DETECTION OF P53 IN INFLAMMATORY TISSUE AND LYMPHOCYTES USING IMMUNOHISTOLOGY AND FLOW-CYTOMETRY - A CRITICAL COMMENT

Aims-To analyse the expression of p53 in lymphatic cells found in infl ammatory tissues and the peripheral blood by immunological methods. Me thods-Immunohistological analysis of synovial tissues from patients wi th rheumatoid arthritis and flow cytometric analysis of peripheral blo od lymphocytes were performed with anti-p53 antibodies from different sources. Results-The anti-p53 antibodies PAb240, PAb421, and PAb1801 f rom one supplier bound to the cytoplasm of lymphocytes, fibroblasts, a nd endothelial cells in rheumatoid synovial tissue, while the same ant i-p53 antibodies from other sources and the p53 specific antibodies PA b1620 and DO1 were negative. Using flow cytometry, the antibodies that labelled cells in inflammatory tissues were shown to bind also to per ipheral lymphocytes, while the antibodies that were negative in immuno histology did not react with peripheral blood lymphocytes. p53 express ion could be confirmed by western blot in rheumatoid synovial tissue, but not in peripheral blood lymphocytes using PAb421 and PAb240 antibo dies from our own laboratory, which had been negative in immuno-histol ogy. Conclusions-Demonstration of p53 by western blot is more sensitiv e and reliable than immunohistology and flow cytometry Western blot is the gold standard for the demonstration of p53 expression and should be used, whenever possible, to confirm p53 expression in normal tissue shown by immunohistology or flow cytometry. All other reports on p53 expression, especially those obtained using antibodies with an unusual staining pattern must be interpreted with caution.