Canterbury DHB
|
|
|
Immunophenotyping may be used to:
The blast cells in blood and marrow carry antigens on their surface indicating their lymphoid origin. In ALL, they are either of T or B-cell lineage. In adults, 70-75% of patients with ALL have precursor B-ALL, 20-25% are of T-cell origin, and about 5% are mature B-cell (Burkitt-like Leukaemia).
The blast cells in precursor B-ALL are commonly TdT, CD19, HLA-DR and cytoplasmic CD79a positive. They are usually CD34 and CD10 positive and have a variable expression of CD20 and 22. Aberrant expression of the myeloid antigens CD13 and 33 may be found in up to one third.
The blast cells in precursor T-ALL are also TdT positive and may express CD1a, 2, 3, 4, 5, 7, and 8. CD7 and cytoplasmic CD3 are most often positive; CD3 is the most specific antigen for the T-cell lineage. Other surface antigens may be expressed including CD10, 13, and 33.
In Burkitt-like Leukaemia, the blast cells express membrane IgM and show light chain restriction. They also usually carry the B-cell antigens CD19, 20 and 22, and 79a. They are also CD10 and bcl-6 positive. They are negative for CD5, 23, 34, and TdT. Ki67 is usually around 100%, indicating a high growth fraction.
|
Note: Only the electronic version is controlled. Once printed, this is no longer a controlled document.
|
|
Topic Code: 8843
Disclaimer