PDCD1 and neoplasm: Clinically it is reflected by an elevated blood level of von Willebrand factor and significant accumulation of CD8+CD279+ (PD-1 –programmed cell death protein 1 receptor) lymphocytes resembling phenotypically those described as tumor-infiltrating lymphocytes (TILs) in the marrow and GvHD in the skin and in a case-dependent manner in other organs.