Growth inhibition of Nalm-6 cells by Ara-C in different concentrations and expression of CD80 and CD86 on Nalm-6 or B-ALL cells stimulated by Ara-C. (A) With the concentration increased, cytotoxicity of Ara-C increased. IC10 was 0.25 μM. (B) At the Ara-C concentration of 0.25 μM, CD80 increased along with prolonged time, but CD86 displayed no obvious change. (C) Stimulated by Ara-C (0.25 μM) for 72 hr, CD80 expression increased on two of five samples of B-ALL patient-derived cells. (D) CD86 expression displayed no obvious change on these five samples. **p<0.01. Ara-C, cytosine arabinoside; B-ALL, B lymphoblastic leukemia.