This issue of Clinics in Laboratory Medicine, guest edited by Dr. Indira Guleria, will focus on New Pipeline of Immunoregulatory Molecules and Biomarkers in Transplantation. Topics include, but are not limited to, T Regulatory cells in Stem cells and Solid organ transplantation, Genetic Polymorphism in Cytokines and Costimulatory Molecules in Stem Cell and Solid Organ Transplantation, microRNAs and Transplantation, Role of B Regulatory Cells in Transplant Tolerance, Complement Activation, Biomarkers in Stem Cell Transplantation, Biomarkers of Transplant Tolerance at the Fetomaternal Interface, Signaling molecules in Transplantation and Post-Transplantation Cancer, Donor specific HLA antibodies as Biomarkers of Transplant Rejection, Novel Targets of Immunosuppression in Transplantation, Nanotechnology and Immune therapies in Transplantation, Role of Costimulatory Pathways in Transplant Tolerance, and Microbiota and Immune system and Implications.