Influenza vaccination does not promote cellular or humoral activation among heart transplant recipients

BACKGROUND: The impact of influenza vaccination on in vitro parameters of cellular and humoral immunity, anti-viral titers, and clinical outcome was evaluated among cardiac transplant recipients. METHODS: Blood was collected from 29 patients before and 3-4 weeks after influenza vaccination and tested for phenotypic changes in lymphoid subpopulations and generation of antibodies against the allograft and vaccine. RESULTS: Vaccination did not change the percentage of lymphoid subpopulations and did not induce generation of anti-HLA alloantibodies. Anti-vaccine response was detected in 12 of 29 patients and did not correlate with rejection history, length of graft survival, or immunosuppressive therapy. Vaccination did not change the frequency of rejection. Flu-like symptoms were reported in one patient but not confirmed microbiologically. CONCLUSION: Despite the small number of patients in the study, influenza vaccination did not induce undesirable side effects, such as graft rejection or allo-sensitization. Generation of a positive anti-vaccine response was lower among the transplant recipients than healthy volunteers (41% vs. 80%). Clinical efficacy of the vaccine among the responders was not evaluated.     

What do we know about the clinical impact of complete withdrawal of immunosuppression in liver transplantation?

The liver is a privileged organ with a lower incidence of rejection than other organs. However, immunosuppressive regimens are still required to control the alloreactive T-lymphocyte response after transplantation. These treatments may lead to severe complications, such as infectious diseases, cancers, cardiovascular diseases, and chronic renal insufficiency. In clinical transplantation, there is increasing evidence that some liver transplant recipients who cease taking immunosuppressive drugs maintain allograft function, suggesting that tolerance is already present. This strategy is feasible in 25% to 33% of liver transplant recipients. Few of the studies performed so far have provided a detailed analysis of the impact of immunosuppression (IS) withdrawal on pre-existing complications derived from the long-term administration of immunosuppressive drugs and the side effects associated with it. In preliminary studies, IS withdrawal was safely achieved in selected liver transplant patients, and improved not only kidney function, but also other IS-associated side-effects such as hypercholesterolemia, hyperuricemia, hypertension, and diabetes control. However, longer follow-up periods are needed to confirm the benefits of IS withdrawal in liver transplant patients.     

Development of donor specific antibodies after SARS-CoV-2 vaccination in kidney and heart transplant recipients

This study examined the development of new or changes in donor specific antibodies (DSA) mean-fluorescence intensity (MFI) after SARS-CoV-2 vaccination in 100 kidney and 50 heart transplant recipients. The study was performed when the Center for Disease Control and Prevention (CDC) recommended two doses of Pfizer/BioNTech [BNT162b2] and Moderna [mRNA-1273 SARS-CoV-2] vaccine or 1 dose Johnson & Johnson/Janssen [Ad26.COV2·S] vaccines for full vaccination in transplant recipients. A novel assay bead-based platform for detecting antibodies against 4 domains of the SARS-CoV-2 spike protein to determine vaccine response (SA) and one nucleocapsid protein (NC) to determine prior SARS-CoV-2 infection was utilized. These assays were performed on the multiplex, bead-based platform utilized to assay DSA levels. 61/150 patients (40.7%) had successful vaccination. 18 patients had confirmed SARS-CoV-2 infection based on positive NC assay or previous Covid-19 oropharyngeal swab. 138 patients had no DSA prior to vaccination but 3 heart recipients developed new DSA's. Among 12 patients with known DSA prior to vaccination, 4 developed new DSA's or increased MFI. All 7 patients with new or increased DSA had stable graft function without rejection and had no changes in immunosuppression. All 8 patients with stable post vaccine DSA had stable graft function and immunosuppression was not changed. The presence of DSA before vaccination was associated with subsequent development of increased MFI or new DSA's (p = 0.001). There was no association between pre-vaccine DSA and positive vaccine response (NS). There was no association with successful vaccination or prior SARS-CoV-2 infection and DSA changes (NS).     

The effects of renal transplantation on peripheral blood dendritic cells

Recent advances allow accurate quantification of peripheral blood (PB) myeloid and plasmacytoid dendritic cell (DC) populations (mDC and pDC, respectively), although the response to renal transplantation (RT) remains unknown. Using flow cytometry, PBDC levels were quantified in patients with end stage renal disease (ESRD) undergoing RT. PBDC levels were significantly reduced in ESRD patients pre-RT compared to healthy controls, with further reduction noted immediately following a hemodialysis session. RT resulted in a dramatic decrease in both subsets, with a greater reduction of pDC levels. Both subset levels were significantly lower than in control patients undergoing abdominal surgery without RT. Subgroup analysis revealed significantly greater mDC reduction in RT recipients receiving anti-lymphocyte therapy, with preferential binding of antibody preparation to this subset. Samples from later time points revealed a gradual return of PBDC levels back to pre-transplant values concurrent with overall reduction of immunosuppression (IS). Finally, PBDC levels were significantly reduced in patients with BK virus nephropathy compared to recipients with stable graft function, despite lower overall IS. Our findings suggest that PBDC levels reflect the degree of IS in renal allograft recipients. Furthermore, PBDC monitoring may represent a novel strategy to predict important outcomes such as acute rejection, long-term graft loss and infectious complications.     

Use of hepatitis C virus-positive grafts in liver transplantation: a single-centre experience

AIM: Our goal was to evaluate the outcome of HCV(+) recipients after liver transplantation (LT) using HCV(+) donors and the interaction between donor and recipient viral strain. METHODS: We performed a retrospective analysis of 21 LT performed between 1998 and 2004 using livers from HCV(+) donors in HCV(+) recipients. Two hundred thirty-seven patients with HCV cirrhosis who underwent LT with livers from HCV(-) donors were the control group. Ishak score (IS) was evaluated for all HCV(+) grafts. The considered variables included donor age, hepatic enzymes, intensive care unit stay, HCV genotype, ischemia time, recipient age, UNOS status, Child score, HCV genotype (before and 6 months after LT) and IS (after LT). We analyzed patient, graft, and disease-free survival. RESULTS: HCV(+) donors were significantly older than HCV(-) donors. The cumulative 5-year patient and graft survivals and disease free intervals were not different between groups. IS grading was more than 2/18 in two cases; the only graft with a staging score over 2/6 was retransplanted for early nonfunction. In two cases, different HCV genotypes were matched and donor strain took over the recipient strain. In one patient, donor genotyping 2a-2c took over recipient genotyping 1b and 9 months after LT recurrent hepatitis was documented, but antiviral therapy cleared HCV. CONCLUSIONS: Livers from HCV(+) donors can safely be used in HCV(+) recipients. Hepatic biopsy must always be performed; livers with bridging fibrosis should not be used. The takeover of one strain by another may change the prognosis of the patient if the predominant strain is more sensitive to antiviral therapy.     

High Risk of Sensitization After Failed Islet Transplantation

Human Leukocyte Antigen (HLA) antibodies posttransplant have been associated with an increased risk of early graft failure in kidney transplants. Whether this also applies to islet transplantation is not clear. To achieve insulin independence after islet transplants multiple donor infusions may be required. Hence, islet transplant recipients are at risk of sensitization after transplantation. Islet transplant recipients were screened for HLA antibodies posttransplant by flow-based methods. A total of 98 patients were studied. Twenty-nine patients (31%) developed de novo donor specific antibodies (DSA) posttransplant. Twenty-three patients developed DSA while on immunosuppression (IS). Among recipients who have discontinued IS, 10/14 (71%) are broadly sensitized with panel reactive antibody (PRA) >or=50%. The risk of becoming broadly sensitized after transplant was 11/69 (16%) if the recipient was unsensitized prior to transplant. The majority of these antibodies have persisted over time. Appearance of HLA antibodies posttransplant is concerning, and the incidence rises abruptly in subjects weaned completely from IS. This may negatively impact the ability of these individuals to undergo further islet, pancreas or kidney transplantation and should be discussed upfront during evaluation of candidates for islet transplantation.     

Serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine in lung transplant recipients

Lung transplant recipients have an increased risk for severe coronavirus disease 2019 (COVID-19) due to infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). A third dose of a SARS-CoV-2 vaccine has been recommended for all solid organ transplant recipients, but data from lung transplant recipients specifically are scarce. In this study, the serologic response to a third dose of an mRNA-based SARS-CoV-2 vaccine was measured in 78 lung transplant recipients. Sixty-two percent (n = 48) had a serological response to vaccination, which was significantly higher than after the second vaccine dose (27 patients (35%); p = 0.0013). A positive serologic response was associated with having had COVID-19 (p = 0.01), and higher serum IgG level and complement mannose binding lectin pathway activity prior to vaccination (p = 0.04 and p = 0.03, respectively). Serologic response was not associated with the dose of mycophenolate mofetil or prednisone or other immune status parameters. Eleven patients (14%) developed COVID-19 after the second or third vaccine dose, but this did not associate with serologic response after the second vaccine dose (9% in patients who developed COVID-19 versus 39% in patients who did not develop COVID-19 (p = 0.09)), or with serologic response above cut-off values associated with clinical protection in previous studies. In conclusion, the response to mRNA-based SARS-CoV-2 vaccines in lung transplant recipients improves significantly after a third vaccine dose. Factors associated with a positive serologic response are having had COVID-19 prior to vaccination, and serum IgG and complement mannose binding lectin pathway activity prior to vaccination. Serologic response did not associate with clinical protection against COVID-19 in this study.     

The impact of high lymphocyte sensitivity to glucocorticoids on kidney graft survival in patients treated with azathioprine and cyclosporine

Lymphocyte sensitivity to methylprednisolone (MP) was examined in 70 consecutive cadaver kidney recipients: 36 recipients were given prednisolone and azathioprine (Aza), while 34 patients received prednisolone and cyclosporine (CsA). Peripheral blood lymphocytes (PBL) isolated just before transplantation, and again 6-12 hr after transplantation and i.v. administration of 120 mg of MP were stimulated with phytohemagglutinin (PHA). The observation period for all recipients was six months. In vivo, administration of MP was followed by a significant (P less than 0.02) decrease in the mitogen response of lymphocyte cultures from Aza-treated patients with graft function (n = 23) at six months. In contrast, the mitogen response of lymphocyte cultures from patients with graft failure (n = 13) did not decrease. Lymphocyte cultures from CsA-treated patients with graft function (n = 26) were not more responsive to i.v. MP than cultures from recipients who lost their grafts (n = 8). In vitro, the dose-response curves to MP were examined in pretransplant PHA cultures. The lymphocyte cultures from Aza-treated patients with graft function were 20 times more sensitive to MP than those of patients with graft failure at six months. The difference was highly significant (P = 0.005). Lymphocyte cultures from CsA-treated patients who maintained graft function were 12 times more sensitive to MP than cultures from recipients who lost their grafts (P = 0.02). Thus, in vivo and in vitro lymphocyte sensitivity to MP, which can be examined before transplantation, is suggested to have an important influence on the graft survival of azathioprine-treated patients. Furthermore, this effect is partly modified by treatment with cyclosporine.     

Minimal Development of Liver Fibrosis in Adult Tolerant Liver Transplant Recipients Late After Immunosuppressive Drug Weaning and Transplantation

BackgroundOperationally tolerant liver transplant (LTx)-recipients can be weaned off immunosuppressive (IS) drugs without development of graft rejection. However, it is feared that liver fibrosis might develop after complete IS weaning. The purpose of this small single-center study was to assess liver fibrosis in adult tolerant LTx recipients long after LTx and IS weaning.MethodsLiver fibrosis was assessed in adult tolerant LTx-recipients (n = 9) using noninvasive transient elastography and measurements of multiple pro- and antifibrotic serum markers associated with liver fibrosis. The data was collected for 2 subsequent years; 8 and 9 years after IS weaning and 19 and 20 years after transplantation. Healthy individuals (n = 9) matched for age and sex were included as a reference for fibrosis-related serum markers. This study was conducted in accordance with the Declaration of Helsinki and approved by the medical ethics committee of our institution.ResultsTransient elastography indicated that 7 of 9 tolerant LTx recipients had no or minimal liver fibrosis (F0-F1), whereas 2 recipients had moderate or severe liver fibrosis (F2-F3). Most fibrosis-related serum markers in tolerant LTx recipients were within or close to the range obtained for healthy individuals.ConclusionsThe results from this small, single-center study indicated that most adult tolerant LTx recipients have no or minimal liver graft fibrosis long after transplantation and IS weaning, and their fibrosis-related serum marker profile indicates an absence of a profibrotic status.     

Panel Reactive Antibody Responses Against Influenza Vaccination in Kidney Transplant Recipients

IntroductionSeasonal influenza is an important cause of morbidity and mortality in the post-transplant period; therefore, the influenza vaccination has been recommended for all kidney transplant recipients before the influenza season. However, at least theoretically, the introduction of antigens via vaccines may trigger rejection attacks by causing an antibody response. In this study, we examined the development of de novo panel reactive antibody (PRA) development against the influenza vaccine in kidney transplant recipients.Materials and MethodsOverall, 41 kidney transplant recipients who received the influenza vaccination and 50 kidney transplant recipients (study group) who refused to receive the influenza vaccination (control group) were enrolled in the study. Following basal biochemistry examination, the inactivated trivalent influenza vaccine was administered intramuscularly. Panel reactive antibodies were screened in all patients before and after vaccination on days 30 and 180. The primary outcome variable was development of de novo panel reactive antibodies.ResultsOne patient in the study group developed de novo class I and II PRA at 6 months after vaccination (P > .05), while no antibody development was noted in the control group. Graft dysfunction or biopsy-confirmed rejection was not observed during the follow-up period in both groups.ConclusionThe influenza vaccination is generally effective and safe in solid organ transplant recipients. The vaccination procedure has the potential to trigger antibody development and occurrence of rejection. Therefore, vaccinated kidney transplant recipients should be monitored more carefully with regard to PRA; if the graft deteriorates, a rapid transplant biopsy should be performed.     

Comparative analysis of humoral responses to BNT162b2 vaccine among patients with hematologic disorders and organ transplant recipients.

Vaccination against SARS-COV-2 is considered the most promising approach to curbing the pandemic. Patients with an immunocompromised state, such as those with hematological malignancies and organ transplantation recipients, are considered more susceptible to infection, but these at-risk patients were underrepresented in early clinical trials for vaccination. Although a growing body of studies suggests that the humoral response to COVID-19 vaccination in each of these at-risk groups of patients may be suboptimal in comparison to healthy controls, a clinical and strategic information for the further comparative analysis among these groups is not fully described. The humoral responses after two doses of BNT162b2 vaccination were evaluated in a total of 187 patients either with allogeneic hematopoietic transplantation, with renal transplantation, with anti-CD20 antibody therapy, or with anti-CD38 antibody therapy, and in 66 healthy controls. The early response at one to three months after vaccination was significantly inferior among patients with renal transplantation, patients with anti-CD20 antibody therapy, and patients with anti-CD38 antibody therapy in comparison to healthy control. But the patients with allogeneic hematopoietic transplantation showed early humoral response comparable to healthy control. The late response at 6 months after vaccination was still suboptimal among patients with renal transplantation and patients with anti-CD20 therapy. Among our patient group, renal transplant recipients had the lowest antibody titers after vaccination regardless of timing of vaccination. Patients who had received allogeneic hematopoietic transplantation attained a comparable serological response to the control group especially if they are vaccinated >300 days after transplantation, but the response was suboptimal if the vaccination was within 300 days after transplantation. Our results may provide policy makers with critical information for the further stratification of at-risk groups, helping contribute to a better allocation of resources, including additional booster vaccination.     

Mortality Due to COVID-19 in Renal Transplant Recipients,Related to Variants of SARS-CoV-2 and Vaccination in Mexico

BackgroundSARS-CoV-2 infection in transplant patients has shown greater lethality and vaccination in this group of patients has shown less information. The objective of this study is to show the statistics in Mexico of lethality in kidney recipients infected with COVID-19 in relation to vaccination and variants of the coronavirus.MethodsThis is a bibliographic search of kidney transplant recipient patients since the start of the pandemic in Mexico to determine lethality after SARS-CoV-2 compared to the general population and in relation to patients, the 4 most important infectious peaks in the country due to identified variants, and also before and after vaccination.ResultsThe global lethality is 26.91% from the beginning of the pandemic to April 9, 2022 in kidney recipients in Mexico (130 deaths of 483 infected kidney transplant recipients) compared to the national lethality of 5.60%. Variant B. 1.1.220 represented the highest lethality with 30.43% and the lowest lethality was Omicron with 16.41%. The lethality prior to vaccination was 30.94% and 23.46% after it.ConclusionBoth some variants and vaccination have influenced a lower lethality due to COVID-19 in Mexico in kidney transplant patients; It is important to consider global recommendations, such as a third or fourth dose, a combination of mRNA vaccines and vectors in order to reduce lethality in this group of patients.     

Liver-kidney recipients with chronic viral hepatitis C treated with interferon-alpha

Antiviral therapy with interferon-alpha (IFN-alpha) and pegylated IFN-alpha (PEG-IFN-alpha) for chronic hepatitis C (HCV)-infected kidney recipients remains controversial. IFN-alpha is not recommended in most cases because it induces severe acute graft rejection. However, IFN-alpha, as PEG-IFN-alpha, is associated with a more pronounced immune response, and is well tolerated in HCV-infected liver recipients without causing graft rejection. In combined liver-kidney transplant (LKT) recipients, IFN-alpha has been occasionally used and appears to be well tolerated. All LKT recipients with a functioning kidney and liver having a HCV replication and who needed IFN-alpha therapy have been included in the study. The occurrence of liver and/or renal acute rejection as well as the HCV replication has been collected. A total of 12 LKT patients treated with PEG-IFN-alpha plus ribavirin have been studied. No acute rejection was observed. Renal function remained stable during and after discontinuing treatment, without any graft dysfunction. Two patients had a partial viral response and four had a sustained viral response. All patients, whatever their viral response, had decreased liver-enzyme levels. Response to PEG-IFN-alpha therapy was correlated with steroid dose and transaminase level when PEG-IFN-alpha was started. These data suggest that the combination therapy of PEG-IFN-alpha plus ribavirin did not have a higher risk of acute kidney-graft rejection after liver-kidney transplantation.     

Safety of minimal immunosuppression in liver transplantation for hepatoblastoma

Background

Despite aggressive chemotherapy, recurrence of disease remains the leading cause of death after liver transplantation (LTx) for hepatoblastoma (HB). Unfortunately, little is known about the effects of immunosuppression on recurrence and posttransplant outcomes. We hypothesized that minimal immunosuppression can be safely used in these recipients.

Methods

In 2004, we adopted a minimal immunosuppression regimen using daclizumab induction and tacrolimus monotherapy. Kaplan-Meier survival curves were generated.

Results

From 2004 to 2006, 6 children underwent primary LTx for HB with neoadjuvant and adjuvant chemotherapy. Patient survival was 100% at 12 months and at 24 months, without graft loss. One patient died 28 months after transplantation. Recurrence-free survival was 83% at 12 months and at 24 months. Despite minimal immunosuppression (IS), 4 of 6 HB recipients remained rejection-free. When compared to other LTx recipients receiving minimal IS, HB recipients trended to have better rejection-free survival (HB, 83% at 12 months and 62.5% at 24 months vs all others, 36% and 36%, respectively; P = .19).

Conclusion

Our short-term patient and graft survival rates are comparable to those reported for all HB recipients in the United Network for Organ Sharing database. Although not statistically significant, our rejection-free survival data suggest that HB recipients may be less likely to reject than other recipients.     

Successful hepatitis B vaccination in liver transplant recipients with donor-specific hyporesponsiveness

Currently, patients are prescribed lifelong treatment with hepatitis B immunoglobulin (HBIg) after liver transplantation (LT) for hepatitis B virus (HBV)-related diseases in order to prevent reinfection with HBV. Active immunization with an HBV vaccine would be a preferable alternative; however, the immunosuppressive environment in LT recipients is believed to elicit a poor response to vaccination. Minimizing the exposure of the HBV-infected LT recipients to immunosuppressants would be beneficial in inducing adaptive immunity against HBV by vaccination. In this study, in addition to efforts to minimize immunosuppression, prophylaxis with HBV vaccination combined with continuous HBIg administration was performed in 17 LT recipients who had undergone transplantation attributable to HBV-related diseases. During the observation period, the overall response rate to HBV vaccination was 64.7%. The immune status of the recipients was evaluated by a mixed lymphocyte reaction assay in response to allostimulation. Patients showing a donor-specific hyporesponse with a well-maintained response to the third-party stimulus always achieved a sustained immune response to the vaccine, whereas patients showing a hyporesponse to both the donor and the third-party stimulus were unable to do so. Thus, inducing an anti-donor-specific immunosuppressive status by minimizing immunosuppression should enable post-transplant HBV vaccination to be a promising prophylactic strategy.     

Cellular and humoral immune response after mRNA-1273 SARS-CoV-2 vaccine in liver and heart transplant recipients

Recently published studies have found an impaired immune response after SARS-CoV-2 vaccination in solid organ recipients. However, most of these studies have not assessed immune cellular responses in liver and heart transplant recipients. We prospectively studied heart and liver transplant recipients eligible for SARS-CoV-2 vaccination. Patients with past history of SARS-CoV-2 infection or SARS-CoV-2 detectable antibodies (IgM or IgG) were excluded. We assessed IgM/IgG antibodies and ELISpot against the S protein 4 weeks after receiving the second dose of the mRNA-1273 (Moderna) vaccine. Side effects, troponin I, liver tests and anti-HLA donor-specific antibodies (DSA) were also assessed. A total of 58 liver and 46 heart recipients received two doses of mRNA-1273 vaccine. Median time from transplantation to vaccination was 5.4 years (IQR 0.3–27). Sixty-four percent of the patients developed SARS-CoV-2 IgM/IgG antibodies and 79% S-ELISpot positivity. Ninety percent of recipients developed either humoral or cellular response (87% in heart recipients and 93% in liver recipients). Factors associated with vaccine unresponsiveness were hypogammaglobulinemia and vaccination during the first year after transplantation. Local and systemic side effects were mild or moderate, and none presented DSA or graft dysfunction after vaccination. Ninety percent of our patients did develop humoral or cellular responses to mRNA-1273 vaccine. Factors associated with vaccine unresponsiveness were hypogammaglobulinemia and vaccination during the first year after transplantation, highlighting the need to further protect these patients.

     

COVID-19 and solid organ transplantation: Finding the right balance

BackgroundThe COVID-19 pandemic has a great impact on solid organ transplant (SOT) recipients due to their comorbidities and their maintenance immunosuppression. So far, studies about the different aspects of the impact of the pandemic on SOT recipients are limited.ObjectivesThis systematic review summarizes the risk factors that make SOT patients more vulnerable for severe COVID-19 disease or mortality and the impact of immunosuppressive therapy. Furthermore, their clinical outcomes, mortality risk, immunosuppression, immunity and COVID-19 vaccination efficacy are discussed.MethodsA systematic search on PubMed was performed to select original articles on SOT recipients concerning the following four topics: (1) mortality and clinical course; (2) risk factors for mortality and composite outcomes; (3) maintenance immunosuppression; (4) immunity to COVID-19 infection and (5) vaccine immunogenicity. Relevant data were extracted, analyzed and summarized in tables.ResultsThis systematic review includes 77 articles. Mortality was associated with advanced age. Post-transplantation time or comorbidities were variably identified as independent risk factors for mortality or severe disease. However, generally, no comorbidity was reported as a major risk factor. SOT recipients have a higher risk of acute kidney injury, but no higher rate of mortality compared to non-transplanted patients was found. Immunosuppression was individually adjusted, without leading to high rates of graft dysfunction. Generally, no association between type of immunosuppression and mortality was found. SOT patients established humoral and cellular immune responses after COVID-19 disease comparable to immunocompetent people. At last, SOT patients experience a diminished immune response after two-dose vaccination with SARS-COV-2-mRNA-vaccines.ConclusionMore research is needed to address the direct effect of COVID-19 disease on the graft in lung transplant recipients, as well as the factors ameliorating the immune response in SOT recipients.     

Pneumococcal vaccination in patients with chronic renal disease and renal allograft recipients

Polyvalent pneumococcal vaccine was administered to 7 patients with chronic renal failure, 14 patients on chronic hemodialysis, 14 splenectomized and 11 nonsplenectomized renal allograft recipients, and 14 normal adults. Ninety-three percent of normal subjects had at least a twofold rise in serum antibody concentration after vaccination, with a geometric mean antibody concentration after vaccination greater than 200 ng N/ml. The response to vaccination in hemodialysis patients was similar to that in normal persons. Renal failure patients showed impaired antibody synthesis in response to the vaccine, with 43% achieving at least a twofold rise in antibody concentration. Allograft recipients had a lower antibody concentration before as well as after vaccination, and among splenectomized recipients the prevaccination antibody concentration was directly related to the interval between transplantation and antibody determination. But, 80% of allograft recipients achieved a twofold rise in antibody concentration after vaccination. The response to pneumococcal vaccine was quantitatively similar for splenectomized and nonsplenectomized allograft recipients.     

Biomarkers of Tolerance in Kidney Transplantation: Are We Predicting Tolerance or Response to Immunosuppressive Treatment?

We and others have previously described signatures of tolerance in kidney transplantation showing the differential expression of B cell–related genes and the relative expansions of B cell subsets. However, in all of these studies, the index group—namely, the tolerant recipients—were not receiving immunosuppression (IS) treatment, unlike the rest of the comparator groups. We aimed to assess the confounding effect of these regimens and develop a novel IS‐independent signature of tolerance. Analyzing gene expression in three independent kidney transplant patient cohorts (232 recipients and 14 tolerant patients), we have established that the expression of the previously reported signature was biased by IS regimens, which also influenced transitional B cells. We have defined and validated a new gene expression signature that is independent of drug effects and also differentiates tolerant patients from healthy controls (cross‐validated area under the receiver operating characteristic curve [AUC] = 0.81). In a prospective cohort, we have demonstrated that the new signature remained stable before and after steroid withdrawal. In addition, we report on a validated and highly accurate gene expression signature that can be reliably used to identify patients suitable for IS reduction (approximately 12% of stable patients), irrespective of the IS drugs they are receiving. Only a similar approach will make the conduct of pilot clinical trials for IS minimization safe and hence allow critical improvements in kidney posttransplant management.     

Influenza vaccination in heart transplant recipients.

Seventy-nine heart transplant recipients were vaccinated with a trivalent influenza virus vaccine 1996/97 containing the strains A/Singapore/6/86 (H1N1), A/Wuhan/395/95 (H3N2), and B/Beijing/184/93. The proportions of patients with protective levels of antibody (HI > or = 40) after vaccination ranged from 100% (A/Singapore [H1N1]) to 31.6% (B/Beijing) and their mean fold titer increases were lower than those recorded for vaccination of 109 healthy subjects with the same batch of vaccine. The vaccinations were tolerated well and did not result in serious side effects, such as graft rejections. Our findings indicate that influenza vaccination can induce protective antibody levels in a substantial proportion of heart transplant recipients and lend support to the recommendation to vaccinate such patients annually against influenza.