FLOW CYTOMETRIC DETECTION OF NEOPLASTIC T-CELLS IN PATIENTS WITH MYCOSIS-FUNGOIDES BASED ON LEVELS OF T-CELL RECEPTOR EXPRESSION

The authors report the flow cytometric detection of neoplastic T cells in the peripheral blood of four out of five (80%) patients with perip heral blood involvement with mycosis fungoides (Sezary syndrome) based on the levels of T-cell receptor expression as measured by CD3 and TC R-alpha beta staining. Antigen receptor expression was abnormal in ter ms of increased density of surface CD3 or TCR-alpha beta per cell. Oth er immunophenotypic abnormalities were present in three of these patie nts. However, in one patient abnormal T-cell receptor expression was t he only immunophenotypic evidence of neoplasia, although morphological ly abnormal lymphocytes were present and a T-cell clone was detected b y polymerase chain reaction (PCR). In another patient, the authors wer e able to detect development of a new, more aggressive neoplastic T-ce ll population based on levels of T-cell receptor expression. Levels of T-cell receptor expression may be of diagnostic utility in the evalua tion of peripheral blood for the presence of neoplastic T-cell populat ions.