Cross-lineage expression in 505 patients with acute lymphoblastic leukemia by multiparametric flow cytometry analysis

The expression of immunological markers of one hematopoietic lineage on the abnormal cells of another lineage (cross-lineage expression) is a known feature of leukemia. The present study was aimed to investigate the cross-lineage expression in ALL cells. The cross-lineage expression in ALL cells from 505 patients was detected by flow cytometry using 23 monoclonal antibodies (McAbs) in triple staining combinations. The results showed that in whole ALL, the expression of myeloid antigens occurred in 56.4% of the cases, and CD13 was the most frequently expressed myeloid marker (32.7%) followed by CD33 (29.5%), CD15 (19.2%) and CD11b (7.7%). CD13/CD33 expressions were more frequent in CD34(+) cases than in CD34(-) cases. In B-ALL, T-cell antigen CD4, CD5, CD7 and CD2 were found in 27 (6.3%), 12 (2.8%), 8 (1.9%), and 6 (1.4%) cases respectively, and CD7(+), CD2(+) and CD4(+) cases commonly expressed CD13/CD33. In T-ALL, B-cell antigen cCD79a, CD19 and CD22 were found in 6 (8.1%), 5 (6.8%), and 2 (2.8%) cases respectively, and all of CD19(+) and CD22(+) cases were all accompanied with CD13/CD33. It is concluded that cross-lineage expression in ALL mostly exists in the immature stages, ALL cells more frequently express phenotypes B(+)M(+), T(+)M(+) and occasionally B(+)T(+)M(+), but B(+)T(+)M(-) phenotype is extremely rare.