The two specific aims of the research study are as follows: 1) Proof of concept with two parts. Firstly, the study plan is to prove that T cells that are very commonly involved in the immune response: CD2, CD3, CD4, and CD8 populations can be captured. These cells will be captured, lysed and their mRNA genomics will be mapped. The second part of the proof of concept will involve exposing the CD2, CD3, CD4 and CD8 populations ex vivo to various serum concentrations of tacrolimus - the main cornerstone immunosuppressive medication in solid organ transplant. Exposure of the three cell types to the various tacrolimus concentrations will demonstrate that there is testing that can detect mRNA transcripts corresponding to under, optimal and over immunosuppressed states. The quantify IL2 production of the three cell types under the various immunosuppressive conditions will then be measured. With these 2 parts of the first specific aim of the study, a technique that can readily and easily isolate the cell populations of interest from the transplant patients and can capture how these cell populations respond to immunosuppression at various concentrations will have been demonstrated. 2) The second specific aim of the research study is running this genomic profiling on kidney transplant recipients. For this portion of the study, there will be two cohorts. A cohort identified as the "prospective" group and a cohort labeled as the "event" group. For the prospective cohort, blood will be obtained from the patients at specific time points. Specifically, blood samples will be obtained in the pre-transplant setting when the patients present to the hospital for their transplant, then at post-kidney transplant day 0, 1, 2, 3 and 7 (+/- 1 day) and at day 14, 21, and 28 (+/-3 days). Blood samples will be obtained again at months 2, 3, 6, 9, and 12 (+/- 1 week ). For the second group, blood samples will be obtained at the time of "events", such as rejection, infection, etc., and apply the same series of tests to their blood. For this group, blood draws will be done at time 0(+/-1 day), at then at one week (+/-2 days), and at one, two and three months (+/-1 week) post time 0. There will be five blood samples collected per patient. For all patients, there will be a comparison of the standard collected clinical information on the patient - graft function, rejection, infection, immunosuppression levels - to the results of our transcriptomics. The culmination of the project will involve revealing how genomics of the specific types of T cells can more precisely reflect a patient's true immunosuppressed state by corresponding to high, optimal and low immunosuppressive clinical phenotypes, and thus allow transplant clinicians to more intelligently and accurately administer immunosuppressive medications.

This study will involve obtaining blood samples on the kidney transplant patients at the time in which they would otherwise have blood collected for standard clinical care. Consent will be obtained for the testing on their blood, but the patients will not suffer any additional pain or inconvenience of the testing. In coordination with the equipment and supplies currently being used by the trauma and critical care department's research, the investigators will organize the collection and running of the labs in a time efficient and minimally expensive way