[Characteristics of T-cell lineage immunophenotype in 95 patients with acute lymphoid leukemia]

The objective of this study was to investigate the immunophenotype of T-lineage acute lymphoid leukemia (T-ALL) and to find valuable immunologic markers in T-ALL diagnosis and therapy. Four-color multiparametric flow cytometry(FCM) with CD45/SSC gating was used for immunophenotyping of 95 patients with newly diagnosed T-ALL. The results demonstrated that T-ALL occurred more frequently in males younger than 30 years of age and was usually accompanied by a high WBC count and tumor mass at diagnosis. Univariate analysis showed an influence on achievement of CR1 for age (< 30 years) but not for WBC count and tumor mass. According to WHO (2008) classification of tumors of haematopoietic and lymphoid tissues, 87 patients with confirmed subtype included 27 cases of Pro-T-ALL (31.0%), 31 cases of Pre-T-ALL (35.6%), 23 cases of cortical-T-ALL (26.4%), 6 cases of medullary-T-ALL (6.9%). CD34 expression in Pro-T-ALL was significantly higher than that of Pre-T-ALL (p = 0.001). After the first chemotherapy, the complete remission rate in Pro-T-ALL was statistically lower than that of Pre-T-ALL. Besides, the complete remission rate of immature T-ALL (including Pro-T-ALL and Pre-T-ALL) was also significantly lower than that in mature T-ALL (including cortical-T-ALL and medullary-T-ALL). Myeloid antigen (CD13, CD33) expression was associated with T-ALL subtype and treatment effect. While 66.7% of CD13(+) patients belonged to Pre-T-ALL, most (60.0%) of CD33(+) patients were classified into Pro-T-ALL; CD13 expression had no effect on CR1 rate whereas CD33(+) patients had worse treatment effect compared with CD33(-) groups (p = 0.001). Notably, the expression of CD117 reached up to 26.7% and the positive cases were primarily distributed in pro-T-TAll and pre-T-ALL. It is found that CD117 expression in CD34(-) group was homogeneous and CD117 expression level was less than 10% in 73.2% patients, but CD117 expression level in CD34(+) group was not homogenous, in which group the CD117 expression levels < 10%, 10% - 20% and > 20% were 44.2%, 17.3% and 38.5% respectively. As compared with CD34(-) group, the proportion of patients with CD117 expression levels < 10%, > 20% in CD34(+) group was higher, and there was significant difference between these 2 group. It is concluded that immunophenotype has great value in T-ALL diagnosis, classification as well as treatment. Flow cytometry provides access to find valuable immunologic markers for T-ALL biological research.