ANALYSIS OF CYTOPLASMIC AND SURFACE-ANTIGENS IN CHILDHOOD T-CELL ACUTE LYMPHOBLASTIC LEUKEMIAS - CLINICAL RELEVANCE OF CYTOPLASMIC TCR-BETACHAIN EXPRESSION

Expression of surface and cytoplasmic antigens on the blasts from 42 c ases of childhood T-cell acute lymphoblastic leukaemia (T-ALL) were an alysed. All with childhood T-ALL, except for one case expressing cytop lasmic TCR delta chain, were classified on the basis of differential e xpression of cytoplasmic CD3 (cCD3), TCR beta chain (cTCR beta) and su rface CD3 (sCD3) into the following three groups: group I (cCD3+, cTCR beta-, sCD3-), eight cases (19.5%); group II (cCD3+, cTCR beta+, sCD3 -), 23 cases (56.1%); group III (cCD3+, cTCR beta+/-, sCD3+), 10 cases (24.4%). Each group defines the stepwise maturational stage of the CD 3/TCR complex along the intrathymic T-cell differentiation. Group I ha d the lowest initial WBC count among the three groups (P < 0.05) and s howed significantly (P < 0.05) a higher event-free survival (0.75) tha n those of group II (0.33). There was no significant difference in bot h the initial WBC count and the event-free survival between groups IT and III. Thus, the absence of cTCR beta in sCD3-negative T-ALL appears to be a good prognostic factor, suggesting that this classification p rovides a useful tool to predict the prognosis of childhood T-ALL. Thi s is the first report, to our knowledge, studying the relationship bet ween the expression of cytoplasmic CD3/TCR antigens and the clinical f eatures in T-ALL.