CD28 (Cluster of Differentiation 28) is a homodimeric stimulatory cell surface receptor of the immunoglobulin (Ig) superfamily that is located on the chromosome 2q33.2. It is expressed on naive T cells and has also been found on the surface of plasma cells, eosinophils, and neutrophils. CD28 remains the most extensively studied costimulatory molecular and is a primary one for T-cell activatio. The control of T-cell responses through CD28 co-stimulation provides a means of anti-self and antimicrobial immunity. CD28 is essential for the lymphocyte activation and survival. A number of antigen-experienced T-cells lose CD28, and then can be re-activated without its engagement. Diseases linked to CD28 involve mycosis fungoides and Sezary's disease and the related pathways are Th2 differentiation pathway and RET signaling. CD30, also known as TNFRSF8 (Tumor necrosis factor (TNF) receptor superfamily member 8), Ki-1 or D1S166E, is an approximately 64 kDa type I transmembrane glycoprotein consisting of 595 amino acids. This cell membrane protein is encoded by the chromosome of 1p36.22 and belongs to the tumor necrosis factor receptor (TNFR) superfamily. In malignant lymphoma, it is expressed on the Reed-Sternberg cells of classical Hodgkin's disease, anaplastic large cell lymphoma (ALCL), and so on. CD30 can interact with TRAF2 and TRAF5, mediating the signal transduction that evokes the activation of NF-kappa-B pathway. This receptor functions as a positive regulator of apoptosis, and also shows a limitation of the proliferative potential of autoreactive CD8 effector T cells and protects the body against autoimmunity.