Re: CD45 Negative/Dim leukaemia case

From: Maryalice Stetler-Stevenson (stetler@box-s.nih.gov)
Date: Mon Aug 21 2000 - 15:25:10 EST


We find that leukemias are usually dim CD45 and some are negative for
CD45. ALL can be CD13 positive- this is not an indication of
biphenotypic leukemia. Because CD13 is only lineage-associated and
not specific, it is not sufficient  to diagnose biphenotypic acute
leukemia in this case.  This diagnosis should be reserved for cases
in which there is ambiguity of lineage assignment because of the
presence of multiple antigens primarily associated with different
lineages. What about MPO?

	Maryalice

>Dear Flowers,
>I've come across a leukaemia case of CD45 dim or maybe negative expression.
>Have any dear friends got experience on this kind of cases?
>We've done the 3-color immunophenotyping, using SS/CD45-PC5 as the gating
>stretegy. The gated population on bone marrow specimen has positive
>expression of CD19, CD10, HLA-DR, CD13, CD34; negative expression of CD14,
>CD3, CD5, CD7 and sIg. Weak expression of CD13 was also observed. We're
>waiting for the t-dT result by immunohistochemical detection. Would you
>consider these findings are case of biphenotyping leukaemia or ALL with
>abberrant expression of myeloid marker??
>
>WK LEE

Maryalice Stetler-Stevenson
Director Flow Cytometry Unit
Laboratory of Pathology, NCI, NIH



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