Phenotypic characterization of ‘non-T, non-B’ acute lymphoblastic leukemia by a new panel (BL) of monoclonal antibodies

✍ Scribed by Ayad Al-Katib; Chang Yi Wang; Ricardo Bardales; Benjamin Koziner

• Publisher: John Wiley and Sons
• Year: 1985
• Tongue: English
• Weight: 739 KB
• Volume: 3
• Category: Article
• ISSN: 0278-0232
• DOI: 10.1002/hon.2900030406

✦ Synopsis

Peripheral blood and/or bone marrow leukemic cell suspensions from 49 patients with 'non-T, non-B' acute lymphoblastic leukemia (ALL) were analysed by flow cytometry using a new panel of four monoclonal antibodies. Anti-BL1 and anti-BL2 originating from NALM-6 and B35M lymphoblastoid cell lines, respectively. These antibodies recognize B-cell differentiation antigens: a heat stable non-immunoprecipitable antigenic determinant, and a 68 000 daltons glycoprotein molecule, respectively. BL5 and BL6 were derived by immunization with the promyelocytic cell line HL-60, recognizing antigens present on early hematopoietic cells: an 85 000 daltons MW glycoprotein (Pro-Iml) and a heat stable antigen (Pro-ImZ), respectively. A11 ALL patients studied had LI or L2 morphology by the FAB classification and a blast count exceeding 50 per cent. There were 25 males and 24 females. Median age was 8 years (range 1-67 years). Thirty-nine cases were studied at initial presentation and 10 at relapse. Cells from 46/49 cases expressed BL2 and/or BL1, but were not reactive with BL5 or BL6. Three of 49 cases did not express BL1 or BL2. However, a small percentage of blasts from one case was positive for BL5 (13 per cent) and the other 2 cases were reactive with BL6 (20 per cent and 36 per cent, respectively). These were one adult and 2 pediatric patients that had other ALL markers and achieved a complete remission with appropriate ALL therapy. One of the BL6 + cases relapsed after 19 months with a change in phenotype to BL1+ BL2 + BL5 -BL6 -. This analysis shows that the majority of 'non-T, non-B ALL'S do express B-cell associated antigens (BLl/BL2) argumentative of their B a l l origin. A small subgroup does not express such antigens and may arise from a more immature cell, since they expressed antigens on early hematopoietic stem cells.