ELEVATED LEVELS OF P53 PROTEIN IN THE NEUTROPHILS AND MONOCYTES OF A PATIENT WITH CHRONIC IDIOPATHIC THROMBOCYTOPENIC PURPURA OR POSSIBLE EARLY MYELODYSPLASIA

A 68 year old female who presented with long-term thrombocytopenia was clinically diagnosed as having chronic idiopathic thrombocytopenia pu rpura (ITP). Increased levels of the tumour suppressor p53 protein wer e detected by immunohistochemistry in the neutrophils and some monocyt es of the peripheral blood preparation using the antibody DO-1, recogn izing mutant and wild type p53 protein conformations. However, no posi tive staining in the peripheral blood samples from 41 myelodysplasias (MDS) and six normal individuals was observed. Single-stranded conform ational polymorphism analysis performed on DNA extracted from the cyto spin preparations from this patient indicated no mutations in exons 5- 8 of the p53 gene. This report describes the unusual detection of elev ated p53 protein in a non-neoplastic condition by immunohistochemistry using the antibody DO-1. This unexpected finding raises the possibili ty of classifying such patients as early MDS on the basis of their p53 status.