainstay of prevention of morbidity in seronegative patients and is especially important in the care of patients undergoing allogeneic BMT. Ganciclovir given either prophylactically or as early therapy for patients detected to be shedding CMV appears to be a promising strategy. Bolstering host immunity through augmentation of anti-CMV cytotoxic T-cell responses appears to be an exciting candidate therapy under development.

Development of human monoclonal antibodies against human cytomegalovirus

Human monoclonal antibodies (HMAbs) against human cytomegalovirus (HCMV) have been developed by fusion of human spleen cells and human lymphoblastoid cell lines (NP101 and NP197). The cell line NP101 had great advantages in its high fusion frequency and the stability of the resultant hybridomas. The specificity of HMAbs was confirmed by enzyme-linked immunosorbent assay (ELISA) and immunofluorescence staining. Two of the six HMAbs obtained, which were IgG3 subclass, neutralized viral infectivity in the absence of complement. The neutralizing activity of one of these two HMAbs was enhanced in the presence of human complement, whereas the other was not. Another IgG1 subclass HMAb neutralized viral infection only in the presence of complement. The remaining three HMAbs showed no neutralizing activity. Those HMAbs may provide an important approach to studying human immune responses to HCMV. HMAbs having neutralizing activity may prove to be useful for passive immunotherapy of HCMV diseases.

Systemic antiviral drugs used in ophthalmology

Over the past two decades, the recognition of viral enzymes and proteins that can serve as molecular targets of drugs has revolutionized the treatment of viral infections. Beginning with acyclovir, a number of systemically administered agents which are both relatively safe and effective for the treatment of herpetic infections and human immunodeficiency virus (HIV) infections have become widely available. Because of increased numbers of herpes virus infections, as well as the rising epidemic of HIV infections, the ophthalmologist is, more likely than ever before to be involved in the treatment of severe and frequent ocular infections caused by herpes viruses. In addition, the acute retinal necrosis (ARN) syndrome has been demonstrated to be caused by herpes viruses and a once rare retinal infection caused by cytomegalovirus is common in patients with the acquired immunodeficiency syndrome (AIDS). In this article, four systemic antiviral drugs (Vidarabine, Acyclovir, Ganciclovir, and Foscarnet) that have demonstrated usefulness in the treatment of ophthalmic disease are reviewed in detail with regard to their mechanisms, applications, effectiveness, and side effects.

Prevention of viral infections after bone marrow transplantation

After bone marrow transplantation, a number of viral infections contribute to the morbidity and mortality of the procedure. Established preventive measures to avoid primary infection and reactivation of herpes-and cytomegaloviruses are outlined. Possible future strategies against these viruses (e. g., monoclonal antibodies, transfer of T-lymphocytes) and the possible role of improved diagnostic tools are briefly discussed.

Intravenous immune globulins. A review of their uses in selected immunodeficiency and autoimmune diseases

Intravenous immune globulin (IGIV) was introduced a decade ago as a therapy for primary immunodeficiency diseases. It proved to be a valuable therapeutic substance for this purpose and is now considered to be the treatment of choice. The intent was to supply ubiquitous anti-infectious agent antibodies through passive immunisation to replace deficient circulating antibody content. During such therapy, unexpected benefits were noted in thrombocytopenic patients. Since that time, the therapeutic indications for IGIV infusions have greatly increased, with a particular interest in infectious, haematological and autoimmune diseases. This review summarises the status of IGIV therapy in haematological diseases within the categories of primary immunodeficiency diseases, secondary immunodeficiency states and autoimmune syndromes. The majority of firm data have been gathered on the treatment of patients with primary immunodeficiency disease. These data are reviewed from the aspect of anticipated therapeutic response and side effects. Emphasis should be placed on the IgG circulating blood levels as there is a need for individualizing therapy because of marked interindividual patient variation. The use of IGIV therapy in primary and secondary immunodeficiency states should consider the potential benefits to be attained in haematological malignancies and related complications which may be magnified by chemotherapy and radiation therapy. The mode of action of IGIV in autoimmune diseases, although not yet precisely determined, may involve establishing reticuloendothelial blockade or immunomodulation by supplying anti-idiotype antibodies.

Cytomegalovirus infection and disease after liver transplantation. An overview

Cytomegalovirus is the single most important pathogen in clinical transplantation. Although much progress has been made in our understanding of the molecular biology and epidemiology of CMV infection and in our ability to diagnosis and treat CMV disease, it remains a major cause of morbidity but is no longer a major cause of mortality after liver transplantation. Risk factors for CMV disease after liver transplantation include donor and recipient serologic status, the use of antilymphocyte therapy, and retransplantation. CMV disease occurs early after transplantation, and the most frequent site of disease is the hepatic allograft. We have treated 79 patients with intravenous ganciclovir, with ultimate control of disease achieved in 69 patients (87.3%). Preliminary results using intravenous immunoglobulin and oral acyclovir for CMV prophylaxis in high-risk patients have been encouraging. In addition to producing clinical syndromes. CMV may have direct immunologic effects and is a marker of the net state of immunosuppression.

Cytomegalovirus infection of the larynx in the acquired immunodeficiency syndrome

CMV is the most important viral opportunist in patients with AIDS. Nearly all patients with AIDS have been exposed to CMV and the virus can be isolated from many. When CMV-related disease occurs in AIDS, it has usually involved the eye or gastrointestinal tract. In lesions in which CMV is the suspected etiology, evidence of direct pathogenicity of the virus should be obtained, usually histologically. Accurate diagnosis is essential because long-term therapy with a relatively toxic drug (ganciclovir) is indicated. We have presented a case of CMV infection of the larynx that responded, albeit slowly, to ganciclovir. Additional cases may arise as the prevalence of AIDS increases. Because of the potential for airway compromise and the tendency toward chronicity, CMV infection of the larynx should be of a significant concern both for the patient and the otolaryngologist.

Cytomegalovirus DNA in the sera of patients with cytomegalovirus pneumonia

We attempted to detect cytomegalovirus DNA (CMV-DNA) in the sera of four leukaemia patients who underwent an allogeneic bone marrow transplant (BMT), in six leukaemia patients who suffered from pneumonia and in 16 healthy subjects, using the polymerase chain reaction (PCR). Three of the four BMT patients subsequently developed CMV pneumonia. In two cases, CMV-DNA was detected in the sera at about the time the pneumonia occurred, and the amount of DNA increased with disease progression. The serum of the third patient became positive for CMV-DNA before he developed pneumonia. The fourth patient did not develop CMV pneumonia, but his urine became persistently positive for CMV-DNA soon after the BMT, whereas the serum was negative. A relationship was found between the occurrence of pneumonia and the serum level of CMV-DNA. CMV-DNA was also detected in three of six pneumonia patients whose anti-CMV IgM antibodies were elevated in the circulation. Sera from the 16 normal subjects were negative for CMV-DNA, regardless of their being seropositive or seronegative for CMV. While it had been previously thought that CMV did not exist in serum, we detected CMV-DNA in serum by PCR in the active disease stage. Our results suggest that PCR would be useful for the early diagnosis of CMV pneumonia and in monitoring its course.

Biological Agents in Infectious Diseases

This article examines the use of classical as well as novel immunological agents to augment the immune system. Strategies to prevent infectious disease using vaccines to prime the immune system are discussed. A prospective overview of acquired immunodeficiency syndrome (AIDS) vaccine development provides insights into the possible agents that may be developed in the near future. The rationale for the use of intravenous immunoglobulin and colony stimulating factors in selected clinical situations is also discussed.

Successful treatment of disseminated cutaneous cytomegalic inclusion disease associated with Hodgkin's disease

A case of disseminated cutaneous cytomegalic inclusion disease associated with Hodgkin's disease is described. The patient had a diffuse eruption of pruritic, erosive erythematous nodules. Histologically, many inclusion bodies were observed in perivascular areas of the skin lesions. Immunohistologically, the inclusion bodies positively stained with both anticytomegalovirus antibody and anti-factor VIII-related antibody. On electron microscopy many virus particles and dense bodies were found in the area where inclusion bodies were observed. Treatment with high-dose intravenous acyclovir and a large amount of immunoglobulin resulted in prompt healing of the skin lesions. Subsequently, the patient's Hodgkin's disease was well controlled on chemotherapy. The patient steadily improved without relapse of skin lesions 1 year after antiviral therapy was administered.

Screening plasma donors for high-titre antibody to cytomegalovirus using a latex agglutination test

Cytomegalovirus (CMV) can cause severe morbidity in immunosuppressed patients. Regional transfusion centres in the UK are required to supply high-titre anti-CMV plasma to the Blood Products Laboratory (BPL), now called 'Bio-Products Laboratory', for the production of specific intravenous immunoglobulin at the Protein Fractionation Centre in Scotland. For this purpose, 703 plasmapheresis donors were screened by a modified latex agglutination test to assess their suitability as donors with high-titre anti-CMV. CMV antibodies were found in 48% of the donors. Seropositivity increased with age ranging from 33% in the 20- to 29-year age group to 57% in the 40-49 age group, although the 50-59 age group showed a slight decline to 53%. In all age ranges except the 40-49 group, seropositivity was highest in the female population. With the latex test, 14% of the total donors screened had a titre greater than or equal to 1 in 64, 7% greater than or equal to 1 in 128 and 4.2% greater than or equal to 1 in 256. Samples from 18 donors with titres greater than or equal to 1 in 128 were sent to BPL and all samples were found to have a sufficiently high titre for the production of CMV immune plasma. For BPL the 'cut-off' level for CMV immune plasma is a titre greater than or equal to 1 in 64 by complement fixation. Since the establishment of a panel of donors with high-titre anti-CMV plasma, more than 10 kg of plasma are dispatched monthly from our centre to BPL.

Sequence requirements for proteolytic processing of glycoprotein B of human cytomegalovirus strain Towne

Truncated versions of the human cytomegalovirus (CMV) strain Towne glycoprotein B (gB) gene were stably expressed in CHO cell lines. The calcium-specific ionophore A23187 inhibited proteolytic cleavage of C-terminal-truncated gB expressed by cell line 67.77. These inhibition studies also showed that the 93-kilodalton cleavage product most likely represents the N-terminal cleavage fragment of gB. The ionophore carboxyl cyanide m-chlorophenyl-hydrazone was used to show that proteolytic cleavage of gB did not occur in the endoplasmic reticulum. Two-dimensional polyacrylamide gel electrophoresis demonstrated that the N- and C-terminal cleavage products of gB remained associated by disulfide linkages after cleavage. Expression studies using constructs in which 80% or all of the N terminus was deleted demonstrated that the N terminus was required for secretion of the gB molecule. The amino acid sequence at the site of cleavage was shown to be critical for cleavage by a cellular protease. Our results indicate that an arginine-to-threonine change at either amino acid 457 or 460, a lysine-to-glutamine change at amino acid 459, or all three substitutions together block gB cleavage. The effect on proteolysis of the arginine-to-threonine amino acid change at residue 457 (position -4 relative to the cleavage site) demonstrated that a basic pair of amino acids at the endoproteolytic processing site is not the only requirement in cis for gB cleavage.

Cytomegalovirus seronegative heart transplant recipients. Prophylactic use of anti-CMV immunoglobulin

Thirty-two CMV seronegative heart transplant patients received prophylactic anti-CMV immunoglobulin during the first three posttransplant months. One of the 16 recipients of a heart from a seronegative donor acquired CMV infection and developed CMV disease. In eight of the 16 recipients of a heart from a seropositive donor, CMV infection was observed. Viremia was diagnosed in seven of them, but only two of these patients developed CMV disease. The incidence of CMV infection and of CMV disease in the globulin-treated CMV seronegative recipients of a heart from a seropositive donor was comparable to the incidence of CMV infection and of CMV disease in 31 nonglobulin-treated CMV seropositive recipients. This was significantly lower (percentage difference 69 percent, 95 percent CI 42-97 percent, p less than 0.001) than expected on the basis of the data from the literature and indicates that passive immunization with anti-CMV immunoglobulins induces the same protection against CMV disease as natural acquired anti-CMV resistance. This protective effect was temporary, as one patient developed symptomatic CMV infection four months after transplantation at a time when the anti-CMV immunoglobulin levels had decreased to pretransplantation values.

Intravenous immune globulin prophylaxis in recipients of a marrow transplant

Bone marrow transplantation is a worldwide activity involving more than 250 transplant centers in more than 40 countries. The ultimate success of the procedure depends in large measure on supportive care of the transplant recipient. A major component of this supportive care is the prevention of opportunistic infections. This article reviews the nature of immunoglobulin class and subclass deficiency after marrow transplantation and the role of intravenous immune globulin in preventing infections and associated complications.

Immunoprophylaxis of cytomegalovirus infections in transplanted patients

Cytomegalovirus causes severe infections in immunosuppressed patients and anti-viral treatments remain unsatisfactory. In an attempt to prevent life-threatening CMV infections, immunoprophylaxis using hyperimmune immunoglobulins has been studied but led to conflicting results in the literature. The role of passive immunization in allogeneic marrow and renal transplant patients is discussed.

The human cytomegalovirus strain Towne glycoprotein H gene encodes glycoprotein p86

The gene encoding the glycoprotein H (gH) homologue of CMV strain Towne was cloned, sequenced, and expressed. The predicted 742 amino acid gH protein had characteristics typical of a membrane glycoprotein including hydrophobic signal and transmembrane domains and six possible N-linked glycosylation sites. The CMV (Towne) gH gene had a 95% nucleotide identity and a 96.6% amino acid identity with the CMV (AD169) gH gene, as described by M. P. Cranage, G. L. Smith, S. E. Bell, H. Hart, C. Brown, A. T. Bankier, P. Tomlinson, B. G. Barrell, and T. C. Minson (1988, J. Virol. 62, 1416-1422). Transcriptional analysis of the gH gene revealed that the 2.9-kilobase (kb) gH transcript was not detected until late after CMV infection, indicating that the kinetics of gH expression were typical of the late class of CMV genes. The gH gene was expressed in COS cells using a vector in which transcription was driven by the SV40 early promoter. The expression of gH was detected by immunofluorescence using the virus neutralizing murine monoclonal antibody 1G6, which is specific for an 86-kilodalton (kDa) CMV virion membrane protein (p86). Amino acid sequence analysis of p86 tryptic peptides revealed sequence identity with peptides from the deduced gH amino acid sequence, confirming that the gH gene encodes p86. These results indicate that CMV gH can induce virus neutralizing antibodies and establishes gH as a candidate antigen for a subunit vaccine against CMV.