Transplantation Infection

Influenza virus is a significant pathogen in pediatric solid organ transplant (SOT) recipients. However, these individuals respond poorly to standard-dose (SD) inactivated influenza vaccine (IIV). Recent studies have investigated two strategies to overcome poor immune responses in SOT recipients: (1) administration of high-dose (HD)-IIV compared to SD-IIV and (2) two doses of SD-IIV compared to one dose of SD-IIV in the same influenza season. One study compared HD-IIV vs. SD-IIV in adult SOT recipients and noted that HD-IIV was safe and more immunogenic; however, the median post-transplant period was 38 months. A phase I pediatric study comparing a single dose of HD-IIV vs. SD-IIV was safe with higher immunogenicity, but the study was limited by small sample size and median post-transplant vaccine administration was 26 months. In another phase II trial of adult SOT recipients, two doses of SD-IIV one month apart compared to one-dose of SD-IIV revealed modestly increased immunogenicity when given at a median of 18 months post-transplant. Therefore, these studies lack both evaluation in the early post-transplant period and substantive pediatric populations. Additionally, the administration of two-doses of HD-IIV in the same influenza season has not been evaluated in pediatric SOT recipients. Thus, the optimal immunization strategy for pediatric SOT recipients less than 24 months post-transplant is unknown. In addition, immunologic predictors and correlates of influenza vaccine immunogenicity in pediatric SOT recipients have not been well-defined. The central hypothesis of our proposal is that pediatric SOT recipients 1-23 months post-transplant who receive two doses of HD-quadrivalent inactivated influenza vaccine (QIV) will have similar safety but higher Hemagglutination Inhibition (HAI) geometric mean titers (GMTs) to influenza antigens compared to pediatric SOT recipients receiving two doses of SD-QIV.

Solid organ transplantation (lung, kidney, liver, and heart) is a major therapeutic option for many end-stage chronic diseases. In France, several hundred patients undergo transplantation each year, supported by advances in surgery, immunosuppression, and care organization (e.g., 308 lung transplants in 2023, +2.5%). This trend includes broader indications, greater use of "marginal" donors, and an ageing recipient population (mean age of lung transplant recipients: 53 years in 2022). Infections remain a leading cause of post-transplant morbidity and mortality: up to 19.2% of early deaths and the main cause of death in the first year. Incidence is especially high after lung transplantation, and the infection risk persists lifelong. Patients receive education on high-risk exposures (food, travel, social contacts, animals, leisure), yet no standardized international guidelines exist. In France, counseling varies widely between centers and is often based on limited evidence. Patient adherence is poorly documented and sometimes low (≈18% for dietary advice). No French data currently describe the actual recommendations given, how patients apply them, or their impact on quality of life. We therefore propose a multicenter cross-sectional study in lung (and heart-lung) transplant recipients to describe the recommendations provided, assess their concordance with patient behaviors, and identify discrepancies. Findings may help harmonize recommendations while accounting for the specificities of lung transplantation. The study will later be extended to kidney, liver, and heart transplant recipients.

* Herpesvirus infections may be severe in immunocompromised patients, with a high risk of complications and mortality. * Recipients of hematopoietic stem cell transplant (HSCT) or patients receiving high-intensity chemotherapy for hematological malignancies are the most vulnerable individuals. * Although the worldwide prevalence of herpes simplex virus 1 (HSV-1) and varicella-zoster virus (VZV), antiviral prophylaxis in seropositive HSCT recipients has significantly reduced the rate of infection. * Acyclovir (ACV) is the first-choice drug for the prophylaxis or the therapy of that kind of infection. * Since the beginning, ACV has demonstrated to be characterized by a large interpatient variability, especially in children. * Therefore, therapeutic drug monitoring and pharmacokinetic studies may help in optimizing drug in children with malignancies.

This project will provide novel data using a large cohort of more than 3000 transplanted patients. Risk and protective factors for SARS-CoV-2 infection and COVID-19 disease severity will be identified. The proportion of patients who develop antibodies after infection will be revealed. In this way the presence of these antibodies can be evaluated as a test for prior infection. Our study additionally will demonstrate how long these antibodies remain present and whether they are protective against a new infection.

Molecular monitoring is conducted in blood cells, plasma samples, urine samples and/or tissue from patients after kidney transplantation. In the present study the investigators examine the hypothesis that noninvasive diagnostic molecular monitoring can improve the outcome after transplantation. Routine clinical and laboratory data from serum and urine are evaluated at baseline and after 0-1-2-3-4-12-16-52 weeks and 1-2-3-4-5-6-7-8-9-10 years after kidney transplantation. Mononuclear cells were obtained from the blood and transcripts of several diagnostic genes (including GATA3 (Trans-acting T-cell-specific transcription factor3), GATA4 (Trans-acting T-cell-specific transcription factor4), GAPDH (Glyceraldehyde 3-phosphate dehydrogenase), TRPC3 (Transient receptor potential cononical type3), TRPC6 (Transient receptor potential cononical type6), granzyme B, perforin, FOXP3 (Forkhead box P3), ISG15 (Interferon-stimulated gene 15), Mx1 (Interferon-induced GTP-binding protein), MMP3 (Matrix metalloproteinase-3), MMP9 (Matrix metalloproteinase-9), long-non-coding RNA, and others) are quantified using standard quantitative RT-PCR (Reverse transcription polymerase chain reaction) techniques. Proteomic analysis were performed in plasma and urine samples. Polymorphisms of selected genes are analyzed using standard techniques. Data are analyzed by descriptive statistics. Differences between groups were analyzed using Mann-Whitney test or Kruskal-Wallis-test and Dunn's multiple comparison post-test, as appropriate. Associations between variables are analyzed using regression analyses. Contingency tables are analyzed using Fisher's exact test.