INFLUENZA-SPECIFIC HUMORAL AND CELLULAR IMMUNITY AFTER VACCINATION IN RECIPIENTS

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This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Our purpose is to determine the immunological conditions post transplant that are required for effective influenza vaccination. We propose to draw 30 milliliters of blood from the stem cell donor prior to transplantation and then to have blood drawn in the transplant recipient at the time of vaccination and several later time points. We will use standard antibody titer assays (ATA) to determine the level of humoral immunity. Further, we will characterize the cellular response in CD8 and CD4 T cells through intracellular cytokine staining (ICS) for IFN-g and CD154 after ex vivo stimulation with Influenza A peptides. Understanding both the humoral and cellular immune responses to influenza vaccination after HSCT may shed light on the optimum conditions for immunization in allogeneic vs autologous HSCT recipients, for patients undergoing GVHD, and for elderly HSCT recipients. Understanding immune response to vaccination in HSCT patients may lead to better prevention against opportunistic infections and morbidity post transplant. Our study will also answer questions as to the durability of the protective response in patients with a developing immune system more than one-year post transplant. One study indicates that it is beneficial to provide immunizations to the family, health care workers and close contacts of HSCT recipients for at least two years post-transplant (36). We propose to follow HSCT recipients for at least one-year post- vaccination to determine the longevity and durability of immune responses in HSCT recipients who are continuing to repopulate and rebuild their immune systems. Further, many studies have show that in healthy elderly recipients of the influenza vaccine the immune response is diminished including CD4 T cell responses (30), CD8 T cell responses (39), and antibody responses (20). We will retrospectively stratify patients over age 60 to compare immune response to HSCT recipients under the age of 60 who are vaccinated to see if these elderly patients might benefit from further study and possibly additional booster immunizations. Studies regarding the protection of the influenza vaccine may also yield useful information for the general public in vaccination against novel strains of influenza.