Approach to Immunization in the Immunosuppressed Host

Vaccination Recommendations in Solid Organ Transplant Adult Candidates and Recipients

Prevention of infections is crucial in solid organ transplant (SOT) candidates and recipients. These patients are exposed to an increased infectious risk due to previous organ insufficiency and to pharmacologic immunosuppression. Besides infectious-related morbidity and mortality, this vulnerable group of patients is also exposed to the risk of acute decompensation and organ rejection or failure in the pre- and post-transplant period, respectively, since antimicrobial treatments are less effective than in the immunocompetent patients. Vaccination represents a major preventive measure against specific infectious risks in this population but as responses to vaccines are reduced, especially in the early post-transplant period or after treatment for rejection, an optimal vaccination status should be obtained prior to transplantation whenever possible. This review reports the currently available data on the indications and protocols of vaccination in SOT adult candidates and recipients.

Assessment of adherence to routine vaccination schedules in oncology patients

INTRODUCTION

Patients diagnosed with cancer are at an increased risk of infection. Vaccines remain one of the most critical public health strategies in limiting infectious diseases, with a heightened importance in cancer patients. Data across the general US population indicates that vaccine adherence rates are suboptimal across all adult vaccine schedules. This study aims to define vaccine adherence rates within the oncology population.

METHODS

This retrospective cohort study includes adult patients with a new cancer diagnosis. Vaccine administrations for COVID-19 (SARS-CoV-2), influenza, pneumococcal, tetanus/diphtheria/pertussis (TDaP), herpes zoster (RZV), human papillomavirus (HPV), and hepatitis B (hepB) were assessed. The primary outcome was complete vaccine adherence.

RESULTS

Two hundred and eighty-three oncology patients were included. The median age at diagnosis was 63 years old, and most subjects were females (60%). The two most common malignancies were gastrointestinal and breast cancer at 26.5% and 15.2%, respectively. Suboptimal vaccine adherence rates were observed across the entire oncology population. Complete adherence was observed in only 1.4% of patients. Vaccine specific adherence rates were as follows, SARS-CoV-2: 38.9%; influenza: 11.4%; pneumococcal: 12.7%; TDaP: 13.1%; RZV: 3.5%; HPV: 0%; and hepB: 34%. Among the vaccine schedules assessed, SARS-CoV-2 vaccination rates were the highest with 38.9% of patients being fully adherent and 73% receiving at least one dose.

CONCLUSION

Lower vaccine adherence rates were observed in oncology patients compared to currently published rates. Providers and pharmacists can play a role in assessing and counseling patients on the importance of vaccine adherence before chemotherapy is initiated and after a remission is obtained.

Programmed Cell Death Protein 1 Axis Inhibition in Viral Infections: Clinical Data and Therapeutic Opportunities

A vital function of the immune system is the modulation of an evolving immune response. It is responsible for guarding against a wide variety of pathogens as well as the establishment of memory responses to some future hostile encounters. Simultaneously, it maintains self-tolerance and minimizes collateral tissue damage at sites of inflammation. In recent years, the regulation of T-cell responses to foreign or self-protein antigens and maintenance of balance between T-cell subsets have been linked to a distinct class of cell surface and extracellular components, the immune checkpoint molecules. The fact that both cancer and viral infections exploit similar, if not the same, immune checkpoint molecules to escape the host immune response highlights the need to study the impact of immune checkpoint blockade on viral infections. More importantly, the process through which immune checkpoint blockade completely changed the way we approach cancer could be the key to decipher the potential role of immunotherapy in the therapeutic algorithm of viral infections. This review focuses on the effect of programmed cell death protein 1/programmed death-ligand 1 blockade on the outcome of viral infections in cancer patients as well as the potential benefit from the incorporation of immune checkpoint inhibitors (ICIs) in treatment of viral infections.

The Protective Effects of Influenza Vaccination in Elderly Patients with Breast Cancer in Taiwan: A Real-World Evidence-Based Study

In elderly patients with newly diagnosed breast cancer, clarity is lacking regarding the effects of influenza vaccines, particularly on clinical outcomes. This study conducted two nationwide, population-based, and propensity score-matched cohorts to estimate and compare the protective effects of influenza vaccine in elderly women and elderly patients with breast cancer. Data were derived from the National Health Insurance Research Database and Cancer Registry Database. Generalized estimating equations (GEEs) were used to compare outcomes between the vaccinated and unvaccinated cohorts. Adjusted odds ratios (aORs) were used to estimate the relative risks, and stratified analyses in the breast cancer cohort were performed to further evaluate elderly breast cancer patients undergoing a variety of adjuvant therapies. The GEE analysis showed that the aORs of death and hospitalization, including for influenza and pneumonia, respiratory diseases, respiratory failure, and heart disease, did not significantly decrease in vaccinated elderly patients with newly diagnosed breast cancer. Conversely, the aORs of all influenza-related clinical outcomes were significantly decreased in elderly women. No protective effects of influenza vaccination were found in the elderly patients with a newly diagnosed breast cancer. More studies focusing on identifying strategies to improve the real-world effectiveness of influenza vaccination to the immunocompromised are needed. Our clinical outcomes will be valuable for future public health policy establishment and shared decision making for influenza vaccine use in elderly patients with newly diagnosed breast cancer. According to our findings, regular influenza vaccine administration for elderly patients with newly diagnosed breast cancer may be reconsidered, with potential contraindications for vaccination. On the other hand, implementing the vaccination of close contacts of patients with breast cancer may be a more important strategy for enhancing protection of those fragile patients.

Influenza Vaccination in Cancer Patients Treated With Immune Checkpoint Inhibitors: A Systematic Review and Meta-analysis

The safety and efficacy of influenza vaccination is not well-studied in cancer patients receiving immune checkpoint inhibitors (ICIs). A systematic review and meta-analysis was performed aiming to summarize available data regarding influenza vaccination in ICI-treated cancer patients. Peer-reviewed studies or nonpeer-reviewed conference abstracts including ICI-treated cancer patients who received at least 1 dose of influenza vaccine were deemed eligible. A systematic search in PubMed/EMBASE was performed until October 26, 2021. Endpoints of interest included mortality as the primary outcome and secondary safety outcomes such as the incidence of immune-related adverse events (irAEs). Twenty-five studies were included in the systematic review, among which 9 were included in the meta-analysis. Meta-analysis of 3 studies (n=589, weighted age 64 y, men 61%, influenza vaccinated 32%) showed pooled odds ratio for death in influenza vaccinated versus nonvaccinated patients at 1.25 [(95% confidence intervals (CI): 0.81-1.92), P=non significant (NS)]. Meta-analysis of 6 studies studies (n=1285, weighted age 60 y, men 59%, influenza vaccinated 48%) showed pooled odds ratio for any irAEs in influenza vaccinated versus nonvaccinated patients at 0.82 [95% CI: 0.63-1.08, P=NS]. Similar results were observed in sensitivity analyses for serious irAEs, as well as when only peer-reviewed studies were included. Influenza vaccination appears to be a safe and reasonable intervention for cancer patients receiving ICIs. Most data are derived from retrospective observational studies. Randomized studies are needed to provide high-quality evidence.

Safety and efficacy of immune checkpoint inhibitors in non-small-cell lung cancer: focus on challenging populations

In recent years, immune-checkpoint inhibitors (ICIs) have represented one of the major breakthroughs in advanced non-small cell lung cancer treatment scenario. However, enrollment in registering clinical trials is usually restricted, since frail patients (i.e., elderly, individuals with poor performance status and/or active brain metastases), as well as patients with chronic infections or who take concurrent medications, such as steroids, are routinely excluded. Thus, safety and efficacy of ICIs for these subgroups have not been adequately assessed in clinical trials, although these populations often occur in clinical practice. We reviewed the available data regarding the use of ICIs in these 'special' populations, including a focus on the issues raised by the administration of immunotherapy in lung cancer patients infected with Sars-Cov-2.

Pneumococcal vaccination in lung transplant patients

Introduction: This review analyzes the efficacy of pneumococcal vaccinations in lung transplant patients before and after transplantation.Areas covered: This review addresses the risk for respiratory infections, in particular pneumococcal infections, in lung transplantation patients in the context of immunodeficiency and immunosuppressive medication. Vaccination is recommended to counteract the increased risk of pneumococcal infection, and the relevant guidelines are discussed in this review. The design of specific vaccination schedules is required because of the impaired antibody response in specific patient categories.Expert opinion: Lung transplantation candidates should be vaccinated with pneumococcal vaccines prior to transplantation. Currently, the 23-valent pneumococcal polysaccharide vaccine offers the broadest coverage, but the antibody response should be monitored. New generation pneumococcal conjugate vaccines with equally broad serotype coverage could be used in the future. During the post-transplantation period, the immune status of the patients should be monitored regularly, and vaccination should be repeated when indicated.

INfluenza Vaccine Indication During therapy with Immune checkpoint inhibitors: a transversal challenge. The INVIDIa study

AIM

Considering the unmet need for the counseling of cancer patients treated with immune checkpoint inhibitors (CKI) about influenza vaccination, an explorative study was planned to assess flu vaccine efficacy in this population.

METHODS

INVIDIa was a retrospective, multicenter study, enrolling consecutive advanced cancer outpatients receiving CKI during the influenza season 2016-2017.

RESULTS

Of 300 patients, 79 received flu vaccine. The incidence of influenza syndrome was 24.1% among vaccinated, versus 11.8% of controls; odds ratio: 2.4; 95% CI: 1.23-4.59; p = 0.009. The clinical ineffectiveness of vaccine was more pronounced among elderly: 37.8% among vaccinated patients, versus 6.1% of unvaccinated, odds ratio: 9.28; 95% CI: 2.77-31.14; p < 0.0001.

CONCLUSION

Although influenza vaccine may be clinically ineffective in advanced cancer patients receiving CKI, it seems not to negatively impact the efficacy of anticancer therapy.

Concomitant medications during immune checkpoint blockage in cancer patients: Novel insights in this emerging clinical scenario

The use of immune checkpoint inhibitors (ICIs) in cancer patients is rapidly growing. However, the potential impact of some widely used concomitant medications is still largely unclear. Emerging data suggest that gut microbiota may affect the efficacy of ICIs, leading to the hypothesis that concurrent antibiotics and proton pump inhibitors use could have a detrimental effect. In addition, steroid use might potentially impair the activity of immunotherapy, due its known immunosuppressive effects, and some safety concerns have been raised in patients receiving commonly used vaccination during ICIs. However, all randomized trials evaluating ICIs consistently excluded patients receiving high corticosteroid doses and data regarding other concomitant medications are lacking. Recently, several retrospective studies have tried to address this unmet medical need. Herein we discuss the latest evidence on the influence of these medications, critically analyzing the data reported so far and the possible implications in our clinical practice.

Mumps: An Emergency Medicine-Focused Update

BACKGROUND

Mumps is a Paramyxoviridae virus. This disease was rampant prior to introduction of the measles, mumps, and rubella vaccine, resulting in decreased incidence. This disease has demonstrated several outbreaks.

OBJECTIVE

This review provides a focused evaluation of mumps, an update on outbreaks, management recommendations, and ways to decrease transmission.

DISCUSSION

Clusters of mumps outbreaks continue to occur. The virus is a paramyxovirus, a single-stranded RNA virus. The vaccine can provide lifelong immunity if administered properly, though prior to 1967 and introduction of the vaccine, the virus was common. In the past decade, there have been several notable outbreaks. Humans are the only known hosts, with disease spread through exposure to droplets and saliva. Factors affecting transmission include age, compromised immunity, time of year, travel, and vaccination status. Upper respiratory symptoms, fever, and headache are common, with unilateral or bilateral parotitis, and the virus may spread to other systems. Diagnosis is clinical, though polymerase chain reaction and immunoglobulin testing are available. This review provides several recommendations for vaccine in pregnancy, patients living in close quarters, health care personnel, and those immunocompromised. Treatment is generally supportive, with emphasis on proper isolation to prevent widespread outbreaks. Although reporting regulations and procedures vary by state, mumps is reportable in most states.

CONCLUSIONS

Mumps is an easily spread virus. Although vaccination is the most effective way to prevent transmission, early recognition of the disease is crucial. As an emergency physician, it is important to recognize the clinical presentation, recommended testing, treatment, and isolation procedures.

Immunization and Organ Transplantation

With the rapid pace of immunologic research, it is more important than ever for readers to understand rational immunodiagnosis, immunopro-phylaxis, and immunotherapy. This column is intended to help you ensure proper immunologic drug use in your practice.

Targeting Vaccines to Specific Clusters of People

With the rapid pace of immunologic research, it is more important than ever for readers to understand rational immunodiagnosis, immunopro-phylaxis, and immunotherapy. This column is intended to help you ensure proper immunologic drug use in your practice.

Immunosuppression in pediatric liver transplant recipients: Unique aspects

Pediatric liver transplantation has experienced improved outcomes over the last 50 years. This can be attributed in part to establishing optimal use of immunosuppressive agents to achieve a balance between minimizing the risks of allograft rejection and infection. The management of immunosuppression in children is generally more complex and can be challenging when compared with the use of these agents in adult liver transplant patients. Physiologic differences in children alter the pharmacokinetics of immunosuppressive agents, which affects absorption, distribution, metabolism, and drug excretion. Children also have a longer expected period of exposure to immunosuppression, which can impact growth, risk of infection (bacterial, viral, and fungal), carcinogenesis, and likelihood of nonadherence. This review discusses immunosuppressive options for pediatric liver transplant recipients and the unique issues that must be addressed when managing this population. Further advances in the field of tolerance and accommodation are needed to relieve the acute and cumulative burden of chronic immunosuppression in children. Liver Transplantation 23 244-256 2017 AASLD.

Vaccinations in children on immunosuppressive medications for renal disease

Renal diseases are often treated with immunosuppressive medications, placing patients at risk of infections, some of which are vaccine-preventable. However, in such patients vaccinations may be delayed or disregarded due to complications of the underlying disease process and challenges in its management. The decision to administer vaccines to immunosuppressed children is a risk-benefit balance as such children may have a qualitatively diminished immunological response or develop diseases caused by the vaccine pathogen. Vaccination may cause a flare-up of disease activity or provocation of graft rejection in renal transplant recipients. Moreover, it cannot be assumed that a given antibody level provides the same protection in immunosupressed children as in healthy ones. We have evaluated the safety and efficacy of licensed vaccines in children on immunosuppressive therapy and in renal transplant recipients. The limited evidence available suggests that vaccines are most effective if given early, ideally before the requirement for immunosuppressive therapy, which may require administration of accelerated vaccine courses. Once treatment with immunosuppressive drugs is started, inactivated vaccines are usually considered to be safe when the disease is quiescent, but supplemental doses may be required. In the majority of cases, live vaccines are to be avoided. All vaccines are generally contraindicated within 3-6 months of a renal transplant.

[Vaccination in patients with chronic renal failure in the pre- and posttransplantation period]

AIM

To clarify whether vaccination provokes renal graft rejection.

SUBJECTS AND METHODS

A total of 131 vaccinations were performed in 92 patients with chronic kidney failure (CKF), including 7 and 85 patients vaccinated before and in different periods after kidney transplantation, respectively. The patients were examined using needle graft biopsy, measurement of proteinuria, and estimation of changes in blood creatinine levels and glomerular filtration rate.

RESULTS

Vaccination was not fount to provoke rejection, as suggested by the results of needle biopsy of renal allografts and examination of their function.

CONCLUSION

Vaccination is safe for patients with CKF as it causes no rejection episodes.

Management of infections pre- and post-liver transplantation: report of an AISF consensus conference

The burden of infectious diseases both before and after liver transplantation is clearly attributable to the dysfunction of defensive mechanisms of the host, both as a result of cirrhosis, as well as the use of immunosuppressive agents. The present document represents the recommendations of an expert panel commended by the Italian Association for the Study of the Liver (AISF), on the prevention and management of infectious complications excluding hepatitis B, D, C, and HIV in the setting of liver transplantation. Due to a decreased response to vaccinations in cirrhosis as well as within the first six months after transplantation, the best timing for immunization is likely before transplant and early in the course of disease. Before transplantation, a vaccination panel including inactivated as well as live attenuated vaccines is recommended, while oral polio vaccine, Calmette-Guerin's bacillus, and Smallpox are contraindicated, whereas after transplantation, live attenuated vaccines are contraindicated. Before transplant, screening protocols should be divided into different levels according to the likelihood of infection, in order to reduce costs for the National Health Service. Recommended preoperative and postoperative prophylaxis varies according to the pathologic agent to which it is directed (bacterial vs. viral vs. fungal). Timing after transplantation greatly determines the most likely agent involved in post-transplant infections, and specific high-risk categories of patients have been identified that warrant closer surveillance. Clearly, specifically targeted treatment protocols are needed upon diagnosis of infections in both the pre- as well as the post-transplant scenarios, not without considering local microbiology and resistance patterns.

Influence of renal replacement therapy on immune response after one and two doses of the A(H1N1) pdm09 vaccine

BACKGROUND

Patients with end-stage renal disease have a reduced response to vaccination because of the general suppression of the immune system associated with uraemia.

OBJECTIVES

We evaluated the immune response and differential factors in the immunogenicity to an adjuvanted A(H1N1) pdm09 vaccine (Pandemrix(®) ) in four populations of renal patients after one and two doses of vaccine. PATIENTS METHODS: 151 patients were included in this study: 58 chronic haemodialysis patients, 52 renal allograft recipients, 14 peritoneal dialysis patients and 27 patients with advanced chronic kidney disease in preparation for kidney replacement therapy. Influenza-specific antibody levels were measured by monitoring A(H1N1) pdm09 titres using a haemagglutination inhibition assay.

RESULTS

The seroconversion rate at 42 days after two vaccine doses was 80% in the haemodialysis group, 64.9% in the renal allograft recipients group, 100% in the advanced chronic kidney disease group and 71.4% in the peritoneal dialysis group (P = 0.041).

CONCLUSIONS

Immune response to two doses of the influenza A H1N1 vaccine is dissimilar in the four renal conditions, confirming that seroprotection in pre-dialysis, haemodialysis and peritoneal dialysis is similar to that in the general population vaccinated with one dose. In contrast, renal transplant recipients with good allograft function showed inadequate protection and triple immunosuppressive therapy including calcineurin inhibitors, mycophenolate and steroids negatively influenced seroconversion after vaccination in renal recipients.

Humoral immune response after post-chemotherapy booster diphtheria-tetanus-pertussis vaccine in pediatric oncology patients

BACKGROUND

The role of post-chemotherapy booster vaccination in pediatric oncology children remains to be established. In this randomized controlled study, we studied the effect of immune responses to diphtheria-tetanus-pertussis (DTP) booster vaccination in children 6 months after completing chemotherapy.

METHODS

Children 1-18 years old with chemotherapy completed for 6 months (baseline) were eligible. Subjects were randomized into vaccine and control group. In the former, three doses of DTP vaccine (Aventis Pasteur Inc., Lyon, France) were administered. IgG antibody titers against diphtheria, tetanus, pertussis, hepatitis B, measles, mumps, and rubella antibodies were measured serially in vaccine and control groups. Subsets of circulating lymphocytes (CD3(+), CD4(+), CD8(+), CD19(+), and CD16/56(+)) were quantified by flow cytometry using fluorescence-labeled monoclonal antibodies.

RESULTS

Fifty-six children (28 vaccinees; 28 controls) were enrolled. Protective antibody levels against diphtheria, tetanus, pertussis were found at baseline in 83.6%, 96.5%, 96.1% of them respectively. After three doses of DTP, all vaccinees demonstrated a sustain rise in antibody levels and the antibody titers were significantly higher than control group. 35.8% of subjects were susceptible to measles mumps and rubella infection and 69% showed anti-HBs antibody titer less than protective level up to 18 months after stopping chemotherapy.

CONCLUSIONS

Post-chemotherapy booster vaccinations produced a strong and sustained effect in humoral immunity against vaccine-preventable infectious diseases.

Immunizations for children with cancer

Children with malignant diseases are at risk of severe outcomes from vaccine preventable infections. Vaccination of these children presents challenges due to efficacy and safety concerns. There is a paucity of data on several aspects of vaccination in this group of children. Consequently, for the most part, data are extrapolated from healthy populations and combined with experts' opinions. This article reviews the use of vaccines in infants and children with cancer. In this context, an all-encompassing review is not the goal. Key principles are reviewed to provide a framework to guide the use of vaccines in children with malignant diseases.

Solid organ transplantation and response to vaccination

Although early vaccination is recommended in candidates for solid organ transplantation (SOT), consensual protocols do not yet exist. We applied an SOT vaccination protocol in the Hospital Clinic of Barcelona (Spain). Serology was performed before and after vaccination and compliance with the vaccination schedule was analysed during the period 2003-2004. Two hundred and thirty seven patients (72.9% male; mean age 56.31 years, range 19-72) were included. A total of 74.5% of subjects susceptible to hepatitis B virus infection responded to hepatitis B vaccination. Most patients were protected against hepatitis A, varicella, measles, rubella and mumps. The vaccine protocol was implemented satisfactorily and the administration of two courses of hepatitis B vaccine was shown to be effective.

Immunization issues before and after solid organ transplantation in children

Solid-organ transplant recipients are at risk from various infectious diseases, many of which can be prevented by immunizations that could reduce morbidity and mortality. However, it is not uncommon for children requiring transplantation to have received inadequate or no immunizations pre-transplant. Every effort should be made to immunize transplant candidates early in the course of their disease according to recommended schedules prior to transplantation. It is also important to immunize their household contacts and healthcare workers. In this review, we summarize the major immunization issues for children undergoing transplantation, the data currently available on immunization safety and efficacy, and suggest immunization practices to reduce vaccine-preventable disease. There is a real need for a standardized approach to the administration and evaluation of immunizations in this group of patients.

Immunization of immunocompromised persons

Advances in medicine, science, and technology have led to increasing numbers of people in the general population with altered host defenses. The risk for clinical infection in an immunocompromised host, such as a person who has received a solid organ transplant, is determined largely by the interaction between two factors: the epidemiologic exposures the person encounters and the person's net state of immunosuppresson. Vaccination represents a crucial approach for preventing infection in the general public and immunocompromised persons. This article reviews the benefits of and risks for immunization in immunocompromised persons and provides recommendations for the use of specific vaccines.

Vaccinations for adult solid-organ transplant recipients: current recommendations and protocols

Recipients of solid-organ transplantation are at risk of severe infections due to their life-long immunosuppression. Despite emerging evidence that vaccinations are safe and effective among immunosuppressed patients, most vaccines are still underutilized in these patients. The efficacy, safety, and protocols of several vaccines in this patient population are poorly understood. Timing of vaccination appears to be critical because response to vaccinations is decreased in patients with end-stage organ disease and in the first 6 months after transplantation. For these reasons, the primary immunizations should be given before transplantation, as early as possible during the course of disease. Vaccination strategy should include vaccination of household contacts and health care workers at transplant centers unless contraindicated. No conclusive data are available on the use of immunoadjuvants and screening for protective titers. Most vaccines appear to be safe in solid-organ transplantation recipients, but live vaccines should be avoided until further studies are available. The risk of rejection appears minimal. Recommended vaccines include pneumovax, hepatitis A and B, influenza, and tetanus-diphtheria. We outline specific protocols and recommendations in this particular patient population. Specific contraindications exist for other vaccines, such as yellow fever, oral polio vaccine, bacillus Calmette-Guerin, and vaccinia. We conclude that solid-organ recipients will benefit from consistent immunization practices. Further studies are recommended to improve established protocols in this patient population.

Immunologic defects and vaccination in patients with chronic renal failure

Patients with chronic renal failure suffer from defective host defenses which are directly the result of the renal impairment, in addition to those dependent on the primary illness leading to the renal failure. The mechanisms underlying the defective responses in phagocytic cells, lymphocytes and antigen processing are likely due to either failure to adequately eliminate suppressive compounds by the defective kidneys or to improper metabolic processing of the factors by the damaged renal parynchema. That some of the defects are reversed by transplantation and not dialysis suggests that renal parenchymal metabolic activities may be involved, although it is also possible that functioning glomerular cells are capable of filtering substances that membranes are not currently capable of eliminating. The current strategy for dealing with the immunodeficiency appears to be totally based on developing means to circumvent the defective function. The other approach, correction of the impaired function, cannot be even considered until the mechanisms underlying the defective function of the cells involved in defenses are better delineated. It seems possible that one or a few compounds are pivotal in altering the function of all the affected cell lines, since, with only a small amount of effort, it is possible to relate the dysfunction to abnormal cell membrane functions in phagocytic cells, dendritic cells and lymphocytes. Until the biochemical basis of the dysfunction of all the cell types affected are better defined, such exercises cannot be translated into better management of patients with chronic renal failure. Proper function of host defenses requires that appropriate cells can properly respond to threats to host viability. For the cells of the immune system (phagocytes and lymphocytes) this means that their response to regulatory molecules be appropriate, that their mobility be normal, that their adherence to substrates be preserved, and that they can generate the appropriate response to the challenge. For neutrophils, for example, it is necessary that they recognize and mobilize appropriately to chemotactic stimuli, that they be able to adhere to and migrate through endothelial lining, that their phagocytic activity be sufficient, and that they can kill and degrade endocytosed particles and generate appropriate secretions. Similar lists of requirements for good function can be generated for any cell type in the immune defense system. Uremia, as well as currently available treatments for uremia, directly or indirectly alters the function of all phases of appropriate immune cell function. Defective host responses in uremia have been recognized for decades and there has been considerable effort in the past decade to better define the extent and mechanisms of impaired defenses. Despite the multitude of major defects in humoral, cellular, and inflammatory processes, uremic patients who are cared for today, although they remain at higher risk of serious infectious complications, can and do maintain a good quality of life, with most remaining free of major infections for years and decades.

Prophylactic measures in the solid-organ recipient before transplantation

Pretransplant screening affords an important opportunity to detect and treat preexisting active infection in the solid-organ transplant recipient. In this article, pretransplant strategies for preventing infections after solid-organ transplantation are reviewed. In addition to the search for active preexisting infection in the transplant candidate, immunization remains a cornerstone of preventive practice. Because there is a suboptimal response to vaccinations in patients who are receiving immunosuppressive therapy, as well as in patients with end-stage organ dysfunction, standard immunization of the transplant candidate should be updated as early as possible in the course of the illness, including pneumococcal, influenza, and hepatitis B vaccines. Liver transplant candidates should receive hepatitis A vaccine, and children should receive Haemophilus influenzae type B conjugate vaccine. All nonimmune pretransplant patients should be considered candidates for the varicella vaccine. The management of special risk groups is discussed in detail.

Infections associated with uremia and dialysis

Patients with chronic renal failure are predisposed to infections. Infections in end-stage renal disease patients are caused by immunosuppressive effects of uremia. Patients with renal failure on dialysis have impaired host defenses and may develop infections related to vascular access. This article reviews the infectious complications related to chronic renal failure in dialysis.

Vaccines for transplant recipients

Immune dysregulation and immunosuppression regimens impact on the ability of transplant recipients to respond to immunizations. The distinct challenges of immunizations to benefit stem cell transplant recipients and solid organ transplant recipients are discussed separately. Recommended vaccines for stem cell transplant recipients and solid organ transplant candidates are suggested. New approaches to consider to enhance immune responses of transplant recipients are discussed.

Influenza virus immunization effectivity in kidney transplant patients subjected to two different triple-drug therapy immunosuppression protocols: mycophenolate versus azathioprine

BACKGROUND

Due to possible complications and treatment limitations, the prevention of influenza in renal transplant (RT) patients is highly indicated.

METHODS

Forty-nine patients with a 1-year functioning RT subjected to two different immunosuppressive regimens and 37 healthy relatives (HR) were administered the anti-influenza vaccine as recommended for 1996 to 1997. Anti-influenza antibody, creatinine, and immunological markers were estimated at 1 and 3 months after vaccination.

RESULTS

Three months after vaccination, 46.2% of the RT patients and 69% of the HR (P=0.06) showed protective antibody titers to influenza A (relative risk [RR]; 0.67; 95% confidence interval: 0.44-1.02). A total of 20.5% of the RT patients and 44.8% of the HR showed antibodies to influenza B (P=0.03). Despite these differences, the incidence of illness was similar. The immunosuppressive regimen had no effect on the antibody response.

CONCLUSIONS

Although the RT patients showed a reduced antibody response, no negative effects on graft outcome were observed.

Vaccination and HIV: a review of the literature

People with HIV are at risk for a variety of infections both at home and abroad. Recent studies have reported conflicting data concerning potential harmful effects following several inactivated vaccines. Antigenic stimulation by vaccines designed to prevent secondary infections may promote HIV-1 replication in certain patients. In HIV-positive subjects, immune response worsens with progression of the HIV infection. When vaccination is considered, administration of the vaccine must be performed as early as possible in the course of HIV infection because an HIV-infected patient's response to inactivated vaccines is closely related to HIV infection stage. A minority of subjects have a protective antibody response to vaccination. Consequently, specific antibody titers should be measured after vaccination to ensure immune protection. Immune response is improved by highly active antiretroviral therapy. Some live attenuated vaccines are considered as beneficial in some specific indications and if administered in the early stages of AIDS. However, viral load variations following administration of live attenuated vaccines have not been studied yet.

Vaccination of the immunosuppressed adult patient with rheumatologic disease

Vaccine-preventable diseases are a major cause of morbidity in immunocompromised patients. This article reviews the data on efficacy and safety of currently licensed vaccines in patients with rheumatologic diseases.

Use of licensed vaccines for active immunization of the immunocompromised host

The latter part of the 20th century has witnessed an unprecedented rise in the number of individuals with impaired immunity. This is primarily attributable to the increased development and use of antineoplastic therapy for malignancies, organ and bone marrow transplantation, and the AIDS epidemic. Individuals with impaired immunity are often at increased risk for infections, and they can experience more severe and complicated courses of infection. The lack of therapy for a variety of viruses and the rise in antimicrobial resistance of many pathogens have focused attention on vaccination to prevent infectious diseases. The efficacy of most licensed vaccines has been established in immunocompetent hosts. However, there is also considerable experience with most vaccines in those with impaired immunity. We reviewed the use of licensed live, inactivated, and polysaccharide vaccines in this group, and several themes emerged: (i) most vaccines are less immunogenic in those with impaired immunity than in normal individuals; (ii) live vaccines are generally contraindicated in this group; and (iii) the efficacy of many commonly used vaccines has not been established in people with impaired immunity. This review suggests that for most vaccines there are little or no efficacy data in those with impaired immunity but their use in this patient group is generally safe.

Infection in Solid Organ Transplantation: Prophylactic Regimens, Clinical Manifestations, and Empiric Therapy

Solid organ transplantation has become an established practice for end-organ disease. Transplantation has inherent risks for infection which can be minimized by appropriate prophylactic, preemptive, and empiric antibiotic regimens. Proper vaccination and appropriate perioperative antibiotic use are of utmost importance in an immunocompromised patient. When immunosuppression is high, further prophylactic regimens against some pathogens, such as cytomegalovirus, are necessary. Empiric antibiotic therapy should be targeted to the most likely pathogens. However, certain antimicrobials may interact with immunosuppressant agents resulting in enhanced toxicity or decreasing immunosuppression. Appropriate monitoring parameters and protective measures should be taken.

Antibody response of pediatric solid organ transplant recipients to immunization against influenza virus

We studied the immunogenicity of the 1992-1993 trivalent split-virus influenza vaccine in pediatric solid organ transplant recipients (PSOTRs) and their healthy siblings. One month after immunization, 41 (82%) of 50 subjects achieved protective titers of antibodies to influenza A, and 30 (60%) to influenza B, rates similar to those in healthy siblings. Achievement and persistence of protective titers occurred significantly more often in children with preexisting antibody. We recommend annual immunization of PSOTRs, their household contacts, and health care workers; immunologically naive PSOTRs may benefit from immunization before transplantation.

Influenza A pneumonitis following treatment of acute cardiac allograft rejection with murine monoclonal anti-CD3 antibody (OKT3)

A 51-year-old man developed fever, cough, and dyspnea 5 days after completing murine monoclonal anti-CD3 antibody (OKT3) treatment for acute cardiac allograft rejection. Samples of BAL fluid grew influenza A virus. Progressive pulmonary infiltrates, respiratory compromise, and hypoxia developed, and the patient ultimately required 5 days of mechanical ventilation. Treatment with amantadine hydrochloride and ribavirin was prescribed, and the patient was discharged after 19 days. Influenza A virus has not been an important pathogen in cardiac transplant recipients. However, this is the first reported case of influenza A pneumonitis complicating anti-T lymphocyte therapy for cardiac allograft rejection. In comparison with our patient, two previously reported cases of influenza A infection in cardiac transplant patients have been less severe. The virulence of our patient's, life-threatening infection appears to be secondary to impairment of T lymphocyte-mediated immunity by OKT3. The role of therapeutic and even prophylactic amantadine therapy in this clinical setting has yet to be determined.

Cytokines as potential vaccine adjuvants

There is a compelling clinical need for adjuvants suitable for human use to enhance the efficacy of vaccines in the prevention of life-threatening infection. Candidate populations for such vaccine-adjuvant strategies include normal individuals at the two extremes of life, as well as the ever increasing population of immunocompromised individuals. In addition, adjuvants that would increase the efficiency of vaccination with such vaccines as those directed against hepatitis B and Streptococcus pneumoniae would have an even greater general use. Cytokines, as natural peptides intimately involved in the normal immune response, have great appeal as potential adjuvants. An increasing body of work utilizing recombinant versions of interleukin-1, -2, -3, -6, -12, gamma-interferon, tumor necrosis factor, and granulocyte-monocyte-colony stimulating factor has shown that cytokines do have vaccine adjuvant activity. However, in order to optimize adjuvant effect and minimize systemic toxicity, strategies in which the cytokine is fused to the antigen, or the cytokine is presented within liposomes or microspheres appear to be necessary to make this a practical approach suitable for human use. There is much promise in this approach, but there is much work to be accomplished in order to optimize the pharmacokinetics of cytokine administration as well as its side effect profile.