Levels of CAF7 (CD98) expression correlate with the complete remission duration in childhood acute leukemia

The levels of expression of the activation antigen CD98 were studied by mAB CAF7 in 51 newly diagnosed consecutive cases of childhood acute lymphoblastic leukemia aged from 1 to 13 years. The mean follow-up was 8 months. A wide range of CAF7 expression was observed, the highest mean fluorescence intensity exceeding the lowest by 20 times. No correlation was revealed between CAF7 cell surface density on the one hand and sex, age, WBC, platelet count, LDH level, FAB groups and immunophenotypes on the other. A positive association between the levels of CAF7 expression and the complete remission (CR) duration was observed. The group of CAF7(low) patients had a significantly shorter CR duration compared to the CAF7(intermediate) and CAF7(high) cases (P=0.0099). Half of the CAF7(low) patients did not respond to the induction therapy and failed to achieve remission. These correlations were clearly marked in common ALL (cALL), which was usually considered to have a favorable outcome. All CAF7(low) cALL cases had a significantly shorter CR duration (P=0.027). Thus CAF7 appears to provide additional information on the biological characteristics of childhood ALL and may have prognostic value regarding the response to therapy and remission duration.