THE EXPRESSION OF COSTIMULATORY MOLECULES AND THEIR RELATIONSHIP TO THE PROGNOSIS OF HUMAN ACUTE MYELOID-LEUKEMIA - POOR-PROGNOSIS OF B7-2-POSITIVE LEUKEMIA

We examined the expression of co-stimulatory molecules on leukaemic ce lls of 52 adult patients with acute myeloid leukaemia (AML) (34 men an d 18 women) and analysed the relationship between these expressions an d the patient's prognosis. B7-1 was not expressed in any of the 23 pat ients investigated, whereas B7-2 was expressed in 26/52 patients (50.0 %). B7-2 was expressed in all AML patients with monocytic morphology ( M4 or M5) and in 16/42 cases without monocytic morphology. CD54 was ex pressed in 28/37 patients examined (75.7%), and CD58 was expressed in all of the AML patients except one (M7). The overall survival of the 2 6 B7-2-positive leukaemia patients (1-24 months, median survival 11.5 months) was significantly shorter than that of the 26 B7-2-negative le ukaemia patients (1-71+ months, median 35.1 months) (P = 0.0080). In a ddition, the B7-2-positive patients exhibited significantly shorter di sease-free survival periods compared to the B7-2-negative patients (P = 0.021), There was no significant difference in age, sex, haematologi cal data and complete remission rate between the B7-2-positive and B7- 2-negative patients. Our results indicated that B7-2 is one of the mos t crucial factors in the prognosis of adult acute leukaemia and can be expected to have an important role in tumour immunity.