Expression of fos proto‐oncogene product by monoclonal antibody FO‐120 in smouldering adult T‐cell leukaemia (ATL)

Abstract
We investigated the expression of c‐fos gene product in peripheral blood mononuclear cells of patients with smouldering adult T‐cell leukaemia (ATL) and healthy human T‐lymphotropic virus type‐I (HTLV‐I) carriers by an immunofluorescence assay, using a mouse monoclonal antibody (FO‐120) specific for fos gene product. Peripheral blood mononuclear cells derived from healthy HTLV‐I carriers were rarely positive for FO‐120, less than 2% of the cells weakly reacted with FO‐120, whereas positive cells were detected in more than about 10% of cells from patients with smouldering ATL.FO‐120 appears to be a useful tool for detecting smouldering ATL in asymptomatic HTLV‐I infected people without using molecular techniques.