Summary of the FCM: 89% B lymphoblasts that express CD19, CD22, cCD79a, CD10, CD34, TdT, CD38, HLA-DR, CD9, CD58, CD33, CD45 (dim to negative), but not CD20, kappa, lambda, CD56, T-cell and other myelomonocytic markers.
Cytogenetic: 46 xx. FISH panel for B-ALL: negative
Diagnosis: B-cell acute lymphoblastic leukemia (B-ALL), NOS
Immunophenotypes:
•B markers (100%)+: CD19, cCD79a, cCD22
•Majority+: sCD22, CD10, CD24, PAX5, TdT
–CD10-: worse prognosis, more asst. with 11q23 translocation
•Variable+: CD34, CD20, CD45
• Aberrant exp: CD13, CD33
•Usually-: sIg
Classification based on phenotype:
Early precursor B-ALL or pro-B-ALL:
CD19+, cCD79a+, cCD22+ and nuclear TdT
5-10%
Seen in infants and is often associated with a t(4;11) translocation
Intermediate stage, common ALL:
CD10+
Pre-B-ALL:
cytoplasmic μ chains (c-μ)+
25% have the t(1;19) translocation with TCF3-PBX1 ( E2A-PBX1)
3% expressing surface Ig heavy chain without light chain, respond well to therapy used for precursor B-cell ALL.
Cytogenetic: 46 xx. FISH panel for B-ALL: negative
Diagnosis: B-cell acute lymphoblastic leukemia (B-ALL), NOS
Immunophenotypes:
•B markers (100%)+: CD19, cCD79a, cCD22
•Majority+: sCD22, CD10, CD24, PAX5, TdT
–CD10-: worse prognosis, more asst. with 11q23 translocation
•Variable+: CD34, CD20, CD45
• Aberrant exp: CD13, CD33
•Usually-: sIg
Classification based on phenotype:
Early precursor B-ALL or pro-B-ALL:
CD19+, cCD79a+, cCD22+ and nuclear TdT
5-10%
Seen in infants and is often associated with a t(4;11) translocation
Intermediate stage, common ALL:
CD10+
Pre-B-ALL:
cytoplasmic μ chains (c-μ)+
25% have the t(1;19) translocation with TCF3-PBX1 ( E2A-PBX1)
3% expressing surface Ig heavy chain without light chain, respond well to therapy used for precursor B-cell ALL.