Vaccinations in kidney transplant recipients: Clearing the muddy waters

Humoral and Cellular Immunity Are Significantly Affected in Renal Transplant Recipients, following Vaccination with BNT162b2

BACKGROUND

Renal transplant recipients (RTRs) tend to mount weaker immune responses to vaccinations, including vaccines against the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2).

METHODS

Humoral immunity was assessed using anti-receptor binding domain (RBD) and neutralizing antibodies (NAb) serum levels measured by ELISA, and cellular immunity was assessed using T-, B-, NK, natural killer-like T (NKT)-cell subpopulations, and monocytes measured by flow cytometry, and also specific T-cell immunity, at predefined time points after BNT162b2 vaccination, in 57 adult RTRs.

RESULTS

Administration of three booster doses was necessary to achieve anti-RBD and NAb protective levels in almost all patients (92.98%). Ab production, at several time points, was positively correlated with the corresponding renal function and inversely correlated with hemodialysis vintage (HDV) and treatment with mycophenolic acid (MPA). A gradual rise in several cell subpopulations, including total lymphocytes (p = 0.026), memory B cells (p = 0.028), activated CD4 (p = 0.005), and CD8 cells (p = 0.001), was observed even after the third vaccination dose, while a significant reduction in CD3+PD1+ (p = 0.002), NKT (p = 0.011), and activated NKT cells (p = 0.034) was noted during the same time interval. Moreover, SARS-CoV-2-specific T-cells were present in 41% of the patients who were unable to develop Nabs, and their positivity rates four months after the second dose were in inverse correlation with monocytes (p = 0.045) and NKT cells (p = 0.01).

CONCLUSIONS

SARS-CoV-2-specific T-cell responses preceded the humoral ones, while two booster doses were needed for this group of immunocompromised patients to mount a protective immune response.

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.

Serologic evaluation of vaccine preventable infections and vaccination rates in kidney transplant candidates

INTRODUCTION

Assessing vaccine serologic status presents opportunities to provide live vaccinations to kidney transplant candidates (KTC). This is especially important given the increased risk of infection while taking lifelong immunosuppression following transplant and the inability to routinely provide live vaccines to patients on immunosuppressive medications. In March 2019, the American Society of Transplantation Infectious Disease Community of Practice (AST-IDCOP) released updated guidelines for vaccination of KTC, which emphasize pretransplant viral serology screening and live vaccine administration prior to transplant.

PRIMARY ENDPOINT

The primary endpoint of this study was to determine adherence to AST-IDCOP guidelines for live measles, mumps, and rubella (MMR) and VZV vaccination prior to transplant in KTC non-immune by serology.

METHODS

This retrospective, descriptive study examined serologic status and rates of live vaccination in 672 patients listed for kidney transplant at our center between July 2014 and July 2019. Secondary endpoints included subgroup analysis of adherence to full AST-IDCOP vaccination recommendations and validation of CDC presumed immunity definitions for measles and VZV.

RESULTS

Seventeen patients (2.7%) were nonimmune by serology for VZV, while 182 (27.1%) were nonimmune by serology to MMR. In a subgroup analysis of the seronegative KTC, none received VZV vaccination, and 6% received MMR vaccination prior to transplant or last follow-up.

CONCLUSIONS

Overall, a large portion of KTC had immunity gaps that were not resolved before transplantation. These findings are limited due to the retrospective, single-center nature of this study and should be confirmed with larger, prospective assessments of serologic status and vaccine administration.

COVID-19 Infection and Response to Vaccination in Chronic Kidney Disease and Renal Transplantation: A Brief Presentation

Chronic kidney disease (CKD) is associated with phenotypic and functional changes in the immune system, followed by detrimental clinical consequences, such as severe infections and defective response to vaccination. Two years of the pandemic, due to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), have undoubtedly changed the world; however, all efforts to confront infection and provide new generation vaccines tremendously improved our understanding of the mechanisms of the immune response against infections and after vaccination. Humoral and cellular responses to vaccines, including mRNA vaccines, are apparently affected in CKD patients, as elimination of recent thymic emigrant and naïve lymphocytes and regulatory T-cells, together with contraction of T-cell repertoire and homeostatic proliferation rate, which characterized CKD patients are responsible for impaired immune activation. Successful renal transplantation will restore some of these changes, although several epigenetic changes are irreversible and even accelerated by the induction of immunosuppression. Response to vaccination is definitely impaired among both CKD and RT patients. In the present review, we analyzed the differences in immune response after vaccination between these patients and healthy individuals and depicted specific parameters, such as alterations in the immune system, predisposing to this deficient response.

Vaccine Response in the Immunocompromised Patient with Focus on Cellular Immunity

During the last few years, we have experienced a shift in how we evaluate the effectiveness of vaccines [...]

Correlation of Fc Receptor Polymorphisms with Pneumococcal Antibodies in Vaccinated Kidney Transplant Recipients

Several polymorphisms within Fc receptors (FCR) have been described, some of which correlate with allograft function. In the current study, we determined three Fcγ receptor and five Fcα receptor dimorphisms in 47 kidney transplant recipients who had been vaccinated against Streptococcus pneumoniae. We analyzed if FCR genotypes correlated with pneumococcal antibodies and their serotype-specific opsonophagocytic function, tested prior to and at months 1 and 12 post-vaccination. In parallel, we assessed antibodies against HLA and MICA and determined kidney function. We observed that IgG2 antibodies against pneumococci at months 1 and 12 after vaccination and IgA antibodies at month 1 differed significantly between the carriers of the three genotypes of FCGR3A rs396991 (V158F, p = 0.02; 0.04 and 0.009, respectively). Moreover, the genotype of FCGR3A correlated with serotype-specific opsonophagocytic function, reaching statistical significance (p < 0.05) at month 1 for 9/13 serotypes and at month 12 for 6/13 serotypes. Heterozygotes for FCGR3A had the lowest antibody response after pneumococcal vaccination. On the contrary, heterozygotes tended to have more antibodies against HLA class I and impaired kidney function. Taken together, our current data indicate that heterozygosity for FCGR3A may be unfavorable in kidney transplant recipients.

The type of SARS-CoV-2 vaccine influences serological response in kidney transplant recipients

Vaccination is a promising strategy to control the ongoing pandemic; however, solid organ recipients tend to develop a weaker immune response to vaccination. Anti-spike SARS-CoV-2 antibodies titers were measured 2-4 weeks post-vaccination completion in 131 KT patients without previous infection. Demographic, clinical, and laboratorial parameters were analyzed to identify which factors contributed to seroconversion. Factors that influenced seroconversion, that occurred in 76 patients (58%), were longer time post-transplant, immunosuppression without an antiproliferative drug and vaccination with mRNA vaccines. Patients who received mRNA vaccines had significantly higher rates of seroconversion compared with adenovirus vector vaccines (67% vs 33%, P < .001) and higher anti-spike IgG titers. These findings reinforce the need to discuss the vaccination strategy in this population, including a third dose with a mRNA vaccine.

Establishment of an ELISpot Assay to Detect Cellular Immunity against S. pneumoniae in Vaccinated Kidney Transplant Recipients

In organ transplant recipients, the rate of invasive pneumococcal diseases is 25 times greater than in the general population. Vaccination against S. pneumoniae is recommended in this cohort because it reduces the incidence of this severe form of pneumococcal infection. Previous studies indicate that transplant recipients can produce specific antibodies after pneumococcal vaccination. However, it remains unclear if vaccination also induces specific cellular immunity. In the current study on 38 kidney transplant recipients, we established an interferon-γ ELISpot assay that can detect serotype-specific cellular responses against S. pneumoniae. The results indicate that sequential vaccination with the conjugated vaccine Prevenar 13 and the polysaccharide vaccine Pneumovax 23 led to an increase of serotype-specific cellular immunity. We observed the strongest responses against the serotypes 9N and 14, which are both components of Pneumovax 23. Cellular responses against S. pneumoniae correlated positively with specific IgG antibodies (r = 0.32, p = 0.12). In conclusion, this is the first report indicating that kidney transplant recipients can mount specific cellular responses after pneumococcal vaccination. The ELISpot we established will allow for further investigations. These could help to define, for example, factors influencing specific cellular immunity in immunocompromised cohorts or the duration of cellular immunity after vaccination.

Management of the Failing Kidney Transplant: Challenges and Solutions

The kidneys are the most transplanted organs, and the number of failed kidney transplants that require reinstitution of renal replacement therapy in patients is on the increase. Increased mortality has been noted in patients with failed grafts compared with transplant- naïve patients with chronic kidney disease who are treated with dialysis. Issues such as management of immunosuppression, the need for transplant nephrectomy, addressing the increased risk of cardiovascular events, malignancies, and infections are debatable and often based on individual or hospital practices. The optimal timing and modality of renal replacement therapy to be reinitiated are sometimes blurred, with considerable variations among physician practices. Guidelines are therefore needed to appropriately manage this special population of patients with the aim of improving outcomes. Here, our objective was to review the current practices in managing patients with failing kidney transplants so that recommendations can be made based on the available evidence.

Preventing Coronavirus Disease 2019 in Kidney Transplant Recipients: Where Should We Begin?

Context

Chronic immunosuppression is associated with an increased risk of opportunistic infections. Although kidney transplant recipients with coronavirus disease 2019 (COVID-19) have higher mortality than the general population, data on their risk of infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are unknown.

Subject of Review

A recent single-center screening study from the UK (Transplantation. 2021 Jan 1;105(1):151–7) showed that 89 (10.4%) of 855 consecutive kidney transplant recipients tested positive for SARS-CoV-2 antibodies. Risk factors for infection included a nonwhite background, diabetes, and a history of allograft rejection. Risk factors for mortality in individuals who developed COVID-19 were older age and receiving steroids.

Second Opinion

This study shows that the rate of SARS-CoV-2 infection in kidney transplant recipients is similar to the one observed in the general population in the same area (13%), indicating that transplant recipients are not at increased risk of COVID-19. However, the investigators raise the interesting point that since transplant individuals were advised to shelter earlier than the general population, they may be in fact more susceptible. This statement is hard to substantiate, but the identification of specific risk factors for infection and poor outcomes is crucial to tailor strategies to prevent spread of the infection. This is particularly important, considering that kidney transplant recipients may be at increased risk of prolonged viral spread and in-host viral mutations, making them not just a particularly fragile population for COVID-19 but also a potentially major source of further contagions.

Establishing best practices in measles, mumps, and rubella serologic screening for kidney transplant candidates

Optimizing immunity against vaccine-preventable diseases improves outcomes in kidney transplant (KT) patients (Arora et al, World J Transplant, 2019, 9:1; Sester et al, Transplant Rev, 2008, 22:274; Fishman, N Engl J Med, 2007, 357:2601). The American Society for Transplantation (AST) Clinical Practice Guidelines advises that serologic screening for measles, mumps, and rubella (MMR) be conducted for all KT candidates, since live-attenuated vaccines are contraindicated post-transplantation (Malinis et al, Clin Transplant, 2019, 33:e13548). Our team at Mayo Clinic Florida (MCF) conducted a quality improvement (QI) initiative to establish a best MMR screening and immunizations clinical practice in KT candidates using a Plan-Do-Study-Act (PDSA) model. By retrospective chart review of all KT candidates evaluated at our institution from January 1, 2016 to December 31, 2017, baseline data determining the rate of MMR serologic screening was established. PDSA cycles were implemented to adopt protocol-driven testing for MMR serologies, immunization documentation, and vaccination in cases of seronegativity to any of the three MMR viruses in all pre-KT candidates. Two PDSA cycles were completed in 4 months. The study population totaled 447 patients (baseline n = 283, PDSA 1 n = 61, PDSA 2 n = 103). Baseline data showed that 83% (n = 235) of pre-KT candidates received infectious disease consultation (IDC). Complete MMR (all three viruses) serological screening in KT candidates improved from baseline 3.9%-87.4% post-PDSA cycle 2 (P < .001). Necessary immunizations per AST guidelines were ordered in only 41.1% (n = 23) of the control cohort vs 100% (n = 12) and 96.9% (n = 31) of PDSA cycles 1 and 2, respectively (P < .001). The data reflect significant practice improvements in MMR screening and immunization rates among KT candidates by using protocol-driven orders combined with our pre-existing IDCs.

Pregnancy in Kidney Transplant Recipients

Women with end-stage kidney disease commonly have difficulty conceiving through spontaneous pregnancy, and many suffer from infertility. Kidney transplantation restores the impairment in fertility and increases the possibility of pregnancy. In addition, the number of female kidney transplant recipients of reproductive age has been increasing. Thus, preconception counseling, contraceptive management, and family planning are of great importance in the routine care of this population. Pregnancy in kidney transplant recipients is complicated by underlying maternal comorbidities, kidney allograft function, the effect of pregnancy on the transplanted kidney, and the effect of the maternal health on the fetus, in addition to immunosuppressive medications and their potential teratogenesis. Given the potential maternal and fetal risks, and possible complications during pregnancy, pretransplant and prepregnancy counseling for women of reproductive age are crucial, including delivery of information regarding contraception and timing for pregnancy, fertility and pregnancy rates, the risk of immunosuppression on the fetus, the risk of kidney allograft, and other maternal complications. In this article, we discuss aspects related to pregnancy among kidney transplant recipients and their management.

The Importance of Prioritizing Pre and Posttransplant Immunizations in an Era of Vaccine Refusal and Epidemic Outbreaks. Transplantation. 2020;104:33-38. [PMID: 31876696 DOI: 10.1097/tp.0000000000002936]

Vaccine-preventable infections are occurring at epidemic rates both nationally and internationally. At the same time, rates of vaccine hesitancy and refusal are increasing across the country leading to decreased herd immunity. For immunosuppressed transplant recipients, this situation poses great risk. Currently, 1 in 6 pediatric solid organ transplant recipients is hospitalized with a vaccine-preventable infection in the first 5 years posttransplant. For many recipients, these infections result in significant morbidity, mortality, and increased hospitalization costs. Surprisingly, despite this risk many transplant recipients are not up-to-date on age appropriate immunizations at the time of transplant and thereafter. As a transplant community, we must prioritize immunizations in both pre and posttransplant care. Research is needed to understand how to monitor immune response to vaccines in immunosuppressed patients and when to optimally immunize patients posttransplant. Finally, recommendations about administration of live vaccines posttransplant may need to be reevaluated in the setting of measles outbreaks and decreased herd immunity.

Human Papillomavirus, Herpes Zoster, and Hepatitis B Vaccinations in Immunocompromised Patients: An Update for Pharmacists

PURPOSE

Current evidence regarding efficacy and safety of human papillomavirus 9-valent (9vHPV), recombinant zoster (RZV), and CpG-adjuvanted recombinant hepatitis B (HepB-CpG) vaccines in adults with human immunodeficiency virus, inflammatory bowel disease, solid organ transplant, and allogeneic hematopoietic stem cell transplant is reviewed.

SUMMARY

Patients immunocompromised due to underlying disease or treatment are at increased risk for infections; however, insufficient understanding of various vaccines' efficacy, safety, indications, and contraindications in this population has led to suboptimal vaccination rates. The Infectious Disease Society of America (IDSA) published guidelines on vaccines in immunocompromised populations in 2013. Since then, several advances have been made including an expanded indication with 9vHPV for use in males and females 9 to 45 years old, and the introduction of new vaccines for herpes zoster (RZV) and hepatitis B (HepB-CpG). Pharmacists are instrumental to vaccination efforts and may benefit from a review of recent vaccine updates.

CONCLUSION

The 9vHPV can be used in men and women ages 9 to 45 years old regardless of immune status. RZV safety and efficacy in several immunocompromised populations has been demonstrated; however, manufacturers and major societies have yet to update their recommendations. HepB-CpG may be used in most immunocompromised patients yet remains under-utilized.

Vaccination in patients with chronic kidney disease-Review of current recommendations and recent advances

Hepatitis B virus (HBV), influenza, pneumococcus and herpes zoster are important infections which could result in significant morbidity and mortality in patients with chronic kidney disease (CKD). While seroconversion rates after vaccination are often lower in CKD patients compared with healthy adults due to impaired innate and adaptive immunity, vaccinations for HBV, influenza, pneumococcus and herpes zoster are generally effective in reducing the transmission and/or severity of these infections. Practical issues that have an impact on the efficacy of vaccination in the CKD population include the timing, dose, schedule of vaccination, the route of administration, and adjuncts applied at time of vaccination. This review discusses the vaccination regimens and the efficacy of HBV, influenza, pneumococcus and zoster vaccines in CKD patients, and highlights recent advances in enhancing vaccine seroconversion rates.

Sex-Specific Differences in HLA Antibodies after Pneumococcal Vaccination in Kidney Transplant Recipients

In transplant recipients vaccination against Streptococcus pneumoniae is recommended to reduce mortality from invasive pneumococcal disease. It is still debated if vaccination in transplant recipients triggers alloresponses. Therefore, it was our aim to define if vaccination with Prevenar 13^®, a 13-valent, conjugated pneumococcal vaccine (Pfizer, New York, NY, USA) that acts T cell dependently, induces human leukocyte antigen (HLA) antibodies in clinically stable kidney transplant recipients. Forty-seven patients were vaccinated once with Prevenar 13^® and HLA antibodies were determined prior to vaccination and at month 1 and 12 thereafter. In parallel, pneumococcal IgG antibodies were measured. Using Luminex™ Mixed Beads technology (One Lambda/Thermo Fisher, Canoga Park, CA, USA) we observed overall no change in HLA antibodies after vaccination. Pneumococcal antibodies increased significantly at month 1 (p < 0.0001) and remained elevated at month 12 (p < 0.005). A more detailed analysis of HLA antibodies showed that in 18 females HLA class I and II antibodies increased significantly at month 1 and 12 (p < 0.05); whereas in 29 males HLA class I and II antibodies tended to decrease. Using Luminex™ Single Antigen Beads assay, no de novo donor-specific HLA antibodies were detected after vaccination. In conclusion, the current data indicate that females may be more susceptible to the induction of (non-specific) HLA antibodies after vaccination.