- CD28 expression on peripheral blood T lymphocytes after orthotopic liver transplant: upregulation in acute rejection. García-Alonso, A.M., Minguela, A., Muro, M., Ontañón, J., Torío, A., Marín, L., López-Segura, P., Miras, M., Alvarez-López, M.R. Hum. Immunol. (1997)